Marsh & McLennan Companies (MRSH)

Company ID: 288 | CIK: 0000062709
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Segments are charted by their disclosed metrics (revenue, segment profit, etc.). Each line is a single segment. Reconciliation/corporate items are excluded. Major customers are shown as a percentage of revenue. Operational KPIs are grouped by metric concept; sub-metrics appear as separate lines.

Geographic Segments

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Major Customers (% of Revenue)

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Operational KPIs

Assets in trusts or funds (aua)

Assets under management (aum)

Marsh offices worldwide (branches)

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Individual shareholder accounts (customers)

Employees (headcount)

Net new money (net_flows)

AI Academy Credentials (other)

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AI Academy credentials earned (other)

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AUM allocation (other)

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Acquisitions completed (other)

Agencies acquired (other)

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Alexander Forbes shares held (other)

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Asset allocation (other)

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Benefits administration participants (other)

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CDO/CBO/CLO assets managed (other)

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Captive facilities (other)

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Closed-end investment companies (other)

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Consulting revenue mix (other)

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Countries of operation (other)

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Deferred performance fees (other)

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Funds over $1B sales (other)

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Investment vehicles (other)

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Investor service centers (other)

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MMA agency acquisitions (other)

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Market capitalization (other)

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Market impact on AUM (other)

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Market services revenue (other)

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Marsh offices (other)

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Marsh revenue mix (other)

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Mercer countries served (other)

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Mindset Academy Completions (other)

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Mindset Academy completions (other)

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Mutual funds managed (other)

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New business growth (other)

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Non-U.S. revenue share (other)

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Non-US investor assets (other)

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Non-White US colleagues (other)

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Non-White US senior leaders (other)

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Number of Putnam Funds (other)

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Number of funds (other)

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Office consolidations completed (other)

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Offices open (other)

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Open-end investment companies (other)

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Operating income margin (other)

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Retirement plan participants (other)

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Sedgwick integration savings (other)

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Shares outstanding (other)

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Stock options outstanding (other)

Stockholders of record (other)

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Thrive program annualized savings (other)

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U.K. pension plan asset allocation (other)

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U.S. pension plan asset allocation (other)

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Women in senior leadership (other)

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Individual shareholders (users)

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Human capital disclosures. Workforce totals and demographics are point-in-time. Flow metrics use the year-to-date period for 10-Q and full year for 10-K. Workforce actions (RIFs, restructurings, acquisition-related changes) are listed in the table at the bottom.

Workforce Totals

Demographics

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HCM Metrics — Point-in-Time

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HCM Metrics — Flow (Annual / YTD)

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Workforce Actions

Period EndTypeStatusAffected% WorkforceAnnouncedExpected CompletionGeographySegment / FunctionChargeSourceNote
2026-06-30restructuringin_progress2025-07-012028-09-30Company-wide (Thrive program)USD 500 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Three-year Thrive program launched Q3 2025; ~$500M total expected cost over three years, primarily severance, technology and outside services; ~$400M expected annualized savings. $239M incurred through June 30, 2026, of which $52M in Q2 and $89M in H1 2026. Severance liability of $80M at June 30, 2026. No employee count affected disclosed.
2026-06-30restructuringin_progressGlobalCompany-wide (all segments and corporate)USD 500 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Thrive three-year program launched Q3 2025; ~$500M total expected cost, $239M incurred through 2026-06-30 ($103M in H1 2026, $58M in Q2 2026), primarily severance; ~$400M annualized savings expected; no employee count disclosed; charges evenly distributed over program period
2026-06-30acquisition_additioncompletedUnited States, GermanyRisk and Insurance Services (3 acquisitions); Consulting (2 acquisitions)USD 181 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions completed in H1 2026 (Robinson & Son, Seitz Insurance Agency, TriBridge Partners, Profil M Beratung, CR3 Partners) for $181M total consideration; no headcount added disclosed
2026-06-30acquisition_additionannounced2026-07-01SpainRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		July 2026 subsequent event: Marsh Risk acquired remaining 60% of Deasterra Partners, S.L.; no headcount disclosed
2026-06-30restructuringin_progress2025-09-302028-12-31GlobalCorporate and SegmentsUSD 103 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Thrive program launched Q3 2025. $103M incurred YTD 2026, primarily severance. Total expected cost ~$500M over three years.
2026-06-30acquisition_additioncompleted2026-06-302026-06-30GlobalRisk and Insurance Services; ConsultingUSD 181 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		5 acquisitions completed in H1 2026 for total consideration of $181M. Headcount not disclosed.
2026-06-30restructuringin_progressUSD 58,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressOperating Segments [Member] / Risk And Insurance Services Segment [Member]USD 39,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressOperating Segments [Member] / Consulting Segment [Member]USD 8,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 11,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressEmployee Severance [Member]USD 74,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressReal Estate Related Costs [Member]USD 10,000,000 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressInformation Technology [Member]USD 0 (absolute)restructuring_footnote
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2026-06-30restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 19,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progress2025-07-01Company-wide (Thrive program); includes formation of Business Client ServicesUSD 45 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Three-year Thrive program launched Q3 2025; ~$500 million total expected cost over three years, primarily severance, technology and outside services. Q1 2026 charge of $45 million ($37 million related to the Thrive program, primarily severance). Cumulative program cost of $187 million through March 31, 2026. No employee count affected was disclosed. Restructuring liability of $94 million at March 31, 2026.
2026-03-31restructuringin_progressGlobalCompany-wideUSD 500 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Thrive three-year program launched in Q3 2025 (exact announcement date not disclosed); expected total cost ~$500M with ~$400M annualized savings; $187M incurred through 2026-03-31, including $37M in Q1 2026; total Q1 2026 restructuring charges were $45M (RIS $27M, Consulting $13M, Corporate $5M); no employees-affected count disclosed
2026-03-31acquisition_additioncompleted2026-01United StatesRisk and Insurance Services (Marsh McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Robinson & Son, LLC (New York-based insurance broker); headcount added not disclosed; total Q1 2026 purchase consideration $45M across both acquisitions
2026-03-31acquisition_additioncompleted2026-01GermanyConsulting (Mercer)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired Profil M Beratung für Human Resources Management GmbH & Co. KG; headcount added not disclosed
2026-03-31restructuringin_progress2025-07-012028-06-30GlobalCorporate and SegmentsUSD 45 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of the 'Thrive' program launched in Q3 2025. Total expected cost is $500 million over three years. Q1 2026 charges were $45 million, primarily severance. Employee count affected not disclosed.
2026-03-31restructuringin_progressUSD 45,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressOperating Segments [Member] / Risk And Insurance Services Segment [Member]USD 27,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressOperating Segments [Member] / Consulting Segment [Member]USD 13,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 5,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressEmployee Severance [Member]USD 32,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressReal Estate Related Costs [Member]USD 5,000,000 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressInformation Technology [Member]USD 0 (absolute)restructuring_footnote
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2026-03-31restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 8,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progress20252028GlobalCompany-wide; includes formation of Business Client Services (BCS)USD 150 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Thrive Program launched in Q3 2025 as a three-year program (through ~2028). FY2025 Program charges of $150M (primarily severance) within a ~$500M three-year expected cost and ~$400M annualized savings target. Total 2025 restructuring costs were $222M including non-Program charges, split RIS $134M / Consulting $64M / Corporate $24M; severance charge of $174M, real estate $32M, outside services $16M. Employee counts affected not disclosed; severance liability at 2025-12-31 was $99M.
2025-12-31acquisition_additioncompleted2025GlobalRisk and Insurance Services (14 acquisitions); Consulting (6 acquisitions)USD 857 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		20 acquisitions completed during 2025; value shown is total purchase consideration (cash of $726M, deferred/contingent consideration of $116M, remeasured equity method investment of $15M), not a workforce charge. Headcount added via acquisitions not disclosed.
2025-12-31divestiture_reductioncompleted2025United StatesMarsh McLennan Agency (MMA) — Technology Consulting and Administrative Solutions (TCAS)USD 25 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		TCAS business sold in Q1 2025 for approximately $25 million with a $15 million gain recorded in revenue; value shown is approximate sale proceeds, not a workforce charge. Headcount removed not disclosed.
2025-12-31restructuringin_progressGlobalCompany-wide (includes Business Client Services formation)USD 150 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Thrive three-year program launched in Q3 2025 (exact announcement date not disclosed); $150M of the ~$500M total program cost incurred in 2025, primarily severance. Total 2025 restructuring charges across all programs were $222M. Expected annualized savings ~$400M; no completion date stated.
2025-12-31acquisition_additioncompletedGlobalRisk and Insurance Services (14 acquisitions); Consulting (6 acquisitions)USD 857 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		20 acquisitions completed in 2025 with total purchase consideration of $857M; headcount added through these acquisitions is not disclosed. Charge field records total purchase consideration, not a severance/restructuring charge.
2025-12-31divestiture_reductioncompletedUnited StatesMarsh McLennan Agency — Technology Consulting and Administrative Solutions (TCAS)USD 25 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		TCAS business sold in Q1 2025 for approximately $25M (gain of $15M recorded in revenue); associated headcount removed is not disclosed. Charge field records sale proceeds, not a restructuring charge.
2025-12-31restructuringin_progress2025-07-012028-12-31GlobalCorporateUSD 222 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Launched 'Thrive' program in Q3 2025. Total expected cost $500M over three years. 2025 costs of $222M include severance, lease exit charges, and consulting services. Employee count not disclosed.
2025-12-31restructuringin_progressUSD 222,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 134,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressConsulting Segment [Member]USD 64,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 24,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 174,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 32,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 0 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 16,000,000 (absolute)restructuring_footnote
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2025-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 222,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progress2025-07-012028-06-30Company-wide (brand strategy, client value, growth, efficiency)USD 500 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Three-year Thrive program launched Q3 2025; ~$500 million total cost over three years, primarily severance, technology and outside services; charges expected evenly distributed. Q3 2025 Thrive-related costs were $38 million (severance and outside services). No employee count affected was disclosed.
2025-09-30restructuringin_progress2022-10-012024-12-31Company-wide (workforce actions, technology and functional services, real estate)USD 96 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Prior restructuring initiative focused on workforce actions, technology/functional services rationalization and real estate reductions, completed at end of 2024; nine months 2025 costs of $96 million (severance, lease exit charges, consulting/outside services) relate to this program. Restructuring liability of $73 million at September 30, 2025, including $44 million severance.
2025-09-30restructuringin_progress2025-09-30GlobalCompany-wide (Risk and Insurance Services, Consulting, Corporate)USD 500 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Three-year 'Thrive' program launched in Q3 2025 (exact announcement date not disclosed); approximately $500M expected cost over three years, primarily severance, technology and outside services, with charges expected evenly distributed; $38M incurred in Q3 2025; annualized savings targeted at approximately $400M. No employee count disclosed. Total Q3 2025 restructuring charges of $46M (RIS $20M, Consulting $18M, Corporate $8M) include the Thrive charge; restructuring liability was $73M at 2025-09-30. MD&A also notes formation of Business Client Services centralizing operations and technology teams.
2025-09-30acquisition_additioncompletedUnited States; FranceRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions completed in Q3 2025 for total purchase consideration of $189M: Excel Insurance LLC and Donald S. Barberie Insurance Agency (July, MMA), Robins Insurance Agency (August, MMA), Validate Health and ConvictionsRH (August, Consulting). No headcount added through these acquisitions is disclosed.
2025-09-30restructuringin_progress2025-09-302028-09-30GlobalCorporateUSD 500 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Company launched three-year 'Thrive' program in Q3 2025. Expected total cost is $500 million over three years, primarily severance, technology, and outside services. $38 million incurred in Q3 2025. Employee count not disclosed.
2025-09-30restructuringin_progressUSD 46,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressOperating Segments [Member] / Risk And Insurance Services Segment [Member]USD 20,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressOperating Segments [Member] / Consulting Segment [Member]USD 18,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 8,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressEmployee Severance [Member]USD 70,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressReal Estate Related Costs [Member]USD 19,000,000 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressInformation Technology [Member]USD 0 (absolute)restructuring_footnote
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2025-09-30restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 7,000,000 (absolute)restructuring_footnote
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2025-06-30restructuringin_progressRisk and Insurance Services; Consulting; CorporateUSD 18 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q2 2025 restructuring charges of $18 million ($50 million YTD), primarily severance and lease exit charges; no employee counts disclosed. Segment split: RIS $8M, Consulting $6M, Corporate $4M for the quarter. Severance liability at June 30, 2025 was $41 million.
2025-06-30acquisition_additioncompletedGreece, Italy, Australia, US, India, US/UKRisk and Insurance Services (Marsh, Guy Carpenter, MMA); Consulting (Mercer)USD 148 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Seven acquisitions completed in H1 2025 (5 in RIS, 2 in Consulting) with total purchase consideration of $148 million; headcount added not disclosed.
2025-06-30divestiture_reductioncompleted2025-01-01USMarsh McLennan Agency — Technology Consulting and Administrative Solutions (TCAS)USD 15 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sold MMA's TCAS business for approximately $25 million, recording a $15 million gain included in revenue; headcount removed not disclosed.
2025-06-30restructuringin_progressRisk and Insurance ServicesUSD 31 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Charge is the six months ended June 30, 2025 restructuring cost for this segment; primarily severance and lease exit charges. No employee counts or program dates disclosed.
2025-06-30restructuringin_progressConsultingUSD 14 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Charge is the six months ended June 30, 2025 restructuring cost for this segment; primarily severance and lease exit charges. No employee counts or program dates disclosed.
2025-06-30restructuringin_progressCorporateUSD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Charge is the six months ended June 30, 2025 restructuring cost for this segment; primarily severance and lease exit charges. No employee counts or program dates disclosed.
2025-06-30acquisition_additioncompleted2025-01GreeceRisk and Insurance Services — Guy Carpenterbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Guy Carpenter acquired the remaining 51.5% of Carpenter Turner Cyprus Ltd. Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-02ItalyRisk and Insurance Services — Marshbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Fontana Rava-Toscano & Partners S.r.l. Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-03AustraliaRisk and Insurance Services — Marshbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired the business of Cohere Insurance Solutions. Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-04United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Arthur C. Hall Insurance, Inc. (Pennsylvania). Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-05United StatesRisk and Insurance Services — Marshbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Thornton Harvey Group, LLC (ProWriters), a Pennsylvania wholesale broker. Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-04IndiaConsulting — Mercerbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired the business of Cerebrus Consultants Private Limited. Headcount added not disclosed; only month of completion stated.
2025-06-30acquisition_additioncompleted2025-05United States / United KingdomConsulting — Mercerbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired SECOR Asset Management, L.P. Headcount added not disclosed; only month of completion stated.
2025-06-30divestiture_reductioncompletedUnited StatesRisk and Insurance Services — Marsh & McLennan Agency (Technology Consulting and Administrative Solutions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sold for approximately $25 million with a $15 million gain recorded in revenue; completed in the first quarter of 2025 (exact date not disclosed). Headcount removed not disclosed.
2025-06-30restructuringin_progressGlobalCorporate and SegmentsUSD 18 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $18 million for Q2 2025, primarily related to severance and lease exit charges. No specific employee count disclosed for this period.
2025-06-30restructuringin_progressGlobalCorporate and SegmentsUSD 50 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $50 million for the six months ended June 30, 2025, primarily related to severance and lease exit charges. No specific employee count disclosed for this period.
2025-06-30restructuringin_progressUSD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressOperating Segments [Member] / Risk And Insurance Services Segment [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressOperating Segments [Member] / Consulting Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressEmployee Severance [Member]USD 36,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressReal Estate Related Costs [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressInformation Technology [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-06-30restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressRisk and Insurance Services ($23M); Consulting ($8M); Corporate ($1M)USD 32 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2025 charges of $32 million primarily severance and lease exit charges, related to remaining restructuring activities; no employee counts disclosed. Restructuring liability at March 31, 2025 was $91 million (severance $53M, real estate $38M).
2025-03-31acquisition_additioncompletedGreece, Italy, AustraliaRisk and Insurance ServicesUSD 62 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Three RIS acquisitions in Q1 2025 (Carpenter Turner Cyprus Ltd., Fontana Rava-Toscano & Partners, Cohere Insurance Solutions) for total consideration of $62 million; no headcount figures disclosed.
2025-03-31divestiture_reductioncompletedMarsh McLennan Agency — Technology Consulting and Administrative Solutions (TCAS)USD 25 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sold MMA's TCAS business for approximately $25 million with a $15 million gain in Q1 2025; no headcount figures disclosed.
2025-03-31restructuringin_progressRisk and Insurance ServicesUSD 23 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2025 charges for remaining restructuring activities, primarily severance and lease exit; employees affected not disclosed. Broader program initiated in Q4 2022 with prior activities completed end of 2024.
2025-03-31restructuringin_progressConsultingUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2025 restructuring charges for Consulting segment; employees affected not disclosed.
2025-03-31restructuringin_progressCorporateUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2025 restructuring charges for Corporate; employees affected not disclosed. Segment components sum to the $32 million total Q1 2025 restructuring charge.
2025-03-31acquisition_additioncompleted2025-01GreeceGuy Carpenter — Risk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of remaining 51.5% of Carpenter Turner Cyprus Ltd.; headcount added not disclosed. Total Q1 2025 acquisition consideration was $62 million across three deals.
2025-03-31acquisition_additioncompleted2025-02ItalyMarsh — Risk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Fontana Rava-Toscano & Partners S.r.l.; headcount added not disclosed.
2025-03-31acquisition_additioncompleted2025-03AustraliaMarsh — Risk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Cohere Insurance Solutions; headcount added not disclosed.
2025-03-31divestiture_reductioncompletedMarsh McLennan Agency — Technology Consulting and Administrative Solutionsbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Business sold during Q1 2025 for approximately $25 million with a $15 million gain recorded in revenue; exact sale date and headcount removed not disclosed.
2025-03-31restructuringin_progressGlobalCorporate and SegmentsUSD 32 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $32 million incurred in Q1 2025, primarily related to severance and lease exit charges. Breakdown: RIS $23M, Consulting $8M, Corporate $1M.
2025-03-31restructuringin_progressUSD 32,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressOperating Segments [Member] / Risk and Insurance Services Segment [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressOperating Segments [Member] / Consulting Segment [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressEmployee Severance [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressReal Estate Related Costs [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressInformation Technology [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2025-03-31restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-12-31restructuringcompleted2022-102024-12-31Global (not separately disclosed)Risk and Insurance ServicesUSD 148 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2024 restructuring charges for the Risk and Insurance Services segment under the program initiated in the fourth quarter of 2022 focused on workforce actions, rationalization of technology and functional services, and reductions in real estate; activities completed at the end of 2024. Program-to-date costs approximately $660 million, primarily severance and lease exit charges ($221 million of the program costs characterized in MD&A as incurred in 2024). 2024 charges by segment: RIS $148M, Consulting $79M, Corporate $49M (total $276M). Employees affected not disclosed.
2024-12-31restructuringcompleted2022-102024-12-31Global (not separately disclosed)ConsultingUSD 79 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2024 restructuring charges for the Consulting segment under the Q4 2022-initiated program (workforce actions, technology rationalization, real estate reductions); completed at end of 2024. Program-to-date costs approximately $660 million, primarily severance and lease exit charges. Employees affected not disclosed.
2024-12-31restructuringcompleted2022-102024-12-31Global (not separately disclosed)CorporateUSD 49 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2024 restructuring charges for Corporate under the Q4 2022-initiated program (workforce actions, technology rationalization, real estate reductions); completed at end of 2024. Program-to-date costs approximately $660 million, primarily severance and lease exit charges. Employees affected not disclosed.
2024-12-31acquisition_additioncompleted2024-11-15United StatesRisk and Insurance Services (Marsh)USD 63 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		Completed acquisition of McGriff Insurance Services, LLC on November 15, 2024 for $7.75 billion in cash consideration (date shown is the completion date; original announcement date not stated in the filing); McGriff had approximately $1.3 billion in annual revenue; resulting headcount not disclosed. One of 17 acquisitions completed in 2024; headcount for other acquisitions also not disclosed. Approximately $63 million of acquisition and retention related costs incurred in 2024, with approximately $450–$500 million of retention incentives expected over the next 3 years, funded through a purchase price adjustment.
2024-12-31divestiture_reductioncompleted2024-01-01United Kingdom; United StatesConsulting (Mercer)USD 18 (millions)other
f5-10k / GLM-5.3-flash-HTML		Sold the Mercer U.K. pension administration and U.S. health and benefits administration businesses on January 1, 2024 for approximately $120 million, recording a net gain of $35 million; transferred headcount not disclosed. $18 million of exit costs (charge shown) incurred in the first quarter of 2024.
2024-12-31restructuringcompleted2022-10-012024-12-31GlobalRisk and Insurance ServicesUSD 148 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2024 charge for multi-year program initiated Q4 2022 (workforce actions, technology rationalization, real estate reductions); program completed end of 2024. Employees affected not disclosed.
2024-12-31restructuringcompleted2022-10-012024-12-31GlobalConsultingUSD 79 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2024 charge for multi-year program initiated Q4 2022; program completed end of 2024. Employees affected not disclosed.
2024-12-31restructuringcompleted2022-10-012024-12-31GlobalCorporateUSD 49 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2024 charge for multi-year program initiated Q4 2022; program completed end of 2024. Employees affected not disclosed. Total FY2024 restructuring charges across all three components: $276M; cumulative program charges through 2024-12-31: ~$660M.
2024-12-31acquisition_additioncompleted2024-11-15United StatesRisk and Insurance Services — MarshUSD 7,750 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Acquired McGriff Insurance Services for $7.75B cash; target had ~$1.3B annual revenue. Headcount added not disclosed. Company completed 17 acquisitions in total during 2024.
2024-12-31divestiture_reductioncompleted2024-01-01United Kingdom / United StatesConsulting — Mercerdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sold for ~$120M; net gain of $35M recorded in revenue. Headcount removed not disclosed.
2024-12-31divestiture_reductioncompleted2024-12-31GlobalConsulting — Oliver Wyman Groupdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sold for ~$24M; gain of $20M recorded in revenue. Headcount removed not disclosed.
2024-12-31divestiture_reductioncompleted2024-09-30RussiaNot specifieddiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Regulatory approval obtained and ownership transferred to local management in Q3 2024 under a 2022 agreement. Headcount removed not disclosed.
2024-12-31restructuringcompleted2022-10-012024-12-31GlobalAll segmentsUSD 276 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Initiated in Q4 2022, completed at end of 2024. Focus on workforce actions, technology rationalization, and real estate reductions. Total costs incurred through Dec 31, 2024 were approx $660M, with $276M incurred in 2024. Employee count affected not explicitly disclosed.
2024-12-31acquisition_additioncompleted2024-11-152024-11-15United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10k / Qwen3.6-27B-Q8_0		Acquisition of McGriff Insurance Services, LLC. Headcount added not explicitly disclosed.
2024-12-31divestiture_reductioncompleted2024-01-012024-01-01United Kingdom; United StatesConsultingbusiness_combinations_footnote
f5-10k / Qwen3.6-27B-Q8_0		Sale of Mercer U.K. pension administration and U.S. health and benefits administration businesses. Headcount removed not explicitly disclosed.
2024-12-31restructuringin_progressSeverance and Lease Exit Charges [Member]USD 221,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 148,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressConsulting Segment [Member]USD 79,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 49,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressUSD 276,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 163,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 66,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 25,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 276,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2024-09-30restructuringin_progress2022-10-012024-12-31Workforce actions, technology and functional services rationalization, real estate reductionsUSD 650 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated Q4 2022; detailed plans finalized Q3 2024 with total anticipated charges of approximately $650 million. Approximately $540 million incurred through September 30, 2024, primarily severance and lease exit charges. Expected savings over $500 million, ~$400 million realized by end of 2024. No employee count disclosed.
2024-09-30restructuringin_progress2022-10-012024-12-31Risk and Insurance ServicesUSD 54 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2024 restructuring charges of $54 million for Risk and Insurance Services segment.
2024-09-30restructuringin_progress2022-10-012024-12-31ConsultingUSD 14 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2024 restructuring charges of $14 million for Consulting segment.
2024-09-30restructuringin_progress2022-10-012024-12-31CorporateUSD 18 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2024 restructuring charges of $18 million for Corporate.
2024-09-30restructuringin_progress2022-10-012024-12-31Risk and Insurance ServicesUSD 73 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		YTD 2024 restructuring charges of $73 million for Risk and Insurance Services segment.
2024-09-30restructuringin_progress2022-10-012024-12-31ConsultingUSD 30 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		YTD 2024 restructuring charges of $30 million for Consulting segment.
2024-09-30restructuringin_progress2022-10-012024-12-31CorporateUSD 37 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		YTD 2024 restructuring charges of $37 million for Corporate.
2024-09-30acquisition_additionannounced2024-09-302024-12-31United StatesRisk and Insurance Services (insurance broking and risk management)USD 7,750 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Agreement to acquire McGriff Insurance Services, LLC for $7.75 billion in cash, funded by cash proceeds and debt financing including a $7.75 billion 364-day bridge loan facility; ~$500 million deferred tax asset expected to be assumed. Targeted to close by end of 2024. No headcount figures disclosed.
2024-09-30restructuringin_progress2022-12-312024-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 650 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; detailed plans finalized in Q3 2024. Anticipated total charges ~$650M, of which ~$540M incurred through 2024-09-30 ($36M in Q3, $96M YTD). No employee headcount affected is disclosed. Related savings expected to exceed $500M, ~$400M realized by end of 2024.
2024-09-30acquisition_additionannounced2024-09-302024-12-31United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Agreement to acquire McGriff Insurance Services, LLC for $7.75B cash, targeted to close by end of 2024 subject to regulatory clearance. No headcount of acquired workforce disclosed. Bridge loan commitment of up to $7.75B entered 2024-09-29.
2024-09-30acquisition_additioncompleted2024-07-012024-09-30GlobalRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Four acquisitions completed in Q3 2024 (13 YTD), largest being The Horton Group, Inc. by Marsh McLennan Agency. Total 2024 purchase consideration $1.3B; goodwill of $826M recognized. No acquired-employee headcount disclosed for any transaction.
2024-09-30divestiture_reductioncompleted2024-01-012024-01-01United Kingdom; United StatesConsulting (Mercer)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Mercer U.K. pension administration and U.S. health and benefits administration businesses for ~$114M; net gain of $21M recorded in revenue. Exit costs of $18M incurred in Q1 2024. No headcount removed disclosed.
2024-09-30divestiture_reductioncompleted2022-06-302024-09-30RussiaAllbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Definitive agreement to exit Russia businesses entered June 2022; regulatory approval obtained and exit completed in Q3 2024, transferring ownership to local management. Announcement date approximate (month only in filing). No headcount disclosed.
2024-09-30restructuringin_progress2022-10-012024-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 140 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Initiated in Q4 2022. Total charges anticipated ~$650M. $140M incurred in first nine months of 2024, primarily severance and lease exit charges. Expected to complete by end of 2024.
2024-09-30acquisition_additioncompleted2024-09-302024-12-31United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Announced agreement to acquire McGriff Insurance Services, LLC for $7.75 billion. Targeted to close by end of 2024. Headcount not disclosed.
2024-09-30restructuringin_progressSeverance and Lease Exit Charges [Member]USD 36,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressUSD 54,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressConsulting Segment [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressEmployee Severance [Member]USD 63,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressReal Estate Related Costs [Member]USD 41,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressInformation Technology [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-09-30restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progress2022-10-012024-12-31Risk and Insurance Services; Consulting; CorporateUSD 44 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; Q2 2024 charge of $44 million ($86 million YTD), primarily severance; remaining costs expected by end of 2024. Segment split: RIS $29M, Consulting $5M, Corporate $10M for the quarter. No employee counts disclosed.
2024-06-30acquisition_additioncompletedRisk and Insurance Services (5 acquisitions); Consulting (4 acquisitions)USD 716 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine acquisitions completed in H1 2024 (total consideration $716 million); no headcount figures disclosed for acquired workforces.
2024-06-30divestiture_reductioncompleted2024-01-012024-01-01United Kingdom; United StatesMercer (Consulting)USD 18 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of Mercer U.K. pension administration and U.S. health and benefits administration businesses for ~$114 million with a $21 million net gain and $18 million exit costs; no headcount figures disclosed.
2024-06-30restructuringin_progress2024-12-31GlobalEnterprise-wide (Risk and Insurance Services, Consulting, Corporate)USD 86 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; $86M charged in first six months of 2024 ($44M in Q2). Employee counts not disclosed; remaining costs expected by end of 2024. Restructuring liability was $60M at 2024-06-30.
2024-06-30acquisition_additioncompletedUnited States, Japan, United Arab Emirates, NetherlandsRisk and Insurance Services (5 acquisitions) and Consulting (4 acquisitions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine acquisitions completed in the six months ended 2024-06-30 with total purchase consideration of $716M; acquired headcount not disclosed. Largest deals: Vanguard Institutional Advisory Services and Fisher Brown Bottrell Insurance.
2024-06-30divestiture_reductioncompleted2024-01-012024-01-01United Kingdom, United StatesConsulting — Mercer (U.K. pension administration and U.S. health and benefits administration businesses)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Businesses sold for approximately $114M with a $21M net gain recorded in revenue; associated headcount not disclosed. $18M of exit costs incurred in Q1 2024.
2024-06-30restructuringin_progress2022-10-012024-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 44 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Initiated in Q4 2022. Q2 2024 charges of $44M (QTD $86M) primarily for severance. Remaining costs expected by end of 2024.
2024-06-30restructuringin_progressSeverance and Lease Exit Charges [Member]USD 30,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressUSD 44,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 29,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressConsulting Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressSegment Reporting, Reconciling Item, Corporate Nonsegment [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressEmployee Severance [Member]USD 42,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressReal Estate Related Costs [Member]USD 21,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressInformation Technology [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-06-30restructuringin_progressLegal, Consulting and Other Outside Services [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progress2022-10-012024-12-31Risk and Insurance Services ($22M), Consulting ($11M), Corporate ($9M)USD 42 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated Q4 2022 covering workforce actions, technology/functional services rationalization, and real estate reductions. Q1 2024 charges of $42M (vs $53M prior-year quarter) include $30M related to the 2022-initiated activities, primarily severance; remaining costs expected by end of 2024. Restructuring liability of $82M at 2024-03-31, including $48M severance. No employee counts disclosed.
2024-03-31divestiture_reductioncompleted2024-01-01United Kingdom and United StatesConsulting — MercerUSD 18 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sold Mercer U.K. pension administration and U.S. health and benefits administration businesses for approximately $114 million, recording a $21 million net gain and incurring $18 million of exit costs. Headcount removed not disclosed.
2024-03-31restructuringin_progress2022-10-012024-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 42 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated Q4 2022 covering workforce actions, technology/functional rationalization, and real estate reductions. Q1 2024 charges: $42M total ($22M RIS, $11M Consulting, $9M Corporate). No employee headcount affected disclosed. Remaining costs expected by end of 2024.
2024-03-31acquisition_additioncompleted2024-03-312024-03-31GlobalRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Two RIS acquisitions in Q1 2024: NOSCO Insurance Service Company Ltd. (Japan, January) and Querbes & Nelson / Louisiana Companies (March). No headcount disclosed.
2024-03-31acquisition_additioncompleted2024-03-312024-03-31GlobalConsultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Four Consulting acquisitions in Q1 2024: SeaTec Consulting (Feb), Vanguard Institutional Advisory Services (Mar), The Talent Enterprise (Mar), Innopay NL B.V. (Mar). No headcount disclosed.
2024-03-31divestiture_reductioncompleted2024-01-012024-01-01United Kingdom; United StatesConsulting (Mercer)USD 18 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Mercer U.K. pension administration and U.S. health and benefits administration businesses for ~$114M; net gain of $21M recorded in revenue; $18M exit costs incurred. No headcount disclosed.
2024-03-31restructuringin_progress2022-10-012024-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 42 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Program initiated in Q4 2022 focused on workforce actions, technology rationalization, and real estate reductions. $42M incurred in Q1 2024, primarily severance. Remaining costs expected by end of 2024.
2024-03-31restructuringin_progressSeverance and Lease Exit Charges [Member]USD 30,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressUSD 42,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressConsulting Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressCorporate, Non-Segment [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 21,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2024-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 42,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-12-31restructuringin_progress20222024-12-31Risk and Insurance ServicesUSD 177 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2023 charges under the program initiated in Q4 2022 (workforce actions, technology rationalization, real estate reductions), plus lease exits for a legacy JLT U.K. location. Consolidated FY2023 restructuring charges: $301M across all segments (incl. $31M of JLT integration costs); program total anticipated at ~$475M, with $441M incurred through 2023-12-31 ($222M attributed to 2023 per MD&A) and ~$400M expected savings ($230M realized in 2023); remaining costs expected by end of 2024. 2023 severance charges company-wide were $148M (not allocated by segment). Headcount affected not disclosed.
2023-12-31restructuringin_progress20222024-12-31ConsultingUSD 62 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2023 charges under the program initiated in Q4 2022 (workforce actions, technology rationalization, real estate reductions). Consolidated FY2023 restructuring charges: $301M across all segments (incl. $31M of JLT integration costs); program total anticipated at ~$475M with remaining costs expected by end of 2024. Headcount affected not disclosed.
2023-12-31restructuringin_progress20222024-12-31CorporateUSD 62 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Corporate restructuring charges per the Note 14 segment roll-forward; part of the Q4 2022-initiated program (workforce actions, technology rationalization, real estate reductions). Headcount affected not disclosed.
2023-12-31acquisition_additioncompletedRisk and Insurance Services (9 acquisitions); Consulting (5 acquisitions)USD 1,181 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		14 acquisitions completed during 2023; associated value is total purchase consideration ($1.1B cash plus $41M deferred/contingent consideration), not a workforce charge. Largest deals: Honan Insurance Group and Graham Company (Risk and Insurance Services) and the Westpac Transaction (Consulting). Employee headcount added through these acquisitions was not disclosed.
2023-12-31divestiture_reductioncompleted2024-01-01United States; United KingdomConsulting — Mercer (U.S. health & benefits; U.K. pension administration)USD 110 (millions)other
f5-10k / GLM-5.3-flash-HTML		Subsequent event: sale completed January 1, 2024, after the 2023 fiscal year-end, for approximately $110M in proceeds (not a workforce charge); $70M of related net assets (primarily goodwill and intangibles) were reclassified as held for sale at 2023-12-31. Gain on sale expected to be immaterial. Employee headcount transferred was not disclosed.
2023-12-31restructuringin_progress2024-12-31GlobalRisk and Insurance ServicesUSD 177 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2023 restructuring charge for the segment. Program initiated in Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; includes $31M of legacy JLT integration and lease-exit costs. No employee count disclosed.
2023-12-31restructuringin_progress2024-12-31GlobalConsultingUSD 62 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2023 restructuring charge for the segment under the program initiated in Q4 2022. No employee count disclosed.
2023-12-31restructuringin_progress2024-12-31GlobalCorporateUSD 62 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2023 restructuring charge for Corporate under the program initiated in Q4 2022. Program totals: approximately $475M expected, $441M incurred through 2023-12-31 (of which $222M in FY2023), with approximately $400M of expected savings and $230M realized in FY2023. Remaining costs expected by end of 2024. No employee count disclosed.
2023-12-31acquisition_additioncompletedGlobalRisk and Insurance Services (9 acquisitions) and Consulting (5 acquisitions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		14 acquisitions completed in FY2023 with total purchase consideration of $1.2B. Largest: Honan Insurance Group ($358M), Graham Company ($307M) and the Westpac Transaction ($232M). No acquired headcount disclosed.
2023-12-31divestiture_reductioncompleted2024-01-01United States; United KingdomConsulting — Mercer U.S. health and benefits and U.K. pension administration businessessubsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale completed 2024-01-01, after fiscal year-end, for approximately $110M; $70M of related net assets reclassified to other current assets at 2023-12-31. Gain on sale and impact on Consulting revenue/operating income expected to be not material. No employee count disclosed.
2023-12-31restructuringin_progress2022-10-012024-12-31GlobalAll SegmentsUSD 301 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Initiated in Q4 2022 focused on workforce actions, technology rationalization, and real estate reductions. $301M incurred in 2023. Total expected charges ~$475M. Remaining costs expected by end of 2024.
2023-12-31restructuringin_progressSeverance and Lease Exit Charges [Member]USD 222,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 177,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressConsulting Segment [Member]USD 62,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressCorporate, Non-Segment [Member]USD 62,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressUSD 301,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 148,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 96,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 42,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 301,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2023-09-30restructuringin_progress2022-10-012023-12-31Company-wide (workforce actions, technology and functional services rationalization, real estate reductions)USD 425 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated Q4 2022; total anticipated charges of $425-$475 million; approximately $325 million incurred through September 30, 2023, primarily severance and lease exit charges; majority of remaining costs expected by end of 2023; estimated savings of approximately $400 million, with $225 million expected in 2023
2023-09-30restructuringin_progress2022-10-012023-12-31Risk and Insurance ServicesUSD 26 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Segment-level restructuring cost for the three months ended September 30, 2023; nine-month figure was $89 million
2023-09-30restructuringin_progress2022-10-012023-12-31ConsultingUSD 17 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Segment-level restructuring cost for the three months ended September 30, 2023; nine-month figure was $33 million
2023-09-30restructuringin_progress2022-10-012023-12-31CorporateUSD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Corporate-level restructuring cost for the three months ended September 30, 2023; nine-month figure was $48 million
2023-09-30othercompleted2023-10-01EuropeUSD 70 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Settled a claim with a competitor regarding unlawful recruiting of a limited number of the Company's employees in Europe; amount includes reimbursement of legal expenses
2023-09-30restructuringin_progress2022-102023-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 325 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2022 covering workforce actions, technology and functional rationalization, and real estate reductions, plus IT/Marsh operational excellence initiatives. Approximately $325M incurred through 2023-09-30 (including $109M in the nine months then ended); total expected charges of $425M-$475M with the majority of remaining costs expected by end of 2023. Nine-month 2023 charges by segment: Risk and Insurance Services $89M, Consulting $33M, Corporate $48M (total $170M). No number of employees affected is disclosed.
2023-09-30acquisition_additioncompletedGlobalRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Twelve acquisitions completed in the nine months ended 2023-09-30 (eight in Risk and Insurance Services, four in Consulting), including the Westpac Transaction (April 2023) and Graham Company (August 2023); total purchase consideration $711M. No headcount added through these acquisitions is disclosed.
2023-09-30restructuringin_progress2022-10-012023-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 170 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Initiated in Q4 2022 focused on workforce actions, technology rationalization, and real estate reductions. Total expected charges $425M-$475M. $170M incurred YTD 2023, including $62M severance and $63M real estate costs. Majority of remaining costs expected by end of 2023.
2023-09-30restructuringin_progressSeverance and Lease Exit Charges [Member]USD 37,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 26,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressConsulting Segment [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressCorporate, Non-Segment [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressUSD 52,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 62,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 63,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 38,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 170,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progress2022-10-012023-12-31Company-wide (Risk and Insurance Services, Consulting, Corporate)USD 400 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated Q4 2022 covering workforce actions, technology/functional services rationalization, and real estate reductions; total charges expected between $375 million and $400 million, with approximately $300 million incurred through June 30, 2023 (including $48 million in Q2 and $72 million in H1 2023). Majority of remaining costs expected in remainder of 2023. No employee count disclosed. Estimated savings of approximately $300 million by 2024, with $200 million expected in 2023.
2023-06-30restructuringin_progress2022-10-012023-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 118 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; no employee counts disclosed. Six-month 2023 charges of $118M split RIS $63M, Consulting $16M, Corporate $39M; ~$300M of total expected $375-400M incurred through 2023-06-30, with most remaining costs expected in remainder of 2023. Announcement date is quarter-level (Q4 2022) as no exact date given.
2023-06-30restructuringin_progress2022-10-012023-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 118 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Program initiated in Q4 2022 focused on workforce actions, technology rationalization, and real estate reductions. Total expected charges $375M-$400M. $118M incurred YTD 2023, primarily severance and lease exit charges. Majority of remaining costs expected in remainder of 2023.
2023-06-30restructuringin_progressSeverance and Lease Exit Charges [Member]USD 48,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 31,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressConsulting Segment [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressCorporate, Non-Segment [Member]USD 27,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressUSD 65,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 46,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 36,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 30,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 118,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progress2022-10-01Company-wide (workforce actions, technology and functional services rationalization, real estate reductions)USD 24 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Program initiated in Q4 2022; total expected charges of $375-400 million, of which $243 million incurred through March 31, 2023 ($24 million in Q1 2023), primarily severance and lease exit charges. Majority of remaining costs expected in 2023; estimated savings of $280-310 million by 2024. No employee count disclosed.
2023-03-31acquisition_additionannounced2023-04-012023-04-01AustraliaConsulting (Mercer)USD 252 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Acquisition of Westpac's financial advisory business (Advance Asset Management) and transfer of BT Financial Group pension funds to Mercer Super Trust completed April 1, 2023; $252 million transferred to trust account on March 30, 2023; ~$17 million of integration expenses incurred in Q1 2023. No headcount figures disclosed.
2023-03-31divestiture_reductionin_progress2023-01-012023-12-31CanadaConsulting (Mercer)USD 19 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Agreement in January 2023 to sell a small individual financial advisory business in Canada, expected to complete by end of 2023; $19 million loss recorded in Q1 2023, primarily write-down of customer relationship intangibles. No headcount figures disclosed.
2023-03-31restructuringin_progress20222023GlobalEnterprise (includes Corporate/global IT function)USD 243 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2022 covering workforce actions, technology/functional rationalization and real estate reductions; $243M incurred through 2023-03-31 (incl. $24M in Q1 2023) of an expected $375M-$400M total; no employee count disclosed; expected savings of $280M-$310M by 2024
2023-03-31restructuringin_progress2022-10-012023-12-31GlobalCorporate, Risk and Insurance Services, ConsultingUSD 53 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Initiated in Q4 2022 focused on workforce actions, technology rationalization, and real estate reductions. Total expected charges $375M-$400M. $53M incurred in Q1 2023 ($32M RIS, $9M Consulting, $12M Corporate). Majority of remaining costs expected in 2023.
2023-03-31acquisition_additioncompleted2023-03-312023-03-31United StatesConsultingUSD 15 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer acquired Leapgen LLC, a human resources consulting technology advisory firm. Purchase consideration $15M.
2023-03-31restructuringin_progressSeverance and Lease Exit Charges [Member]USD 243,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressUSD 53,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 32,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressConsulting Segment [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressCorporate, Non-Segment [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2023-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 53,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-12-31restructuringin_progress20222024Not specified (company-wide)Workforce actions, rationalization of technology and functional services, reductions in real estateUSD 219 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Program initiated in Q4 2022; charges primarily severance and lease exit costs. Expected 2023 savings of $125–150 million; activities to continue through 2023 into 2024, with additional charges unlikely to exceed 2022 levels; plans still being finalized. Included within 2022 restructuring charges excluding JLT of $312 million; total 2022 restructuring charges were $427 million (RIS $254M, Consulting $77M, Corporate $96M), including $111 million of severance charges per the roll-forward. Employee headcount affected not disclosed.
2022-12-31restructuringcompleted2022Primarily United KingdomRisk and Insurance Services (legacy JLT U.K. location)USD 115 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2022 JLT integration and restructuring costs; MD&A cites $89 million of lease exit charges for a legacy JLT U.K. location in RIS. Multi-year integration program originating from the April 1, 2019 JLT acquisition; the company completed the JLT integration in 2022. Employee headcount affected not disclosed.
2022-12-31restructuringin_progressGlobalRisk and Insurance ServicesUSD 104 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2022 covering workforce actions, technology/functional rationalization and real-estate reductions; $104M of the $219M company-wide program. Total 2022 RIS restructuring charges were $254M. Employees affected not disclosed; activities expected to continue through 2023 into 2024, with additional charges unlikely to exceed 2022 costs.
2022-12-31restructuringin_progressGlobalConsultingUSD 53 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Q4 2022-initiated program component ($53M of the $219M company-wide program). Total 2022 Consulting restructuring charges were $77M. Employees affected not disclosed; expected 2023 savings of $125M-$150M company-wide.
2022-12-31restructuringin_progressGlobalCorporateUSD 62 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Primarily lease exit charges for real-estate reductions; $62M of the $219M company-wide Q4 2022 program. Total 2022 Corporate restructuring charges were $96M.
2022-12-31plant_closurein_progressUnited KingdomRisk and Insurance ServicesUSD 89 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Office lease exit for a legacy JLT U.K. site; headcount impact not disclosed. Included within the $254M of 2022 RIS restructuring charges.
2022-12-31acquisition_additioncompletedGlobalRisk and Insurance Servicesbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		16 acquisitions completed during 2022 (Marsh, Guy Carpenter and MMA), including HMS Insurance Associates. Headcount added not disclosed; total 2022 purchase consideration across all 20 acquisitions was $705M.
2022-12-31acquisition_additioncompletedGlobalConsultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Four Consulting-segment acquisitions completed during 2022 (Azure Consulting, GeFi Assurances, Booz Allen Hamilton MENA strategy business, Avascent Group). Headcount added not disclosed.
2022-12-31acquisition_additionannounced2022-05-31AustraliaConsultingUSD 21 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Agreement entered May 2022 to acquire Advance Asset Management and transfer BT Financial Group pension funds to Mercer Super Trust; expected to close in the first half of 2023 subject to regulatory approvals. $21M of pre-acquisition integration costs incurred in 2022; headcount not disclosed.
2022-12-31divestiture_reductioncompleted2022-04United StatesConsultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of the U.S. affinity insurance marketing, brokerage and administration business for cash proceeds of approximately $140M with a net gain of $112M recorded in revenue. Headcount removed not disclosed.
2022-12-31divestiture_reductioncompleted2022-03-31RussiaRisk and Insurance Services; ConsultingUSD 39 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Wholly-owned Russian businesses deconsolidated effective end of Q1 2022 due to sanctions; $39M loss recorded in revenue ($52M total including other related charges). A June 2022 definitive agreement to exit Russia and transfer ownership to local management remains pending regulatory approvals; headcount not disclosed.
2022-12-31divestiture_reductioncompletedUnited Kingdom; Czech Republic; Brazil; BelgiumMultiplebusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cash proceeds of approximately $15M with a net gain of $15M recorded. Headcount removed not disclosed.
2022-12-31restructuringin_progress2022-10-012024-12-31GlobalAll SegmentsUSD 427 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Initiated in Q4 2022. Includes severance and lease exit charges for workforce actions, technology rationalization, and real estate reductions. Expected to continue into 2024.
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 427,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 254,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 77,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 96,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 111,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 195,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 106,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 427,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2022-09-30restructuringin_progressCompany-wide: global IT and HR functions, JLT integration, Marsh operational excellence, real estate exitsUSD 38 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2022 restructuring costs of $38 million ($18M RIS, $5M Consulting, $15M Corporate); no employee counts disclosed
2022-09-30restructuringin_progressCompany-wide: global IT and HR functions, JLT integration, Marsh operational excellence, real estate exitsUSD 96 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2022 restructuring costs of $96 million ($44M RIS, $16M Consulting, $36M Corporate); severance liability of $10 million at 9/30/22; no employee counts disclosed
2022-09-30divestiture_reductioncompleted2022-04-01United StatesMercer — U.S. affinity businessUSD 112 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer sold U.S. affinity insurance business for ~$140 million cash proceeds; net gain of $112 million; headcount transferred not disclosed
2022-09-30othercompleted2022-03-31RussiaMarsh and Oliver Wyman — Russian businessesUSD 52 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Loss on deconsolidation of Russian businesses and related charges; June 2022 agreement to exit Russia and transfer ownership to local management pending regulatory approvals; employee counts not disclosed
2022-09-30restructuringin_progressGlobalRisk and Insurance ServicesUSD 44 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2022-09-30 charges for RIS; program covers IT/HR streamlining, JLT integration, Marsh operational excellence and real estate exits. No employee counts disclosed; program ongoing since 2021.
2022-09-30restructuringin_progressGlobalConsultingUSD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2022-09-30 charges for Consulting segment; no employee counts disclosed.
2022-09-30restructuringin_progressGlobalCorporateUSD 36 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2022-09-30 charges for Corporate, primarily global IT and HR function streamlining; no employee counts disclosed. Total 2022 program charges $96M; restructuring liability $34M at 2022-09-30.
2022-09-30acquisition_additioncompletedUnited States, Japan, France, Australia, Middle East/North AfricaRisk and Insurance Services (8 acquisitions); Consulting (3 acquisitions)USD 227 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Eleven acquisitions completed in the nine months ended 2022-09-30 with $227M total consideration; acquired headcount not disclosed. Charge value shown is total purchase consideration, not a workforce charge.
2022-09-30divestiture_reductioncompleted2022-04United StatesConsulting — Mercer U.S. affinity businessbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer sold its U.S. affinity insurance marketing/brokerage business for ~$140M cash proceeds with a $112M net gain; associated headcount not disclosed.
2022-09-30divestiture_reductionin_progress2022-06RussiaMarsh; Oliver Wyman GroupUSD 52 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Russian businesses deconsolidated in Q1 2022 (loss of $52M including related charges); definitive agreement signed June 2022 to exit and transfer ownership to local management, pending regulatory approvals. Headcount affected not disclosed.
2022-09-30restructuringin_progressGlobalInformation Technology, HR, Real EstateUSD 38 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Q3 2022 charges of $38M for global IT/HR streamlining, JLT integration, Marsh operational excellence, and real estate exits. Employee count not disclosed.
2022-09-30restructuringin_progressGlobalInformation Technology, HR, Real EstateUSD 96 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		YTD 2022 charges of $96M for global IT/HR streamlining, JLT integration, Marsh operational excellence, and real estate exits. Employee count not disclosed.
2022-09-30divestiture_reductioncompleted2022-04-012022-04-30United StatesConsulting (Mercer)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Sale of Mercer U.S. affinity business in April 2022. Headcount impact not disclosed.
2022-09-30divestiture_reductioncompleted2022-06-012022-06-30RussiaRisk and Insurance Services, ConsultingUSD 52 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Deconsolidation of Russian businesses due to sanctions. $52M loss recorded. Headcount impact not disclosed.
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 38,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 71,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 96,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressCompany-wide (RIS $26M, Consulting $11M, Corporate $21M YTD)USD 58 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Ongoing initiatives covering global IT and HR functions, JLT integration, Marsh operational excellence, and real estate exits. Severance liability of $8 million at 2022-06-30; no employee counts disclosed.
2022-06-30divestiture_reductioncompletedUnited StatesMercer — U.S. affinity businessUSD 112 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer sold its U.S. affinity insurance marketing, brokerage and administration business in April 2022 for approximately $140 million cash, recording a $112 million net gain. No headcount figures disclosed.
2022-06-30othercompletedRussiaMarsh and Oliver WymanUSD 52 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Company deconsolidated wholly-owned Russian businesses effective end of Q1 2022 due to sanctions; recorded $52 million loss including cumulative translation losses and write-off of net assets. June 2022 definitive agreement to transfer ownership to local management pending regulatory approvals. No headcount figures disclosed.
2022-06-30restructuringin_progressGlobalCorporate; Risk and Insurance Services; ConsultingUSD 58 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six months ended 2022-06-30 charges: $26M RIS, $11M Consulting, $21M Corporate; covers IT/HR streamlining, JLT integration, Marsh operational excellence, real estate exits. No employee counts disclosed; severance liability was $8M at 2022-06-30
2022-06-30acquisition_additioncompletedUnited States; France; AustraliaRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions in H1 2022 (Heil & Kay, Regional Treaty Services, Clark Insurance, Azure Consulting, GeFi Assurances) totaling $158M consideration; no headcount added disclosed
2022-06-30divestiture_reductioncompleted2022-04-01United StatesConsulting (Mercer)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer sold U.S. affinity business for ~$140M cash proceeds with $112M net gain; no associated headcount disclosed
2022-06-30divestiture_reductioncompletedRussiaRisk and Insurance Services; ConsultingUSD 52 (millions)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Russian businesses deconsolidated Q1 2022 with $52M loss including related charges; definitive agreement to exit Russia signed June 2022 pending regulatory approvals; no headcount disclosed
2022-06-30restructuringin_progressGlobalCorporate, Risk and Insurance Services, ConsultingUSD 58 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Charges for six months ended June 30, 2022 include severance, real estate, IT, and consulting costs. Employee count not disclosed.
2022-06-30divestiture_reductioncompletedUnited StatesConsulting (Mercer)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer sold its U.S. affinity business in April 2022. Employee count not disclosed.
2022-06-30divestiture_reductioncompletedBrazilConsulting (Mercer)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer sold retirement plan administration and call center operations in Brazil. Employee count not disclosed.
2022-06-30divestiture_reductionin_progress2022-06-30RussiaRisk and Insurance Services, ConsultingUSD 52 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Company entered into definitive agreement to exit Russian businesses and transfer ownership to local management. Loss on deconsolidation recorded in Q1 2022.
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 28,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 41,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 58,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31divestiture_reductionin_progress2022-03-10RussiaMarsh and Oliver Wyman GroupUSD 52 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Company announced exit from Russia and transfer of Russian businesses to local management; deconsolidated at quarter-end due to sanctions. Total loss of $52 million including related charges ($39 million recorded in revenue), comprising cumulative translation losses and write-off of net assets. Closing subject to Russian regulatory approval. No employee count disclosed.
2022-03-31restructuringin_progressRisk and Insurance ServicesUSD 16 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2022 restructuring costs of $16 million in RIS related to global IT/HR functions, JLT integration, and Marsh operational excellence program. No employee counts disclosed.
2022-03-31restructuringin_progressConsultingUSD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2022 restructuring costs of $6 million in Consulting segment. No employee counts disclosed.
2022-03-31restructuringin_progressCorporateUSD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2022 restructuring costs of $8 million in Corporate. No employee counts disclosed.
2022-03-31divestiture_reductioncompletedBrazilMercer — retirement plan administration and call center operationsbusiness_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer sold its Brazil retirement plan administration and call center operations for cash proceeds of approximately $4 million during Q1 2022. No employee count disclosed.
2022-03-31divestiture_reductioncompleted2022-04-012022-04-01United StatesMercer — U.S. affinity businessUSD 145 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		On April 1, 2022, Mercer sold its U.S. affinity business providing insurance marketing, brokerage and administration to association and affinity groups for cash proceeds of approximately $145 million and a net gain of approximately $110 million. No employee count disclosed.
2022-03-31restructuringin_progressGlobalConsolidated (charges: $16M RIS, $6M Consulting, $8M Corporate)USD 30 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Ongoing program covering global IT and HR functions, JLT integration, Marsh operational excellence, and real estate exits. No employee counts disclosed; liability was $54M at 2022-03-31. Program began 2021, so no announcement date within the quarter.
2022-03-31divestiture_reductioncompleted2022-03-102022-03-31RussiaMarsh (RIS) and Oliver Wyman (Consulting)USD 52 (millions)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Russian businesses deconsolidated at end of Q1 2022; ownership transferring to local management, closing subject to Russian regulatory approval. Charge comprises $39M loss on deconsolidation plus related charges ($27M RIS, $12M Consulting). No headcount disclosed.
2022-03-31acquisition_additioncompleted2022-01-31United StatesRisk and Insurance Services (Marsh McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Heil & Kay Insurance Agency Inc. (January 2022); no headcount disclosed. Total Q1 2022 acquisition consideration was $28M across three deals.
2022-03-31acquisition_additioncompleted2022-02-28AustraliaConsulting (Oliver Wyman)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Oliver Wyman acquired Azure Consulting (February 2022); no headcount disclosed. Announcement date approximated to month-end since only month is stated.
2022-03-31acquisition_additioncompleted2022-03-31FranceConsulting (Mercer)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired GeFi Assurances (March 2022); no headcount disclosed. Announcement date approximated to month-end since only month is stated.
2022-03-31divestiture_reductionannounced2022-04-012022-04-01United StatesConsulting (Mercer) — U.S. affinity businesssubsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer sold its U.S. affinity insurance marketing/brokerage business for ~$145M cash proceeds with ~$110M net gain; no headcount disclosed.
2022-03-31restructuringin_progressGlobalCorporate, Risk and Insurance Services, ConsultingUSD 30 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Charges include severance, real estate, IT, and consulting costs. Employee count not disclosed.
2022-03-31divestiture_reductioncompletedRussiaRisk and Insurance Services, ConsultingUSD 52 (millions)subsequent_events
f5-10q / Qwen3.6-27B-Q8_0		Deconsolidation of Russian businesses due to sanctions. Ownership transferred to local management. Charge includes loss on deconsolidation and related charges.
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2022-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 30,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-12-31restructuringin_progress2019-04-012022GlobalRisk and Insurance Services ($53M), Consulting ($36M), Corporate ($4M) — 2021 charge splitUSD 93 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2021 charges for JLT integration and restructuring: severance $14M, real estate $26M, information technology $23M, consulting/other outside services $30M. Multi-year program: cumulative integration costs of $679M through Dec 31, 2021 (program originating with the JLT acquisition completed April 1, 2019), with remaining ~$46M expected in 2022 (~$42M cash); filer expects to complete the integration during 2022 and has realized at least $425M of annualized savings. No affected-employee counts disclosed. Also shown in MD&A restructuring-items table ($93M in 2021).
2021-12-31restructuringin_progressGlobalRisk and Insurance Services ($31M), Consulting ($12M), Corporate ($27M) — 2021 charge splitUSD 70 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2021 charges covering streamlining of global information technology and HR functions, the Marsh Centers of Excellence program, and adjustments for future rent under non-cancellable leases (includes actions initiated in 2021 and prior years; no single announcement date disclosed). Severance accrued in 2021: $24M; severance cash paid: $42M; severance liability at Dec 31, 2021: $18M (total other-restructuring liability $48M). No affected-employee counts disclosed. Also reported in MD&A as 'Restructuring costs, excluding JLT' of $70M.
2021-12-31restructuringin_progress2022-12-31GlobalEnterprise (JLT integration)USD 93 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2021 charge of $93M ($53M RIS, $36M Consulting, $4M Corporate); cumulative $679M through 2021 with $46M remaining in 2022. No employee-affected count disclosed. At least $425M of annualized savings realized.
2021-12-31restructuringin_progressGlobalEnterprise (IT/HR streamlining, Marsh Centers of Excellence, lease exits)USD 70 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2021 charge of $70M ($31M RIS, $12M Consulting, $27M Corporate), covering severance and future rent under non-cancellable leases. No employee-affected count disclosed.
2021-12-31acquisition_additioncompleted2021-12-31United States, France, IndiaRisk and Insurance Services (8 acquisitions, incl. PayneWest, Vaaler, Pelnik, SAM, Marsh India step-up to 92%)USD 1,431 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Total purchase consideration ~$1.4B (cash $888M, deferred/contingent $153M, previously-held Marsh India investment $390M). No headcount added disclosed.
2021-12-31acquisition_additioncompleted2021-11-30United States, United KingdomConsulting (Oliver Wyman Group — Huron life sciences strategy practice)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		One Consulting-segment acquisition in 2021; headcount added not disclosed.
2021-12-31divestiture_reductioncompleted2021-12-31United States, United KingdomRisk and Insurance Services (primarily U.K. commercial networks business)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cash proceeds ~$84M with net gain ~$50M recognized in 2021. Headcount removed not disclosed.
2021-12-31restructuringin_progress2022-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 93 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		JLT integration costs incurred in 2021. Total program cost $679M through 2021, with $46M remaining expected in 2022. Employee count not explicitly disclosed for 2021 actions.
2021-12-31restructuringin_progressGlobalRisk and Insurance Services; Consulting; CorporateUSD 70 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Other restructuring actions including IT/HR streamlining and real estate exits. Employee count not explicitly disclosed.
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 53,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 36,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 26,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 30,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 93,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressUSD 70,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressRisk and Insurance Services Segment [Member]USD 31,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressConsulting Segment [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressCorporate, Non-Segment [Member]USD 27,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressEmployee Severance [Member]USD 24,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-12-31restructuringin_progressOther Restructuring [Member]USD 46,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2021-09-30restructuringin_progress2021-12-31Risk and Insurance Services; ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Final stages of JLT integration; $61M of costs in the nine months ended 2021-09-30 ($19M in Q3), split $38M RIS / $21M Consulting YTD; remaining ~$77M expected substantially in 2021, ~$69M cash; no employee counts disclosed
2021-09-30restructuringin_progressGlobal information technology and HR functionsUSD 35 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs of $12M in Q3 and $35M YTD for global IT and HR functions and adjustments to restructuring liabilities for future rent under non-cancellable leases; no employee counts disclosed
2021-09-30acquisition_additioncompletedUnited StatesRisk and Insurance Services (MMA)USD 546 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Three MMA acquisitions in 2021 (PayneWest, The Pryor Group, Vaaler Insurance); total consideration $546M; no headcount added disclosed
2021-09-30divestiture_reductioncompletedUnited States; United KingdomUSD 50 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sold certain businesses in the U.S. and U.K. for ~$84M cash proceeds with ~$50M net gain, primarily the U.K. commercial networks business; no headcount removed disclosed
2021-09-30restructuringin_progress2019-042021-12-31GlobalRisk and Insurance Services and ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT integration program in final stages; $61M of costs in the nine months ended 2021-09-30 ($19M in Q3), split $38M RIS / $21M Consulting YTD. Cumulative $647M since the April 2019 acquisition. Remaining $77M expected substantially in 2021, of which ~$69M cash. Severance liability at 2021-09-30 was $10M; no employees-affected count disclosed.
2021-09-30restructuringin_progressGlobalGlobal information technology and HR functions; real estateUSD 35 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Costs of $35M for the nine months ended 2021-09-30 ($12M in Q3) for IT/HR function actions and lease-related adjustments; covers actions initiated prior to 2021. Related liability at 2021-09-30 was $46M. No employees-affected count disclosed.
2021-09-30acquisition_additioncompleted2021-04United States (Montana, Texas)Risk and Insurance Services (Marsh McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired PayneWest Insurance, Inc. and The Pryor Group, LLC in April 2021. Headcount added not disclosed; total 2021 acquisition consideration was $546M ($405M cash, $141M deferred/contingent).
2021-09-30acquisition_additioncompleted2021-09United States (North Dakota)Risk and Insurance Services (Marsh McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Vaaler Insurance, Inc. in September 2021. Headcount added not disclosed.
2021-09-30divestiture_reductioncompletedUnited States and United KingdomRisk and Insurance Services (primarily U.K. commercial networks business)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Certain businesses sold during the first nine months of 2021 for ~$84M cash proceeds with a ~$50M net gain. Headcount removed not disclosed.
2021-09-30restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services; ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in Q3 2021. Filing states company expects to incur remaining costs substantially in 2021. Employee count not disclosed for this period's activity.
2021-09-30restructuringin_progressGlobalInformation Technology; Human ResourcesUSD 35 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring costs for nine months ended Sept 30, 2021 related to global IT and HR functions. Employee count not disclosed.
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 61,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressGlobal Information Technology, HR Functions and Future Rent [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressEmployee Severance [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressOther Restructuring [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-09-30restructuringin_progressUSD 35,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progress2021-12-31Risk and Insurance Services; Consulting; CorporateUSD 42 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Final stages of JLT integration; $42 million of costs in the six months ended June 30, 2021 ($19 million in Q2). Remaining ~$97 million expected substantially in 2021, primarily real estate and technology, of which ~$86 million cash. No employee counts disclosed. Company expects at least $425 million of annualized savings.
2021-06-30restructuringin_progressGlobal information technology and HR functionsUSD 23 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs of $12 million in Q2 and $23 million in the six months ended June 30, 2021 related to global IT and HR functions and adjustments to restructuring liabilities for future rent under non-cancellable leases. No employee counts disclosed.
2021-06-30acquisition_additioncompleted2021-04-01United StatesRisk and Insurance Services (MMA)USD 505 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Two acquisitions in April 2021 (PayneWest Insurance, Inc. and The Pryor Group, LLC); total purchase consideration $505 million. No headcount figures disclosed.
2021-06-30divestiture_reductioncompletedUnited States; United KingdomUSD 50 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sold certain businesses in the U.S. and U.K. for cash proceeds of approximately $81 million; net gain of approximately $50 million, primarily the U.K. commercial networks business. No headcount figures disclosed.
2021-06-30restructuringin_progress2021-12-31GlobalEnterprise (Risk and Insurance Services, Consulting, Corporate)USD 42 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT integration and restructuring in final stages; $42M charged in six months 2021 ($19M in Q2). No employee counts disclosed. Remaining $97M of costs expected substantially in 2021, ~$86M cash. Cumulative $628M since 2019 acquisition.
2021-06-30restructuringin_progressGlobalGlobal information technology and HR functions; real estateUSD 23 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Other restructuring: $23M charged in six months 2021 ($12M in Q2) for IT/HR function actions and lease cost adjustments; no employee counts disclosed. Related liability $55M at 2021-06-30.
2021-06-30acquisition_additioncompleted2021-04-012021-06-30United States (Montana, Texas)Risk and Insurance Services (Marsh McLennan Agency)USD 505 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		April 2021 acquisitions of PayneWest Insurance and The Pryor Group; total consideration $505M ($367M cash, $138M deferred/contingent). No headcount added disclosed. Charge value is purchase consideration, not a severance charge.
2021-06-30divestiture_reductioncompleted2021-06-30United States and United KingdomRisk and Insurance Services (U.K. commercial networks business)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sold certain U.S. and U.K. businesses in first six months of 2021 for ~$81M proceeds with ~$50M net gain; no headcount removed disclosed.
2021-06-30restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 42 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in Q2 2021. Includes severance, real estate rationalization, and technology. Company expects to incur remaining costs substantially in 2021.
2021-06-30restructuringin_progressGlobalInformation Technology; Human ResourcesUSD 23 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring costs for global IT and HR functions and lease adjustments incurred in Q2 2021.
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 42,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressGlobal Information Technology, HR Functions and Future Rent [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressEmployee Severance [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressOther Restructuring [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-06-30restructuringin_progressUSD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services ($16M), Consulting ($6M), Corporate ($1M) in Q1 2021USD 23 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Final stages of JLT integration; $609M cumulative costs since April 2019 acquisition; remaining $116M expected substantially in 2021, ~$100M cash; severance, real estate and technology costs; no employee counts disclosed.
2021-03-31restructuringin_progressGlobalGlobal information technology and HR functionsUSD 11 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2021 costs relate to global IT and HR functions and adjustments to restructuring liabilities for future rent under non-cancellable leases; no employee counts disclosed.
2021-03-31acquisition_additionannounced2021-04-012021-04-01United StatesRisk and Insurance Services (MMA)USD 38 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		MMA completed acquisitions of PayneWest Insurance (Montana) and The Pryor Group (Texas) on April 1, 2021; paid $27M deferred and $11M contingent consideration related to prior-year acquisitions; no headcount figures disclosed.
2021-03-31restructuringin_progress2021-12-31GlobalEnterprise (JLT integration across Risk and Insurance Services and Consulting)USD 23 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2021 charge of $23M ($16M RIS, $6M Consulting, $1M Corporate) versus $80M in Q1 2020; $609M incurred since the April 2019 JLT acquisition. Remaining $116M expected substantially in 2021, of which about $100M cash. No employee-affected count disclosed; costs cover severance, real estate rationalization, technology, consulting and legal fees.
2021-03-31restructuringin_progressGlobalGlobal information technology and HR functions; real estateUSD 11 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2021 charge of $11M for actions initiated prior to 2021, including adjustments to restructuring liabilities for future rent under non-cancellable leases. Restructuring liability of $64M at March 31, 2021 ($21M severance, $43M future rent and other). No employee-affected count disclosed.
2021-03-31acquisition_additioncompleted2021-04-01United States (Montana and Texas)Risk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Subsequent-event acquisitions of PayneWest Insurance, Inc. and The Pryor Group, LLC completed April 1, 2021 (after quarter-end). No headcount added disclosed. No acquisitions occurred during the first three months of 2021.
2021-03-31restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 23 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in Q1 2021 were $23 million ($16M RIS, $6M Consulting, $1M Corporate). Program expected to complete substantially in 2021.
2021-03-31restructuringin_progressGlobalInformation Technology; Human ResourcesUSD 11 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring costs incurred in Q1 2021 were $11 million, associated with global IT and HR functions and lease adjustments.
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressSeverance and Future Rent [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressEmployee Severance [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressOther Restructuring [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2021-03-31restructuringin_progressUSD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-12-31restructuringin_progress2019-04-012021GlobalRisk and Insurance ServicesUSD 171 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2020 charge for the Risk and Insurance Services segment under the multi-year JLT integration and restructuring program that began at the April 1, 2019 acquisition close. Total 2020 program charges were $251M across segments, including $43M of severance; remaining $139M of program costs expected in 2021 ($134M cash). No affected-employee counts disclosed.
2020-12-31restructuringin_progress2019-04-012021GlobalConsultingUSD 51 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2020 Consulting-segment charge under the same multi-year JLT integration/restructuring program (2020 program total $251M, incl. $43M severance; $139M remaining expected in 2021).
2020-12-31restructuringin_progress2019-04-012021GlobalCorporateUSD 29 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2020 Corporate charge under the same multi-year JLT integration/restructuring program (2020 program total $251M, incl. $43M severance; $139M remaining expected in 2021).
2020-12-31restructuringcompleted2018Consulting — MercerUSD 54 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Mercer business restructuring initiated in the fourth quarter of 2018 to optimize its operating model; $54M of restructuring severance and consulting costs incurred in FY2020; filer states the initiative was completed. Affected-employee count not disclosed.
2020-12-31restructuringcompletedCorporateUSD 32 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Mixed FY2020 corporate costs: IT systems/security modernization, consulting for a Global HR function restructure, and adjustments to restructuring liabilities for future rent under non-cancellable leases. Headcount impact not quantified; no explicit completion status stated.
2020-12-31restructuringin_progress2021-12-31GlobalEnterprise (JLT integration)USD 251 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2020 charges only: $171M RIS, $51M Consulting, $29M Corporate. Remaining $139M expected in 2021 ($134M cash). No employee headcount disclosed; charges cover severance, real estate, IT, and consulting. Cumulative program since 2019.
2020-12-31restructuringin_progressGlobalEnterprise (non-JLT restructuring)USD 89 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2020 net restructuring costs excluding JLT; includes Mercer restructuring program ($54M) and Corporate IT/HR modernization ($32M). No employee headcount disclosed.
2020-12-31acquisition_additioncompleted2020-12-31United StatesRisk and Insurance Services (Marsh & McLennan Agency)USD 877 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Seven acquisitions completed in 2020 (Momentous, Ironwood, Assurance Holdings, Nico, Heritage, Inspro, Compass Financial Partners); total consideration $877M. Added ~$169M revenue and $11M operating income. No headcount added disclosed.
2020-12-31divestiture_reductioncompleted2020-12-31United States, United Kingdom, CanadaMultiplediscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Certain businesses sold during 2020 for cash proceeds of ~$98M. No headcount removed disclosed.
2020-12-31restructuringcompletedGlobalRisk and Insurance ServicesUSD 171 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in 2020. Includes severance, real estate rationalization, technology, and consulting fees.
2020-12-31restructuringcompletedGlobalConsultingUSD 51 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in 2020.
2020-12-31restructuringcompletedGlobalCorporateUSD 29 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in 2020.
2020-12-31restructuringcompletedGlobalConsultingUSD 54 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Mercer restructuring program initiated in Q4 2018, completed in 2020. Includes severance and consulting costs.
2020-12-31restructuringcompletedGlobalCorporateUSD 32 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Corporate costs to modernize information technology and other restructuring activities.
2020-12-31restructuringcompletedGlobalOtherUSD 89 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Restructuring costs excluding JLT, including severance and lease exit costs.
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 171,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 51,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 29,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 43,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 69,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 62,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 77,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 251,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressSeverance and Future Rent [Member]USD 32,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressEmployee Severance [Member]USD 39,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressOther Restructuring [Member]USD 50,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-12-31restructuringin_progressUSD 89,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2020-09-30restructuringin_progress2021-12-31GlobalRisk and Insurance Services ($125M), Consulting ($31M), Corporate ($25M)USD 181 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT integration program with total expected pre-tax costs of approximately $700 million; $335 million incurred in 2019 and $181 million in the first nine months of 2020, remainder expected in Q4 2020 and 2021. No employee counts disclosed.
2020-09-30restructuringin_progressCorporateUSD 24 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Corporate costs in 2020 for IT modernization, HR function restructuring consulting, and adjustments to restructuring liabilities for future rent under non-cancellable leases; includes a $3 million right-of-use asset impairment
2020-09-30restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance ServicesUSD 125 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2020 charge for the RIS portion of JLT integration; program-wide estimate is about $700M pre-tax with $335M incurred in 2019 and the remainder expected in Q4 2020 and 2021. No employee counts disclosed; severance liability at 2020-09-30 was $10M.
2020-09-30restructuringin_progress2019-04-012021-12-31GlobalConsultingUSD 31 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2020 charge for the Consulting portion of the same JLT integration program; no employee counts disclosed.
2020-09-30restructuringin_progress2019-04-012021-12-31GlobalCorporateUSD 25 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2020 charge for the Corporate portion of the JLT integration program; no employee counts disclosed.
2020-09-30restructuringin_progress2018GlobalRisk and Insurance Services (Marsh)USD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh programs initiated in 2018 and 2019 to simplify organization structure and rebrand businesses; nine-month 2020 severance and consulting cost. No employee counts disclosed.
2020-09-30restructuringin_progress2018GlobalConsulting (Mercer)USD 17 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer restructuring program initiated in Q4 2018 to optimize operating model; nine-month 2020 severance and consulting cost. No employee counts disclosed.
2020-09-30restructuringin_progress2020GlobalCorporateUSD 24 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Corporate 2020 costs covering IT and security modernization, consulting on the Global HR function restructure, and restructuring liability adjustments for non-cancellable lease rent; not solely workforce-related. No employee counts disclosed.
2020-09-30acquisition_additioncompleted2020-01United States (California)Risk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Momentous Insurance Brokerage Inc., a high-net-worth and entertainment-industry risk management and benefits firm. Headcount added not disclosed.
2020-09-30acquisition_additioncompleted2020-01United States (Georgia)Risk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Ironwood Insurance Services, LLC, an Atlanta-based commercial P&C, benefits and private client broker. Headcount added not disclosed.
2020-09-30acquisition_additioncompleted2020-04United States (Illinois)Risk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Assurance Holdings, Inc., a full-service independent brokerage agency. Headcount added not disclosed.
2020-09-30acquisition_additioncompleted2020-06United States (California)Risk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Nico Insurance Services, Inc., an employee benefits agency. Headcount added not disclosed.
2020-09-30divestiture_reductioncompletedUnited States, United Kingdom, CanadaMultiple businessesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Certain businesses sold during the nine months ended 2020-09-30 for about $93 million cash proceeds; no material dispositions in Q3 specifically. Exact timing within the period and headcount removed not disclosed.
2020-09-30restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 181 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring. $181M incurred in first nine months of 2020 ($125M RIS, $31M Consulting, $25M Corporate). Includes severance, real estate, IT, and consulting costs. Expected remaining costs in Q4 2020 and 2021.
2020-09-30restructuringin_progress2018-10-01GlobalMarsh; Mercer; CorporateUSD 43 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring programs initiated in 2018/2019. $43M incurred in first nine months of 2020 ($2M Marsh, $17M Mercer, $24M Corporate). Includes severance, consulting, and IT modernization.
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 181,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 125,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 31,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 25,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 38,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 42,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 45,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 56,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 181,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressSeverance and Consulting Costs [Member] / Marsh Insurance Group [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressCorporate, Non-Segment [Member] / Cost To Modernize IT Systems And Security Protocols, Consulting Costs, And Adjustments To Restructuring Liabilities [Member]USD 24,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressEmployee Severance [Member]USD 15,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressOther Restructuring [Member]USD 28,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-09-30restructuringin_progressUSD 43,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progress2021-12-31GlobalRisk and Insurance Services, Consulting, CorporateUSD 700 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT integration program with estimated total pre-tax costs of ~$700 million (~$625 million cash); $335 million incurred in 2019, $137 million in H1 2020 (RIS $100M, Consulting $17M, Corporate $20M), remainder mostly in 2020 with modest amount in 2021. Severance and related costs included in compensation and benefits; no employee counts disclosed.
2020-06-30restructuringin_progressUnited StatesMarshUSD 2 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh programs initiated in 2018-2019 to simplify organization structure and realign/rebrand businesses; severance and consulting costs of $2 million in H1 2020. No employee counts disclosed.
2020-06-30restructuringin_progressMercerUSD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer restructuring program initiated Q4 2018 to optimize operating model; severance and consulting costs of $6 million in H1 2020. No employee counts disclosed.
2020-06-30restructuringin_progressCorporateUSD 12 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Corporate costs of $12 million in 2020 for consulting related to Global HR function restructuring and adjustments to restructuring liabilities for future rent under non-cancellable leases; includes an $11 million ROU asset impairment charge in Q2 2020.
2020-06-30restructuringin_progress2021-12-31GlobalRisk and Insurance ServicesUSD 100 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT integration and restructuring charges for six months ended 2020-06-30; no employee counts disclosed. No announcement date stated; program stems from JLT Transaction completed 2019-04-01. Severance liability at 2020-06-30 was $15M company-wide.
2020-06-30restructuringin_progress2021-12-31GlobalConsultingUSD 17 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sub-component of JLT integration program; charges for six months ended 2020-06-30. No employee counts disclosed.
2020-06-30restructuringin_progress2021-12-31GlobalCorporateUSD 20 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sub-component of JLT integration program; charges for six months ended 2020-06-30. Program total estimated at ~$700M ($335M incurred 2019, $137M in 1H2020, ~$228M remaining); most remaining costs expected in next two quarters of 2020, remainder in 2021. No employee counts disclosed.
2020-06-30restructuringin_progressGlobalMarshUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance and consulting costs for six months ended 2020-06-30 for Marsh organization simplification and rebranding programs initiated in 2018-2019. No employee counts disclosed.
2020-06-30restructuringin_progressGlobalMercerUSD 6 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance and consulting costs for six months ended 2020-06-30 for Mercer restructuring program initiated in Q4 2018. No employee counts disclosed.
2020-06-30restructuringin_progressGlobalCorporateUSD 12 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		2020 Corporate costs covering Global HR function restructure consulting plus restructuring liability adjustments for future lease rent; not purely severance. A separate $11M right-of-use asset impairment was recorded in Q2 2020 on sublease assumption review. No employee counts disclosed.
2020-06-30restructuringin_progress2021-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 137 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring. $137M incurred in first six months of 2020 ($100M RIS, $17M Consulting, $20M Corporate). Includes severance, real estate, IT, and consulting costs. Most remaining costs expected in 2020 with modest amount in 2021.
2020-06-30restructuringin_progressGlobalMarsh; Mercer; CorporateUSD 20 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring initiatives initiated prior to 2020. $20M accrued in first six months of 2020 ($2M Marsh, $6M Mercer, $12M Corporate). Includes severance and consulting costs.
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 137,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 100,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 20,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 29,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 31,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 37,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 40,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 137,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressSeverance and Consulting Costs [Member] / Marsh Insurance Group [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressCorporate, Non-Segment [Member] / Consulting Costs And Adjustments To Restructuring Liabilities For Future Rent Under Non-Cancellable Leases [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressEmployee Severance [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressOther Restructuring [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-06-30restructuringin_progressUSD 20,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progress2021-12-31GlobalCompany-wide (JLT integration)USD 80 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2020 charge of $80M ($61M Risk and Insurance Services, $10M Consulting, $9M Corporate); total program cost estimated at ~$700M with $335M incurred in 2019; remaining costs mostly in 2020 with modest amount in 2021; no employee counts disclosed
2020-03-31restructuringin_progressUnited StatesMarsh; Mercer; CorporateUSD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2020 charges of $2M (Marsh organization simplification), $4M (Mercer business restructuring initiated Q4 2018), and $3M (Corporate severance and future rent under non-cancelable leases); no employee counts disclosed
2020-03-31restructuringin_progress2019-04-012021GlobalEnterprise-wide (Risk and Insurance Services, Consulting, Corporate)USD 80 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT integration program: $80M charge in Q1 2020 ($61M RIS, $10M Consulting, $9M Corporate), of which severance and related costs sit in compensation and benefits. Total program estimated at $700M pre-tax (~$625M cash); $335M incurred in 2019, ~$285M projected remaining, most in the balance of 2020 with a modest amount in 2021. Run-rate savings target of at least $350M. No number of employees affected is disclosed.
2020-03-31restructuringin_progress2018GlobalMarsh, Mercer, CorporateUSD 9 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Legacy programs: Marsh organization simplification ($2M), Mercer business restructuring ($4M) and Corporate severance/future rent ($3M) in Q1 2020. Restructuring liability of $68M at March 31, 2020. No number of employees affected is disclosed.
2020-03-31acquisition_additioncompleted2020-01United StatesRisk and Insurance Services (Marsh & McLennan Agency)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Two Q1 2020 acquisitions: Momentous Insurance Brokerage (California) and Ironwood Insurance Services (Georgia). Total consideration $245M ($201M cash plus $44M deferred/contingent). Acquired headcount not disclosed.
2020-03-31acquisition_additionannounced2020-04-012020-04-01United StatesRisk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA completed the acquisition of Assurance Holdings, Inc. (Illinois-based brokerage) on April 1, 2020, after the quarter close. Acquired headcount not disclosed.
2020-03-31restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services, Consulting, CorporateUSD 80 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring. Q1 2020 charges: $61M RIS, $10M Consulting, $9M Corporate. Total expected costs ~$700M. Most remaining costs expected in 2020, modest amount in 2021.
2020-03-31restructuringin_progress2018-01-01GlobalMarsh, Mercer, CorporateUSD 9 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring (Marsh simplification/rebranding, Mercer optimization, Corporate). Q1 2020 charges: $2M Marsh, $4M Mercer, $3M Corporate.
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 80,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 61,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 23,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 21,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 20,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 80,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressSeverance and Consulting Costs [Member] / Marsh Insurance Group [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressCorporate, Non-Segment [Member] / Severance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressEmployee Severance [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2020-03-31restructuringin_progressUSD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-12-31restructuringin_progress2019-04-012021GlobalRisk and Insurance ServicesUSD 229 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Segment allocation of 2019 JLT integration and restructuring charges. Date reflects the JLT Transaction close that initiated the integration; no separate program announcement date disclosed. Program-level 2019 charges of $335M comprised severance $154M, real estate $38M, IT $45M, consulting/other outside services $98M, within an expected program of approximately $700M (about $625M cash), with remaining costs expected mostly in 2020 and the remainder in 2021.
2019-12-31restructuringin_progress2019-04-012021GlobalConsultingUSD 18 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Segment allocation of 2019 JLT integration and restructuring charges; same program as the Risk and Insurance Services and Corporate components (program total $335M in 2019 of an expected ~$700M).
2019-12-31restructuringin_progress2019-04-012021GlobalCorporateUSD 88 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Corporate allocation of 2019 JLT integration and restructuring charges; same program as the RIS and Consulting components (program total $335M in 2019 of an expected ~$700M). 2019 JLT severance charges of $154M with a severance liability of $42M remaining at December 31, 2019.
2019-12-31restructuringcompleted2019-12-31Marsh (Risk and Insurance Services)USD 34 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Severance and consulting costs from programs initiated during 2018 and 2019 to simplify organization structure and realign and rebrand certain businesses. One of three components (Marsh $34M, Mercer $56M, Corporate $22M) of 2019 restructuring costs excluding JLT of $112M; programs substantially completed as of December 31, 2019. Legacy restructuring liability at year-end 2019 was $102M ($51M severance; $51M future rent/other).
2019-12-31restructuringcompleted2019-12-31Mercer (Consulting)USD 56 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Severance and consulting costs in 2019 from a program initiated in the fourth quarter of 2018 to restructure Mercer's operating model. One of three components of 2019 restructuring costs excluding JLT of $112M; substantially completed as of December 31, 2019.
2019-12-31restructuringcompleted2019-12-31CorporateUSD 22 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Primarily future rent under non-cancelable leases. One of three components of 2019 restructuring costs excluding JLT of $112M; substantially completed as of December 31, 2019.
2019-12-31acquisition_additioncompleted10,0002018-09-182019-04-01Global - JLT operated in 41 countriesRisk and Insurance Services (JLT Specialty combined into Marsh; JLT Reinsurance into Guy Carpenter) and Consulting (majority of JLT Employee Benefits into Mercer Health and Wealth)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		Filer states the Transaction added over 10,000 colleagues; value recorded as the disclosed floor. Acquisition of Jardine Lloyd Thompson Group plc completed April 1, 2019 (approximately $5.6B equity value). Announcement date per Exhibit 2.2 (Rule 2.7 Announcement dated September 18, 2018).
2019-12-31acquisition_additioncompleted10,0002018-09-182019-04-01Global (41 countries, incl. U.K., Asia, Pacific, U.S.)Company-wide (JLT Specialty into Marsh; JLT Reinsurance into Guy Carpenter; JLT Employee Benefits into Mercer)USD 5,568 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Filer states the transaction added over 10,000 colleagues; charge shown is total JLT cash consideration, not a workforce charge
2019-12-31restructuringin_progress2019-04-012021-12-31GlobalCompany-wide (RIS $229M, Consulting $18M, Corporate $88M of 2019 charges)USD 335 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		JLT integration program; $335M charged in FY2019 (severance $154M, real estate $38M, IT $45M, consulting/other $98M) of an estimated $700M total program, most remaining cost in 2020 with a modest amount in 2021; $265M cash paid in 2019; employees affected not disclosed
2019-12-31restructuringcompleted2018-10-012019-12-31GlobalMarshUSD 34 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Marsh program to simplify organization structure and realign/rebrand businesses; FY2019 severance and consulting costs; announcement date approximate (program initiated during 2018)
2019-12-31restructuringcompleted2018-10-012019-12-31GlobalMercer (Consulting)USD 56 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Mercer restructuring initiated in Q4 2018 to optimize operating model; FY2019 severance and consulting costs; announcement date approximate
2019-12-31restructuringcompleted2018-10-012019-12-31GlobalCorporateUSD 22 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Primarily future rent under non-cancelable leases; programs substantially completed as of 2019-12-31; announcement date approximate
2019-12-31divestiture_reductioncompleted2019-04-012019-06-01GlobalRisk and Insurance Services (JLT global aerospace business)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Divested as part of European Commission approval of the JLT Transaction; $165M cash proceeds plus ~$65M contingent consideration; headcount not disclosed
2019-12-31divestiture_reductioncompleted2019-07-012019-09-30United StatesRisk and Insurance Services (Marsh U.S. Specialty) and Consulting (Mercer U.S. large market health and defined benefit)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Two business sales completed in Q3 2019 for ~$60M cash proceeds; announcement date approximate (only quarter disclosed); headcount not disclosed
2019-12-31acquisition_additionannounced2020-01-312020-01-31United States (California and Georgia)Risk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Momentous Insurance Brokerage and Ironwood Insurance Services during January 2020, after fiscal year-end; announcement date approximate (only month disclosed); headcount not disclosed
2019-12-31acquisition_additioncompleted10,0002019-04-012019-04-01GlobalRisk and Insurance Services; ConsultingItem 5. Acquisitions and Dispositions
f5-10k / Qwen3.6-27B-Q8_0		Acquisition of Jardine Lloyd Thompson Group plc (JLT). Text states 'addition of over 10,000 colleagues'.
2019-12-31restructuringin_progress2019-04-012021-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 335 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		JLT integration and restructuring costs incurred in 2019. Total expected pre-tax charges $700 million. Includes staff reductions, lease exit costs, consulting, and legal fees. Employee count not explicitly disclosed for the reduction component.
2019-12-31restructuringcompleted2019-01-012019-12-31GlobalRisk and Insurance Services; Consulting; CorporateUSD 112 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Restructuring costs excluding JLT. Includes severance and related charges from restructuring activities. Employee count not explicitly disclosed.
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 229,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 88,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 154,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 38,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 45,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 98,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 335,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressSeverance and Future Rent [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressEmployee Severance [Member]USD 73,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressOther Restructuring [Member]USD 39,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-12-31restructuringin_progressUSD 112,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2019-09-30acquisition_additioncompleted2019-04-01Global (41 countries; significant revenue in UK, Pacific, Asia, US)Risk and Insurance Services (Marsh, Guy Carpenter); Consulting (Mercer)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT acquisition completed April 1, 2019; filing states the transaction added over 10,000 colleagues providing deeper industry expertise. No precise headcount figure disclosed.
2019-09-30restructuringin_progress2019-04-01GlobalRIS, Consulting and Corporate (severance, real estate rationalization, technology, consulting and legal fees)USD 375 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT integration and restructuring program expected to cost at least $375 million over three years; $192 million incurred to date ($77 million in Q3 2019). Severance liability of $33 million at 9/30/19. Company targets at least $250 million of cost savings over three years. No employee counts disclosed.
2019-09-30restructuringin_progress2018-04-01GlobalMarsh (all segments)USD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh program to simplify organization through reduced management layers; $6 million of severance and consulting costs incurred in the nine months ended September 30, 2019. No employee counts disclosed.
2019-09-30restructuringin_progress2018-10-01GlobalMercer (Consulting)USD 43 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer business restructuring initiated Q4 2018; $10 million (Q3) and $43 million (nine months) of severance and consulting costs in 2019. No employee counts disclosed.
2019-09-30divestiture_reductioncompleted2019-06-012019-06-01GlobalGuy Carpenter (JLT aerospace business)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT global aerospace business divested June 1, 2019 for $165 million cash plus ~$65 million contingent consideration; required by European Commission approval. Headcount impact not disclosed.
2019-09-30divestiture_reductioncompleted2019-07-012019-09-30United StatesMarsh (U.S. Specialty business) and Mercer (U.S. large market health and defined benefit business)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2019 sales of a U.S. Specialty business at Marsh and a U.S. large market health/defined benefit business at Mercer for combined cash proceeds of approximately $60 million. Headcount impact not disclosed.
2019-09-30acquisition_additioncompleted2019-04-012019-04-01Global (41 countries)Risk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT acquisition added over 10,000 colleagues; JLT Specialty folded into Marsh, JLT Reinsurance into Guy Carpenter, JLT Employee Benefits into Mercer.
2019-09-30restructuringin_progress2019-04-012022-03-31GlobalEnterprise-wide (JLT integration)USD 375 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT integration and restructuring program; at least $375M expected over three years, $192M incurred through 2019-09-30. Severance, real estate rationalization, technology, consulting, and legal fees. No employee count disclosed.
2019-09-30restructuringin_progress2018-04-012019-12-31GlobalRisk and Insurance Services (Marsh)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh organizational simplification program initiated Q2 2018; $6M severance and consulting costs incurred in nine months ended 2019-09-30. No employee count disclosed.
2019-09-30restructuringin_progress2018-10-012019-12-31GlobalConsulting (Mercer)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer restructuring program initiated Q4 2018; $43M severance and consulting costs incurred in nine months ended 2019-09-30. No employee count disclosed.
2019-09-30divestiture_reductioncompleted2019-06-012019-06-01GlobalRisk and Insurance Services (JLT aerospace business)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		JLT global aerospace business divested as required for European Commission approval of JLT Transaction; $165M cash proceeds. No employee count disclosed.
2019-09-30divestiture_reductioncompleted2019-07-012019-09-30United StatesRisk and Insurance Services (Marsh U.S. Specialty); Consulting (Mercer U.S. large market health and defined benefit)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of a U.S. Specialty business at Marsh and a U.S. large market health and defined benefit business at Mercer for approximately $60M cash proceeds. No employee count disclosed.
2019-09-30restructuringin_progress2019-04-01GlobalRisk and Insurance Services; Consulting; CorporateUSD 192 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring. Expected total costs at least $375 million over three years. $192 million incurred to date (9 months ended Sept 30, 2019). Includes severance, real estate rationalization, technology, and consulting fees. Employee count not disclosed.
2019-09-30restructuringin_progress2018-06-01GlobalMarsh; Mercer; CorporateUSD 56 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Other restructuring programs (Marsh simplification, Mercer optimization, Corporate). $56 million incurred in 9 months ended Sept 30, 2019. Programs substantially completed. Employee count not disclosed.
2019-09-30acquisition_additioncompleted10,0002019-04-01GlobalRisk and Insurance Services; ConsultingMD&A
f5-10q / Qwen3.6-27B-Q8_0		Acquisition of Jardine Lloyd Thompson Group plc (JLT). MD&A states 'addition of over 10,000 colleagues'.
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 77,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 58,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 92,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 21,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Information Technology [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 70,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 192,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressSeverance and Consulting Costs [Member] / Risk and Insurance Services Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressCorporate, Non-Segment [Member] / Severance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressEmployee Severance [Member]USD 44,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressOther Restructuring [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-09-30restructuringin_progressUSD 56,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30acquisition_additioncompleted10,0002019-04-012019-04-01Global (41 countries; significant revenue in UK, Pacific, Asia, US)Risk and Insurance Services (Marsh, Guy Carpenter) and Consulting (Mercer)USD 5,925 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT acquisition completed April 1, 2019; filing states the transaction added over 10,000 colleagues. JLT Specialty combined into Marsh, JLT Reinsurance into Guy Carpenter, and most of JLT Employee Benefits into Mercer Health and Wealth. Total purchase consideration $5,925 million.
2019-06-30restructuringin_progress2019-04-012021-12-31GlobalRIS $95M, Consulting $5M, Corporate $34M (six months)USD 134 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		JLT integration and restructuring: combining business practices, collocating colleagues, real estate rationalization, systems migration. Total expected costs approximately $375 million, roughly half in 2019 with remainder over next two years. Expected annualized cost savings of approximately $250 million ($75M in 2019, $175M in 2020, full $250M in 2021). Costs incurred: $98M in Q2 2019 and $134M in six months ended June 30, 2019. Severance liability at June 30, 2019: $46 million; consulting and other outside services liability: $28 million.
2019-06-30restructuringin_progress2018-04-012019-06-30GlobalMarshUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh program initiated Q2 2018 to simplify organization through reduced management layers and more common structures across regions and businesses. Costs of $2 million (three months) and $7 million (six months) ended June 30, 2019. Program substantially completed as of June 30, 2019.
2019-06-30restructuringin_progress2018-10-012019-06-30GlobalMercerUSD 32 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer program initiated Q4 2018 to restructure its business toward a more fluid and nimble operating model. Costs of $22 million (three months) and $32 million (six months) ended June 30, 2019. Program substantially completed as of June 30, 2019.
2019-06-30restructuringin_progress2019-01-012019-06-30Primarily CorporateCorporateUSD 5 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Additional $5 million of restructuring costs related to severance and future rent under non-cancelable leases, primarily in Corporate, in the six months ended June 30, 2019.
2019-06-30divestiture_reductioncompleted2019-06-012019-06-01GlobalJLT aerospace business (Risk and Insurance Services)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Disposition of JLT's global aerospace business completed June 1, 2019 for cash proceeds of $165 million plus contingent consideration receivable of approximately $65 million; divested as a condition of European Commission approval of the JLT Transaction. Headcount removed not disclosed.
2019-06-30acquisition_additioncompleted10,0002019-04-012019-04-01Global (JLT operated in 41 countries)Risk and Insurance Services and Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Filer states the JLT acquisition added 'over 10,000 colleagues'; value recorded as the stated lower bound, not an exact count. JLT businesses folded into Marsh, Guy Carpenter and Mercer effective 2019-04-01.
2019-06-30restructuringin_progress2021-12-31GlobalEnterprise-wide (JLT integration: severance, real estate rationalization, technology)USD 134 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		No employee counts disclosed; severance liability roll-forward shows $73M accrued and $27M paid through 2019-06-30. Charge shown is six-month total ($98M in Q2). Total program estimated at ~$375M, roughly half expected in 2019 with the remainder evenly over the following two years; no explicit announcement date stated.
2019-06-30restructuringcompleted2019-06-30GlobalMarsh (organizational simplification) and Mercer (operating model restructuring), plus CorporateUSD 44 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		No employee counts disclosed; severance liability at 2019-06-30 was $72M total across programs. Charge shown is six-month total ($26M in Q2). Filer states these legacy programs were substantially completed as of 2019-06-30.
2019-06-30divestiture_reductioncompleted2019-06-01GlobalRisk and Insurance Services (JLT global aerospace business)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Aerospace business divested as a condition of European Commission approval of the JLT Transaction; cash proceeds $165M plus ~$65M contingent consideration. No headcount associated with the divestiture is disclosed.
2019-06-30restructuringin_progress2019-04-012021-12-31GlobalCorporate / All SegmentsUSD 375 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		JLT integration and restructuring program. Expected costs of $375 million primarily related to severance, real estate rationalization, and technology. Half expected in 2019, remainder evenly over next two years. Employee count not disclosed.
2019-06-30restructuringin_progress2018-04-01GlobalRisk and Insurance ServicesUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh simplification program initiated Q2 2018. $7 million incurred in first six months of 2019. Employee count not disclosed.
2019-06-30restructuringin_progress2018-10-01GlobalConsultingUSD 32 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer restructuring program initiated Q4 2018. $32 million incurred in first six months of 2019. Employee count not disclosed.
2019-06-30acquisition_additioncompleted10,0002019-04-012019-04-01GlobalAll SegmentsMD&A
f5-10q / Qwen3.6-27B-Q8_0		Acquisition of Jardine Lloyd Thompson Group plc completed April 1, 2019. MD&A states 'addition of over 10,000 colleagues'.
2019-06-30restructuringin_progressSeverance and Consulting Costs [Member] / Risk and Insurance Services Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 22,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressCorporate, Non-Segment [Member] / Severance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressEmployee Severance [Member]USD 38,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressOther Restructuring [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressUSD 44,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 98,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 75,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Employee Severance [Member]USD 73,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Real Estate Related Costs [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Legal, Consulting and Other Outside Services [Member]USD 61,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-06-30restructuringin_progressJardine Lloyd Thompson Group plc [Member]USD 134,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progress2018-04-01Risk and Insurance Services (Marsh)USD 5 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh program to simplify organization through reduced management layers; Q1 2019 severance and consulting costs of $5 million.
2019-03-31restructuringin_progress2018-10-01Consulting (Mercer)USD 10 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Mercer program to restructure its business and optimize its operating model; Q1 2019 severance and consulting costs of $10 million.
2019-03-31restructuringin_progressCorporateUSD 3 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Additional restructuring costs for severance and future rent under non-cancelable leases, primarily in Corporate.
2019-03-31restructuringin_progress2019-01-01Risk and Insurance Services ($19 million) and Corporate ($1 million)USD 20 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Restructuring program initiated in anticipation of the JLT acquisition; costs included in compensation and benefits. Integration plans for combined MMC and JLT operations to be initiated in Q2 2019.
2019-03-31acquisition_additioncompleted2019-04-012019-04-01United Kingdom / globalRisk and Insurance Services and Consultingsubsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Acquisition of Jardine Lloyd Thompson Group plc completed April 1, 2019 for approximately £4.3 billion ($5.6 billion) plus assumed debt of approximately $1 billion; no headcount figures disclosed.
2019-03-31restructuringin_progress2018GlobalRisk and Insurance Services (Marsh)USD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q2 2018 to reduce management layers and standardize structures across regions and businesses. Charge shown is Q1 2019 severance and consulting cost only, not total program cost. No employee count or completion date disclosed; total restructuring liability across all programs was $111M at 2019-03-31.
2019-03-31restructuringin_progress2018GlobalConsulting (Mercer)USD 10 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q4 2018 to optimize Mercer's operating model. Charge shown is Q1 2019 restructuring severance and consulting costs only. No employee count or completion date disclosed.
2019-03-31restructuringin_progress2018GlobalCorporateUSD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2019 costs covering severance plus future rent on non-cancelable leases, primarily in Corporate. No employee count disclosed.
2019-03-31restructuringin_progress2019GlobalRisk and Insurance ServicesUSD 19 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program initiated in Q1 2019 in anticipation of the JLT acquisition closing 2019-04-01. Filer presents the $20M total Q1 charge split by segment (RIS $19M, Corporate $1M); no employee counts disclosed. Costs recorded in compensation and benefits.
2019-03-31restructuringin_progress2019GlobalCorporateUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Corporate component of the $20M Q1 2019 JLT-related restructuring charge; shares announcement timing with the RIS component. No employee count disclosed.
2019-03-31acquisition_additioncompleted2019-04-01Global (UK-domiciled target)Not specifiedsubsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Jardine Lloyd Thompson Group plc completed 2019-04-01, after quarter end; £19.15 cash per share valuing share capital at ~£4.3 billion (~$5.6 billion) plus ~$1 billion of assumed JLT debt. No headcount added disclosed; JLT results excluded from pro-forma information.
2019-03-31restructuringannounced2019-04-26GlobalCombined MMC and JLT operationsMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Announcement date is the 10-Q filing date. MD&A states plans for integration and restructuring of combined MMC and JLT operations worldwide were still being completed, with actions expected to begin in Q2 2019. No employee count, charge, or completion date disclosed.
2019-03-31restructuringin_progress2018-04-01GlobalRisk and Insurance Services (Marsh)USD 5 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh initiative to simplify organization through reduced management layers. Q1 2019 incurred $5M in severance and consulting costs.
2019-03-31restructuringin_progress2018-10-01GlobalConsulting (Mercer)USD 10 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer initiative to restructure business for more fluid operating model. Q1 2019 incurred $10M in severance and consulting costs.
2019-03-31restructuringin_progress2019-01-01GlobalCorporateUSD 3 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Corporate restructuring costs related to severance and future rent under non-cancelable leases.
2019-03-31restructuringin_progress2019-01-01GlobalRisk and Insurance Services / CorporateUSD 20 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		JLT-related restructuring initiated in anticipation of acquisition. $19M in RIS and $1M in Corporate. Costs included in compensation and benefits.
2019-03-31restructuringin_progressUSD 38,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressCorporate, Non-Segment [Member] / Jardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressCorporate, Non-Segment [Member] / Severance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member]USD 20,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressJardine Lloyd Thompson Group plc [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressSeverance and Consulting Costs [Member] / Risk and Insurance Services Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressSeverance and Consulting Costs [Member] / Mercer Consulting Group [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressEmployee Severance [Member]USD 37,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2019-03-31restructuringin_progressOther Restructuring [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-12-31restructuringin_progress2018Global (Marsh operations across regions and businesses)Risk and Insurance Services — MarshUSD 96 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Program initiated in the second quarter of 2018 to simplify the organization through reduced management layers and more common structures across regions and businesses; $96 million of severance and consulting costs incurred through December 31, 2018; headcount affected not disclosed.
2018-12-31restructuringin_progress2018Not specified (Mercer operates in 43 countries)Consulting — MercerUSD 51 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Program initiated in the fourth quarter of 2018 to optimize Mercer's operating structure and model; $51 million of severance and consulting costs incurred through December 31, 2018, with approximately $20–30 million of additional costs expected in 2019; headcount affected not disclosed. Company-wide 2018 restructuring expense totaled $161 million (including $14 million of other severance and future-rent costs across RIS $3M, Consulting $1M, Corporate $10M), with a $112 million restructuring liability at year-end per the Note 14 roll-forward.
2018-12-31acquisition_additionannounced10,0002018-09-182019Global — UK-based target with operations in the U.K., Asia, South America and AustraliaRisk and Insurance Services and Consulting (insurance, reinsurance and employee benefits broking)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		Recommended cash acquisition of Jardine Lloyd Thompson Group plc at £19.15 per share, valuing JLT at approximately £4.3 billion (~$5.6 billion); JLT disclosed with approximately 10,000 colleagues and ~$2 billion annual revenue — this headcount would be added upon closing. Shareholder approval received November 7, 2018; completion expected in spring 2019, subject to High Court sanction and antitrust/regulatory approvals, and no later than December 31, 2019.
2018-12-31restructuringin_progressGlobalRisk and Insurance Services (Marsh)USD 96 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Marsh simplification program initiated in Q2 2018 (exact date not disclosed) to reduce management layers and standardize structures; $96M of severance and consulting costs incurred through 2018-12-31, with a remaining restructuring liability at year-end.
2018-12-31restructuringin_progressGlobalConsulting (Mercer)USD 51 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Mercer business restructuring initiated in Q4 2018 (exact date not disclosed); $51M of severance and consulting costs incurred through 2018-12-31. Company expects an additional $20-30M of costs in 2019.
2018-12-31restructuringin_progressGlobalRisk and Insurance Services ($3M); Consulting ($1M); Corporate ($10M)USD 14 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Other 2018 restructuring costs for severance and future rent on non-cancelable leases, separate from the Marsh and Mercer initiatives. Total 2018 net restructuring costs were $161M per the Five-Year Statistical Summary.
2018-12-31acquisition_additioncompletedUnited States; internationalRisk and Insurance Servicesbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Twelve acquisitions completed during 2018 (MMA, Marsh and Guy Carpenter entities); acquired headcount not disclosed. Total 2018 purchase consideration was approximately $1.04 billion.
2018-12-31acquisition_additioncompletedUnited Kingdom; France; Australia; India; Canada; United StatesConsultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Eight acquisitions completed during 2018 (Oliver Wyman and Mercer entities); acquired headcount not disclosed.
2018-12-31divestiture_reductioncompleted2018-092018-09Not disclosedRisk and Insurance Services (risk management software and services business)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Marsh completed the sale of a risk management software and services business in September 2018, generating a pre-tax gain of $46M; employees transferred not disclosed.
2018-12-31acquisition_additionannounced10,0002018-09-18United Kingdom (global operations)Risk and Insurance Services and employee benefits brokeragesubsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Pending cash acquisition of JLT, announced 2018-09-18 and approved by JLT shareholders 2018-11-07; JLT has approximately 10,000 colleagues and about $2 billion of annual revenue. Expected to complete in spring 2019 (no exact date given); consideration approximately £4.3 billion (~$5.6 billion). Count reflects target headcount, not MMC headcount.
2018-12-31restructuringin_progress2018-04-01GlobalRisk and Insurance ServicesUSD 96 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Marsh simplification initiative; incurred $96 million in restructuring severance and consulting costs.
2018-12-31restructuringin_progress2018-10-01GlobalConsultingUSD 51 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Mercer business restructuring; incurred $51 million in costs. Additional costs of $20-30 million expected in 2019.
2018-12-31restructuringin_progressUSD 161,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressSeverance and Future Rent [Member]USD 14,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressEmployee Severance [Member]USD 137,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-12-31restructuringin_progressOther Restructuring [Member]USD 24,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2018-09-30restructuringin_progress2018-04-01Risk and Insurance Services (Marsh)USD 84 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh simplification initiative begun Q2 2018 to reduce management layers; $84M severance and consulting costs incurred through September 30, 2018, with approximately $20M additional expected. No employee count disclosed.
2018-09-30restructuringin_progressRisk and Insurance Services, Consulting, CorporateUSD 11 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Separate $11M of restructuring costs for severance and future rent under non-cancelable leases, split RIS $3M, Consulting $1M, Corporate $7M. No employee count disclosed.
2018-09-30acquisition_additioncompletedRisk and Insurance Services (Marsh, MMA, Guy Carpenter)USD 661 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Eight RIS acquisitions completed in first nine months of 2018 (total consideration $661M); no headcount figures disclosed for acquired employees.
2018-09-30acquisition_additioncompletedConsulting (Oliver Wyman, Mercer)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Five Consulting acquisitions completed in first nine months of 2018; no headcount figures disclosed for acquired employees.
2018-09-30divestiture_reductioncompleted2018-09-012018-09-30Risk and Insurance Services (Marsh)USD 46 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh sold a risk management software and services business in September 2018, pre-tax gain of $46M; no headcount figures disclosed.
2018-09-30restructuringin_progressGlobalRisk and Insurance Services (Marsh)USD 84 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh simplification program initiated during Q2 2018 (exact announcement date not disclosed) to reduce management layers and align with segmentation strategy. $84M severance and consulting costs incurred through 2018-09-30; MD&A states approximately $20M of additional costs expected. No employee count or completion date disclosed.
2018-09-30restructuringin_progress2018-04-01GlobalRisk and Insurance Services (Marsh)USD 84 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh initiated a program to simplify the organization through reduced management layers. Incurred $84 million in severance and consulting costs as of Sept 30, 2018. Expected to incur additional costs of approx $20 million. Employee count not disclosed.
2018-09-30restructuringin_progressGlobalRisk and Insurance Services, Consulting, CorporateUSD 11 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Additional restructuring costs of $11 million related to severance and future rent under non-cancelable leases. Breakdown: R&I Services $3M, Consulting $1M, Corporate $7M. Employee count not disclosed.
2018-09-30restructuringin_progressUSD 95,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressSeverance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressEmployee Severance [Member]USD 78,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-09-30restructuringin_progressOther Restructuring [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progress2018-06-30Marsh (Risk and Insurance Services)USD 55 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh simplification initiative to reduce management layers and align with segmentation strategy; $55 million of severance and consulting costs incurred in Q2 2018, with additional expected costs of approximately $25-45 million
2018-06-30restructuringin_progress2018-06-30Risk and Insurance Services, Consulting, and CorporateUSD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Separate $9 million of restructuring costs for severance and future rent under non-cancelable leases, split $3 million Risk and Insurance Services, $1 million Consulting, $5 million Corporate
2018-06-30acquisition_additionannounced5302018-06-252018-09-30United States (Houston, Texas)Risk and Insurance Services (Marsh)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Agreement to acquire Wortham Insurance, an independent insurance broker with more than $130 million of revenue and 530 colleagues; expected to close in Q3 2018
2018-06-30restructuringin_progressGlobalRisk and Insurance Services — MarshUSD 55 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh simplification program initiated in Q2 2018: fewer management layers and more common structures across regions; charge covers severance and consulting costs. No employee count disclosed; further costs of roughly $25-45 million expected. Restructuring raised underlying segment expenses by about 4% in the quarter.
2018-06-30restructuringin_progressGlobalRisk and Insurance Services ($3M), Consulting ($1M), Corporate ($5M)USD 9 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Other restructuring costs incurred in Q2 2018 for severance and future rent on non-cancelable leases; no employee count disclosed. Total restructuring liability was $87 million at June 30, 2018.
2018-06-30restructuringin_progress2018-06-30GlobalRisk and Insurance ServicesUSD 55 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh initiated a program to simplify the organization through reduced management layers. Incurred $55 million in severance and consulting costs in Q2 2018. Expected additional costs of $25-45 million.
2018-06-30restructuringin_progress2018-06-30GlobalCorporate and OtherUSD 9 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Incurred $9 million in restructuring costs related to severance and future rent under non-cancelable leases across Risk and Insurance Services, Consulting, and Corporate.
2018-06-30acquisition_additioncompleted5302018-06-252018-09-30United StatesRisk and Insurance Servicessubsequent_events
f5-10q / Qwen3.6-27B-Q8_0		Announced agreement to acquire Wortham Insurance, an independent insurance broker with 530 colleagues. Expected to close in Q3 2018.
2018-06-30restructuringin_progressUSD 64,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressSeverance and Future Rent Under Non-Cancelable Leases and Other Costs [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressEmployee Severance [Member]USD 51,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-06-30restructuringin_progressOther Restructuring [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressRisk and Insurance Services ($3M), Consulting ($1M), Corporate ($2M)USD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2018 restructuring costs primarily for severance at Marsh and Corporate, plus future rent under non-cancelable leases at Corporate. No employee counts disclosed. Total restructuring liability of $63 million at March 31, 2018 (severance $15M; future rent and other $48M).
2018-03-31restructuringin_progressRisk and Insurance Services (Marsh)USD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Share of the $6 million of Q1 2018 restructuring costs recorded in Risk and Insurance Services; primarily severance at Marsh. No employee count disclosed.
2018-03-31restructuringin_progressConsultingUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Share of the $6 million of Q1 2018 restructuring costs recorded in the Consulting segment. No employee count disclosed.
2018-03-31restructuringin_progressCorporateUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Share of the $6 million of Q1 2018 restructuring costs recorded at Corporate; includes severance and future rent under non-cancelable leases. Restructuring liability was $63 million at 2018-03-31 (includes pre-2018 actions). No employee count disclosed.
2018-03-31acquisition_additioncompletedUnited States, Japan, United KingdomRisk and Insurance Services and ConsultingUSD 36 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Four Q1 2018 acquisitions (Highsmith Insurance Agency, Hoken Soken, Draw, 8Works Limited); charge field shows total purchase consideration, not a workforce charge. No headcount added disclosed.
2018-03-31restructuringin_progressGlobalMarsh, Corporate, ConsultingUSD 6 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $6 million recorded in Q1 2018, primarily for severance at Marsh and Corporate, and future rent under non-cancelable leases at Corporate. Employee count not disclosed.
2018-03-31restructuringin_progressUSD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressEmployee Severance [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2018-03-31restructuringin_progressOther Restructuring [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-12-31restructuringin_progressGlobalRisk and Insurance ServicesUSD 11 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2017 restructuring costs of $11 million for the segment; severance at Marsh plus future rent on vacated space. Employees affected not disclosed. Liability balance of $65 million remained at year-end.
2017-12-31restructuringin_progressGlobalConsultingUSD 19 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2017 restructuring costs of $19 million for the segment; severance at Mercer plus future rent on vacated space. Employees affected not disclosed.
2017-12-31restructuringin_progressGlobalCorporateUSD 10 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2017 restructuring costs of $10 million for Corporate; severance plus future rent on non-cancelable leases. Total 2017 net restructuring costs were $40 million (severance expense incurred $31 million, future rent and other $9 million). Employees affected not disclosed.
2017-12-31acquisition_additioncompletedGlobalRisk and Insurance Services (7 acquisitions) and Consulting (3 acquisitions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Ten acquisitions completed during 2017 with total purchase consideration of approximately $777 million; headcount added through these acquisitions is not disclosed.
2017-12-31restructuringcompletedGlobalRisk and Insurance Services, Consulting, CorporateUSD 40 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Total costs of $40 million incurred in 2017. Breakdown: Risk and Insurance Services $11 million; Consulting $19 million; Corporate $10 million. Costs consist primarily of severance and future rent under non-cancelable leases. Employee count not disclosed.
2017-12-31restructuringin_progressUSD 40,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-12-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-12-31restructuringin_progressEmployee Severance [Member]USD 31,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-12-31restructuringin_progressOther Restructuring [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2017-09-30restructuringin_progressMercer, Marsh and CorporateUSD 32 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2017 restructuring costs of $32 million, primarily severance at Mercer, Marsh and Corporate plus future rent under non-cancelable leases at Corporate; split $7M Risk and Insurance Services, $18M Consulting, $7M Corporate. No employee counts disclosed.
2017-09-30restructuringin_progressConsulting (Mercer)USD 18 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Consulting segment's share of the nine-month 2017 restructuring costs; MD&A cites higher severance costs related to the Mercer business restructuring.
2017-09-30restructuringin_progressRisk and Insurance ServicesUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Risk and Insurance Services segment's share of nine-month 2017 restructuring costs.
2017-09-30restructuringin_progressCorporateUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Corporate segment's share of nine-month 2017 restructuring costs, including future rent under non-cancelable leases.
2017-09-30restructuringin_progressGlobalRisk and Insurance Services; Consulting; CorporateUSD 32 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Total restructuring costs of $32M in first nine months 2017, primarily severance at Mercer, Marsh and Corporate plus future rent on non-cancelable leases at Corporate. Segment charge split: RIS $7M, Consulting $18M, Corporate $7M. Severance liability at 9/30/17 was $14M; rent/other liability $55M. No employee counts disclosed.
2017-09-30acquisition_additioncompleted2017-01United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired J. Smith Lanier & Co., a privately held U.S. insurance brokerage. Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-02United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired iaConsulting Services, a Texas-based employee benefits consulting firm. Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-03United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Blakestad, Inc. (Minnesota insurance agency) and RJF Financial Services (Minnesota retirement advisory firm). Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-05United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Insurance Partners of Texas, a Texas-based employee benefits consulting firm. Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-08United StatesRisk and Insurance Services — Marshbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired International Catastrophe Insurance Managers, LLC, a Colorado-based property and casualty insurance agent. Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-08United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Hendrick & Hendrick, Inc., a Texas-based insurance agency. Headcount added not disclosed.
2017-09-30acquisition_additioncompleted2017-08PortugalConsulting — Mercerbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired Jaeson Associates, a Portugal-based talent management consulting organization. Headcount added not disclosed.
2017-09-30restructuringin_progressGlobalMercer, Marsh, CorporateUSD 32 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $32 million recorded in the first nine months of 2017, primarily for severance at Mercer, Marsh and Corporate, as well as future rent under non-cancelable leases at Corporate. Specific employee counts affected are not disclosed.
2017-09-30restructuringin_progressUSD 32,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-09-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 18,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-09-30restructuringin_progressEmployee Severance [Member]USD 24,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-09-30restructuringin_progressOther Restructuring [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressPrimarily Mercer; also Risk and Insurance Services and CorporateUSD 24 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First-half 2017 restructuring costs of $24 million, primarily severance at Mercer and future rent under non-cancelable leases; split across Risk and Insurance Services ($4M), Consulting ($16M) and Corporate ($4M). No employee counts disclosed. Restructuring liability of $74 million at June 30, 2017.
2017-06-30restructuringin_progressRisk and Insurance ServicesUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First six months of 2017 restructuring cost; no employee count disclosed. Program includes severance and future rent on non-cancelable leases; liability of $74M remained at 2017-06-30.
2017-06-30restructuringin_progressConsultingUSD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Largest share of the $24M first-half 2017 restructuring cost; primarily severance at Mercer plus future rent on non-cancelable leases. No employee count disclosed.
2017-06-30restructuringin_progressCorporateUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First six months of 2017 restructuring cost; no employee count disclosed.
2017-06-30acquisition_additioncompleted2017-01United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired J. Smith Lanier & Co., a U.S. insurance brokerage. Headcount added not disclosed; consolidated H1 2017 purchase consideration was $510M across five acquisitions.
2017-06-30acquisition_additioncompleted2017-02United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired iaConsulting Services, a Texas-based employee benefits consulting firm. Headcount added not disclosed.
2017-06-30acquisition_additioncompleted2017-03United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Blakestad, Inc., a Minnesota-based private client and commercial lines insurance agency. Headcount added not disclosed.
2017-06-30acquisition_additioncompleted2017-03United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired RJF Financial Services, a Minnesota-based retirement advisory firm. Headcount added not disclosed.
2017-06-30acquisition_additioncompleted2017-05United StatesRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Insurance Partners of Texas, a Texas-based employee benefits consulting firm. Headcount added not disclosed.
2017-06-30restructuringin_progressGlobalMercerUSD 16 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Includes severance and future rent under non-cancelable leases. Employee count not disclosed.
2017-06-30restructuringin_progressGlobalRisk and Insurance ServicesUSD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Includes severance and future rent under non-cancelable leases. Employee count not disclosed.
2017-06-30restructuringin_progressGlobalCorporateUSD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Includes severance and future rent under non-cancelable leases. Employee count not disclosed.
2017-06-30restructuringin_progressUSD 24,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressEmployee Severance [Member]USD 19,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-06-30restructuringin_progressOther Restructuring [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31othercompleted2017-03-012017-12-31Canadarestructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		In March 2017 the Company modified its Canadian defined benefit pension plans to discontinue further benefit accruals for participants after December 31, 2017, replacing them with a defined contribution arrangement; post-retirement benefits plan also amended for individuals retiring after April 1, 2019. Plans were re-measured on the amendment date. This is a benefits-plan change rather than a headcount reduction.
2017-03-31restructuringin_progressRisk and Insurance Services ($4M), Consulting ($3M), Corporate ($2M)USD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $9 million in Q1 2017, primarily severance and future rent under non-cancelable leases. No employee counts disclosed. Restructuring liability of $74 million at March 31, 2017 ($15M severance, $59M future rent and other).
2017-03-31restructuringin_progressGlobalRisk and Insurance Services; Consulting; CorporateUSD 9 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Costs of $9M for severance and future rent under non-cancelable leases; split $4M RIS, $3M Consulting, $2M Corporate. No employee count disclosed.
2017-03-31acquisition_additioncompletedUnited StatesRisk and Insurance ServicesUSD 509 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Four acquisitions in Q1 2017 (JSL, iaConsulting, Blakestad, RJF Financial Services); total consideration $509M. No headcount added disclosed.
2017-03-31restructuringin_progressGlobalRisk and Insurance Services, Consulting, CorporateUSD 9 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $9 million recorded in Q1 2017, primarily for severance and future rent under non-cancelable leases. Breakdown: RIS $4M, Consulting $3M, Corporate $2M. Employee count not disclosed.
2017-03-31restructuringin_progressUSD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31restructuringin_progressEmployee Severance [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2017-03-31restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-12-31restructuringin_progressNot specifiedRisk and Insurance ServicesUSD 3 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2016 restructuring expense for the segment; costs consist primarily of severance, benefits and future rent/real estate costs. Employee counts not disclosed.
2016-12-31restructuringin_progressNot specifiedConsultingUSD 34 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2016 restructuring expense for the segment; largest component of the $44 million total 2016 net restructuring cost. Employee counts not disclosed.
2016-12-31restructuringin_progressNot specifiedCorporateUSD 7 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2016 restructuring expense at corporate level. Segment components ($3M + $34M + $7M) sum to the disclosed $44 million total 2016 net restructuring cost; restructuring liability balance was $93 million at both 12/31/2015 and 12/31/2016, indicating an ongoing multi-year program.
2016-12-31acquisition_additioncompletedUnited States, Brazil, United Kingdom, AustraliaRisk and Insurance Services and ConsultingUSD 901 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Fifteen business combinations completed during 2016 (nine in Risk and Insurance Services, six in Consulting) with total purchase consideration of approximately $901 million; acquired headcount not disclosed. Charge value represents total purchase consideration, not a restructuring charge.
2016-12-31acquisition_additionannounced2017-01-132017-03-31United StatesRisk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		MMA entered a definitive agreement to acquire J. Smith Lanier & Co., described as one of the largest privately held U.S. insurance brokerage firms; expected to close in Q1 2017 pending customary approvals. Headcount not disclosed.
2016-12-31restructuringcompletedGlobalRisk and Insurance Services, Consulting, CorporateUSD 44 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Total costs of $44 million incurred in 2016: RIS $3M, Consulting $34M, Corporate $7M. Employee count not disclosed.
2016-12-31restructuringin_progressUSD 44,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-12-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 34,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-12-31restructuringin_progressEmployee Severance [Member]USD 40,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-12-31restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2016-09-30restructuringin_progressRisk and Insurance Services ($2M), Corporate ($6M), Consulting ($1M)USD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2016 restructuring costs primarily for future severance and rent under non-cancelable leases; no employee counts disclosed. Restructuring liability of $71 million at September 30, 2016 (severance $4M; future rent and other $67M).
2016-09-30otherannounced2016-10-012016-12-31United StatesMD&A
f5-10q / GLM-5.3-flash-fp4-HTML		U.S. defined benefit pension plans modified in October 2016 to freeze benefit accruals after December 31, 2016; concurrent defined contribution plan amendment adds a 4% automatic company contribution from January 1, 2017. Benefit plan change rather than headcount action.
2016-09-30restructuringin_progressRisk and Insurance Services, Corporate, ConsultingUSD 9 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $9M recorded in the nine months ended 2016-09-30 for future severance and rent under non-cancelable leases; segment split disclosed as Risk and Insurance Services $2M, Corporate $6M, Consulting $1M. No employee counts, announcement dates, or completion dates disclosed. Restructuring liability was $71M at 2016-09-30.
2016-09-30acquisition_additioncompletedUnited StatesRisk and Insurance Services; ConsultingUSD 119 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Seven acquisitions completed in the first nine months of 2016 (five Marsh & McLennan Agency brokerages, two Mercer acquisitions) with total purchase consideration of $119M. No headcount added through these acquisitions is disclosed.
2016-09-30restructuringin_progressGlobalRisk and Insurance Services, Consulting, CorporateUSD 9 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $9 million recorded in the first nine months of 2016, primarily for future severance and rent under non-cancelable leases. Employee count affected is not disclosed.
2016-09-30restructuringin_progressUSD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-09-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-09-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-09-30restructuringin_progressEmployee Severance [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-09-30restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressRisk and Insurance Services ($3M), Corporate ($4M), Consulting ($1M)USD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First-half 2016 restructuring costs of $8 million, primarily future severance and rent under non-cancelable leases; no employee counts disclosed. Restructuring liability of $77 million at June 30, 2016 includes actions from prior periods.
2016-06-30restructuringin_progressRisk and Insurance ServicesUSD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Portion of $8 million total restructuring charge for the six months ended June 30, 2016; covers future severance and rent on non-cancelable leases. No employee counts disclosed.
2016-06-30restructuringin_progressCorporateUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Portion of $8 million total restructuring charge for the six months ended June 30, 2016. No employee counts disclosed.
2016-06-30restructuringin_progressConsultingUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Portion of $8 million total restructuring charge for the six months ended June 30, 2016. Restructuring liability stood at $77 million at June 30, 2016. No employee counts disclosed.
2016-06-30acquisition_additioncompletedUnited States; United KingdomRisk and Insurance Services; ConsultingUSD 105 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions completed in the first six months of 2016 (three in Risk and Insurance Services, two in Consulting); total purchase consideration of $105 million. Headcount added not disclosed; acquired 2016 businesses contributed about $9 million of six-month revenue.
2016-06-30restructuringin_progressGlobalRisk and Insurance Services, Consulting, CorporateUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $8 million recorded in the first six months of 2016, primarily for future severance and rent under non-cancelable leases. Breakdown: Risk and Insurance Services ($3 million), Corporate ($4 million), and Consulting ($1 million). Employee count not disclosed.
2016-06-30restructuringin_progressUSD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressEmployee Severance [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-06-30restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-03-31restructuringin_progressRisk and Insurance Services ($1 million); Corporate ($2 million)USD 3 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2016 restructuring costs of $3 million primarily for future severance and rent under non-cancelable leases; no employee counts disclosed. Restructuring liability of $85 million at March 31, 2016 includes actions prior to 2016.
2016-03-31restructuringin_progressRisk and Insurance ServicesUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2016 restructuring costs of $1 million in this segment, for future severance and rent under non-cancelable leases. No employee count disclosed; program includes actions initiated prior to 2016.
2016-03-31restructuringin_progressCorporateUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2016 restructuring costs of $2 million in Corporate, for future severance and rent under non-cancelable leases. No employee count disclosed; program includes actions initiated prior to 2016.
2016-03-31acquisition_additioncompleted2016-01United KingdomConsulting — Mercerbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired The Positive Ageing Company Limited, an aging-workforce advisory firm. Headcount added not disclosed; part of four Q1 2016 acquisitions totaling $103 million purchase consideration.
2016-03-31acquisition_additioncompleted2016-02United States — FloridaRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired The Celedinas Agency, Inc., a property/casualty, marine and employee benefits brokerage. Headcount added not disclosed.
2016-03-31acquisition_additioncompleted2016-02United States — MissouriRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Aviation Solutions, LLC, an aviation risk advisor and insurance broker. Headcount added not disclosed.
2016-03-31acquisition_additioncompleted2016-03United States — New YorkRisk and Insurance Services — Marsh & McLennan Agencybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Corporate Consulting Services, Ltd., an insurance brokerage and HR consulting firm. Headcount added not disclosed.
2016-03-31restructuringin_progressRisk and Insurance Services, CorporateUSD 3 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $3 million recorded in Q1 2016, primarily for future severance and rent under non-cancelable leases. $1 million in Risk and Insurance Services, $2 million in Corporate. Employee count not disclosed.
2016-03-31restructuringin_progressUSD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-03-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-03-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-03-31restructuringin_progressEmployee Severance [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2016-03-31restructuringin_progressOther Restructuring [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-12-31restructuringin_progressRisk and Insurance ServicesUSD 8 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2015 restructuring charge allocated to the Risk and Insurance Services segment. Part of company-wide 2015 restructuring costs of $28 million, consisting primarily of severance and benefits plus future rent and other real estate costs; 2015 severance expense was $17 million company-wide (not allocated by segment). No completion date disclosed; restructuring liability of $93 million (including prior-year actions) remained at December 31, 2015.
2015-12-31restructuringin_progressConsultingUSD 8 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2015 restructuring charge allocated to the Consulting segment. Part of company-wide 2015 restructuring costs of $28 million, consisting primarily of severance and benefits plus future rent and other real estate costs; 2015 severance expense was $17 million company-wide (not allocated by segment). No completion date disclosed; restructuring liability of $93 million (including prior-year actions) remained at December 31, 2015.
2015-12-31restructuringin_progressCorporateUSD 12 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2015 restructuring charge at the corporate level. Part of company-wide 2015 restructuring costs of $28 million, consisting primarily of severance and benefits plus future rent and other real estate costs; 2015 severance expense was $17 million company-wide (not allocated by segment). No completion date disclosed; restructuring liability of $93 million (including prior-year actions) remained at December 31, 2015.
2015-12-31restructuringin_progressGlobalRisk and Insurance ServicesUSD 8 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2015 restructuring expense of $8M for this segment (severance and future rent/real estate costs); employees affected not disclosed. Expense incurred during fiscal year 2015 only.
2015-12-31restructuringin_progressGlobalConsultingUSD 8 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2015 restructuring expense of $8M for this segment; employees affected not disclosed. Expense incurred during fiscal year 2015 only.
2015-12-31restructuringin_progressGlobalCorporateUSD 12 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2015 restructuring expense of $12M at corporate level; employees affected not disclosed. Total 2015 restructuring expense $28M; $93M liability remains at year-end, primarily future rent under non-cancelable leases plus $15M severance.
2015-12-31acquisition_additioncompletedVarious (U.S., Canada, U.K., Korea, Argentina, Switzerland, Brazil, Hong Kong and others)Risk and Insurance Services (13 acquisitions) and Consulting (8 acquisitions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		21 acquisitions completed in 2015 with total purchase consideration of approximately $1.2 billion; headcount added through these acquisitions not disclosed.
2015-12-31divestiture_reductioncompleted2015-12United StatesConsulting — Mercer Retirement (U.S. defined contribution recordkeeping business)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Mercer sold its U.S. defined contribution recordkeeping business in December 2015, recognizing a $37M pre-tax gain; employees removed through the sale not disclosed. Sale includes contingent consideration based on client retention and renewal.
2015-12-31restructuringcompletedGlobalRisk and Insurance Services, Consulting, CorporateUSD 28 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Total costs of $28 million incurred in 2015. Breakdown: Risk and Insurance Services $8 million; Consulting $8 million; Corporate $12 million. Costs consist primarily of severance, benefits, future rent, and other real estate costs. Employee count not disclosed.
2015-12-31restructuringin_progressUSD 28,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-12-31restructuringin_progressCorporate, Non-Segment [Member] / Acquisition Related [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Consulting Segment [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-12-31restructuringin_progressOperating Segments [Member] / Acquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-12-31restructuringin_progressEmployee Severance [Member]USD 17,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-12-31restructuringin_progressOther Restructuring [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2015-09-30restructuringin_progressRisk and Insurance Services ($3 million); Corporate ($5 million)USD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2015 restructuring costs of $8 million, primarily for future severance and rent under non-cancelable leases; no employee counts disclosed. Restructuring liability of $74 million at September 30, 2015 includes actions prior to 2015.
2015-09-30restructuringin_progressGlobalRisk and Insurance Services; CorporateUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		YTD restructuring costs of $8M for severance and future rent; $3M in Risk and Insurance Services and $5M in Corporate. No employee counts disclosed. Restructuring liability was $74M at 2015-09-30.
2015-09-30restructuringin_progressGlobalRisk and Insurance Services; CorporateUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $8 million recorded in the first nine months of 2015, primarily for future severance and rent under non-cancelable leases. $3 million incurred in Risk and Insurance Services and $5 million in Corporate. Employee count affected is not disclosed.
2015-09-30restructuringin_progressUSD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-09-30restructuringin_progressEmployee Severance [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-09-30restructuringin_progressOther Restructuring [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-09-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-09-30restructuringin_progressCorporate Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-06-30restructuringin_progressRisk and Insurance Services ($2M); Corporate ($3M)USD 5 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First-half 2015 restructuring costs of $5 million, primarily future severance and rent under non-cancelable leases; no employee counts disclosed. Restructuring liability of $85 million at June 30, 2015 includes severance ($5M) and future rent/other costs ($80M).
2015-06-30restructuringin_progressRisk and Insurance ServicesUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $2M in RIS for first six months of 2015, primarily future severance and rent under non-cancelable leases; no employee count disclosed.
2015-06-30restructuringin_progressCorporateUSD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $3M in Corporate for first six months of 2015, primarily future severance and rent under non-cancelable leases; no employee count disclosed.
2015-06-30acquisition_additioncompletedMultiple (Argentina, Switzerland, Canada, U.S., Korea, U.K.)Risk and Insurance Services; ConsultingUSD 331 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Eight acquisitions completed in first six months of 2015 with total purchase consideration of $331M; no headcount added disclosed.
2015-06-30restructuringin_progressRisk and Insurance Services; CorporateUSD 5 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $5 million recorded in first six months of 2015, primarily for future severance and rent under non-cancelable leases. Specific employee counts not disclosed.
2015-06-30restructuringin_progressUSD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-06-30restructuringin_progressEmployee Severance [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-06-30restructuringin_progressOther Restructuring [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-06-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-06-30restructuringin_progressCorporate Segment [Member]USD 3,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-03-31restructuringin_progressCorporateUSD 2 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2015 restructuring costs of $2 million primarily for future rent under non-cancelable leases, incurred in Corporate; no employee counts disclosed. Restructuring liability of $86 million at March 31, 2015 includes severance ($5 million) and future rent/other costs ($81 million) from actions prior to 2015.
2015-03-31restructuringin_progressGlobalCorporateUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2015 restructuring costs of $2M incurred in Corporate, primarily for future rent on non-cancelable leases. Severance roll-forward shows $2M cash paid with no new accrual in Q1 2015; total restructuring liability $86M at 2015-03-31. No employee count disclosed.
2015-03-31acquisition_additioncompletedArgentina; United States (Georgia); SwitzerlandRisk and Insurance Services (Marsh); Consulting (Oliver Wyman, Mercer)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Three acquisitions completed in Q1 2015 (INGESEG, TeamSAI, Strategic Capital Management) with total purchase consideration of $32M. Headcount added through these acquisitions was not disclosed.
2015-03-31restructuringin_progressCorporateCorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Company recorded total restructuring costs of $2 million primarily for future rent under non-cancelable leases incurred in Corporate. No employee count disclosed.
2015-03-31restructuringin_progressUSD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-03-31restructuringin_progressEmployee Severance [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-03-31restructuringin_progressOther Restructuring [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2015-03-31restructuringin_progressCorporate Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-12-31restructuringcompleted2014Risk and Insurance ServicesUSD 5 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Segment allocation of the $12M of 2014 restructuring costs (primarily severance/benefits and future rent on vacated space). Headcount affected not disclosed; no completion timeline given. Residual $92M liability at 12/31/2014 relates largely to pre-2014 actions.
2014-12-31restructuringcompleted2014ConsultingUSD 1 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Segment allocation of the $12M of 2014 restructuring costs (primarily severance/benefits and future rent on vacated space). Headcount affected not disclosed; no completion timeline given.
2014-12-31restructuringcompleted2014CorporateUSD 6 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Corporate allocation of the $12M of 2014 restructuring costs (primarily severance/benefits and future rent on vacated space). Headcount affected not disclosed; no completion timeline given.
2014-12-31acquisition_additioncompleted2014Primarily United States; also Scotland, Panama, Canada, Belgium, Australia, ChileRisk and Insurance Services (15 acquisitions); Consulting (6 acquisitions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		21 acquisitions completed during 2014 for total purchase consideration of $772M (net cash outflow $554M). Headcount added through acquisitions is not disclosed. Includes Marsh & McLennan Agency, Marsh, Mercer and Oliver Wyman bolt-ons such as Barney & Barney, Torrent Technologies, Transition Assist, AUSREM, Denarius and OC&C (Boston).
2014-12-31restructuringin_progressNot specifiedRisk and Insurance ServicesUSD 5 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2014 restructuring costs for the segment, comprising severance/benefits and future rent and other real estate costs; employees affected not disclosed. Restructuring liability of $92 million remained at 2014 year-end.
2014-12-31restructuringin_progressNot specifiedConsultingUSD 1 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2014 restructuring costs for the segment; employees affected not disclosed.
2014-12-31restructuringin_progressNot specifiedCorporateUSD 6 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2014 restructuring costs at corporate level; employees affected not disclosed. Segment components sum to the $12 million total 2014 net restructuring cost.
2014-12-31acquisition_additioncompletedUnited States and internationalRisk and Insurance Services and Consultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		21 acquisitions completed during 2014 (15 in Risk and Insurance Services, 6 in Consulting) with total purchase consideration of $772 million; headcount added through these acquisitions was not disclosed.
2014-12-31restructuringcompletedGlobalRisk and Insurance Services, Consulting, CorporateUSD 12 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Total costs of $12 million incurred in 2014. Breakdown: Risk and Insurance Services $5 million; Consulting $1 million; Corporate $6 million. Consists primarily of severance, benefits, future rent, and other real estate costs.
2014-12-31restructuringin_progressUSD 12,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-12-31restructuringin_progressAcquisition Related [Member] / Consulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-12-31restructuringin_progressAcquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-12-31restructuringin_progressAcquisition Related [Member] / Corporate Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-12-31restructuringin_progressEmployee Severance [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-12-31restructuringin_progressOther Restructuring [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2014-09-30restructuringin_progressCorporateUSD 10 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2014 restructuring costs of $10 million primarily for severance and future rent under non-cancelable leases; no employee counts disclosed. Severance liability of $7 million and future rent/other liability of $91 million at September 30, 2014.
2014-09-30restructuringin_progressCorporateCorporateUSD 10 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $10 million recorded in the first nine months of 2014, primarily severance and future rent under non-cancelable leases; severance liability was $7 million and total restructuring liability $98 million at 2014-09-30. No employee counts or completion dates disclosed.
2014-09-30acquisition_additioncompletedUnited States, Canada, United Kingdom, Scotland, Panama, QuebecRisk and Insurance Services; ConsultingUSD 573 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Twelve acquisitions completed in the first nine months of 2014 (total consideration $573 million); headcount added through these acquisitions not disclosed.
2014-09-30restructuringin_progressCorporateCorporateUSD 10 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $10 million recorded in the first nine months of 2014, primarily due to severance and future rent under non-cancelable leases. Employee count not disclosed.
2014-09-30restructuringin_progressCorporate Segment [Member]USD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-09-30restructuringin_progressUSD 10,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-09-30restructuringin_progressOther Restructuring [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-09-30restructuringin_progressEmployee Severance [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-06-30restructuringin_progressCorporateUSD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Six-month 2014 restructuring costs of $6 million primarily for future rent under non-cancelable leases, incurred in Corporate; no employee counts disclosed. Severance liability of $8 million and future rent/other liability of $101 million at June 30, 2014.
2014-06-30restructuringin_progressGlobalCorporateUSD 6 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six-month 2014 restructuring costs of $6M, primarily future rent on non-cancelable leases; no employee count disclosed. Severance liability was $8M at 2014-06-30 (accrued $2M, paid $5M during 2014).
2014-06-30acquisition_additioncompletedUnited States; United Kingdom (Scotland)Risk and Insurance Services (Marsh, Marsh & McLennan Agency); Consulting (Mercer)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine acquisitions completed in the first six months of 2014 with total purchase consideration of $534M; headcount added through these acquisitions was not disclosed.
2014-06-30otherin_progress2014-012014-08-01United KingdomCorporate — U.K. defined benefit pension plansother
f5-10q / MiMo-V2.6-Flash-fp8-HTML		U.K. defined benefit plans closed to future benefit accrual effective 2014-08-01 and to be replaced by a defined contribution arrangement; curtailment gain of $65M recognized in Q1 2014. Number of affected employees not disclosed.
2014-06-30restructuringin_progressCorporateCorporateUSD 6 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $6 million recorded in first six months of 2014, primarily for future rent under non-cancelable leases. No employee count disclosed.
2014-06-30restructuringcompleted2014-01-012014-08-01United KingdomConsultingMD&A
f5-10q / Qwen3.6-27B-Q8_0		Amended U.K. defined benefit pension plans to close to future benefit accruals effective August 1, 2014. Replaced with defined contribution arrangement. Curtailment gain of $65 million recognized in Q1 2014. No specific employee headcount affected disclosed.
2014-06-30restructuringin_progressUSD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-06-30restructuringin_progressOther Restructuring [Member]USD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-06-30restructuringin_progressEmployee Severance [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-06-30restructuringin_progressCorporate Segment [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-03-31restructuringin_progressCorporateUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2014 charge of $2M was primarily future rent on non-cancelable leases; no employees-affected count disclosed. Severance roll-forward shows $3M cash paid during Q1 2014 against a $8M severance liability at 3/31/14 (no new severance accrued in the quarter); total restructuring liability $111M at 3/31/14.
2014-03-31acquisition_additioncompletedUnited States; ScotlandRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six acquisitions completed Jan-Mar 2014 (Barney & Barney, Central Insurance Services, Great Lakes Employee Benefits, Bond Network, Capstone Insurance Services, Transition Assist) for $444M total consideration; headcount added not disclosed. Acquired businesses contributed approximately $21M of revenue in Q1 2014.
2014-03-31restructuringin_progressGlobalCorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $2 million recorded in Q1 2014, primarily for future rent under non-cancelable leases incurred in Corporate. No employee count disclosed.
2014-03-31restructuringin_progressUSD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-03-31restructuringin_progressOther Restructuring [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-03-31restructuringin_progressEmployee Severance [Member]USD 0 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2014-03-31restructuringin_progressCorporate Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-12-31restructuringin_progress2013Risk and Insurance ServicesUSD 7 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Restructuring actions implemented during fiscal 2013; costs consist primarily of severance/benefits and future rent and other real estate costs. Headcount affected and completion timeline not disclosed. Consolidated 2013 program totaled $22 million across three sub-components ($9M severance and $13M future rent/other per the liability roll-forward); a restructuring liability of $124 million remained at year-end with ongoing cash payments. Also referenced in MD&A (deduplicated).
2013-12-31restructuringin_progress2013ConsultingUSD 2 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Segment component of the $22 million fiscal 2013 restructuring program. Headcount affected and completion timeline not disclosed.
2013-12-31restructuringin_progress2013Corporate (parent company)USD 13 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Corporate segment component of the $22 million fiscal 2013 restructuring program. Headcount affected and completion timeline not disclosed.
2013-12-31otherannounced2014-012014-08-01United KingdomU.K. defined benefit pension plans (company-wide U.K. workforce)subsequent_events
f5-10k / GLM-5.3-flash-HTML		Benefits redesign rather than a headcount action: after a consultation period, the U.K. defined benefit plans were amended in January 2014 to close to future benefit accruals effective August 1, 2014, replaced with a new comprehensive defined contribution arrangement. Remeasurement increased the projected benefit obligation by ~$147 million and reduced funded status by ~$137 million; a $63 million curtailment gain is expected in Q1 2014, largely offset by a transition benefit to affected employees, with ~$30 million of additional defined contribution cost expected. Also discussed in MD&A (deduplicated).
2013-12-31restructuringin_progressGlobalRisk and Insurance ServicesUSD 7 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2013 restructuring actions; severance and benefits plus future rent/real estate costs. Employees affected not disclosed
2013-12-31restructuringin_progressGlobalConsultingUSD 2 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2013 restructuring actions; employees affected not disclosed
2013-12-31restructuringin_progressGlobalCorporateUSD 13 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2013 restructuring actions; total 2013 restructuring cost $22M with $124M liability remaining at year-end; employees affected not disclosed
2013-12-31acquisition_additioncompletedGlobalRisk and Insurance Services; ConsultingUSD 178 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Eight acquisitions completed in 2013 (six RIS, two Consulting) for $178M total consideration; acquired headcount not disclosed
2013-12-31acquisition_additionannounced2014-01-31United States (San Diego, California)Risk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		MMA acquired Barney & Barney in January 2014, after fiscal year-end; headcount not disclosed
2013-12-31acquisition_additionannounced2014-01-31United Kingdom (Scotland)Risk and Insurance Services (Marsh)subsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Definitive agreement announced January 2014 to acquire Central Insurance Services; headcount not disclosed
2013-12-31restructuringcompleted2013GlobalRisk and Insurance Services, Consulting, CorporateUSD 22 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Costs totaling $22 million incurred in 2013. Breakdown: Risk and Insurance Services $7 million; Consulting $2 million; Corporate $13 million. Consists primarily of severance, benefits, future rent, and other real estate costs.
2013-12-31restructuringin_progressUSD 22,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-12-31restructuringin_progressOther Restructuring [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-12-31restructuringin_progressEmployee Severance [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-12-31restructuringin_progressAcquisition Related [Member] / Corporate Segment [Member]USD 13,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-12-31restructuringin_progressAcquisition Related [Member] / Risk and Insurance Services Segment [Member]USD 7,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-12-31restructuringin_progressAcquisition Related [Member] / Consulting Segment [Member]USD 2,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2013-09-30restructuringin_progressRisk and Insurance Services ($5M), Consulting ($1M), Corporate ($11M)USD 17 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2013 restructuring costs of $17 million for severance and future rent under non-cancelable leases; no employee counts disclosed. Restructuring liability at 9/30/13 was $130 million, including $12 million severance.
2013-09-30restructuringin_progressRisk and Insurance ServicesUSD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2013 restructuring costs for severance and future rent under non-cancelable leases; employee counts not disclosed. Program includes liabilities from actions prior to 2013; restructuring liability of $130 million remained at 2013-09-30.
2013-09-30restructuringin_progressConsultingUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2013 restructuring costs for severance and future rent under non-cancelable leases; employee counts not disclosed.
2013-09-30restructuringin_progressCorporateUSD 11 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2013 restructuring costs for severance and future rent under non-cancelable leases; employee counts not disclosed. Segment components sum to the disclosed $17 million total.
2013-09-30acquisition_additioncompleted2013-09Czech Republic and SlovakiaMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired an additional stake in Insia a.s., gaining controlling interest; previously equity-method accounted. Headcount added not disclosed.
2013-09-30acquisition_additioncompleted2013-08South AfricaMercer (Consulting)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Mercer acquired Global Remuneration Solutions, a compensation consulting firm. Headcount added not disclosed.
2013-09-30acquisition_additioncompleted2013-07United KingdomOliver Wyman Group (Consulting)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Oliver Wyman acquired Corven, a management consultancy. Headcount added not disclosed.
2013-09-30acquisition_additioncompleted2013-07United States (Maine)Guy Carpenter (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Guy Carpenter acquired Smith Group, a disability reinsurance risk manager and consultant. Headcount added not disclosed.
2013-09-30acquisition_additioncompleted2013-06PeruMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Rehder y Asociados Group, including broker Rehder y Asociados and Humanasalud. Headcount added not disclosed.
2013-09-30acquisition_additioncompleted2013-06Dominican RepublicMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Franco & Acra Tecniseguros, an insurance advisor. Headcount added not disclosed.
2013-09-30restructuringin_progressGlobalRisk and Insurance Services, Consulting, CorporateUSD 17 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $17 million recorded in the first nine months of 2013, related to severance and future rent under non-cancelable leases. Breakdown: Risk and Insurance Services $5 million, Consulting $1 million, Corporate $11 million. Employee count not disclosed.
2013-09-30restructuringin_progressRisk and Insurance Services Segment [Member]USD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-09-30restructuringin_progressConsulting Segment [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-09-30restructuringin_progressUSD 17,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-09-30restructuringin_progressCorporate Segment [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-09-30restructuringin_progressOther Restructuring [Member]USD 9,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-09-30restructuringin_progressEmployee Severance [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-06-30restructuringin_progressUSD 13 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $13 million in first six months of 2013 for severance and future rent under non-cancelable leases; no employee counts disclosed. Severance accrual of $7 million in the period; severance liability of $15 million at June 30, 2013.
2013-06-30restructuringin_progressUSD 13 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $13 million recorded in the first six months of 2013 for severance and future rent under non-cancelable leases; no employee counts, announcement dates, or completion dates disclosed. Restructuring liability was $135 million at 2013-06-30.
2013-06-30acquisition_additioncompleted2013-06PeruRisk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Rehder y Asociados Group, including health and benefits specialist Humanasalud; no headcount added disclosed. Part of $109 million total consideration for H1 2013 acquisitions.
2013-06-30acquisition_additioncompletedDominican RepublicRisk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Franco & Acra Tecniseguros during the first six months of 2013; exact date and headcount added not disclosed.
2013-06-30acquisition_additionannouncedConsulting (Oliver Wyman Group)USD 30 (millions)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Post-quarter Oliver Wyman acquisition for an aggregate purchase price of approximately $30 million; initial accounting not yet complete and no headcount disclosed.
2013-06-30restructuringin_progressUSD 13 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $13 million recorded in first six months of 2013 related to severance and future rent under non-cancelable leases. Employee count not disclosed.
2013-06-30restructuringin_progressUSD 13,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2013-03-31restructuringin_progressUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $7 million in Q1 2013, majority related to severance; severance liability of $20 million and lease/other liability of $123 million at March 31, 2013. No employee counts disclosed.
2013-03-31restructuringin_progressUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2013 restructuring costs of $7M, majority severance; severance liability $20M at 3/31/13. No employee count or completion date disclosed; includes actions initiated prior to 2013
2013-03-31restructuringin_progressUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $7 million recorded in Q1 2013, majority related to severance. No specific employee count disclosed.
2013-03-31restructuringin_progressUSD 7,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2012-12-31restructuringcompletedRisk and Insurance ServicesUSD 8 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2012 restructuring costs of $8 million, all described as acquisition related. Headcount affected not disclosed.
2012-12-31restructuringcompletedConsulting (primarily Mercer)USD 58 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Includes ~$51 million recorded in Q4 2012 from senior management's operations review, of which ~$16 million related to disposal of a portion of Mercer's Canadian outsourcing business ($1 million of segment total was acquisition related). Program-wide 2012 expense comprised ~$46 million severance and ~$32 million future rent and other real estate costs. Headcount affected not disclosed.
2012-12-31restructuringcompletedCorporateUSD 12 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2012 restructuring costs incurred at the Corporate level. Headcount affected not disclosed.
2012-12-31divestiture_reductioncompletedCanadaConsulting — Mercer (Outsourcing)USD 16 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Exit/disposal of a portion of Mercer's Canadian outsourcing business; exit costs recorded in Q4 2012 and included within the $58 million Consulting restructuring charge (not additive to it). Headcount impact not disclosed.
2012-12-31divestiture_reductioncompletedUnited StatesRisk and Insurance Services — Marsh (Business Processing Outsourcing, Marsh U.S. Consumer)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Sale of Marsh's BPO business completed in August 2012; sale plan initiated in Q4 2011. A related capitalized software write-off of $17 million (net of tax) was recorded in discontinued operations in 2011. Headcount impact not disclosed.
2012-12-31otherannounced2012United StatesRisk and Insurance Services — Marsh (Marsh U.S. Consumer)Item_1_Business
f5-10k / GLM-5.3-flash-HTML		Marsh decided in 2012 to exit its U.S. individual life insurance business (Private Client Life Insurance Services); exit method, timing, and headcount impact not quantified.
2012-12-31restructuringin_progressWorldwideRisk and Insurance Services $8M; Consulting $58M; Corporate $12MUSD 78 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		FY2012 restructuring actions totaling $78M; ~$58M related to Mercer, ~$51M of that recorded in Q4 2012 from senior management's operations review, including ~$16M for exit of part of Mercer's Canadian outsourcing business. Costs are severance, benefits and future rent/real estate. Employees affected not disclosed. Liability balance $170M at 12/31/2012.
2012-12-31acquisition_additioncompletedWorldwide (US, Africa, Japan, Norway, France)Risk and Insurance Services (12 acquisitions); Consulting (3 acquisitions)USD 360 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		15 acquisitions completed in 2012 with total purchase consideration of $360M (cash $252M, deferred/contingent $46M, $62M escrow released). Headcount added through acquisitions not disclosed; 2012 acquisitions contributed ~$113M of revenue.
2012-12-31divestiture_reductioncompleted2011-12-312012-08-31United StatesMarsh U.S. Consumer — Business Processing Outsourcing (BPO)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Marsh BPO business completed August 2012; plan initiated in Q4 2011. Capitalized software write-off of $17M net of tax recorded in 2011 discontinued operations. Employees affected not disclosed. Announcement date reflects Q4 2011 initiation (month/day not specified).
2012-12-31restructuringcompleted2012-12-31GlobalConsulting (Mercer)USD 58 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Approximately $58 million of restructuring charges related to Mercer, including $51 million in Q4 2012 for senior management operations review and $16 million for disposal of portion of Canadian outsourcing business. Costs consist primarily of severance, benefits, and future rent.
2012-12-31restructuringcompleted2012-12-31GlobalRisk and Insurance ServicesUSD 8 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		$8 million in restructuring costs for Risk and Insurance Services, all acquisition related.
2012-12-31restructuringcompleted2012-12-31GlobalCorporateUSD 12 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		$12 million in restructuring costs for Corporate.
2012-12-31restructuringin_progressUSD 78,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-12-31restructuringin_progressConsulting [Member]USD 58,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-12-31restructuringin_progressAcquisition Related [Member]USD 1,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-12-31restructuringin_progressDisposal of Canadian Outsourcing Business, Mercer [Member]USD 16,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-12-31restructuringin_progressCorporate Restructuring [Member]USD 12,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-12-31restructuringin_progressAcquisition Related, Risk and Insurance Services [Member]USD 8,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2012-09-30restructuringin_progressUSD 21 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $21 million in first nine months of 2012, majority related to severance; severance liability of $10 million and future rent/other of $133 million at September 30, 2012; no employee counts disclosed
2012-09-30restructuringin_progressNot specifiedCompany-wide (includes actions initiated prior to 2012)USD 21 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $21 million recorded in the first nine months of 2012, described as mostly severance. Severance liability roll-forward: $27 million accrued and $35 million cash paid in 2012 YTD, leaving $10 million of severance and $133 million of lease/other obligations at 2012-09-30 (total $143 million). No employee counts, announcement dates, or completion dates disclosed.
2012-09-30acquisition_additioncompletedUnited States, South Africa, Botswana, Namibia, Japan, Norway, FranceRisk and Insurance Services (7 acquisitions); Consulting (3 acquisitions)USD 205 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Ten acquisitions completed in the first nine months of 2012 with total purchase consideration of $205 million (cash paid $124 million, deferred/contingent consideration $19 million, $62 million escrow released). Headcount added through these acquisitions is not disclosed.
2012-09-30acquisition_additionannouncedNot specifiedRisk and Insurance Services (Marsh)USD 60 (millions)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Subsequent to 2012-09-30, Marsh completed two additional acquisitions for an aggregate purchase price of approximately $60 million; initial accounting not yet complete. Headcount added not disclosed.
2012-09-30restructuringin_progressGlobalCorporate and Operating SegmentsUSD 21 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $21 million recorded in the first nine months of 2012, majority related to severance. No specific employee count disclosed.
2012-09-30restructuringin_progressUSD 21,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2012-06-30restructuringin_progressUSD 11 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $11 million in first six months of 2012, majority related to severance; no employee counts disclosed. Severance liability of $11 million and lease/other liability of $134 million at June 30, 2012.
2012-06-30restructuringin_progressUSD 11 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Ongoing multi-year program (origins pre-date 2012); $11M recorded in first six months of 2012, mostly severance. No employee counts, geographies, or completion dates disclosed. Program liability was $145M at 2012-06-30 ($11M severance, $134M future lease and other costs).
2012-06-30acquisition_additioncompletedUnited States, South Africa, Botswana, Namibia, Japan, Norway, FranceRisk and Insurance Services; ConsultingUSD 183 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Eight acquisitions completed in first six months of 2012 (five in Risk and Insurance Services, three in Consulting); total purchase consideration $183M. No headcount added disclosed. Charge value shown is total purchase consideration, not a workforce charge.
2012-06-30restructuringin_progressUSD 11 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $11 million recorded in the first six months of 2012, majority related to severance. No specific employee count disclosed.
2012-06-30restructuringin_progressUSD 11,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2012-03-31restructuringin_progressUSD 4 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $4 million in Q1 2012, majority related to severance; no employee counts disclosed. Severance liability of $17 million and lease/other liability of $142 million at March 31, 2012.
2012-03-31restructuringin_progressUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2012 restructuring costs of $4 million, mostly severance; no employee counts or completion dates disclosed. Severance liability was $17 million at 2012-03-31 (roll-forward includes pre-2012 actions).
2012-03-31acquisition_additioncompletedUnited States; South Africa; Botswana; Namibia; Japan; Norway; FranceRisk and Insurance Services; ConsultingUSD 148 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six acquisitions completed in Q1 2012 (Alexander Forbes South Africa ops, KSPH, Cosmos Services (America), Yokogawa-ORC remaining 49%, Pensjon & Finans, REPCA); total purchase consideration $148 million. No headcount added disclosed.
2012-03-31restructuringin_progressUSD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $4 million recorded in Q1 2012, majority related to severance. Employee count not disclosed.
2012-03-31restructuringin_progressUSD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2011-12-31restructuringcompleted2011Risk and Insurance ServicesUSD 1 (millions)MD&A
f5-10k / GLM-5.3-flash-HTML		Component of 2011 restructuring actions; position eliminations for this segment not separately quantified. Program-wide 2011 costs of $51 million were primarily severance and benefits plus future rent (Note 14 roll-forward shows $29 million severance and $22 million future rent/other accrued in 2011); expected annualized savings approximately $45 million.
2011-12-31restructuringcompleted4002011Consulting (Mercer)USD 31 (millions)MD&A
f5-10k / GLM-5.3-flash-HTML		Approximately 400 positions eliminated at Mercer as part of 2011 restructuring actions; segment charge includes $8 million acquisition-related cost-reduction costs. Program-wide expected annualized savings approximately $45 million.
2011-12-31restructuringcompleted402011CorporateUSD 19 (millions)MD&A
f5-10k / GLM-5.3-flash-HTML		Approximately 40 positions eliminated at Corporate as part of 2011 restructuring actions. Program-wide expected annualized savings approximately $45 million.
2011-12-31divestiture_reductionannounced2011Marsh — Business Process Outsourcing (BPO) unitUSD 17 (millions)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Management initiated a plan in Q4 2011 to sell the Marsh BPO business (outsourced policy, claims, call center and accounting operations for life insurance carriers); associated $17 million net-of-tax capitalized software write-off is not a workforce charge; headcount impact not quantified.
2011-12-31restructuringin_progress400Consulting (Mercer)USD 31 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2011 restructuring costs of $31 million in Consulting, of which $8 million related to acquisitions made in 2011 and 2010; primarily severance plus future rent and other real estate costs. Part of a $51 million total 2011 restructuring charge; annualized cost savings expected of approximately $45 million. Restructuring liability of $181 million remained at 2011-12-31.
2011-12-31restructuringin_progress40CorporateUSD 19 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Corporate portion of the 2011 restructuring program; part of the $51 million consolidated 2011 restructuring charge.
2011-12-31restructuringin_progressRisk and Insurance ServicesUSD 1 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		No position eliminations were disclosed for this segment; only the $1 million cost allocation of the $51 million total 2011 restructuring charge is stated.
2011-12-31acquisition_additioncompletedUnited StatesRisk and Insurance Services (7 acquisitions) and Consulting (5 acquisitions)USD 197 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Headcount added through these acquisitions is not disclosed. Consideration comprised $164 million cash plus $33 million deferred/estimated contingent consideration; 2011 acquisitions contributed approximately $79 million of revenue and $12 million of net operating income.
2011-12-31divestiture_reductionannounced2011-12-31United StatesMarsh — Business Process Outsourcing (BPO)USD 17 (millions)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		In Q4 2011 management initiated a plan to exit the BPO business via sale; capitalized software written off, $17 million net of tax, recorded in discontinued operations. Affected headcount not disclosed; announcement date approximated to fiscal year-end as only the quarter is given.
2011-12-31acquisition_additionannounced2012-01-31South Africa, Botswana, NamibiaRisk and Insurance Services (Marsh)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Subsequent event after 2011-12-31 and before the 2012-02-28 filing date; consideration and headcount not disclosed. Announcement date approximated to January 2012 as only the month is given.
2011-12-31restructuringcompleted4402011-01-012011-12-31GlobalConsulting (Mercer) and CorporateUSD 51 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 400 positions at Mercer and 40 positions at Corporate. Total costs of $51 million, primarily severance and benefits.
2011-12-31restructuringin_progressUSD 51,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2011-09-30restructuringin_progressUSD 16 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $16 million in first nine months of 2011, majority related to severance; no employee counts disclosed. Restructuring liability at 9/30/11 was $159 million (severance $12 million; future rent and other $147 million).
2011-09-30restructuringin_progressUSD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $16 million recorded in the first nine months of 2011, mostly severance; includes about $5 million for acquisition-related cost reductions. No employee count, announcement date, or completion date disclosed. Liability at 9/30/11 was $159 million ($12 million severance, $147 million future lease and other costs).
2011-09-30acquisition_additioncompletedUnited StatesRisk and Insurance Services; ConsultingUSD 132 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Seven acquisitions completed in the first nine months of 2011 (four Marsh, three Mercer) for total purchase consideration of $132 million; no headcount added disclosed. 2011 acquisitions contributed about $55 million of revenue in the nine-month period.
2011-09-30acquisition_additionannounced2011-08-312011-12-31South AfricaRisk and Insurance Services (Marsh)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh agreed in August 2011 to acquire the brokerage business of Alexander Forbes, subject to regulatory approval and targeted for completion in Q4 2011; no headcount disclosed. Announcement month only, day not stated.
2011-09-30restructuringin_progressUSD 16 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $16 million recorded in the first nine months of 2011, majority related to severance. Includes approximately $5 million for cost reduction activities related to acquisitions.
2011-09-30restructuringin_progressUSD 16,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2011-06-30restructuringin_progressUSD 5 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Total restructuring costs of $5 million in the first six months of 2011, primarily severance; no employee count disclosed. Restructuring liability at 6/30/11 was $169 million, including $17 million severance and $152 million future rent and other costs.
2011-06-30restructuringin_progressUSD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Restructuring costs of $5M recorded in first six months of 2011, primarily severance; no employee counts, geographies, or completion dates disclosed. Severance liability roll-forward shows $5M accrued and $29M cash paid in 2011 (includes prior-year actions).
2011-06-30acquisition_additioncompletedUnited StatesRisk and Insurance Services; ConsultingUSD 114 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions completed in first six months of 2011 (Marsh: RJF Agencies, Hampton Roads Bonding, Kinloch Boston office; Mercer: Hammond Associates, Evaluation Associates) for $114M total consideration; no headcount added disclosed.
2011-06-30restructuringin_progressUSD 5 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $5 million recorded in first six months of 2011, primarily related to severance.
2011-06-30restructuringin_progressUSD 5,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2011-03-31restructuringin_progressUSD 4 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2011 restructuring costs of $4 million, primarily severance, including about $2 million tied to cost reduction activities for 2010 acquisitions; no employee counts disclosed
2011-03-31acquisition_additioncompletedUnited StatesRisk and Insurance Services; ConsultingUSD 106 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Four Q1 2011 acquisitions (RJF Agencies, Hampton Roads Bonding, Kinloch Boston office, Hammond Associates) for total consideration of $106 million; no headcount figures disclosed
2011-03-31restructuringin_progressCompany-wideUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2011 restructuring costs of $4M, primarily severance, including about $2M tied to cost-reduction actions for 2010 acquisitions; no employee count or completion date disclosed. Restructuring liability was $189M at 2011-03-31 (includes non-severance items such as future lease costs from prior programs).
2011-03-31acquisition_additioncompletedUnited StatesRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Four Q1 2011 acquisitions (RJF Agencies, Hampton Roads Bonding, Kinloch Boston office in Marsh; Hammond Associates in Mercer) with total consideration of $106M; headcount added not disclosed.
2011-03-31restructuringin_progressUSD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $4 million recorded, primarily severance, including approx $2 million related to cost reduction activities for acquisitions made in 2010.
2011-03-31acquisition_additioncompleted2011-01-01United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh acquired RJF Agencies in January 2011.
2011-03-31acquisition_additioncompleted2011-02-01United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh acquired Hampton Roads Bonding and the Boston office of Kinloch Consulting Group in February 2011.
2011-03-31acquisition_additioncompleted2011-01-01United StatesConsultingbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Mercer acquired Hammond Associates in January 2011.
2011-03-31restructuringin_progressUSD 4,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2010-12-31restructuringcompleted450Marsh (Risk and Insurance Services)USD 65 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Position eliminations occurred during 2010 as part of $114 million of 2010-initiated actions (severance/benefits plus future rent and real estate costs); $46 million of the Marsh charge related to cost-reduction for 2010 acquisitions. Annualized savings of approximately $100 million expected program-wide. Residual restructuring liability of $211 million (severance $40 million; future rent $171 million) at 12/31/2010.
2010-12-31restructuringcompleted80Guy Carpenter (Risk and Insurance Services)USD 16 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Position eliminations during 2010 as part of 2010-initiated actions; $6 million of the charge related to cost-reduction for 2010 acquisitions.
2010-12-31restructuringcompleted240Mercer (Consulting)USD 25 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Position eliminations during 2010 as part of 2010-initiated actions; $11 million of the charge related to cost-reduction for 2010 acquisitions.
2010-12-31restructuringcompleted70CorporateUSD 8 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Position eliminations during 2010 as part of 2010-initiated actions (total $114 million across all four components).
2010-12-31restructuringin_progressFirm-wide (actions initiated prior to 2010)USD 27 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2010 costs relate to prior-year restructuring initiatives, mainly severance and related benefits plus adjustments to estimated future rent and real estate costs on previously vacated space; no new position count attributed to 2010.
2010-12-31divestiture_reductioncompleted2010-08-03Risk Consulting and Technology segment (Kroll Inc.)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Entire Risk Consulting and Technology segment divested via sale of Kroll to Altegrity, Inc. for $1.13 billion cash, completed August 3, 2010; Kroll reported as discontinued operations. Subsidiary Kroll Laboratory Specialists (KLS) was sold separately in Q1 2010 for $110 million. No headcount figure disclosed for the divested operations.
2010-12-31restructuringcompleted450GlobalMarsh (Risk and Insurance Services)USD 65 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2010 actions; $46M of the $65M charge related to cost reduction for 2010 acquisitions. Part of a consolidated $114M program eliminating approximately 840 positions firm-wide, with expected annualized savings of about $100M.
2010-12-31restructuringcompleted80GlobalGuy Carpenter (Risk and Insurance Services)USD 16 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2010 actions; $6M of the $16M charge related to cost reduction for 2010 acquisitions. Sub-component of the consolidated $114M 2010 restructuring program.
2010-12-31restructuringcompleted240GlobalMercer (Consulting)USD 25 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2010 actions; $11M of the $25M charge related to cost reduction for 2010 acquisitions. Sub-component of the consolidated $114M 2010 restructuring program.
2010-12-31restructuringcompleted70GlobalCorporateUSD 8 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2010 actions. Sub-component of the consolidated $114M 2010 restructuring program; approximately $63M of the total program related to acquisition cost reductions.
2010-12-31restructuringin_progressGlobalFirm-wideUSD 27 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Costs incurred in fiscal 2010 for restructuring actions initiated prior to 2010 (severance and future rent/real estate on vacated space); employees affected in 2010 not disclosed. Restructuring liability of $211M remained at 2010-12-31.
2010-12-31acquisition_additioncompletedUnited States, United Kingdom, Hong Kong, Singapore, China, Middle EastRisk and Insurance Services (6 acquisitions); Consulting (2 acquisitions)USD 754 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Eight acquisitions completed in 2010 with total purchase consideration of $754M; headcount added through these acquisitions not disclosed. Charge value shown is total purchase consideration, not a workforce charge.
2010-12-31divestiture_reductioncompleted2010-08-03GlobalRisk Consulting and Technology (Kroll)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Kroll to Altegrity completed 2010-08-03 for $1.13B cash; Kroll had revenue of $381M in 2010 (partial year). Headcount removed through the disposition not disclosed. Kroll Laboratory Specialists (KLS) was also sold in Q1 2010.
2010-12-31restructuringcompleted4502010WorldwideMarshUSD 65 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Actions initiated in 2010. Marsh elimination of approximately 450 positions. Charge of $65 million, of which $46 million was acquisition-related.
2010-12-31restructuringcompleted802010WorldwideGuy CarpenterUSD 16 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Actions initiated in 2010. Guy Carpenter elimination of approximately 80 positions. Charge of $16 million, of which $6 million was acquisition-related.
2010-12-31restructuringcompleted2402010WorldwideMercerUSD 25 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Actions initiated in 2010. Mercer elimination of approximately 240 positions. Charge of $25 million, of which $11 million was acquisition-related.
2010-12-31restructuringcompleted702010WorldwideCorporateUSD 8 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Actions initiated in 2010. Corporate elimination of approximately 70 positions. Charge of $8 million.
2010-12-31divestiture_reductioncompleted2010-08-03WorldwideRisk Consulting and Technology (Kroll)Item 1. Business
f5-10k / Qwen3.6-27B-Q8_0		Sale of 100% of Kroll Inc. to Altegrity, Inc. on August 3, 2010. Kroll previously constituted the Risk Consulting and Technology segment. Employee count not explicitly disclosed for the divested entity in the action context, though total company headcount excludes them post-sale.
2010-12-31restructuringin_progressUSD 114,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2010-12-31restructuringin_progressMMC [Member]USD 100,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2010-12-31restructuringin_progressGuy Carpenter [Member] / Acquisition [Member]USD 6,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2010-12-31restructuringin_progressMarsh [Member] / Acquisition [Member]USD 46,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2010-12-31restructuringin_progressMercer [Member] / Acquisition [Member]USD 11,000,000 (absolute)restructuring_footnote
f5-10k / no-ai-xblr
2010-09-30restructuringin_progress2602010-01-01MarshUSD 35 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs primarily severance and benefits; about $34 million of the 2010 program related to cost reduction for 2010 acquisitions; annualized savings expected around $55 million
2010-09-30restructuringin_progress802010-01-01Guy CarpenterUSD 16 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs primarily severance and benefits
2010-09-30restructuringin_progress1202010-01-01MercerUSD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs primarily severance and benefits
2010-09-30restructuringin_progress502010-01-01MMC (corporate)USD 2 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Costs primarily severance and benefits
2010-09-30restructuringin_progressFirm-wide (actions initiated prior to 2010)USD 26 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2010 costs mainly severance and adjustments to future rent on vacated space; liability roll-forward shows $201 million total restructuring liability at September 30, 2010
2010-09-30divestiture_reductioncompleted2010-08-032010-08-03Kroll (former Risk Consulting & Technology segment)USD 1,130 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of Kroll to Altegrity for $1.13 billion cash; Kroll headcount removed from MMC's approximately 50,000 employees; KLS sold in Q1 2010
2010-09-30restructuringin_progress260GlobalMarshUSD 35 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated under restructuring actions initiated in 2010; costs primarily severance and benefits, with about $34 million of 2010 program costs firm-wide relating to acquisition-related cost reductions.
2010-09-30restructuringin_progress80GlobalGuy CarpenterUSD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated under restructuring actions initiated in 2010; annualized cost savings from the full 2010 program expected to be approximately $55 million.
2010-09-30restructuringin_progress120GlobalMercerUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated under restructuring actions initiated in 2010.
2010-09-30restructuringin_progress50GlobalCorporate (MMC)USD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated under restructuring actions initiated in 2010; total 2010 program cost of $61 million across all components.
2010-09-30restructuringin_progressGlobalFirm-wideUSD 26 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Costs incurred in the nine months ended 2010 for actions initiated prior to 2010 (staff reductions and facility consolidations); employee counts not disclosed. Restructuring liability of $201 million remained at 2010-09-30.
2010-09-30divestiture_reductioncompleted2010-08-03GlobalKroll (Risk Consulting & Technology)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Kroll to Altegrity for $1.13 billion cash completed 2010-08-03; associated headcount removed not disclosed.
2010-09-30divestiture_reductioncompleted2010-03-31GlobalKroll Laboratory Specialistsother
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of KLS completed in the first quarter of 2010; exact completion date and associated headcount removed not disclosed.
2010-09-30restructuringin_progress2602010-01-01MarshUSD 35 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-09-30restructuringin_progress802010-01-01Guy CarpenterUSD 16 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-09-30restructuringin_progress1202010-01-01MercerUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-09-30restructuringin_progress502010-01-01MMC CorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-09-30restructuringin_progressFirm-wideUSD 26 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated prior to 2010; primarily severance and rent adjustments.
2010-09-30restructuringin_progressUSD 61,000,000 (absolute)restructuring_footnote
f5-10q / no-ai-xblr
2010-06-30restructuringin_progress1502010-01-01MarshUSD 22 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Position eliminations at Marsh from 2010 restructuring actions; charge primarily severance and benefits
2010-06-30restructuringin_progress702010-01-01Guy CarpenterUSD 15 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Position eliminations at Guy Carpenter from 2010 restructuring actions
2010-06-30restructuringin_progress402010-01-01MercerUSD 2 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Position eliminations at Mercer from 2010 restructuring actions
2010-06-30restructuringin_progress502010-01-01MMC (corporate)USD 2 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Position eliminations at MMC corporate from 2010 restructuring actions
2010-06-30restructuringin_progressFirm-wide infrastructure and operating company business processesUSD 16 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Six months ended June 30, 2010 costs for pre-2010 initiatives, primarily severance and lease/real-estate adjustments
2010-06-30divestiture_reductioncompleted2010-06-062010-08-03Risk Consulting & Technology (Kroll)USD 1,130 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of Kroll to Altegrity for $1.13 billion cash; Kroll results reported as discontinued operations; headcount removed from continuing workforce
2010-06-30divestiture_reductioncompletedKroll Laboratory SpecialistsUSD 110 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		KLS sold in Q1 2010; results reclassified to discontinued operations; $110 million cash generated from disposition
2010-06-30restructuringin_progress150Marsh (Risk and Insurance Services)USD 22 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated in first six months of 2010, primarily severance and benefits; part of a $41 million program total, of which about $25 million related to cost reduction at recent acquisitions. Program-wide annualized savings expected to be about $35 million.
2010-06-30restructuringin_progress70Guy Carpenter (Risk and Insurance Services)USD 15 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated in first six months of 2010; sub-component of the $41 million 2010 restructuring program.
2010-06-30restructuringin_progress40Mercer (Consulting)USD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated in first six months of 2010; sub-component of the $41 million 2010 restructuring program.
2010-06-30restructuringin_progress50MMC corporateUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated in first six months of 2010; sub-component of the $41 million 2010 restructuring program.
2010-06-30restructuringin_progressGlobalFirm-wide (actions initiated prior to 2010)USD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Costs incurred in the six months ended June 30, 2010 for legacy initiatives (severance, benefits, vacated real estate); no employee count disclosed. Remaining liability for all restructuring initiatives was about $211 million, including $49 million future severance and $133 million future lease obligations; $89 million paid during the first half of 2010.
2010-06-30acquisition_additioncompletedUnited StatesMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Haake Companies, Inc., one of the largest independent insurance broking firms in the Midwest, acquired in the first quarter of 2010; headcount added not disclosed.
2010-06-30acquisition_additioncompletedUnited StatesMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Thomas Rutherfoord, Inc., acquired in the first quarter of 2010 to expand Marsh's middle-market share; headcount added not disclosed.
2010-06-30acquisition_additioncompleted2010-04-01United Kingdom / Asia / Middle EastMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		HSBC Insurance Brokers Ltd. acquired April 1, 2010, deepening Marsh's presence in the U.K., Hong Kong, Singapore, China and the Middle East; headcount added not disclosed.
2010-06-30acquisition_additioncompleted2010-04-30United StatesMarsh (Risk and Insurance Services)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Bostonian Group acquired April 30, 2010, one of the largest regional insurance brokerages in New England; headcount added not disclosed. Four 2010 acquisitions carried total purchase consideration of $472 million.
2010-06-30acquisition_additioncompleted2010-07-01Mercer (Consulting)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Innovative Process Administration (IPA), a health benefits record keeping and enrollment technology provider, acquired July 1, 2010; headcount added not disclosed.
2010-06-30acquisition_additioncompleted2010-07-30Mercer (Consulting)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		ORC Worldwide, a human resource knowledge provider, acquired July 30, 2010; headcount added not disclosed. MMC paid about $45 million for the IPA and ORC Worldwide acquisitions combined.
2010-06-30divestiture_reductioncompleted2010-08-03GlobalRisk Consulting & Technology (Kroll)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Kroll sold to Altegrity for $1.13 billion cash, completed August 3, 2010, to be recorded in Q3 2010; headcount removed not disclosed. MD&A indicates the post-sale firm has approximately 50,000 employees.
2010-06-30divestiture_reductioncompletedRisk Consulting & Technology (Kroll Laboratory Specialists)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Kroll Laboratory Specialists (KLS) sold in the first quarter of 2010; results reclassified to discontinued operations and after-tax loss included in 2010 discontinued operations. Headcount removed not disclosed.
2010-06-30restructuringin_progress1502010-01-01MarshUSD 22 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-06-30restructuringin_progress702010-01-01Guy CarpenterUSD 15 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-06-30restructuringin_progress402010-01-01MercerUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-06-30restructuringin_progress502010-01-01MMC CorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2010; primarily severance and benefits.
2010-03-31restructuringin_progressPrimarily Risk and Insurance Services and CorporateUSD 9 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2010 charges relate to actions initiated in prior years, mainly adjustments to estimated future rent and real estate costs for previously vacated space; $53 million of restructuring payments made in the quarter; remaining liability of $215 million at quarter-end, comprising $45 million future severance and benefit payments and $133 million future lease agreements
2010-03-31acquisition_additioncompleted2010-02-01Midwest, U.S.Risk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		No headcount figures disclosed for the acquired workforce
2010-03-31acquisition_additioncompleted2010-03-01Southeast and mid-Atlantic, U.S.Risk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		No headcount figures disclosed for the acquired workforce
2010-03-31acquisition_additioncompleted2010-04-01U.K., Hong Kong, Singapore, China, Middle EastRisk and Insurance Services (Marsh)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Closed April 1, 2010; $194 million paid into escrow March 31, 2010; no headcount disclosed
2010-03-31acquisition_additioncompleted2010-04-30New England, U.S.Risk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Closed April 30, 2010; approximately $230 million paid for HSBC Insurance Brokers and Bostonian Group combined; no headcount disclosed
2010-03-31divestiture_reductioncompletedRisk Consulting & Technology (Kroll)USD 22 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		After-tax loss on disposal of $22 million included in discontinued operations; cash proceeds of $110 million; operating results not reclassified due to immateriality; no headcount disclosed
2010-03-31restructuringin_progressPrimarily Risk and Insurance Services and CorporateUSD 9 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2010 charges relate mainly to prior-year actions, driven by revised rent and real-estate estimates for vacated space; $53M paid during the quarter, $215M liability remaining ($45M severance/benefits, $133M future leases). No employee count disclosed.
2010-03-31acquisition_additioncompleted2010-022010-02United States (Midwest)Risk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Haake Companies, Inc.; part of a combined $253M purchase consideration with Thomas Rutherfoord. No headcount disclosed.
2010-03-31acquisition_additioncompleted2010-032010-03United States (Southeast and mid-Atlantic)Risk and Insurance Services (Marsh)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh acquired Thomas Rutherfoord, Inc.; combined purchase consideration with Haake was $253M (cash $20M, 7.4M shares at $178M, contingent consideration $55M). No headcount disclosed.
2010-03-31divestiture_reductioncompleted2010-03-31Risk Consulting & Technology (Kroll)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Kroll sold Kroll Laboratory Specialists in Q1 2010; $110M cash generated, after-tax loss in discontinued operations. Operating results not reclassified as immaterial. No headcount disclosed.
2010-03-31acquisition_additioncompleted2010-04-012010-04-01United Kingdom, Hong Kong, Singapore, China, Middle EastRisk and Insurance Services (Marsh)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh completed acquisition of HSBC Insurance Brokers Ltd.; $194M escrowed at March 31, 2010 and released April 1, 2010. Includes strategic partnership with HSBC Bank. No headcount disclosed.
2010-03-31acquisition_additioncompleted2010-04-302010-04-30United States (New England)Risk and Insurance Services (Marsh & McLennan Agency)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Bostonian Group Insurance Agency and Bostonian Solutions; approximately $230M paid for this and the HSBC acquisition combined. No headcount disclosed.
2010-03-31restructuringin_progressUSD 9 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Total restructuring costs of $9 million recorded in Q1 2010, primarily related to adjustments to estimated future rent and real estate costs for previously vacated space. Remaining liability of $215 million includes $45 million for future severance and benefit payments.
2010-03-31acquisition_additioncompleted2010-02-01MidwestRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh acquired Haake Companies, Inc. in February 2010.
2010-03-31acquisition_additioncompleted2010-03-01Southeast and mid-Atlantic regionsRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh acquired Thomas Rutherfoord, Inc. in March 2010.
2010-03-31divestiture_reductioncompleted2010-03-31Risk Consulting & Technologydiscontinued_operations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Kroll completed the sale of KLS in Q1 2010.
2009-12-31restructuringcompleted1,500GlobalRisk and Insurance Services — MarshUSD 171 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2009 program charge of $171 million for this sub-component; part of consolidated 2009 restructuring charges of $237 million (severance, benefits, and future rent/real estate costs); positions eliminated during 2009
2009-12-31restructuringcompleted100GlobalRisk and Insurance Services — Guy Carpenterrestructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sub-component of the consolidated 2009 restructuring program ($237 million total charge); charge not broken out separately for this sub-component
2009-12-31restructuringcompleted600GlobalConsulting — MercerUSD 45 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2009 program charge of $45 million for the Consulting segment; part of consolidated 2009 restructuring charges of $237 million
2009-12-31restructuringcompleted200GlobalRisk Consulting & Technology — KrollUSD 8 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2009 program charge of $8 million for this segment; part of consolidated 2009 restructuring charges of $237 million
2009-12-31restructuringcompleted40GlobalCorporateUSD 13 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2009 program charge of $13 million for Corporate; part of consolidated 2009 restructuring charges of $237 million; annualized cost savings from the 2009 program expected to be approximately $200 million
2009-12-31acquisition_additioncompletedUnited States, United Kingdom, Bermuda, AustraliaRisk and Insurance Services (Marsh and Guy Carpenter)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Six acquisitions completed in 2009 (Collins, RJ Neville, IAS, Rattner Mackenzie, Insurance Alliance, NIA Group) with total purchase consideration of $414 million; headcount added through these acquisitions not disclosed
2009-12-31divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Kroll Government Servicesdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Kroll Government Services sold in the second quarter of 2009 and classified as a discontinued operation; headcount removed not disclosed
2009-12-31divestiture_reductionannounced2010-02-282010-03-31United StatesRisk Consulting & Technology — Kroll Laboratory Specialistssubsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Substance abuse testing business sold in February 2010 for $110 million; to be recorded in Q1 2010; exact announcement date not disclosed, month only; headcount removed not disclosed
2009-12-31restructuringcompleted1,5002009GlobalRisk and Insurance ServicesUSD 171 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 1,500 positions at Marsh. Costs of $171 million primarily related to severance, benefits, and future rent.
2009-12-31restructuringcompleted1002009GlobalRisk and Insurance ServicesUSD 171 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 100 positions at Guy Carpenter. Included in total Risk and Insurance Services charge.
2009-12-31restructuringcompleted6002009GlobalConsultingUSD 45 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 600 positions at Mercer. Costs of $45 million.
2009-12-31restructuringcompleted2002009GlobalRisk Consulting & TechnologyUSD 8 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 200 positions at Kroll. Costs of $8 million.
2009-12-31restructuringcompleted402009GlobalCorporateUSD 13 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of approximately 40 positions at Corporate. Costs of $13 million.
2009-12-31divestiture_reductioncompleted2009-05GlobalRisk Consulting & TechnologyMD&A
f5-10k / Qwen3.6-27B-Q8_0		Sale of Kroll Government Services (KGS) in May 2009. Classified as discontinued operations. Employee count not explicitly disclosed for this specific divestiture.
2009-09-30restructuringin_progress200Marsh (Risk and Insurance Services)USD 26 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2009 charges primarily severance, benefits, and future rent/real estate costs
2009-09-30restructuringin_progress200Mercer (Consulting)USD 26 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2009 charges primarily severance, benefits, and future rent/real estate costs
2009-09-30restructuringin_progress5Kroll (Risk Consulting & Technology)USD 1 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2009 charges primarily severance, benefits, and future rent/real estate costs
2009-09-30restructuringin_progress10CorporateUSD 1 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2009 charges primarily severance, benefits, and future rent/real estate costs
2009-09-30restructuringin_progress1,100Marsh (Risk and Insurance Services)USD 97 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine months ended September 30, 2009; annualized savings from all 2009 actions expected at approximately $150 million
2009-09-30restructuringin_progress75Guy Carpenter (Risk and Insurance Services)USD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine months ended September 30, 2009
2009-09-30restructuringin_progress430Mercer (Consulting)USD 34 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine months ended September 30, 2009
2009-09-30restructuringin_progress210Kroll (Risk Consulting & Technology)USD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine months ended September 30, 2009
2009-09-30restructuringin_progress25CorporateUSD 1 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine months ended September 30, 2009
2009-09-30divestiture_reductioncompleted2009-06-30United StatesKroll Government Services (Risk Consulting & Technology)other
f5-10q / GLM-5.3-flash-fp4-HTML		Kroll completed sale of KGS in Q2 2009; headcount impact not disclosed
2009-09-30restructuringin_progress1,100GlobalMarsh (Risk and Insurance Services)USD 97 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30; includes severance, benefits and future rent/real estate costs. Q3 2009 subset: 200 positions, $26 million. Annualized cost savings from the overall 2009 program expected to be about $150 million.
2009-09-30restructuringin_progress75GlobalGuy Carpenter (Risk and Insurance Services)USD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30; no positions reported eliminated in Q3 2009 specifically
2009-09-30restructuringin_progress430GlobalMercer (Consulting)USD 34 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30. Q3 2009 subset: 200 positions, $26 million.
2009-09-30restructuringin_progress210GlobalKroll (Risk Consulting & Technology)USD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30. Q3 2009 subset: 5 positions, $1 million.
2009-09-30restructuringin_progress25GlobalCorporateUSD 1 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30. Q3 2009 subset: 10 positions, $1 million.
2009-09-30restructuringin_progressGlobalFirm-wide (prior-year initiatives)USD 16 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine months ended 2009-09-30 costs for actions initiated before 2009, mainly adjustments to future rent and real estate costs for vacated New York headquarters space; remaining liability of $242 million at 2009-09-30. No employee count disclosed.
2009-09-30acquisition_additioncompletedGlobalRisk and Insurance ServicesUSD 240 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Three acquisitions in nine months ended 2009-09-30 for total purchase consideration of $240 million (includes John B. Collins Associates in April 2009 and International Advisory Services in September 2009); no headcount added disclosed.
2009-09-30divestiture_reductioncompletedUnited StatesKroll Government Services (discontinued operation)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		KGS sale completed in Q2 2009; classified as discontinued operations. No headcount disclosed.
2009-09-30restructuringin_progress2002009-09-30MarshUSD 26 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Third quarter 2009 actions; primarily severance and related benefits.
2009-09-30restructuringin_progress2002009-09-30MercerUSD 26 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Third quarter 2009 actions; primarily severance and related benefits.
2009-09-30restructuringin_progress52009-09-30KrollUSD 1 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Third quarter 2009 actions; primarily severance and related benefits.
2009-09-30restructuringin_progress102009-09-30CorporateUSD 1 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Third quarter 2009 actions; primarily severance and related benefits.
2009-09-30restructuringin_progress1,1002009-09-30MarshUSD 97 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Nine months ended 2009 actions; primarily severance and benefits.
2009-09-30restructuringin_progress752009-09-30Guy CarpenterUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Nine months ended 2009 actions; primarily severance and benefits.
2009-09-30restructuringin_progress4302009-09-30MercerUSD 34 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Nine months ended 2009 actions; primarily severance and benefits.
2009-09-30restructuringin_progress2102009-09-30KrollUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Nine months ended 2009 actions; primarily severance and benefits.
2009-09-30restructuringin_progress252009-09-30CorporateUSD 1 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Nine months ended 2009 actions; primarily severance and benefits.
2009-06-30restructuringin_progress5502009-04-01Marsh (Risk and Insurance Services)USD 47 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Second quarter 2009 restructuring; approximately 550 positions eliminated at Marsh
2009-06-30restructuringin_progress752009-04-01Guy Carpenter (Risk and Insurance Services)USD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Second quarter 2009 restructuring; approximately 75 positions eliminated at Guy Carpenter
2009-06-30restructuringin_progress2302009-04-01Mercer (Consulting)USD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Second quarter 2009 restructuring; approximately 230 positions eliminated at Mercer
2009-06-30restructuringin_progress2002009-04-01Kroll (Risk Consulting and Technology)USD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Second quarter 2009 restructuring; approximately 200 positions eliminated at Kroll
2009-06-30restructuringin_progress8752009-01-01Marsh (Risk and Insurance Services)USD 71 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2009; approximately 875 positions eliminated at Marsh; annualized savings from all 2009 actions expected to be approximately $110 million
2009-06-30restructuringin_progress752009-01-01Guy Carpenter (Risk and Insurance Services)USD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2009; approximately 75 positions eliminated at Guy Carpenter
2009-06-30restructuringin_progress2302009-01-01Mercer (Consulting)USD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2009; approximately 230 positions eliminated at Mercer
2009-06-30restructuringin_progress2002009-01-01Kroll (Risk Consulting and Technology)USD 6 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2009; approximately 200 positions eliminated at Kroll
2009-06-30divestiture_reductioncompleted2009-05-31United StatesKroll Government Services (Risk Consulting and Technology)USD 30 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		Kroll completed sale of Kroll Government Services in Q2 2009; after-tax loss on disposal of $30 million; headcount not disclosed
2009-06-30restructuringin_progress875Not specifiedRisk and Insurance Services — MarshUSD 71 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated during the first six months of 2009; second-quarter portion was 550 positions and $47 million. Charges primarily severance and benefits; annualized cost savings from all 2009 actions expected to be about $110 million.
2009-06-30restructuringin_progress75Not specifiedRisk and Insurance Services — Guy CarpenterUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated during the first six months of 2009; the same 75 positions and $7 million charge were recorded in the second quarter.
2009-06-30restructuringin_progress230Not specifiedConsulting — MercerUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated during the first six months of 2009; the same 230 positions and $8 million charge were recorded in the second quarter.
2009-06-30restructuringin_progress200Not specifiedRisk Consulting & Technology — KrollUSD 6 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions eliminated during the first six months of 2009; the same 200 positions and $6 million charge were recorded in the second quarter (segment labeled Risk Consulting and Technology in the footnote).
2009-06-30restructuringin_progressUnited States (New York headquarters among sites)Firm-wide infrastructure, organization structure and operating company business processesUSD 17 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Costs incurred in the first six months of 2009 for programs begun before 2009, mainly rent and real estate adjustments for vacated New York headquarters space; remaining liability of $243 million at June 30, 2009. Headcount affected not disclosed.
2009-06-30acquisition_additioncompletedUnited StatesRisk and Insurance Services — Guy Carpenterbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Guy Carpenter completed its acquisition of John B. Collins Associates, Inc. in April 2009; headcount added not disclosed.
2009-06-30divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Kroll (Kroll Government Services)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Kroll completed the sale of Kroll Government Services in the second quarter of 2009 (May 2009 per MD&A); business classified as discontinued operations. Headcount removed not disclosed.
2009-06-30divestiture_reductioncompletedNot specifiedRisk Consulting & Technology — Corporate Advisory and Restructuring (residual businesses)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Two small residual businesses within Corporate Advisory and Restructuring were exited in the first quarter of 2009 (principal operations had been divested in Q4 2008). Headcount removed not disclosed.
2009-06-30restructuringin_progress8752009-06-30GlobalMarshUSD 71 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2009; primarily severance and benefits.
2009-06-30restructuringin_progress752009-06-30GlobalGuy CarpenterUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2009; primarily severance and benefits.
2009-06-30restructuringin_progress2302009-06-30GlobalMercerUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2009; primarily severance and benefits.
2009-06-30restructuringin_progress2002009-06-30GlobalKrollUSD 6 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Actions initiated in 2009; primarily severance and benefits.
2009-03-31restructuringin_progress3202009-01-01Marsh (Risk and Insurance Services)USD 25 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2009 restructuring charge primarily severance and benefits from eliminating approximately 320 positions at Marsh; MD&A notes annualized cost savings expected of approximately $27 million
2009-03-31restructuringin_progressFirm-wide infrastructure and operating company business processesUSD 15 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2009 net restructuring costs of $15 million for prior-year initiatives, mainly adjustments to estimated future rent and real estate costs for vacated New York headquarters space; remaining liability $206 million at March 31, 2009
2009-03-31restructuringannounced2009-03-312009-06-30Oliver Wyman Group (Consulting)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 severance driven by capacity reduction; additional capacity-related severance expected in Q2 2009
2009-03-31restructuringin_progress320Marsh (Risk and Insurance Services)USD 25 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First-quarter 2009 charge, primarily severance and benefits, from eliminating approximately 320 positions at Marsh; annualized cost savings expected to be about $27 million. No announcement date or completion timeline disclosed.
2009-03-31restructuringin_progressPrimarily United States (New York headquarters)Firm-wide infrastructure, organization structure and operating company business processesUSD 15 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Net restructuring costs incurred in Q1 2009 on pre-2009 initiatives, mainly from revising estimated future rent and real estate costs for vacated space at the New York headquarters. Remaining liability of $206 million at March 31, 2009; no employee count disclosed.
2009-03-31divestiture_reductioncompletedUnited StatesRisk Consulting & Technology (Corporate Advisory and Restructuring residual businesses)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Two small residual businesses of the Corporate Advisory and Restructuring operation were exited in the first quarter of 2009, following divestiture of the principal operations in Q4 2008. No headcount associated with the exits was disclosed.
2009-03-31acquisition_additionannouncedUnited StatesGuy Carpenter (Risk and Insurance Services)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Guy Carpenter completed its acquisition of John B. Collins Associates, Inc. in April 2009 (after quarter end); no headcount added was disclosed.
2009-03-31restructuringin_progress3202009-03-31MarshUSD 25 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Initiated in Q1 2009; primarily severance and benefits related to elimination of approximately 320 positions at Marsh.
2008-12-31restructuringin_progress1,660Risk and Insurance Services — Marshrestructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 1,660 positions eliminated at Marsh during 2008. Restructuring and related charges of $218 million for the Risk and Insurance Services segment cover Marsh and Guy Carpenter combined and are not allocated between them. Program ongoing; additional charges expected in first half of 2009.
2008-12-31restructuringin_progress360Risk and Insurance Services — Guy Carpenterrestructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 360 positions eliminated at Guy Carpenter during 2008. Restructuring and related charges of $218 million for the Risk and Insurance Services segment cover Marsh and Guy Carpenter combined and are not allocated between them.
2008-12-31restructuringin_progress490Consulting — MercerUSD 40 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 490 positions eliminated at Mercer during 2008 as part of an operational efficiency effort; charge comprises restructuring and related charges recorded at Mercer.
2008-12-31restructuringin_progress300Risk Consulting & TechnologyUSD 45 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 300 positions eliminated in the segment during 2008. The $45 million segment charge includes the $28 million loss on disposal of the U.K. restructuring businesses, shown separately below.
2008-12-31restructuringin_progress85CorporateUSD 9 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 85 positions eliminated at Corporate level for actions initiated in 2008. Corporate also recorded $76 million of charges for actions initiated in prior years (see separate record).
2008-12-31othercompleted700United KingdomRisk and Insurance Services — Marshrestructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 700 positions outsourced rather than eliminated as part of Marsh's U.K. back office outsourcing initiative during 2008.
2008-12-31restructuringin_progressUnited States / United KingdomCorporateUSD 76 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2008 charges for restructuring actions initiated in prior years, primarily a $62 million charge to exit five floors of the New York headquarters plus $11 million for previously vacated U.K. and other space. Primarily real estate; no headcount reduction disclosed. Remaining liability of approximately $126 million at year-end.
2008-12-31divestiture_reductioncompletedUnited KingdomRisk Consulting & Technology — Corporate Advisory and Restructuringdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		U.K. restructuring business sold to its management team in a leveraged buyout during Q4 2008; net assets written off. The $28 million loss on disposal is included in the $45 million Risk Consulting & Technology restructuring and related charges. Headcount not disclosed; MMC receives royalties on future revenue over four years.
2008-12-31divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Corporate Advisory and Restructuringdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		U.S. restructuring business sold to its management team in a leveraged buyout during Q4 2008, financed with a seller note. Headcount not disclosed. Filer expects an $18 million gain if scheduled payments are received.
2008-12-31divestiture_reductioncompletedBrazilRisk and Insurance Services — Marshdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Mediservice, a Brazilian claims administration operation, completed in the first quarter of 2008; gain net of tax reported in discontinued operations. Headcount not disclosed.
2008-12-31divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Krolldiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Kroll Crucible, a division of Kroll's government services operation, completed in the third quarter of 2008; loss net of tax reported in discontinued operations. Headcount not disclosed.
2008-12-31acquisition_additioncompletedbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		12 acquisitions completed during 2008 for total purchase consideration of $166 million, plus $14 million of contingent purchase consideration on prior acquisitions. Headcount added through acquisitions not disclosed.
2008-12-31restructuringcompleted1,6602008GlobalMarshUSD 218 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of positions at Marsh. Part of 2008 restructuring actions.
2008-12-31restructuringcompleted3602008GlobalGuy CarpenterMD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of positions at Guy Carpenter. Included in Risk and Insurance Services total charge.
2008-12-31restructuringcompleted4902008GlobalMercerUSD 40 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of positions at Mercer. Part of Consulting segment restructuring.
2008-12-31restructuringcompleted3002008GlobalRisk Consulting & TechnologyUSD 45 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of positions in Risk Consulting & Technology segment.
2008-12-31restructuringcompleted852008GlobalCorporateUSD 9 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Elimination of positions at Corporate level.
2008-12-31divestiture_reductioncompleted2008-12-31United KingdomRisk Consulting & TechnologyUSD 28 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Sale of U.K. restructuring businesses to management team. Net assets written off.
2008-12-31divestiture_reductioncompleted2008-12-31United StatesRisk Consulting & TechnologyMD&A
f5-10k / Qwen3.6-27B-Q8_0		Sale of U.S. restructuring business to management team. Financed with seller note.
2008-09-30restructuringin_progress6342008-09-30Marsh (Risk and Insurance Services)USD 78 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q3 2008 charge includes severance and related benefits, consulting fees, accelerated amortization and real estate costs; 634 positions eliminated at Marsh
2008-09-30restructuringin_progress3192008-09-30Guy Carpenter (Risk and Insurance Services)USD 28 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2008 restructuring costs; 319 positions eliminated at Guy Carpenter
2008-09-30restructuringin_progress832008-09-30Risk Consulting and TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2008 restructuring costs; 83 positions eliminated
2008-09-30restructuringin_progress702008-09-30CorporateUSD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month 2008 restructuring costs; 70 positions eliminated
2008-09-30otherin_progress6002008-09-30United KingdomMarsh back officerestructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Marsh outsourced approximately 600 positions as part of U.K. back office outsourcing initiative; positions transferred rather than eliminated
2008-09-30plant_closurein_progress2008-09-30New York, NYCorporate — New York headquartersUSD 49 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Charge for future rent and other real estate costs to exit five floors of MMC's New York headquarters building under 2006 restructuring plan; remaining liability for prior initiatives $118 million at quarter-end
2008-09-30divestiture_reductioncompleted2008-10-31United StatesCorporate Advisory and Restructuring (Risk Consulting & Technology)other
f5-10q / GLM-5.3-flash-fp4-HTML		U.S. corporate advisory and restructuring operations sold in a leveraged management buyout in October 2008; MMC negotiating disposition of two remaining U.K.-based components and may incur exit costs; no headcount disclosed
2008-09-30restructuringin_progress1,142GlobalRisk and Insurance Services — MarshUSD 117 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2008 positions eliminated; 634 of the 1,142 were eliminated in Q3 2008 alone, within a Q3 charge of $81M firm-wide. Annualized cost savings from 2008 actions expected to be about $170M; further charges expected in Q4 2008.
2008-09-30restructuringin_progress319GlobalRisk and Insurance Services — Guy CarpenterUSD 28 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2008 positions eliminated; primarily severance and benefits.
2008-09-30restructuringin_progress83GlobalRisk Consulting & TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2008 positions eliminated.
2008-09-30restructuringin_progress70GlobalCorporateUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Nine-month 2008 positions eliminated.
2008-09-30otherin_progress600United KingdomRisk and Insurance Services — Marsh (back office)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Approximately 600 positions outsourced under Marsh's U.K. back office outsourcing initiative during the first nine months of 2008; described as outsourcing rather than elimination.
2008-09-30restructuringcompletedUnited StatesCorporate (New York headquarters)USD 49 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q3 2008 charge for future rent and real estate costs to exit five floors of the New York HQ under a 2006 plan; no headcount reduction disclosed. Corporate expenses also included a $9M charge for reserve adjustments on exiting certain London facilities.
2008-09-30divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Corporate Advisory and Restructuringsubsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		In October 2008 (after quarter-end) MMC sold the U.S. corporate advisory and restructuring operations in a leveraged management buyout; MMC was negotiating with management of two remaining U.K. components and may incur exit costs. No headcount disclosed.
2008-09-30divestiture_reductioncompletedUnited StatesRisk Consulting & Technology — Kroll (government services)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Kroll completed the sale of Kroll Crucible, a division of its government services operation; loss on disposal included in Q3 2008 discontinued operations. No headcount disclosed.
2008-09-30divestiture_reductioncompleted2008-02-01BrazilRisk and Insurance Services — Marsh (Mediservice)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Marsh completed the sale of a medical administrative claims business in Brazil on February 1, 2008; gain included in nine-month 2008 discontinued operations. No headcount disclosed.
2008-09-30restructuringin_progress1,1422008-01-01GlobalMarshUSD 117 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of 2008 actions resulting in $160M total costs for the nine months ended Sept 30, 2008.
2008-09-30restructuringin_progress3192008-01-01GlobalGuy CarpenterUSD 28 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of 2008 actions resulting in $160M total costs for the nine months ended Sept 30, 2008.
2008-09-30restructuringin_progress832008-01-01GlobalRisk Consulting and TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of 2008 actions resulting in $160M total costs for the nine months ended Sept 30, 2008.
2008-09-30restructuringin_progress702008-01-01GlobalCorporateUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of 2008 actions resulting in $160M total costs for the nine months ended Sept 30, 2008.
2008-09-30restructuringin_progress6002008-01-01United KingdomMarshrestructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh outsourced an additional 600 positions as part of its U.K. back office outsourcing initiative. No specific charge attributed to this headcount reduction in the footnote.
2008-06-30restructuringin_progress5082008-01-01Marsh (risk and insurance services)USD 39 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2008 restructuring actions; 508 positions eliminated at Marsh
2008-06-30restructuringin_progress3232008-01-01Guy Carpenter (risk and insurance services)USD 25 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2008 restructuring actions; 323 positions eliminated at Guy Carpenter
2008-06-30restructuringin_progress772008-01-01Risk Consulting and TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2008 restructuring actions; 77 positions eliminated
2008-06-30restructuringin_progress702008-01-01CorporateUSD 8 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		First six months of 2008 restructuring actions; 70 positions eliminated at Corporate
2008-06-30restructuringin_progress508GlobalRisk and Insurance Services — MarshUSD 39 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six-month 2008 cumulative figures; Q2 2008 portion was 362 positions and $25 million. Primarily severance and benefits; annualized cost savings expected to be about $100 million firm-wide.
2008-06-30restructuringin_progress323GlobalRisk and Insurance Services — Guy CarpenterUSD 25 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six-month 2008 cumulative figures; all of these actions occurred in Q2 2008 (same counts and charge). Primarily severance and benefits.
2008-06-30restructuringin_progress77GlobalRisk Consulting & TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six-month 2008 cumulative figures; Q2 2008 portion was 49 positions and $3 million. Primarily severance and benefits.
2008-06-30restructuringin_progress70GlobalCorporateUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Six-month 2008 cumulative figures; Q2 2008 portion was 38 positions and $2 million. Primarily severance and benefits.
2008-06-30restructuringin_progressLondon, United Kingdom (primarily)Firm-wide infrastructure and operating company business processesUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Pre-2008 initiatives; six-month 2008 charge of $7 million (Q2 2008 was a $2 million net credit) from revising estimated costs to exit certain London facilities. Remaining liability of $83 million at June 30, 2008; no position counts disclosed for the 2008 activity.
2008-06-30restructuringin_progress5082008-06-30GlobalMarshUSD 39 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of six-month 2008 actions resulting in $79 million total costs.
2008-06-30restructuringin_progress3232008-06-30GlobalGuy CarpenterUSD 25 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of six-month 2008 actions resulting in $79 million total costs.
2008-06-30restructuringin_progress772008-06-30GlobalRisk Consulting and TechnologyUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of six-month 2008 actions resulting in $79 million total costs.
2008-06-30restructuringin_progress702008-06-30GlobalCorporateUSD 8 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of six-month 2008 actions resulting in $79 million total costs.
2008-03-31restructuringin_progress1462008-03-31Marsh (Risk and Insurance Services)USD 14 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Part of Q1 2008 restructuring totaling $25 million, primarily severance and related benefits
2008-03-31restructuringin_progress282008-03-31Risk Consulting and TechnologyUSD 3 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Part of Q1 2008 restructuring totaling $25 million
2008-03-31restructuringin_progress322008-03-31CorporateUSD 7 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Part of Q1 2008 restructuring totaling $25 million
2008-03-31restructuringannounced3002008-03-312008-06-30Guy CarpenterUSD 30 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Over 300 positions to be eliminated in Q2 2008; expected annualized savings of $40 million
2008-03-31restructuringin_progress146Risk and Insurance Services (Marsh)USD 14 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First-quarter 2008 restructuring; charge primarily severance and related benefits. Part of a $25 million program totaling 206 positions across three components.
2008-03-31restructuringin_progress28Risk Consulting & TechnologyUSD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First-quarter 2008 restructuring component; charge primarily severance and related benefits.
2008-03-31restructuringin_progress32CorporateUSD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		First-quarter 2008 restructuring component; charge primarily severance and related benefits.
2008-03-31restructuringin_progressLondonCorporate / firm-wide infrastructureUSD 8 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Pre-2008 cost-savings initiatives; Q1 2008 charge driven mainly by higher estimated costs to exit certain London facilities. Remaining liability of $96 million at March 31, 2008. No employee count disclosed.
2008-03-31restructuringannounced3002008-06-30Guy Carpenter (Risk and Insurance Services)USD 30 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Actions expected during Q2 2008; filer states elimination of 'over 300' positions with expected annualized savings of $40 million. Count recorded as 300 per filer's stated floor.
2008-03-31restructuringcompleted1462008-01-01MarshUSD 14 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Q1 2008 actions; primarily severance and related benefits.
2008-03-31restructuringcompleted282008-01-01Risk Consulting and TechnologyUSD 3 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Q1 2008 actions; primarily severance and related benefits.
2008-03-31restructuringcompleted322008-01-01CorporateUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Q1 2008 actions; primarily severance and related benefits.
2008-03-31restructuringannounced3002008-03-312008-06-30Guy CarpenterUSD 30 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Expected to be completed in Q2 2008; elimination of over 300 positions.
2007-12-31restructuringcompleted2005-03Primarily Risk and Insurance ServicesUSD 4 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Multi-year program of staff reductions and facility consolidations announced March 2005; actions complete. 2007 activity: $4 million expense plus utilization of $34 million of prior accruals; cumulative accrued charges of $376 million (2005-2006); annualized savings approximately $400 million.
2007-12-31restructuringin_progress2006-09Risk and Insurance ServicesUSD 2 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		2007 net restructuring charges of $10 million, primarily severance and benefits, split RIS $2M / Consulting $3M / Corporate $5M. Additional $21 million of related 2007 charges, mainly accelerated leasehold-improvement amortization; cumulative first-phase costs $56 million since inception; annualized savings approximately $135 million; actions substantially complete except certain headquarters-building items. Total 2007 net restructuring costs across all plans were $98 million.
2007-12-31restructuringin_progress2006-09ConsultingUSD 3 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Component of the $10 million of 2007 severance-and-benefits restructuring charges under the first phase announced September 2006; actions substantially complete at year-end 2007 except certain headquarters-building items.
2007-12-31restructuringin_progress2006-09CorporateUSD 5 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Component of the $10 million of 2007 severance-and-benefits restructuring charges under the first phase announced September 2006; actions substantially complete at year-end 2007 except certain headquarters-building items.
2007-12-31reduction_in_forcein_progress1702006Marsh (Risk and Insurance Services)USD 39 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Approximately 170 positions eliminated through staff reductions and attrition; actions identified in Q4 2006. 2007 charges of $39 million (roll-forward: $37 million severance and benefits, $2 million future rent); cumulative charges $53 million through 2007; annualized savings approximately $40 million; filer states actions substantially complete.
2007-12-31reduction_in_forcecompleted842007Marsh (Risk and Insurance Services)USD 16 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Fourth-quarter 2007 Marsh actions; charges recorded for severance and related benefits; annualized savings of $12 million.
2007-12-31divestiture_reductioncompleted2007-01-312007-08-03Investment management segment (Putnam)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Great-West Lifeco completed its $3.9 billion cash purchase of Putnam Investments Trust on August 3, 2007 (agreement dated January 31, 2007); MMC's after-tax gain was $1.9 billion. Headcount of the divested business is not disclosed in this filing.
2007-12-31restructuringcompleted84Risk and Insurance Services (Marsh)USD 16 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Actions taken in the fourth quarter of 2007 eliminated 84 positions; charges were for severance and related benefits. Announcement date not specified beyond Q4 2007.
2007-12-31restructuringin_progressFirm-wide infrastructure, organization structure and operating company business processesUSD 10 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Program announced September 2006; $10M of net restructuring charges recorded in FY2007 (risk and insurance services $2M, consulting $3M, corporate $5M). First phase substantially complete except for certain headquarters building actions; first phase delivered approximately $135M annualized savings.
2007-12-31restructuringcompleted170Risk and Insurance Services (Marsh)USD 39 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 170 positions eliminated through staff reductions and attrition identified in Q4 2006; $39M of the $53M cumulative charges were recorded in FY2007. Actions resulted in approximately $40M annualized savings.
2007-12-31restructuringcompletedRisk and Insurance ServicesUSD 4 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		2005 Plan (announced March 2005) actions are complete; $4M of expense recorded in FY2007 in risk and insurance services. Program to date delivered approximately $400M annualized savings.
2007-12-31divestiture_reductioncompleted2007-08-03Investment management (Putnam Investments Trust)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Great-West Lifeco completed its purchase of Putnam on August 3, 2007 for $3.9 billion cash; headcount removed through the disposition not disclosed.
2007-12-31acquisition_additioncompletedbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Six acquisitions completed during 2007 for total purchase consideration of $159 million; headcount added through these acquisitions not disclosed.
2007-12-31restructuringcompleted1702006-10-012007-12-31GlobalRisk and Insurance Services (Marsh)USD 53 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Marsh identified actions resulting in elimination of approximately 170 positions through staff reductions and attrition. Charges of $53 million incurred through Dec 31, 2007 ($39 million in 2007). Annualized savings of $40 million.
2007-12-31restructuringcompleted842007-10-012007-12-31GlobalRisk and Insurance Services (Marsh)USD 16 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		In Q4 2007, Marsh took additional actions resulting in elimination of 84 positions. Charges of $16 million for severance and related benefits. Annualized savings of $12 million.
2007-12-31restructuringcompleted2006-09-012007-12-31GlobalCorporate / Firm-wideUSD 56 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		2006 Cost-Savings Initiative (Phase 1). Total costs of $56 million incurred through Dec 31, 2007 ($20 million restructuring charges, $36 million related charges). Net of $74 million gain on sale of HQ floors. Annualized savings of $135 million.
2007-09-30restructuringin_progress2006-09-012008-12-31Firm-wide infrastructure, organization structure and operating company business processesUSD 225 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		2006 Savings Initiative targeting ~$350M annualized savings when fully implemented by end of 2008; Phase 1 substantially complete with ~$135M annualized savings realized through 2007-09-30
2007-09-30reduction_in_forcein_progress1702006-12-01Marsh (insurance services)USD 45 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Elimination of 170 positions via staff reductions and attrition; expected annualized savings ~$40M; $41M of charges incurred through 2007-09-30, of which $27M in first nine months of 2007
2007-09-30restructuringin_progress2005-03-01Risk and insurance servicesUSD 3 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2005 Plan restructuring initiatives involving staff reductions and facility consolidations; $3M expense recorded in nine months ended 2007-09-30; remaining liability $64M at 2007-09-30
2007-09-30divestiture_reductioncompleted2007-08-032007-08-03Putnam (investment management segment)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Great-West Lifeco completed purchase of Putnam Investments Trust for $3.9B; entire investment management segment removed from MMC; pre-tax gain $3.0B ($1.9B after tax); no headcount figure disclosed
2007-09-30restructuringin_progress2006-092008-12-31GlobalFirm-wide (corporate infrastructure, IT, real estate, operating company processes)USD 7 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Phase 1 net restructuring charges of $7M in first nine months of 2007; MD&A describes the same program as the 2006 Savings Initiative targeting ~$350M annualized savings by end-2008 at ~$225M of costs. No employee count disclosed.
2007-09-30restructuringin_progress1702006-12Not specifiedRisk and Insurance Services (Marsh)USD 45 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Position eliminations via staff reductions and attrition; ~$45M of severance and facility exit costs expected, of which $27M recorded in first nine months of 2007. Expected annualized savings of ~$40M; $30M realized through 9/30/07.
2007-09-30restructuringin_progress2005-03GlobalFirm-wide (staff reductions and facilities consolidation)USD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Expense of $3M recorded in nine months ended 9/30/07 within risk and insurance services; remaining liability of $64M at 9/30/07. No employee count disclosed for the 2007 activity.
2007-09-30divestiture_reductioncompleted2007-08-032007-08-03United StatesInvestment Management (Putnam Investments Trust)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale to Great-West Lifeco completed 8/3/07 for $3.9B cash; pre-tax gain of $3.0B ($1.9B after tax). Headcount removed not disclosed.
2007-09-30acquisition_additioncompletedNot specifiedNot specifiedUSD 141 (millions)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Three acquisitions in nine months ended 9/30/07 for total purchase consideration of $141M; individual closing dates and headcount added not disclosed.
2007-09-30restructuringin_progress1702006-12-01Risk and Insurance ServicesUSD 45 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh identified actions expected to result in elimination of 170 positions through staff reductions and attrition. Expected charges of approx $45 million for severance and exit costs. $27 million incurred in first nine months of 2007.
2007-09-30restructuringin_progress2006-09-012008-12-31CorporateUSD 225 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		2006 Savings Initiative announced Sept 2006. Expected to entail restructuring and related costs of approx $225 million. Phase 1 substantially complete. Further actions expected through end of 2008.
2007-06-30restructuringin_progress2006-09-012007-09-30Firm-wide (corporate infrastructure, organization structure, operating company business processes)USD 225 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Phase 1 began September 2006, expected complete Q3 2007; targeted annualized savings of ~$350 million when fully implemented by end of 2008. Restructuring costs from inception through June 30, 2007 were $17 million with related charges of $30 million (net of a $74 million gain on sale of headquarters floors). Phase 1 substantially complete as of June 30, 2007.
2007-06-30reduction_in_forcein_progress1702006-09-01Marsh (risk and insurance services)USD 45 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Elimination of 170 positions via staff reductions and attrition; expected annualized savings ~$40 million. Through June 30, 2007, $39 million of charges incurred, of which $25 million in the first six months of 2007; remaining liability of $30 million at June 30, 2007.
2007-06-30restructuringin_progress2005-03-01Risk and insurance servicesUSD -3 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		MMC recorded a $3 million credit in the six months ended June 30, 2007 under the 2005 Plan; remaining liability of $65 million at June 30, 2007.
2007-06-30divestiture_reductionannounced2007-02-012007-08-03Putnam (investment management segment)USD 3,900 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Great-West Lifeco Inc. purchase of Putnam Investments Trust for $3.9 billion in cash closed August 3, 2007 (subsequent event); entire investment management segment divested. Gain to be recognized in Q3 2007; proceeds after taxes and minority interest expected to approach $2.5 billion. Headcount of affected employees not disclosed.
2007-06-30restructuringin_progress2006-092007-09-30GlobalRisk and Insurance ServicesUSD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sub-component of 2006 Plan Phase 1; net restructuring charges of $5 million incurred in first six months of 2007, primarily severance. Program-wide Phase 1 expected to yield ~$160 million annualized savings; no employee count disclosed.
2007-06-30restructuringin_progress2006-092007-09-30GlobalConsultingUSD 2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sub-component of 2006 Plan Phase 1; net restructuring charges of $2 million incurred in first six months of 2007. No employee count disclosed.
2007-06-30restructuringin_progress170Risk and Insurance Services (Marsh)USD 25 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Positions to be eliminated through staff reductions and attrition; expected total charges ~$45 million (severance and facility exit costs), of which $39 million incurred through June 30, 2007 and $25 million recorded in first six months of 2007; expected annualized savings ~$40 million.
2007-06-30restructuringin_progress2005-03GlobalRisk and Insurance Servicesrestructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Legacy plan; a net credit of $3 million recorded in first six months of 2007 within risk and insurance services; remaining liability of $65 million at June 30, 2007. No employee count disclosed for the period.
2007-06-30divestiture_reductioncompleted2007-02-012007-08-03United StatesInvestment Management (Putnam)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Great-West Lifeco completed its $3.9 billion cash purchase of Putnam on August 3, 2007 (after quarter end); gain to be recognized in Q3 2007, after-tax proceeds expected to approach $2.5 billion. Headcount removed not disclosed.
2007-06-30restructuringin_progress1702007-01-01Risk and Insurance ServicesUSD 45 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh identified actions expected to result in elimination of 170 positions through staff reductions and attrition. Expected charges of $45 million for severance and exit costs. $25 million incurred in first six months of 2007.
2007-06-30restructuringin_progress2006-09-012007-09-30Corporate / Firm-wideUSD 7 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2006 Plan Phase 1. Net restructuring charges of $7 million incurred in first six months of 2007. Phase 1 expected to be completed during third quarter of 2007.
2007-03-31restructuringin_progress2006-09-012008-12-31Firm-wideUSD 225 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Announced September 2006; expected annualized savings of approximately $350 million when fully implemented by end of 2008. Phase 1 began September 2006; Q1 2007 restructuring costs of $4 million and related charges of $11 million.
2007-03-31reduction_in_forcein_progress1702007-01-01Marsh (risk and insurance services)USD 45 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Elimination of 170 positions through staff reductions and attrition; expected annualized savings of approximately $40 million. Through March 31, 2007, $22 million of charges recorded, including in Q1 2007.
2007-03-31restructuringin_progress2006-092007-06-30WorldwideFirm-wide — corporate infrastructure, IT, real estate and operating company processesUSD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Phase 1 net restructuring charges of $4 million in Q1 2007 (risk and insurance services $3M, consulting $1M); no employee count disclosed. Phase 1 expected savings ~$160M; full 2006 Plan targets ~$350M annualized savings and ~$225M costs by end of 2008. Phase 1 expected complete by Q2 2007 except certain headquarters-building actions.
2007-03-31restructuringin_progress170Risk and Insurance Services (Marsh)USD 45 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Ongoing review identified elimination of 170 positions via staff reductions and attrition; ~$45M expected severance and facility exit charges, of which $22M recorded in Q1 2007; expected annualized savings ~$40M; remaining liability $29M at 2007-03-31. Announcement date not disclosed.
2007-03-31restructuringin_progress2005-03WorldwideFirm-wide — staff reductions and facilities consolidationUSD -2 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Negative value reflects a $2 million credit recorded in Q1 2007 in risk and insurance services; no employees affected disclosed for the quarter. Remaining liability $80M at 2007-03-31.
2007-03-31divestiture_reductionannounced2007-02-012007-06-30United StatesInvestment Management (Putnam Investments Trust)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Agreement to sell Putnam to Great-West Lifeco for $3.9 billion cash; expected to close in Q2 2007. No headcount impact of the sale is disclosed in this filing.
2007-03-31restructuringin_progress1702007-01-01Risk and Insurance ServicesUSD 22 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Marsh identified actions expected to result in elimination of 170 employee positions through staff reductions and attrition. Q1 2007 costs incurred were $22 million.
2007-03-31restructuringin_progress2006-09-012007-06-30Corporate / Firm-wideUSD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2006 Plan Phase 1. Net restructuring charges of $4 million incurred in Q1 2007. Phase 1 expected to be completed by Q2 2007.
2006-12-31restructuringcompleted2005-03Primarily Risk and Insurance Services; also corporate (headquarters space reduction)USD 66 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Plan initiated in Q1 2005. FY2006 charges of $66 million ($39 million risk and insurance services, $27 million corporate); severance utilization of $87 million in FY2006. Actions complete as of this filing, with annualized savings of approximately $400 million being realized; FY2006 activity also included headquarters space-reduction costs of approximately $40 million through June 30, 2006. Employee counts for the plan are not disclosed in this filing.
2006-12-31restructuringin_progress7502006-092007-06Firm-wideCorporate infrastructure (IT, real estate, corporate functions) and operating company business processesUSD 59 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Disclosed as staff reductions of more than 750. FY2006 net Phase 1 charge was $10 million: $59 million severance and benefits, $6 million future rent, and $(55) million other exit credits, including a $74 million gain on the sale of five floors of the New York headquarters building. Phase 1 targets approximately $160 million of annualized savings, with roughly $110 million expected from Q1 2007; completion expected by Q2 2007 except certain headquarters-building actions.
2006-12-31restructuringin_progress1702006-12Risk and Insurance Services (Marsh)USD 14 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Marsh actions identified during 2006 to eliminate 170 positions; exact announcement date not disclosed. Q4 2006 costs of $14 million ($7 million severance and benefits, $7 million future rent on non-cancelable leases). Total Phase 2 charges expected at approximately $40 million; expected to raise 2006 Plan annualized savings by approximately $40 million.
2006-12-31restructuringannounced2006-092008-12Firm-wide infrastructure (IT, procurement, human resources, finance, real estate), organizational structure, business processesMD&A
f5-10k / GLM-5.3-flash-HTML		One or more additional phases expected to yield approximately $190 million of annualized savings; detailed plans not yet complete, so headcount impacts and costs are not quantified. Overall 2006 Plan targets approximately $350 million of annualized savings with approximately $225 million of associated charges by end of 2008.
2006-12-31divestiture_reductioncompleted2005-122006-01-31Risk and Insurance Services (claims management — majority interest in Sedgwick CMS Holdings)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Agreement reached December 2005; sale completed January 31, 2006. Headcount not disclosed; gain on sale recognized in discontinued operations.
2006-12-31divestiture_reductioncompleted2006-032006-09United KingdomRisk and Insurance Services (wholesale insurance brokerage — Price Forbes)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		U.K.-based wholesale insurance broker classified as a discontinued operation in Q1 2006; sale completed September 2006. Headcount not disclosed; loss on disposal recognized in discontinued operations.
2006-12-31divestiture_reductioncompleted2006-122006-12InternationalRisk Consulting & Technology (Kroll Security International — high-risk asset and personal protection division)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		Kroll completed the sale of KSI in Q4 2006; gain on disposal and related results reported in discontinued operations. Headcount not disclosed.
2006-12-31divestiture_reductionannounced2,6002007-01-312007-06United States (Boston headquarters); offices in London and TokyoInvestment Management (Putnam Investments — entire segment)subsequent_events
f5-10k / GLM-5.3-flash-HTML		Stock purchase agreement to sell Putnam Investments Trust to Great-West Lifeco Inc. for $3.9 billion in cash, with expected after-tax proceeds of approximately $2.5 billion. Putnam employed approximately 2,600 colleagues as of January 1, 2007. Closing expected mid-2007; Putnam to be reported as a discontinued operation from Q1 2007, and MMC retains specified indemnification obligations.
2006-12-31restructuringin_progress7502006-092007-06-30GlobalFirm-wide infrastructure, IT, real estate, corporate functions and operating company processesUSD 10 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Staff reductions of more than 750 expected. Net 2006 charge of $10M includes a $74M gain on sale of five headquarters floors offset by severance and exit costs. Phase 1 expected annualized savings of approximately $110M beginning Q1 2007; actions expected complete by Q2 2007 except certain headquarters building actions.
2006-12-31reduction_in_forcein_progress1702006-12GlobalMarsh (Risk and Insurance Services)USD 40 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Phase 2 identified through Marsh's ongoing review of operations; $14M of the approximately $40M expected charges incurred in Q4 2006. Expected to increase annualized savings by approximately $40M. Announcement month not specified beyond Q4 2006.
2006-12-31restructuringcompleted2005-032006-12-31GlobalRisk and Insurance Services; CorporateUSD 66 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Multi-year program; only fiscal 2006 activity captured ($66M: risk and insurance services $39M, corporate $27M). Actions under the 2005 Plan are complete; program is currently realizing annualized savings of approximately $400M. Employees affected during 2006 not separately disclosed.
2006-12-31acquisition_additioncompleted2006-12-31GlobalMultipleUSD 200 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		16 acquisitions during 2006 for total purchase consideration of $200M (goodwill of $132M). Headcount added through these acquisitions not disclosed.
2006-12-31divestiture_reductioncompleted2005-122006-01-31GlobalRisk and Insurance Services (Sedgwick Claims Management Services)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of MMC's majority interest in SCMS completed January 31, 2006; gain recognized in Q1 2006. Headcount removed not disclosed.
2006-12-31divestiture_reductioncompleted2006-032006-09-30United KingdomRisk and Insurance Services (Price Forbes wholesale brokerage)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Classified as discontinued operation in Q1 2006; sale completed September 2006 with a loss on disposal. Headcount removed not disclosed.
2006-12-31divestiture_reductioncompleted2006-12-31InternationalRisk Consulting and Technology (Kroll Security International)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Kroll's international high-risk asset and personal protection division completed in Q4 2006; gain on disposal recognized in discontinued operations. Headcount removed not disclosed.
2006-12-31restructuringin_progress7502006-09-012007-06-30GlobalCorporate Infrastructure and Operating CompaniesUSD 10 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Phase 1 of the 2006 Plan. Staff reductions of more than 750 expected. Net charge of $10 million recorded in 2006.
2006-12-31restructuringannounced1702006-12-31GlobalRisk and Insurance ServicesUSD 40 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Phase 2 of the 2006 Plan. Marsh identified additional actions to reduce 170 positions. Expected additional charges of approximately $40 million. Costs of $14 million incurred in Q4 2006.
2006-09-30restructuringin_progress7502006-09-012007-03-31Firm-wide infrastructure, organization structure and operating company business processesUSD 41 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Phase 1 of 2006 Plan; staff reductions of more than 750 expected; Q3 2006 charge of $41M per footnote ($42M per MD&A including facility exit costs); phase 1 actions expected to be completed by Q1 2007; total program charges expected of $225M with ~$350M annualized savings by end of 2008
2006-09-30restructuringin_progress2005-03-01Risk and insurance services $43M, corporate $27M, consulting $(1)M of 2006 chargesUSD 69 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2005 Plan actions substantially complete; $69M of charges/changes in estimates in the nine months ended September 30, 2006; remaining liability of $110M at 9/30/06; annual savings of approximately $400 million being realized
2006-09-30restructuringin_progress2004-11-01restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2004 Plan actions substantially complete; $28M utilized in 2006; remaining liability of $32M at 9/30/06
2006-09-30restructuringin_progress7502006-092007-03-31GlobalFirm-wide (corporate infrastructure and operating company processes)USD 41 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Filer states 'more than 750' staff reductions expected in Phase 1; 750 is a disclosed floor, not an exact count. Q3 2006 charge of $41M split: risk and insurance services $18M, risk consulting and technology $1M, consulting $18M, corporate $4M (charges presented by segment; headcount not disaggregated, so one consolidated record emitted). Phase 1 expected complete by Q1 2007; full program targets ~$350M annualized savings and ~$225M total charges through end of 2008. MD&A separately cites $42M of Phase 1 costs recorded in Q3 2006; footnote figure used per deduplication rule.
2006-09-30restructuringin_progress2005-03GlobalRisk and insurance services; corporate; consultingUSD 69 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Staff reductions and facility consolidations; no employee count disclosed. Charge is the nine-months-ended 2006 amount (risk and insurance services $43M, corporate $27M, consulting $(1)M). Filer states actions are substantially complete and annual savings of about $400M are being realized. Remaining liability at 9/30/06 was $110M.
2006-09-30divestiture_reductioncompleted2006-092006-09-30United KingdomRisk and insurance services (U.K. wholesale insurance brokerage)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Price Forbes completed September 2006; classified as a discontinued operation in Q1 2006. Headcount impact not disclosed.
2006-09-30divestiture_reductioncompleted2006-01-312006-01-31United StatesRisk and insurance services (claims management)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of majority interest in Sedgwick Claims Management Services completed January 31, 2006 (within year-to-date period). Headcount impact not disclosed.
2006-09-30restructuringin_progress7502006-09-302007-03-31GlobalCorporate Infrastructure and Operating CompaniesUSD 42 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Phase 1 of the 2006 Plan; staff reductions of more than 750 expected; costs primarily related to severance and exit costs for facilities.
2006-06-30restructuringin_progress2005-03-01Risk and Insurance ServicesUSD 26 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q2 2006 charge for staff reductions and facility consolidations under the 2005 Plan; six-month charge of $45 million for this segment. Actions substantially completed as of June 30, 2006.
2006-06-30restructuringin_progress2005-03-01CorporateUSD 1 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q2 2006 charge under the 2005 Plan; six-month charge of $27 million for Corporate. Includes future rent on non-cancelable leases for vacated floors of the New York headquarters building.
2006-06-30restructuringin_progress2004-11-01restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2004 Plan involving staff reductions and facility consolidations; $25 million utilized in 2006 through June 30, remaining liability $35 million. No employee counts disclosed.
2006-06-30divestiture_reductioncompleted2006-01-31United StatesRisk and Insurance ServicesUSD 176 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of majority interest in Sedgwick CMS Holdings (claims management services) completed January 31, 2006; $176 million after-tax gain recorded in discontinued operations. Headcount removed not disclosed.
2006-06-30divestiture_reductioncompleted2005-12-31United StatesRisk and Insurance Servicesother
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of Crump Group, Inc., U.S.-based wholesale insurance broker, in Q4 2005; presented as discontinued operations. Headcount removed not disclosed.
2006-06-30divestiture_reductionin_progressUnited KingdomRisk and Insurance Servicesother
f5-10q / GLM-5.3-flash-fp4-HTML		Price Forbes, U.K.-based insurance wholesale operation, classified as discontinued operation in Q1 2006 with charge to reduce assets to fair value less cost to sell; held for sale at June 30, 2006. Headcount not disclosed.
2006-06-30restructuringin_progress2005-03GlobalRisk and Insurance ServicesUSD 45 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Staff reductions and facility consolidations; $45M of the $72M six-month 2006 charges incurred in this segment. No employee count disclosed; actions substantially completed by 2006-06-30 with $138M remaining liability across the plan.
2006-06-30restructuringin_progress2005-03United StatesCorporateUSD 27 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Corporate portion of the 2005 Plan; six-month 2006 charge. MD&A indicates corporate restructuring charges of $30M in the period, primarily future rent on vacated floors of the New York headquarters; no headcount impact disclosed.
2006-06-30restructuringin_progress2004-11Globalrestructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Staff reductions and facility consolidations; $25M of the accrual utilized during the first six months of 2006 and $35M remaining liability at 2006-06-30. No new charges or employee counts disclosed for the current period.
2006-06-30restructuringin_progress2005-01-012007-06-30GlobalRisk and Insurance ServicesUSD 26 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Q2 2006 net restructuring expenses of $26M primarily comprise severance and other termination benefits. Actions under 2005 plan essentially completed by June 30, 2006. Expected savings of $400M annually.
2006-06-30restructuringin_progress2006-01-012007-12-31New York, United StatesCorporateUSD 40 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Plan to eliminate excess space in corporate headquarters. $40M costs recognized through Q2 2006 including losses on sub-leases and incremental amortization. Additional $20M net costs expected over next 18 months.
2006-03-31restructuringin_progress2005-03-01Risk and Insurance Services; CorporateUSD 45 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Q1 2006 charges of $45M: $19M in risk and insurance services, $26M in corporate; comprises $14M severance and benefits, $25M future rent on non-cancelable leases, $6M other exit costs. Additional ~$15M expected after March 31, 2006; annual savings of $375M expected when fully implemented.
2006-03-31restructuringin_progress2004-11-01restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2004 Plan wind-down: $12M utilized in Q1 2006; remaining liability of $48M at March 31, 2006.
2006-03-31divestiture_reductioncompleted2006-01-31United StatesRisk and Insurance ServicesUSD 306 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of majority interest in Sedgwick CMS Holdings (claims management services) completed January 31, 2006; pre-tax gain on disposal of $306M, $176M net of tax. Headcount removed not disclosed.
2006-03-31divestiture_reductionin_progressUnited KingdomRisk and Insurance Servicesother
f5-10q / GLM-5.3-flash-fp4-HTML		Price Forbes, U.K.-based insurance wholesale operation, classified as discontinued operation in Q1 2006, including a charge to reduce carrying amount of assets to fair value less cost to sell. Headcount not disclosed.
2006-03-31restructuringin_progress2005-03GlobalRisk and Insurance ServicesUSD 19 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2006 charge of $19 million for the 2005 Plan in this segment; plan involves staff reductions and facility consolidations. No employee count disclosed. Additional charges of about $15 million expected in 2006, primarily real estate.
2006-03-31restructuringin_progress2005-03GlobalCorporateUSD 26 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Q1 2006 charge of $26 million, primarily future rent on vacated floors of the New York headquarters; MMC expects to vacate 12 more floors over 18 to 24 months. No employee count disclosed.
2006-03-31restructuringin_progress2004-11GlobalCorporaterestructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		2004 Plan (staff reductions and facility consolidations) still being wound down: $12 million of the accrual utilized in Q1 2006, remaining liability of $48 million at 2006-03-31. No employee count or incremental charge disclosed for the quarter.
2006-03-31restructuringin_progress2005-01-012006-12-31GlobalRisk and Insurance ServicesUSD 19 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Charges related to 2005 restructuring plan. Additional charges of approx $15M expected in 2006.
2006-03-31restructuringin_progress2005-01-012006-12-31GlobalCorporateUSD 26 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Primarily related to future rent on non-cancellable leases for vacated floors in NY headquarters.
2005-12-31restructuringin_progress2,6002005-032006-06-30GlobalRisk and Insurance Services ($255 million of FY2005 charges) and Corporate ($55 million); all expected annualized savings relate to the Risk and Insurance Services segmentUSD 310 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Announced March 2005: staff reductions and consolidation of facilities. FY2005 charge of $310 million, approximately two-thirds severance: severance and termination benefits of $197 million (Note 13; MD&A cites $196 million) related to the elimination of approximately 2,600 employee positions; future rent under non-cancelable leases of $114 million (Note 13; MD&A cites $116 million); remaining liability of $157 million at 12/31/2005. Remaining actions to be completed largely in the first half of 2006 with approximately $50 million of additional charges expected; expected annualized savings of $375 million, all in the Risk and Insurance Services segment ($160 million realized in 2005, approximately $215 million expected in 2006). MD&A reports total net restructuring expenses of $317 million for 2005, which additionally include $3 million under the 2004 Plan and a $4 million increase to future rent liabilities related to the Johnson and Higgins and Sedgwick acquisitions; the corporate component of the 2005 Plan includes a $49 million first-quarter charge for consolidation of London office space and $6 million of severance.
2005-12-31restructuringcompleted2004-11GlobalProgram charges by segment: Risk and Insurance Services ($234 million), Consulting ($62 million), Investment Management ($26 million), Corporate ($18 million)USD 3 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Announced November 2004 (prior fiscal year); captured here for FY2005 residual activity only. FY2005 charge of $3 million; program charges totaled $337 million in FY2004 plus $3 million in FY2005. $221 million of the accrued liability was utilized in 2005; remaining liability of $60 million at 12/31/2005. Savings of $400 million, substantially all realized in 2005, with no incremental savings expected in 2006. Headcount reduction under this plan is not quantified in this filing.
2005-12-31divestiture_reductioncompleted2005-102005-10United StatesRisk and Insurance Services — wholesale insurance broking (Crump Group, Inc.)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		MMC completed the sale of Crump Group, Inc., its U.S.-based wholesale insurance broker, in October 2005 (fourth quarter), recognizing a $14 million net-of-tax gain; business classified as discontinued operations. Headcount transferred with the divestiture is not disclosed.
2005-12-31divestiture_reductioncompleted2005-12-232006-01-31North AmericaRisk and Insurance Services — claims administration (Sedgwick Claims Management Services / Sedgwick CMS Holdings)discontinued_operations_footnote
f5-10k / GLM-5.3-flash-HTML		On December 23, 2005 MMC agreed to sell its majority stake in Sedgwick Claims Management Services (SCMS), a majority-owned Marsh subsidiary providing claims administration and related services in North America; the sale closed on January 31, 2006 (after fiscal year-end, before the filing date). SCMS was classified as discontinued operations at December 31, 2005. Headcount transferred with the divestiture is not disclosed.
2005-12-31divestiture_reductioncompleted2005-05-312005-05-31GlobalMMC Capital (private equity management subsidiary; Risk and Insurance Services segment prior to sale)Item_1_Business
f5-10k / GLM-5.3-flash-HTML		In May 2005 (sale dated May 31, 2005), MMC sold the assets of MMC Capital, its private equity management subsidiary, to Stone Point Capital LLC, an entity controlled by the former managers of MMC Capital, for approximately $3 million. Headcount impact is not disclosed.
2005-12-31restructuringin_progress2,6002005-032006-06-30GlobalRisk and Insurance Services (all expected savings); corporateUSD 310 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Announced in March 2005 (day not disclosed). Charges of $310M incurred in 2005 ($255M in risk and insurance services, $55M corporate), including severance and benefits of $197M per Note 13 ($196M per MD&A) for about 2,600 positions and future rent on non-cancelable leases; additional charges of about $50M expected in 2006, largely first half; annualized savings of $375M expected, with about $160M realized in 2005. Corporate also recorded a separate $49M charge in Q1 2005 for London office consolidation. Completion date reflects stated goal of full implementation in the first half of 2006.
2005-12-31restructuringin_progress2004-11GlobalRisk and Insurance Services, Consulting, Investment Management, corporateUSD 3 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Multi-year program announced November 2004; only current-year (2005) activity of $3M shown here. Cumulative charges were $337M in 2004; about $400M of savings realized in 2005; remaining liability of $60M at December 31, 2005. Employees affected not disclosed.
2005-12-31divestiture_reductioncompletedUnited StatesRisk and Insurance Services — U.S. wholesale broking (Crump Group, Inc.)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sale of Crump Group completed in October 2005; classified as discontinued operations. Headcount removed not disclosed; $14M gain net of tax recognized in Q4 2005.
2005-12-31divestiture_reductioncompleted2005-12-232006-01-31North AmericaRisk and Insurance Services — claims management (Sedgwick CMS Holdings)discontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Majority stake agreed for sale December 23, 2005 and closed January 31, 2006 (subsequent to fiscal year end); classified as discontinued operations. Headcount removed not disclosed; associated gain to be recognized in Q1 2006.
2005-12-31acquisition_additioncompletedGlobalMultiple segmentsUSD 68 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Nine acquisitions completed during 2005 for total purchase consideration of $68M (goodwill of $45M); headcount added not disclosed. Prior-year Kroll acquisition (July 2004, $1.9B) contributed a full year of operations in 2005 but is not a 2005 workforce action.
2005-12-31restructuringin_progress2,6002005-01-012006-06-30WorldwideRisk and Insurance ServicesUSD 317 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		2005 restructuring plan initiated in Q1 2005. Net expenses of $317 million in 2005, primarily related to elimination of approximately 2,600 employee positions. Additional charges of approx $50 million expected in 2006.
2005-12-31restructuringcompleted2004-10-012005-12-31WorldwideCorporate and Operating SegmentsUSD 337 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		2004 restructuring plan initiated in Q4 2004. Total charges of $337 million in 2004. Savings of approx $400 million realized in 2005.
2005-09-30restructuringin_progress2,3002005-03-012006-06-30Risk and Insurance Services ($190M); Corporate ($55M)USD 245 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Nine-month charges include $170M severance for approximately 2,300 positions, $77M future rent on non-cancelable leases, and other costs, partially offset by a $16M gain on dispositions. Q3 component included severance of $33M for approximately 200 positions, primarily in Europe. Additional charges of approximately $95M expected through first half of 2006; annualized savings of approximately $375M expected when fully implemented.
2005-09-30restructuringcompleted2004-11-01Risk and Insurance Services ($236M); Consulting ($62M); Investment Management ($26M); Corporate ($18M)USD 337 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Charges of $337M incurred in 2004 plus $5M in 2005; actions essentially complete with approximately $300M of savings realized through Q3 2005. Employee count not disclosed.
2005-09-30divestiture_reductioncompleted2005-10-01United StatesWholesale insurance broking (Crump Group, Inc.)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of U.S.-based wholesale broking operation completed in October 2005; gain to be recognized in Q4 2005. Headcount removed not disclosed.
2005-09-30restructuringin_progress2,2002005-032006-06-30GlobalRisk and Insurance ServicesUSD 190 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		2005 Plan charges of $190M recorded in this segment; MD&A reports staff reductions affecting approximately 2,200 employees year-to-date. Additional charges of about $95M expected over the remainder of 2005 and first half of 2006; annualized savings of about $375M expected when fully implemented. Consolidated third-quarter detail: approximately 200 positions eliminated in Q3, primarily in Europe.
2005-09-30restructuringin_progress2005-032006-06-30GlobalCorporateUSD 55 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Corporate portion of the 2005 Plan; charge primarily reflects consolidation of London office facilities ($49M) plus $6M of severance and termination benefits. Headcount impact not separately disclosed for Corporate.
2005-09-30restructuringcompleted2004-11GlobalAll segmentsUSD 5 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		2004 Plan announced November 2004 with $337M accrued in 2004; $5M additional charge incurred in 2005. Actions described as essentially complete, with about $300M of savings realized through Q3 2005. Employee counts not disclosed.
2005-09-30divestiture_reductionannounced2005-102005-10United StatesWholesale broking (Risk and Insurance Services)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Crump Group, Inc. completed in October 2005 (after quarter end); gain to be recognized in Q4 2005. Headcount not disclosed.
2005-09-30divestiture_reductioncompleted2005-052005-05-31United StatesRisk and Insurance Services (MMC Capital)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Assets of MMC Capital, the private equity manager, sold to Stone Point Capital LLC on May 31, 2005. Headcount not disclosed.
2005-09-30acquisition_additioncompletedUSD 79 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Five acquisitions completed during the first nine months of 2005 for total purchase consideration of $79M (goodwill of $56M). Acquired headcount not disclosed.
2005-09-30restructuringin_progress2002005-01-012006-06-30EuropeRisk and Insurance ServicesUSD 33 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Q3 2005 Plan activity: 200 positions eliminated primarily in Europe; $33M severance/termination benefits. Part of broader 2005 Plan.
2005-09-30restructuringin_progress2,3002005-01-012006-06-30GlobalRisk and Insurance ServicesUSD 170 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		YTD 2005 Plan activity: ~2,300 positions eliminated; $170M severance/termination benefits. Includes Q3 activity.
2005-09-30restructuringin_progress2,2002005-01-012006-06-30GlobalRisk and Insurance ServicesUSD 190 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		YTD 2005 Plan charges of $190M for staff reductions affecting approx 2,200 employees and future rent. Slight variance in headcount count vs MD&A summary likely due to timing of recognition.
2005-09-30restructuringin_progress2005-01-012006-06-30LondonCorporateUSD 49 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Consolidation of office space in London. Charge recorded in Q1 2005.
2005-09-30restructuringin_progress2005-01-012006-06-30GlobalCorporateUSD 6 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Severance and other termination benefits related to 2005 Plan.
2005-09-30restructuringcompleted2004-11-012005-09-30GlobalGlobalUSD 5 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		2004 Plan actions essentially complete. $5M charges incurred in 2005.
2005-06-30restructuringin_progress2,0502005-03-012006-12-31Risk and Insurance Services ($141M) and Corporate ($54M)USD 195 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Six-month charges include severance for ~2,050 positions, future rent on non-cancelable leases, and other exit costs; ~$148M additional charges expected through early 2006; ~$375M annual savings expected when fully implemented
2005-06-30restructuringin_progress3502005-03-012006-12-31Risk and Insurance ServicesUSD 54 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Second-quarter net restructuring expense of $54M includes $46M severance for ~350 positions, $6M future rent, $10M other costs, offset by $8M gain on sale of small commercial accounts
2005-06-30restructuringin_progress2004-11-01Risk and Insurance Services ($231M), Consulting ($62M), Investment Management ($26M), Corporate ($18M)USD 337 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		2004 Plan charges of $337M in 2004 plus $3M in 2005; actions essentially complete with ~$100M savings realized in Q2 2005; remaining liability $118M at 6/30/05
2005-06-30restructuringin_progress2,0502005-03GlobalRisk and insurance services; corporateUSD 195 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Staff reductions and facility consolidations announced March 2005. About 2,050 positions eliminated year-to-date, including roughly 350 in the second quarter. Charges of $195M year-to-date split $141M risk and insurance services and $54M corporate; severance accrual $138M with $103M remaining at June 30, 2005. Further charges of about $148M expected over the remainder of 2005 and early 2006; annual savings of about $375M targeted.
2005-06-30restructuringcompleted2004-11GlobalUSD 3 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program announced November 2004; actions described as essentially complete. Charge shown is the 2005 addition per the footnote (MD&A cites $4M). $163M of the 2004 accrual was utilized during 2005, leaving a $118M liability at June 30, 2005. No employee count disclosed for 2005 activity.
2005-06-30divestiture_reductioncompleted2005-05-312005-05-31Risk and insurance services (MMC Capital private equity business)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of MMC Capital assets to Stone Point Capital LLC; former MMC Capital managers moved with the business. Headcount impact not disclosed.
2005-06-30restructuringin_progress3502005-01-01USD 46 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		2005 Plan Q2: Severance and other termination benefits related to elimination of approximately 350 positions.
2005-06-30restructuringin_progress2,0502005-01-01USD 148 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		2005 Plan YTD: Severance and other termination benefits related to elimination of approximately 2,050 positions.
2005-06-30restructuringin_progress2004-11-01USD 3 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		2004 Plan: Restructuring charges incurred in 2005. Actions essentially complete.
2005-03-31restructuringin_progress1,7002005-03-012005-12-31Primarily United States and United KingdomRisk and Insurance Services (Marsh risk management and insurance broking)USD 92 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Severance and benefits for elimination of approximately 1,700 positions; $92M recorded in risk and insurance services segment
2005-03-31plant_closurein_progress2005-03-012005-12-31London, United KingdomCorporate (consolidation of office facilities)USD 49 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Future rent on non-cancelable leases and lease termination costs for consolidation of London office facilities; recorded in corporate expenses
2005-03-31restructuringin_progress2004-11-01Risk and Insurance Services, Consulting, Investment Management, CorporateUSD 4 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Additional $4 million of charges incurred in Q1 2005 under the 2004 Plan announced November 2004; $337 million charged in 2004, remaining liability $189 million at 3/31/05
2005-03-31restructuringin_progress1,7002005-032005-12-31United States and United KingdomRisk and Insurance ServicesUSD 92 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance and benefits for elimination of approximately 1,700 positions; total 2005 Plan charge incurred in Q1 was $141 million including $49 million of lease-related costs. Annualized savings of approximately $375 million expected when fully implemented.
2005-03-31restructuringannounced2005-032005-12-31Risk and Insurance ServicesUSD 205 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Expected charges over the remainder of 2005: approximately $110 million severance for reduction of 800-1,000 additional positions, $75 million lease costs, $20 million other; headcount disclosed only as a range.
2005-03-31restructuringin_progress2005-032005-12-31United Kingdom (London)CorporateUSD 49 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Consolidation of London office facilities; affected Mercer colleagues to be relocated to existing Marsh space. No headcount reduction disclosed for this component.
2005-03-31restructuringin_progress2004-11USD 4 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Charge shown is 2005 additions; initial program charge of $337 million was recorded in 2004, with $189 million remaining liability at March 31, 2005. No employee count disclosed for this plan.
2005-03-31acquisition_additioncompleted2005-01Risk Consulting and Technologybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Talbot-Hughes acquired in January 2005 for a total cost of $29 million; no headcount disclosed for the acquired business.
2005-03-31restructuringin_progress1,7002005-03-312005-12-31United States and United KingdomRisk and Insurance ServicesUSD 92 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Severance and benefits related to staff reductions affecting approximately 1,700 employees primarily in the United States and United Kingdom.
2005-03-31restructuringin_progress2005-03-312005-12-31LondonCorporateUSD 49 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Future rent and other lease termination costs related to the consolidation of office facilities in London.
2005-03-31restructuringin_progress2004-10-31USD 4 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Restructuring charges incurred in the quarter related to the restructuring plan initiated in the fourth quarter of 2004.
2004-12-31restructuringin_progress2,7502004-112005-06-30GlobalAll segments (Risk and Insurance Services, Consulting, Investment Management, Corporate)USD 337 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Staff reductions of approximately 2,750 achieved through reductions and attrition in Q4 2004; expected annual savings of approximately $400 million when fully implemented in mid-2005. Charge comprises severance/benefits $273M, future rent $28M, lease terminations $18M, other exit costs $18M; a further $14M of accelerated amortization/abandonment of leasehold improvements was recorded separately, and approximately $7M-$14M of additional costs were expected in the first half of 2005.
2004-12-31restructuringannounced2,500GlobalMarsh Inc. (Risk and Insurance Services)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Ongoing Marsh restructuring to improve efficiencies and eliminate unprofitable accounts; filing states it 'could affect approximately 2,500 people' with annual expense savings exceeding $375 million when fully implemented, and will result in additional restructuring charges. No charge quantified and no announcement date given.
2004-12-31acquisition_additioncompleted2004-07GlobalRisk and Insurance Services (risk consulting)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Kroll Inc. completed July 2004 for approximately $1.9 billion ($37 per share); acquired headcount not disclosed.
2004-12-31acquisition_additioncompleted2004-01United StatesConsulting (HR technology and outsourcing)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Synhrgy HR Technologies for a total cost of $115 million; filing states substantially all employees became MMC employees but gives no headcount. Other 2004 acquisitions (Heath Lambert ANZ, Prentis Donegan, PanAgora additional 30%, Centerlink, Corporate Systems) also completed without disclosed headcount.
2004-12-31othercompleted1,3002005-01-012005-01-01United StatesInvestment Management / Consulting (defined contribution plan servicing)Item_1_Business
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Effective January 1, 2005, approximately 1,300 employees transferred from Putnam Fiduciary Trust Company to newly formed Mercer HR Services and Mercer Trust Company subsidiaries; these employees are included in the 18,000 consulting headcount as of January 31, 2005.
2004-12-31divestiture_reductionannounced2005-02-282005-06-30GlobalMMC Capital (private equity / Risk and Insurance Services)subsequent_events
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Subsequent event: letter of intent signed February 28, 2005 to transfer MMC Capital's business, including management of the Trident Funds, to a company formed by MMC Capital's senior management; expected to close by end of Q2 2005. Headcount not disclosed; MMC will maintain a strategic alliance.
2004-12-31restructuringcompleted2,7502004-11-012005-06-30GlobalAll SegmentsUSD 337 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Announced in November 2004. Global headcount reduction of 2,750 through staff reductions and attrition in Q4 2004. Pre-tax costs of $337 million incurred in Q4 2004, primarily related to severance, termination benefits, and lease costs. Expected annual savings of $400 million when fully implemented in mid-2005.
2004-12-31restructuringin_progress2,5002004-12-31GlobalRisk and Insurance ServicesMD&A
f5-10k / Qwen3.6-27B-Q8_0		Marsh Inc. continues to restructure operations, affecting approximately 2,500 people. Expected annual expense savings exceeding $375 million. Additional restructuring charges expected.
2004-09-30restructuringannounced3,0005%2004-10GlobalApproximately three-quarters from risk and insurance services; also includes Putnam defined contribution administration combination with Mercer HR outsourcing and Kroll integrationUSD 325 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Announced global staff reduction of 5% (~3,000 positions) with expected pretax restructuring charges of approximately $325 million over the next six months; expected annual cost savings of approximately $400 million when fully implemented. Announced in October 2004, after quarter-end.
2004-09-30restructuringannounced3,0005%2005-05-09WorldwidePrimarily risk and insurance services (three-quarters of reductions)USD 325 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Global headcount reduction of about 5%, roughly 3,000 positions, over the following six months; pretax charges of about $325M with about $400M annual savings. Includes reductions from combining Putnam's DC administration with Mercer HR outsourcing and Kroll integration. No announcement date stated; completion date inferred from filing date plus stated six-month horizon.
2004-09-30acquisition_additioncompletedUnited StatesRisk and insurance services — risk consulting and advisorybusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		All-cash acquisition of Kroll Inc. completed July 2004 for about $1.9 billion; no employee count disclosed.
2004-09-30restructuringin_progressUnited StatesInvestment Management (Putnam)USD 57 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance charge recorded in the nine months ended September 30, 2004 as part of repositioning Putnam; no employee count disclosed.
2004-09-30restructuringannounced3,0005%2004-10-262005-03-31GlobalRisk and Insurance Services (75% of reductions)USD 325 (millions)subsequent_events
f5-10q / Qwen3.6-27B-Q8_0		Announced Oct 26, 2004. Expected to reduce staff by 5% or approx 3,000 positions. Three-quarters from risk and insurance services. Includes reductions from Putnam/Mercer combination and Kroll integration. Pretax charges approx $325M over next six months.
2004-06-30restructuringin_progressPutnam InvestmentsUSD 27 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Incremental severance costs of $27 million in Q2 related to repositioning Putnam; no employee count disclosed
2004-06-30restructuringin_progressPutnam InvestmentsUSD 52 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Severance of $52 million recorded in first six months of 2004 related to repositioning Putnam; no employee count disclosed
2004-06-30acquisition_additionannounced2004-07-14Risk and Insurance ServicesUSD 1,900 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Kroll Inc. acquired in July 2004 for approximately $1.9 billion in cash; no headcount figures disclosed
2004-06-30acquisition_additioncompleted2004-01-01ConsultingUSD 115 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Synhrgy HR Technologies acquired January 2004 for $115 million; substantially all former employees became MMC employees, no headcount disclosed
2004-06-30acquisition_additioncompleted2004-03-01Australia and New ZealandRisk and Insurance ServicesUSD 53 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Heath Lambert Australia and New Zealand operations acquired March 2004 for $53 million cash; no headcount disclosed
2004-06-30othercompleted2004-06-09Putnam InvestmentsUSD 25 (millions)other
f5-10q / GLM-5.3-flash-fp4-HTML		Final settlement of arbitration with former Putnam CEO Lawrence Lasser; cash payment of $78 million, approximately $25 million less than previously accrued compensation expense
2004-06-30acquisition_additionannounced2004-05-182004-07-31United StatesRisk and Insurance ServicesUSD 1,900 (millions)subsequent_events
f5-10q / MiMo-V2.6-Flash-fp8-HTML		All-cash acquisition of Kroll Inc. at $37/share; headcount not disclosed; initially funded with commercial paper
2004-06-30acquisition_additioncompleted2004-01-312004-01-31United StatesConsultingUSD 115 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Synhrgy HR Technologies acquired for $115M; substantially all former employees became MMC employees; headcount not disclosed
2004-06-30acquisition_additioncompleted2004-03-312004-03-31Australia and New ZealandRisk and Insurance ServicesUSD 53 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Heath Lambert Australia and New Zealand operations acquired for $53M cash; headcount not disclosed
2004-06-30restructuringin_progress2004-01-01United StatesInvestment Management (Putnam)USD 52 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance of $52M for six months related to streamlining management and repositioning Putnam; employee count not disclosed
2004-06-30acquisition_additioncompleted2004-01-01GlobalConsultingUSD 115 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Synhrgy HR Technologies for $115 million; substantially all former employees are now MMC employees.
2004-06-30acquisition_additioncompleted2004-03-01Australia and New ZealandRisk and Insurance ServicesUSD 53 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Australia and New Zealand operations of Heath Lambert for $53 million.
2004-06-30restructuringin_progress2004-06-30GlobalInvestment ManagementUSD 27 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Incremental severance costs of $27 million related to streamlining management and repositioning Putnam.
2004-06-30restructuringin_progress2004-06-30GlobalInvestment ManagementUSD 52 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		YTD severance costs of $52 million related to streamlining management and repositioning Putnam.
2004-03-31restructuringcompletedInvestment Management (Putnam)USD 25 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Putnam recorded $25 million of severance expense in Q1 2004; no employee count disclosed. Also $15 million of incremental regulatory-related costs recorded in the quarter.
2004-03-31acquisition_additioncompleted2004-01-31United StatesConsultingUSD 115 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Synhrgy HR Technologies acquired for $115M total cost; substantially all former employees became MMC employees; headcount not disclosed; $7M of consideration recorded as compensation over three years
2004-03-31acquisition_additioncompleted2004-03-31Australia and New ZealandRisk and Insurance ServicesUSD 53 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Heath Lambert Australia and New Zealand operations acquired for $53M cash in March 2004; headcount not disclosed
2004-03-31restructuringin_progressUnited StatesInvestment Management (Putnam)USD 25 (millions)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Severance of $25M recorded in Q1 2004 at Putnam; no employee count, announcement date, or completion timing disclosed
2004-03-31acquisition_additioncompleted2004-01-01GlobalConsultingUSD 115 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Synhrgy HR Technologies in Jan 2004. Substantially all former employees are now MMC employees.
2004-03-31acquisition_additioncompleted2004-03-01Australia and New ZealandRisk and Insurance ServicesUSD 53 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Australia and New Zealand operations of Heath Lambert in March 2004.
2004-03-31restructuringcompleted2004-03-31GlobalInvestment ManagementUSD 25 (millions)MD&A
f5-10q / Qwen3.6-27B-Q8_0		Severance charges of $25 million recorded in Q1 2004.
2003-12-31acquisition_additioncompleted2003-04-01GlobalConsultingUSD 265 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Oliver, Wyman & Company acquired for $265 million. Substantially all former employees became MMC employees; specific headcount not disclosed.
2003-12-31reduction_in_forcecompleted15United StatesInvestment Management (Putnam)other
f5-10k / MiMo-V2.6-Flash-fp8-HTML		15 employees terminated following review of trading activity of more than 12,000 former and current Putnam employees related to market timing investigation.
2003-12-31restructuringcompleted1999-01-01GlobalRisk and Insurance ServicesUSD 5 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Sedgwick Plan: MMC paid $5 million of costs related to the 1999 Sedgwick acquisition integration plan. Actions under the plan are complete.
2003-12-31restructuringcompleted1999-01-01GlobalCorporateUSD 5 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		MMC Plan: MMC paid $5 million of costs related to the 1999 MMC integration plan. Actions under the plan are complete.
2003-12-31restructuringcompleted2001-09-01GlobalConsultingUSD 1 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		2001 Plan: MMC paid $1 million of costs related to the 2001 staff reductions and office consolidations, primarily in consulting. Actions under the plan are complete.
2003-09-30acquisition_additioncompleted2003-04GlobalConsulting (Management Consulting)USD 35 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Headcount added not quantified; filing states substantially all former OWC employees became MMC employees. $35M of the $265M purchase consideration is contingent on continued employment and expensed as compensation over four years.
2003-09-30acquisition_additioncompleted2003-04-01ConsultingUSD 35 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Oliver Wyman & Company in April 2003. Substantially all former employees are now MMC employees. $35 million purchase consideration subject to continued employment recorded as compensation expense.
2003-09-30restructuringin_progress1999-01-01Risk and Insurance ServicesUSD 3 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Sedgwick Plan: Paid $3 million in 2003. Remaining liability $31 million. Activities substantially complete.
2003-09-30restructuringin_progress1999-01-01CorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		MMC Plan: Paid $2 million in 2003. Remaining liability $15 million. Activities substantially complete.
2003-09-30restructuringin_progress2001-09-01ConsultingUSD 3 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2001 Plan: Paid $3 million in 2003. Remaining liability $15 million. Activities substantially complete.
2003-06-30restructuringcompleted2,40019992000-12-31USD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Staff reductions and office consolidations tied to the 1998 Sedgwick combination; actions substantially complete by year-end 2000, with residual accruals of $32 million at June 30, 2003 primarily for future rent under noncancelable leases; 125 office consolidations planned
2003-06-30restructuringcompleted2,10019992000-12-31USD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Merger-related staff reductions and office consolidations for MMC employees recorded as a 1999 special charge; actions substantially complete by year-end 2000, with residual accruals of $16 million at June 30, 2003; 50 office consolidations planned
2003-06-30restructuringcompleted7502001-09-302002-09-30ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Staff reductions and office consolidations primarily in the consulting segment following weakening business conditions exacerbated by September 11; charge comprised $44 million severance for 750 people and $17 million future rent; actions completed by September 30, 2002, residual accruals of $16 million at June 30, 2003
2003-06-30acquisition_additioncompleted2003-04-01Consulting (management consulting practice)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMC acquired Oliver, Wyman & Company in April 2003 for $265 million; substantially all former OWC employees became MMC employees. Headcount added not disclosed. Announcement date shown as month-start because only the month is stated.
2003-06-30acquisition_additioncompleted2003-04-01ConsultingUSD 35 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquired Oliver Wyman & Company in April 2003. Substantially all former employees are now MMC employees. $35M purchase consideration subject to continued employment recorded as compensation expense.
2003-06-30restructuringcompleted7502001-09-012002-09-30ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2001 Plan adopted in Q3 2001 for staff reductions and office consolidations. Actions completed by Sept 30, 2002. Initial charge $61M ($44M severance for 750 people, $17M future rent).
2003-06-30restructuringcompleted2,4001999-01-012000-12-31USD 285 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan. Actions substantially complete by year-end 2000. Initial balance $285M.
2003-06-30restructuringcompleted2,1001999-01-012000-12-31USD 266 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan. Actions substantially complete by year-end 2000. Initial balance $266M.
2003-03-31restructuringcompleted2,4001999-01-012000-12-31USD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Legacy plan tied to 1998 Sedgwick combination; actions substantially complete by year-end 2000. Remaining balance of $33 million at March 31, 2003, mostly future rent and leasehold costs; $1 million utilized in Q1 2003.
2003-03-31restructuringcompleted2,1001999-01-012000-12-31USD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Legacy 1999 special charge for MMC staff reductions and office consolidations; actions substantially complete by year-end 2000. Remaining balance of $17 million at March 31, 2003.
2003-03-31restructuringcompleted7502001-07-012002-09-30ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Staff reductions and office consolidations primarily in consulting segment; $44 million severance for 750 people and $17 million future rent. Actions completed by September 30, 2002; $2 million utilized in Q1 2003, $16 million balance remains.
2003-03-31restructuringin_progress11999-01-01USD 1 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan: $1M utilized in Q1 2003 for future rent under noncancelable leases. Actions substantially complete by year-end 2000.
2003-03-31restructuringin_progress22001-09-01ConsultingUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2001 Plan: $2M utilized in Q1 2003 for termination payments and future rent. Actions completed by September 30, 2002.
2002-12-31restructuringcompleted24420012002-09-30Not specifiedConsultingUSD 61 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Program announced in 2001 ($61M charge; 750 employees affected, $44M severance plus $17M future rent). 244 of the 750 terminations occurred during fiscal 2002; actions were completed by September 30, 2002. Fiscal 2002 utilization was $29M, leaving an $18M accrual at year-end.
2002-12-31acquisition_additioncompletedNot specifiedRisk and insurance services; Consulting; Investment managementbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		MMC completed several insurance/reinsurance broking, consulting and investment management acquisitions in 2002 for a total cost of $99 million; no headcount added through these transactions is disclosed.
2002-12-31restructuringcompleted7502001-12-312002-09-30GlobalConsultingUSD 61 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Plan adopted in 2001 for staff reductions and office consolidations, primarily in consulting. Actions completed by Sept 30, 2002.
2002-09-30restructuringcompleted7502001-09-302002-09-30Consulting (primarily)USD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan adopted Q3 2001 due to weakening business conditions; $44M severance for 750 people and $17M future rent under noncancelable leases. Actions substantially complete by September 30, 2002; remaining balance $22M at Sept 30, 2002.
2002-09-30restructuringcompleted7502001-09-302002-09-30ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		2001 Plan adopted in Q3 2001 (exact announcement date not disclosed) for staff reductions and office consolidations, primarily in consulting; charge comprises $44M severance for 750 people plus $17M future rent. 506 terminations occurred in 2001 and 244 in the nine months ended 2002-09-30, leaving none pending; actions substantially complete by 2002-09-30 with residual rent accruals payable over several years.
2002-09-30restructuringcompleted2442001-09-302002-09-30GlobalConsultingUSD 22 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		244 terminations utilized in nine months ended Sept 30, 2002. Plan substantially complete by Sept 30, 2002.
2002-09-30restructuringcompleted2,4001999-01-012000-12-31GlobalRisk and Insurance ServicesUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2 terminations utilized in nine months ended Sept 30, 2002. Actions substantially complete by year-end 2000.
2002-09-30restructuringcompleted2,1001999-01-012000-12-31GlobalCorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2 terminations utilized in nine months ended Sept 30, 2002. Actions substantially complete by year-end 2000.
2002-06-30restructuringin_progress7502001-09-302002-09-30Consulting (primarily)USD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan adopted Q3 2001 due to weakening business conditions exacerbated by September 11; charge comprises $44M severance for 750 people and $17M future rent under noncancelable leases. During six months 2002, $21M utilized and 221 terminations executed; 23 terminations and $26M balance remain at June 30, 2002. Expected substantially complete by September 30, 2002.
2002-06-30restructuringin_progress7502002-09-30ConsultingUSD 61 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Plan adopted in Q3 2001 (exact announcement date not disclosed) amid weakening business conditions exacerbated by September 11; charge comprises $44M severance/benefits for 750 people and $17M future rent on noncancelable leases. Six months 2002 utilization: 221 employee terminations and $21M of the charge; 23 terminations and $26M accrual remained at June 30, 2002. Actions expected substantially complete by September 30, 2002.
2002-06-30restructuringin_progress232001-09-012002-09-30ConsultingUSD 11 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2001 Plan: 23 employee terminations remaining as of June 30, 2002. $11 million balance for termination payments.
2002-06-30restructuringin_progress1999-01-01USD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan: $2 million balance for termination payments as of June 30, 2002. No employee terminations remaining.
2002-06-30restructuringin_progress1999-01-01USD 5 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan: $5 million balance for termination payments as of June 30, 2002. No employee terminations remaining.
2002-03-31restructuringin_progress7502001-07-012002-06-30Consulting (primarily)USD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan adopted Q3 2001 due to weakening business conditions exacerbated by September 11; $44M severance for 750 people and $17M future rent. Through Q1 2002, 661 of 750 terminations utilized (506 in 2001, 155 in Q1 2002), leaving 89 remaining; charge balance $37M at March 31, 2002.
2002-03-31restructuringcompleted2,4001999-01-012000-12-31Sedgwick integrationUSD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Employee terminations and office consolidations (125 offices) from Sedgwick combination; substantially complete by year-end 2000. Remaining balance $41M at March 31, 2002, primarily future rent and salary continuance paid over several years.
2002-03-31restructuringcompleted2,1001999-01-012000-12-31MMC employees and officesUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Recorded as 1999 special charge; 50 office consolidations; substantially complete by year-end 2000. Remaining balance $20M at March 31, 2002, primarily future rent under noncancelable leases.
2002-03-31restructuringin_progress7502001-09-302002-06-30Not specifiedPrimarily consulting segmentUSD 61 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Adopted in Q3 2001 (announcement date approximate; filing states only the quarter) amid weakening business conditions exacerbated by September 11. Charge comprises $44M severance/benefits for 750 employees plus $17M future rent on non-cancelable leases. During Q1 2002, 155 employee terminations and 6 office consolidations were executed; 89 terminations and 1 office consolidation remained as of 2002-03-31.
2002-03-31restructuringin_progress1552001-09-012002-06-30ConsultingUSD 10 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		2001 Plan: 155 terminations utilized in Q1 2002. Total plan charge $61M ($44M severance, $17M rent). Expected completion June 30, 2002.
2002-03-31restructuringin_progress11999-01-01Risk and Insurance ServicesUSD 1 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan: 1 employee termination utilized in Q1 2002. Primarily rent and leasehold costs remaining.
2002-03-31restructuringin_progress11999-01-01CorporateUSD 2 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan: 1 employee termination utilized in Q1 2002. Primarily rent and leasehold costs remaining.
2001-12-31restructuringin_progress75020012002-06-30Primarily consulting segmentUSD 61 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Plan for staff reductions and office consolidations adopted amid weakening business conditions exacerbated by September 11. Charge comprises $44 million of severance and related benefits for approximately 750 people and $17 million for future rent under non-cancelable leases, recorded within the $187 million of pretax September 11-related charges. By year-end 2001, $14 million was utilized, 506 of 750 terminations and 2 of 9 office consolidations were completed; actions expected substantially complete by June 30, 2002.
2001-12-31restructuringcompleted2,40019992001-12-31USD 285 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Cumulative-to-date figures. 1999 Sedgwick integration plan covering employees and offices of Sedgwick; the $285 million cost was included in the acquisition purchase price. Approximately 2,400 terminations (all completed by 2000) and 125 office consolidations (9 in 2001). $36 million of charges utilized in 2001, leaving a $42 million reserve at year-end largely for future rent payable over several years; $3 million of reserves reversed in Q4 2001 against goodwill. Note 4 states actions were substantially complete by year-end 2000, while the MD&A states the integration plan was completed by the end of 2001.
2001-12-31restructuringcompleted2,10019992001-12-31WorldwideUSD 266 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Cumulative-to-date figures. Merger-related costs for MMC employees and offices in connection with the 1998 Sedgwick combination, recorded as part of the 1999 special charge; includes $194 million of severance for approximately 2,100 position reductions worldwide. Terminations completed by 2000; 6 of 50 office consolidations in 2001. $57 million of charges utilized in 2001, leaving a $22 million balance at year-end; Q4 2001 estimate reversals of $7 million were recorded as a special credit. Actions completed by the end of 2001 per MD&A.
2001-12-31restructuringin_progress7502001-12-312002-06-30Primarily United StatesConsultingUSD 44 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Total charge of $61M includes $44M severance for ~750 people and $17M future rent under non-cancelable leases. 506 terminations completed by year-end; 244 remaining. Driven by weakening business conditions exacerbated by September 11.
2001-12-31restructuringcompleted01999-12-312001-12-31GlobalRisk and Insurance Services (Sedgwick integration)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		1999 Sedgwick Plan: 2,400 total planned terminations (1,700 in 1999, 700 in 2000, 0 in 2001). Actions substantially complete by year-end 2000; $42M accrual remaining at Dec 31, 2001 primarily for future rent. No employee terminations in FY2001.
2001-12-31restructuringcompleted01999-12-312001-12-31GlobalMMC (Sedgwick integration — MMC offices and staff)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		1999 MMC Plan: 2,100 total planned terminations (1,300 in 1999, 800 in 2000, 0 in 2001). Actions substantially complete by year-end 2000; $22M accrual remaining at Dec 31, 2001 primarily for future rent. No employee terminations in FY2001.
2001-09-30restructuringin_progress7472001-09-302001-12-31Consulting (primarily)USD 61 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan to reduce staff and consolidate offices in response to weakening business conditions; $44M for severance and related benefits and $17M for future rent under non-cancelable leases. As of Sept 30, 201 of 747 planned terminations had been rescinded, leaving 546 remaining; 9 office consolidations planned.
2001-09-30restructuringcompleted2,4001999-01-01Sedgwick integration (Sedgwick Plan)USD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		1999 Sedgwick Plan: all 2,400 employee terminations completed; 7 office consolidations remain as of Sept 30, 2001; $46M balance primarily future rent and leasehold costs.
2001-09-30restructuringcompleted2,1001999-01-01MMC integration (MMC Plan)USD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		1999 MMC Plan: all 2,100 employee terminations completed; 1 office consolidation remains as of Sept 30, 2001; $42M balance primarily severance continuance and lease costs.
2001-09-30restructuringin_progress7472001-09-302001-12-31Consulting (primarily)USD 61 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Plan to reduce staff and consolidate offices amid weakening business conditions exacerbated by the September 11 attacks. Charge comprises $44M severance and related benefits plus $17M future rent on noncancelable leases. 201 of 747 planned terminations completed as of September 30, 2001 (546 remaining); nine office consolidations planned, none yet completed. Filing states no exact announcement date; charge recorded in Q3 2001. Part of the broader $173M pretax September 11 charges.
2001-09-30restructuringin_progress2,4001999Sedgwick Group operationsUSD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sedgwick integration plan adopted in 1999 to reduce staff and consolidate duplicative offices; $285M is the initial program balance. All 2,400 planned terminations were completed through 2000, with none in the nine months ended September 30, 2001. Seven of 125 office consolidations remain outstanding; $32M of the balance was utilized during the period. Remaining accruals, mainly future rent, payable over several years.
2001-09-30restructuringin_progress2,1001999Enterprise-wide (MMC)USD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMC merger-related staff reduction and office consolidation plan recorded within a 1999 special charge; $266M is the initial program balance. All 2,100 planned terminations were completed through 2000, with none in the nine months ended September 30, 2001. One of 50 office consolidations remains outstanding; $37M of the balance was utilized during the period.
2001-09-30restructuringin_progress7472001-09-302001-12-31GlobalConsultingUSD 61 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Plan to reduce staff and consolidate office locations primarily in consulting business. Charge includes $44M for severance and $17M for future rent. 201 terminations utilized as of Sept 30, 2001.
2001-09-30restructuringcompleted2,4001999-01-012001-09-30GlobalRisk and Insurance ServicesUSD 285 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan integration. Actions substantially complete. 2,400 employee terminations fully utilized.
2001-09-30restructuringcompleted2,1001999-01-012001-09-30GlobalCorporateUSD 266 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan integration. Actions substantially complete. 2,100 employee terminations fully utilized.
2001-06-30restructuringin_progress2,4001999Risk and Insurance Services (Sedgwick integration)USD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sedgwick integration plan: 2,400 employee terminations and 125 office consolidations; all terminations utilized through 2000, actions substantially complete; remaining $55 million balance at June 30, 2001 primarily future rent and leasehold costs
2001-06-30restructuringin_progress2,1001999Corporate / MMC legacy operationsUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		MMC Plan recorded as 1999 special charge: 2,100 employee terminations and 50 office consolidations; terminations utilized through 2000, actions substantially complete; remaining $47 million balance at June 30, 2001 primarily future rent and leasehold costs
2001-06-30restructuringin_progress2,4001999GlobalSedgwick Group plc employees and officesUSD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program totals: 2,400 employee terminations and 125 office consolidations; all terminations completed through 2000, 9 office consolidations remained. No employee terminations in six months 2001; $23M of the plan utilized in the period. Remaining accrual $55M at 2001-06-30, mainly future rent and leasehold costs.
2001-06-30restructuringin_progress2,1001999GlobalMarsh & McLennan corporate employees and officesUSD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Program totals: 2,100 employee terminations and 50 office consolidations; all terminations completed through 2000, 5 office consolidations remained (1 completed in six months 2001). $32M of the plan utilized in the period. Remaining accrual $47M at 2001-06-30.
2001-06-30restructuringcompleted2,4001999-01-012001-12-31GlobalRisk and Insurance Services (Sedgwick)USD 285 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan: 2,400 employee terminations. Actions substantially complete. Remaining balances primarily for future rent and salary continuance.
2001-06-30restructuringcompleted2,1001999-01-012001-12-31GlobalCorporate / MMCUSD 266 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan: 2,100 employee terminations. Actions substantially complete. Remaining balances primarily for future rent and salary continuance.
2001-03-31restructuringin_progress2,4001999-01-01Sedgwick integrationUSD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sedgwick Plan staff reduction and office consolidation; 2,400 employee terminations planned, all utilized through 2000; actions substantially complete as of March 31, 2001; remaining balance $64 million, mostly termination payments expected in 2001
2001-03-31restructuringin_progress2,1001999-01-01MMC integrationUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		MMC Plan staff reduction and office consolidation; 2,100 employee terminations planned, all utilized through 2000; actions substantially complete as of March 31, 2001; remaining balance $61 million, mostly termination payments expected in 2001
2001-03-31restructuringin_progress1999United KingdomRisk and Insurance Services (Sedgwick)USD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Staff reduction and office consolidation plan; all 2,400 employee terminations completed through 2000, none in Q1 2001. Actions substantially complete at March 31, 2001; 9 of 125 office consolidations remain, $64M of initial $285M charge unutilized, mostly future rent and leasehold costs
2001-03-31restructuringin_progress1999GlobalCorporate / MMC-wideUSD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Merger-related plan recorded in a 1999 special charge; all 2,100 employee terminations completed through 2000, none in Q1 2001. One additional office consolidation occurred in Q1 2001, 5 of 50 remain; $61M of initial $266M charge unutilized, majority expected to be paid in 2001
2001-03-31restructuringcompleted1999-01-012001-03-31GlobalRisk and Insurance Services (Sedgwick Integration)USD 14 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 Sedgwick Plan integration costs utilized in Q1 2001. Actions contemplated by these plans were substantially complete as of March 31, 2001.
2001-03-31restructuringcompleted1999-01-012001-03-31GlobalCorporate and Other (MMC Integration)USD 18 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		1999 MMC Plan integration costs utilized in Q1 2001. Actions contemplated by these plans were substantially complete as of March 31, 2001.
2000-12-31restructuringcompleted70019992000-12-31Sedgwick operations — insurance/reinsurance broking and consultingUSD 60 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2000 portion of multi-year Sedgwick integration plan: 700 of 2,400 planned position eliminations (1,700 occurred in 1999). Termination payments of $60M utilized in 2000, along with 66 office consolidations and ~$23M of lease/office-consolidation costs. Filing states plan actions were substantially complete at year-end 2000, with the residual $23M termination accrual payable in early 2001. The $285M initial charge was recorded in acquisition cost (goodwill), not as a special charge; a $7M reduction of the termination accrual was recorded as a reduction of goodwill.
2000-12-31restructuringcompleted80019992000-12-31WorldwidePrimarily risk and insurance services; 1999 special charges of $337M were attributed $292M to risk and insurance services, $36M to consulting and $9M to corporateUSD 73 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		FY2000 portion of multi-year merger-related plan for MMC employees/offices tied to the Sedgwick combination: 800 of 2,100 planned position eliminations (1,300 in 1999); MD&A describes the reductions as worldwide. Termination payments of $73M utilized in 2000; a $7M increase from changes in estimates was recorded as a 2000 special charge. 24 office consolidations occurred in 2000. Substantially complete at year-end 2000, with the remaining $54M termination accrual expected to be paid in early 2001.
2000-12-31restructuringin_progress7001999-01-012000-12-31GlobalRisk and Insurance ServicesUSD 84 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cumulative plan: 2,400 total employee terminations planned; 700 utilized in 2000 (1,700 in 1999). 66 office consolidations in 2000 (50 in 1999). Actions substantially complete by year-end 2000. Charge includes severance, rent, and leasehold costs.
2000-12-31restructuringin_progress8001999-01-012000-12-31GlobalCorporate / Multiple segmentsUSD 87 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cumulative plan: 2,100 total employee terminations planned; 800 utilized in 2000 (1,300 in 1999). 24 office consolidations in 2000 (20 in 1999). Actions substantially complete by year-end 2000. Charge includes severance, rent, and leasehold costs.
2000-12-31acquisition_additioncompletedGlobalConsultingUSD 193 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Delta Consulting Group acquired in 2000 along with several insurance/consulting businesses for total cost of $193 million; headcount added not disclosed.
2000-12-31restructuringcompleted2,1001999-01-012000-12-31WorldwideRisk and Insurance Services; Consulting; CorporateUSD 266 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Merger-related costs associated with the combination with Sedgwick. Included personnel-related expenses principally involving severance and related benefits associated with the reduction of approximately 2,100 positions worldwide. Actions contemplated by the integration plan were substantially completed by the end of 2000.
2000-12-31restructuringcompleted2,4001999-01-012000-12-31WorldwideRisk and Insurance Services; ConsultingUSD 285 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Costs for planned reductions of approximately 2,400 positions included in the cost of the Sedgwick acquisition. Actions contemplated by the integration plan were substantially completed by the end of 2000.
2000-09-30restructuringin_progress2,4001999-01-012000-12-31GlobalSedgwick operationsUSD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan to reduce staff and consolidate duplicative offices; 1,700 terminations utilized in 1999, 400 in nine months 2000, 300 remaining at Sep 30, 2000; 125 office consolidations planned, 115 completed. Actions substantially complete, expected finalized by end of 2000. Charge was included in acquisition cost.
2000-09-30restructuringin_progress2,1001999-01-012000-12-31GlobalMMC operationsUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Merger-related costs for employees and offices of MMC tied to Sedgwick combination; 1,300 terminations utilized in 1999, 400 in nine months 2000, 400 remaining at Sep 30, 2000; 50 office consolidations planned, 45 completed. Actions substantially complete, expected finalized by end of 2000.
2000-09-30restructuringin_progress2,40019992000-12-31GlobalSedgwick employees and officesUSD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sedgwick Plan program total of 2,400 employee terminations; 1,700 completed in 1999 and 400 in the nine months ended 2000-09-30, leaving 300 remaining. Also includes 125 office consolidations (10 remaining). Charge included in cost of the Sedgwick acquisition; actions substantially complete as of quarter-end.
2000-09-30restructuringin_progress2,10019992000-12-31GlobalMMC employees and officesUSD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMC Plan program total of 2,100 employee terminations; 1,300 completed in 1999 and 400 in the nine months ended 2000-09-30, leaving 400 remaining. Also includes 50 office consolidations (5 remaining). Charge recorded within the 1999 special charge; actions substantially complete as of quarter-end.
2000-09-30restructuringin_progress3001999-01-012000-12-31GlobalSedgwick Group plc (Risk and Insurance Services)USD 106 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Remaining balance of Sedgwick Plan terminations and office consolidations. Actions substantially complete, expected to finalize by end of 2000.
2000-09-30restructuringin_progress4001999-01-012000-12-31GlobalMarsh & McLennan Companies (MMC)USD 89 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Remaining balance of MMC Plan terminations and office consolidations. Actions substantially complete, expected to finalize by end of 2000.
2000-06-30restructuringin_progress2,4001999-01-012000-12-31Sedgwick operationsUSD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan to reduce staff and consolidate duplicative offices of Sedgwick; $285M included in acquisition cost. Through June 30, 2000: 2,000 terminations and 105 office consolidations completed; $123M balance remaining, including future rent under noncancelable leases.
2000-06-30restructuringin_progress2,1001999-01-012000-12-31MMC operationsUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Merger-related costs for employees and offices of MMC recorded as 1999 special charge. Through June 30, 2000: 1,600 terminations and 40 office consolidations completed; $105M balance remaining, including future rent under noncancelable leases.
2000-06-30restructuringin_progress30019992000-12-31GlobalSedgwick Group plc operationsUSD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sedgwick Plan: 300 employee terminations utilized in six months ended 2000-06-30; 400 of 2,400 planned terminations remain, plus 20 of 125 office consolidations. Charge shown is the initial program balance included in acquisition cost; $49M utilized in the period. Plan adopted 1999, exact announcement date not disclosed
2000-06-30restructuringin_progress30019992000-12-31GlobalMarsh & McLennan corporate operationsUSD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMC Plan: 300 employee terminations utilized in six months ended 2000-06-30; 500 of 2,100 planned terminations remain, plus 10 of 50 office consolidations. Charge shown is the initial program balance recorded in 1999 special charges; $54M utilized in the period. Plan adopted 1999, exact announcement date not disclosed
2000-06-30acquisition_additioncompleted2000-05Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Delta Consulting Group in May 2000; headcount added not disclosed
2000-06-30divestiture_reductioncompleted2000-03-31Otherbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Business held for sale as part of Sedgwick combination sold in Q1 2000 for $33 million; headcount removed not disclosed. Announcement date approximated to quarter-end of sale
2000-06-30restructuringin_progress3001999-01-012000-12-31GlobalSedgwick Group plc (Risk and Insurance Services)USD 34 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Termination payments to employees under the Sedgwick Plan utilized in the six months ended June 30, 2000. Total plan balance $123 million.
2000-06-30restructuringin_progress3001999-01-012000-12-31GlobalMarsh & McLennan Companies (MMC)USD 45 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Termination payments to employees under the MMC Plan utilized in the six months ended June 30, 2000. Total plan balance $105 million.
2000-03-31restructuringin_progress2,4001999-01-012000-12-31Sedgwick operationsUSD 285 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Plan to reduce staff and consolidate duplicative offices of Sedgwick; 1,700 terminations and 50 office consolidations utilized in 1999, 200 terminations and 40 consolidations in Q1 2000; 500 terminations and 35 consolidations remaining at 2000-03-31. Charge was included in the cost of the Sedgwick acquisition.
2000-03-31restructuringin_progress2,1001999-01-012000-12-31MMC operationsUSD 266 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Merger-related costs for employees and offices of MMC recorded as part of a 1999 special charge; 1,300 terminations and 20 office consolidations utilized in 1999, 150 terminations and 15 consolidations in Q1 2000; 650 terminations and 15 consolidations remaining at 2000-03-31.
2000-03-31restructuringin_progress2,40019992000-12-31Global (Sedgwick operations)Sedgwick Group plc — insurance broking and consultingUSD 285 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Initial program: 2,400 employee terminations and 125 office consolidations; 1,700 terminations utilized in 1999 and 200 in Q1 2000 (charge utilization $31M in Q1 2000), leaving 500 terminations and 35 office consolidations at 2000-03-31. Charge included in Sedgwick purchase price.
2000-03-31restructuringin_progress2,10019992000-12-31Global (MMC operations)MMC corporate and operating officesUSD 266 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Initial program: 2,100 employee terminations and 50 office consolidations; 1,300 terminations utilized in 1999 and 150 in Q1 2000 (charge utilization $26M in Q1 2000), leaving 650 terminations and 15 office consolidations at 2000-03-31. Part of a $337M special charge recorded in 1999.
2000-03-31divestiture_reductioncompletedNot disclosedBusiness acquired via Sedgwick combination and held for saleUSD 33 (millions)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sold during Q1 2000 for $33 million, approximating carrying value; no headcount associated with the sale was disclosed.
2000-03-31restructuringin_progress2001999-01-012000-12-31GlobalSedgwick Group plc (Risk and Insurance Services)USD 31 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of Sedgwick Plan initiated in 1999. 200 terminations occurred in Q1 2000. Remaining balance of 500 terminations expected by end of 2000.
2000-03-31restructuringin_progress1501999-01-012000-12-31GlobalMarsh & McLennan Companies (MMC)USD 26 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Part of MMC Plan initiated in 1999. 150 terminations occurred in Q1 2000. Remaining balance of 650 terminations expected by end of 2000.
1999-12-31restructuringin_progress2,40019992000-12-31Sedgwick operations (acquired November 1998)USD 285 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Integration plan adopted in 1999; the $285M cost was included in the cost of the acquisition rather than as a separate special charge (components: $183M termination payments, $5M other employee costs, $48M future rent, $49M leasehold termination). During 1999, 1,700 of 2,400 planned terminations and 50 of 125 planned office consolidations were executed ($113M utilized), leaving 700 terminations and 75 consolidations. Part of a broader Sedgwick integration program expected to eliminate roughly 4,500 positions and consolidate about 175 offices, targeting net annual savings approaching $160M.
1999-12-31restructuringin_progress2,10019992000-12-31WorldwideUSD 266 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Merger-related costs for MMC's own employees and offices, recorded within the $337M 1999 special charge (components: $194M severance for about 2,100 positions worldwide, $31M future rent, $16M leasehold termination, $25M other integration costs). During 1999, 1,300 terminations and 20 of 50 planned office consolidations were executed ($107M utilized), leaving 800 terminations and 30 consolidations. The total $337M special charge was attributed $292M to risk and insurance services, $36M to consulting and $9M to corporate.
1999-12-31restructuringcompleted5019971999Johnson & Higgins operations (acquired March 1997)USD 20 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Tail-end activity of the 1997 J&H integration plan (program total about 900 positions); only current-year activity captured. Fifty terminations and five office consolidations were executed in 1999, utilizing $20M of the $143M reserve; filer states remaining actions were completed in early 1999.
1999-12-31restructuringcompleted5019971999WorldwideMMC employees/offices (J&H integration)USD 27 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Tail-end activity of the 1997 MMC plan tied to the J&H combination (program total about 1,300 positions); only current-year activity captured. Fifty terminations and three office consolidations were executed in 1999, utilizing $27M of the $168M reserve. Remaining accruals, mainly future rent and salary continuance largely in Canada and the Netherlands, will be paid over several years.
1999-12-31restructuringin_progress2,4002000-12-31GlobalRisk and Insurance Services (Sedgwick operations)USD 285 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		1999 Sedgwick Plan: 2,400 positions planned; 1,700 executed in 1999, 700 remaining at year-end. Also 125 office consolidations planned (50 executed in 1999). Charge included in cost of Sedgwick acquisition.
1999-12-31restructuringin_progress2,1002000-12-31GlobalRisk and Insurance Services / Consulting / Corporate (MMC operations)USD 266 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		1999 MMC Plan: 2,100 positions planned; 1,300 executed in 1999, 800 remaining at year-end. Also 50 office consolidations planned (20 executed in 1999). Recorded as 1999 special charge.
1999-12-31restructuringcompleted501997-03-271999-12-31GlobalRisk and Insurance Services (J&H operations)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Residual 1999 activity from 1997 J&H Plan (900 total positions). 50 terminations executed in 1999; plan completed with zero balance at year-end. Original charge recorded in 1997.
1999-12-31restructuringcompleted501997-03-271999-12-31GlobalRisk and Insurance Services / Consulting / Corporate (MMC operations)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Residual 1999 activity from 1997 MMC Plan (1,300 total positions). 50 terminations executed in 1999; plan completed with zero balance at year-end. Original charge recorded in 1997.
1999-12-31restructuringin_progress2,1001999-11-012000-12-31WorldwideRisk and Insurance Services; Consulting; CorporateUSD 266 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Merger-related costs associated with the combination with Sedgwick (1999 MMC Plan). Includes severance for reduction of approximately 2,100 positions and office consolidations. Actions expected to be completed by end of 2000.
1999-12-31restructuringin_progress2,4001999-11-012000-12-31WorldwideRisk and Insurance Services; ConsultingUSD 285 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		Integration plan for Sedgwick employees and offices (1999 Sedgwick Plan). Included in cost of acquisition. Reduction of approximately 2,400 positions. Actions expected to be completed by end of 2000.
1999-09-30restructuringin_progress1,0001999-04-011999-12-31WorldwideRisk and insurance services ($73M); Consulting ($11M)USD 71 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Special charge recorded Q2 1999 for severance and related benefits tied to planned reduction of approximately 1,000 MMC positions; $50 million paid through September 30, 1999 covering roughly 980 terminated employees; remaining actions expected complete by end of 1999
1999-09-30restructuringin_progress1,5001999-04-011999-12-31WorldwideSedgwick operationsUSD 99 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Severance and related benefits for planned reduction of over 1,500 Sedgwick positions allocated to acquisition cost; $70 million paid through September 30, 1999 covering roughly 1,300 terminated employees
1999-09-30acquisition_additioncompleted1998-11-01United Kingdom / globalRisk and insurance services; ConsultingUSD 2,200 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sedgwick Group plc business combination completed Q4 1998 for approximately $2.2 billion cash; no headcount figure disclosed for employees added
1999-09-30restructuringin_progress1,0001999-12-31WorldwideMMC (excludes Sedgwick); $73M of charge allocated to risk and insurance services, $11M to consultingUSD 71 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Planned reduction of approximately 1,000 MMC positions; charge recorded in Q2 1999 (no specific announcement date disclosed). Through 1999-09-30, $50M paid for termination of approximately 980 MMC employees. Remaining actions expected completed by end of 1999. A separate $13M acquisition-related award charge is not a headcount action.
1999-09-30restructuringin_progress1,5001999-12-31Sedgwick Group plc (acquired operations)USD 99 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Planned reduction of over 1,500 Sedgwick positions; severance allocated to the cost of the Sedgwick acquisition rather than expensed as a special charge. Through 1999-09-30, $70M paid for termination of approximately 1,300 Sedgwick employees. Count is a stated lower bound ('over 1,500').
1999-09-30restructuringannouncedSedgwick integrationrestructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Filer states a further charge will be taken in Q4 1999 for additional integration efforts including staff reductions and office consolidations; no employee count, charge amount, or completion date disclosed
1999-09-30restructuringin_progress1,0001999-06-301999-12-31WorldwideRisk and Insurance Services; ConsultingUSD 71 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		MMC positions reduced. $71 million charge recorded in Q2 1999. $50 million paid through Sept 30, 1999 for approx 980 employees.
1999-09-30restructuringin_progress1,5001999-06-301999-12-31WorldwideSedgwick Group plcUSD 99 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Sedgwick positions reduced. $99 million allocated to cost of acquisition. $70 million paid through Sept 30, 1999 for approx 1,300 employees.
1999-06-30restructuringin_progress1,0001999-06-301999-12-31WorldwidePrimarily risk and insurance services; remainder consultingUSD 71 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Severance and related benefits for planned reduction of approximately 1,000 MMC positions; part of $84M Q2 1999 special charge ($73M risk and insurance services, $11M consulting). Through June 30, 1999, $22M paid related to termination of approximately 650 MMC employees. Remaining actions expected to be completed by end of 1999; another charge expected in Q4 for additional integration efforts.
1999-06-30otherin_progress1999-06-30USD 13 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Acquisition-related awards pertaining to the Sedgwick transaction, included in the $84M special charge
1999-06-30restructuringin_progress1,5001999-06-301999-12-31Primarily United KingdomSedgwick operationsUSD 99 (millions)restructuring_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Severance and related benefits for planned reduction of over 1,500 Sedgwick positions, allocated to the cost of the acquisition rather than expensed as special charge. Through June 30, 1999, $51M paid related to termination of approximately 950 Sedgwick employees. Combined severance-related costs of $170M; approximately $73M paid as of June 30, 1999.
1999-06-30restructuringin_progress1,0001999-06-301999-12-31WorldwideRisk and insurance services and consultingUSD 71 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Planned reduction of approximately 1,000 MMC positions as part of Sedgwick integration; no specific announcement date disclosed, charge recorded in Q2 1999. Total $84M special charge split $73M risk and insurance services / $11M consulting and also includes $13M acquisition-related awards. Approximately 650 MMC employees already terminated through 1999-06-30 with $22M cash paid; remaining actions expected complete by end of 1999. Another integration charge expected in Q4 1999.
1999-06-30restructuringin_progress1,5001999-06-301999-12-31United KingdomSedgwick Group plcUSD 99 (millions)restructuring_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Filer states 'over 1,500' Sedgwick positions planned for reduction; $99M severance and benefits allocated to the cost of the acquisition rather than expensed as a period charge. Sedgwick is London-based; specific locations not disclosed. Approximately 950 Sedgwick employees already terminated through 1999-06-30 with $51M cash paid. Combined with MMC program, total severance-related costs of $170M with ~$73M cash paid as of 1999-06-30.
1999-06-30divestiture_reductionannounced1999-06-30Run-off insurance underwriting companies and non-core consulting businesses acquired with Sedgwickbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		MMC states intent to sell these operations in the near future; $85M of net assets classified as held for sale at 1999-06-30. No headcount associated with the planned divestitures is disclosed.
1999-06-30restructuringin_progress1,0001999-06-301999-12-31WorldwideRisk and Insurance Services; ConsultingUSD 71 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		MMC positions reduced as part of Sedgwick integration. $71 million charge recorded in Q2 1999. $22 million paid through June 30, 1999.
1999-06-30restructuringin_progress1,5001999-06-301999-12-31WorldwideRisk and Insurance Services; ConsultingUSD 99 (millions)restructuring_footnote
f5-10q / Qwen3.6-27B-Q8_0		Sedgwick positions reduced as part of integration. $99 million allocated to acquisition cost. $51 million paid through June 30, 1999.
1999-03-31acquisition_additioncompleted1998-11-01Global (London-based)Risk and Insurance Services; ConsultingUSD 2,200 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Sedgwick Group plc acquired in Q4 1998 for approximately $2.2 billion cash; headcount added not quantified in this filing
1999-03-31restructuringin_progress1999-03-312000-12-31Sedgwick operationsMD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Early stages of Sedgwick integration; special charges expected in 1999 but amount not yet determinable; gross consolidation savings of approximately $200 million targeted, majority expected in 2000
1999-03-31divestiture_reductionannounced1999-03-31Insurance underwriting (run-off) and non-compatible consulting businessesUSD 92 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Run-off underwriting companies and incompatible consulting businesses acquired with Sedgwick to be sold; $92 million of net assets classified as held for sale at March 31, 1999; headcount affected not quantified
1999-03-31acquisition_additioncompletedUnited KingdomRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sedgwick acquired in Q4 1998 for ~$2.2B; no employee headcount disclosed in filing
1999-03-31restructuringin_progressGlobalRisk and Insurance Services; ConsultingMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sedgwick integration underway; special charges expected in 1999 but amount not yet determined; no employee count disclosed
1999-03-31divestiture_reductionin_progressUnited KingdomInsurance underwriting (run-off); non-core consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Run-off underwriting companies and non-core consulting businesses acquired via Sedgwick to be sold; $92M net assets classified as held for sale; no headcount disclosed
1998-12-31restructuringin_progress25019971999-12-31WorldwideRisk and Insurance Services and ConsultingUSD 143 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		1998 activity under the J&H integration program adopted in 1997 with a total charge of $143 million allocated to the J&H acquisition cost ($74 million employee-related for over 900 planned terminations; $69 million for about 50 office consolidations). 600 terminations occurred in 1997 and 250 during 1998; 50 terminations and 5 office consolidations remained at year-end 1998, with the final ~100 employees across the J&H and MMC plans severed in January 1999. $56 million of the charge was utilized in 1998. Combined with the MMC plan, approximately 2,200 position eliminations and about 80 office consolidations were expected to be completed by end of 1999, supporting roughly $200 million of gross annual savings.
1998-12-31restructuringin_progress45019971999-12-31WorldwideRisk and Insurance Services and ConsultingUSD 168 (millions)business_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		1998 activity under the MMC-side integration program, whose $168 million special charge was recorded in 1997 ($117 million severance for approximately 1,300 positions; $38 million for about 30 office consolidations; $13 million other integration costs). 800 terminations occurred in 1997 and 450 during 1998; 50 terminations and 3 office consolidations remained at year-end 1998 and were completed in January 1999. $66 million of the charge was utilized in 1998; remaining balances are largely future rent and salary continuance, primarily in Canada and the Netherlands.
1998-12-31othercompleted1998United Kingdom (London)Risk and Insurance Services (insurance and reinsurance back-office operations)USD -15 (millions)restructuring_footnote
f5-10k / GLM-5.3-flash-HTML		Reversal (credit) in 1998 of the remaining $15 million severance accrual from a 1996 London restructuring plan that had provided for a planned reduction of over 600 employees. Following the Sedgwick acquisition, management concluded the staff-reduction portion could no longer be executed and no terminations were carried out under it; a redefined accrual will be recorded when a revised plan meets requirements. No employees were affected in 1998 under this action.
1998-12-31acquisition_additioncompleted1998-11-03United Kingdom (headquarters); global operationsRisk and Insurance Services and Consultingbusiness_combinations_footnote
f5-10k / GLM-5.3-flash-HTML		Cash tender offer for Sedgwick Group plc commenced September 4, 1998 and was declared unconditional November 3, 1998; total cash consideration approximately $2.2 billion (£1.25 billion), reflected in MMC results beginning November 1998; compulsory acquisition of remaining shares completed February 1999. Headcount added is not separately quantified in the filing; the year-end 1998 headcount of about 54,300 includes the Sedgwick operations. Also includes an $11 million 1998 charge for acquisition-related stock unit awards issued to certain senior Sedgwick employees (Note 12).
1998-12-31restructuringannounced1998United Kingdom and international Sedgwick operationsRisk and Insurance Services (to be combined with J&H Marsh & McLennan) and Consulting (Sedgwick Noble Lowndes to be combined with William M. Mercer)MD&A
f5-10k / GLM-5.3-flash-HTML		Integration plans associated with the Sedgwick acquisition were in process at fiscal year-end 1998; a special charge will be recorded in 1999 but was not yet quantifiable. MMC expects gross synergy savings of approximately $200 million, with net annual savings expected to be similar to those achieved in the J&H integration. Headcount impact not disclosed.
1998-12-31restructuringin_progress2501997-03-271999-12-31GlobalJ&H (Johnson & Higgins) operationsUSD 143 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cumulative program: 900 planned terminations; 600 utilized in 1997, 250 in 1998, 50 remaining at year-end. Charge allocated to acquisition cost.
1998-12-31restructuringin_progress4501997-03-271999-12-31GlobalMMC corporate and operationsUSD 168 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Cumulative program: 1,300 planned terminations; 800 utilized in 1997, 450 in 1998, 50 remaining at year-end. Recorded as special charge in 1997.
1998-12-31acquisition_additioncompleted1998-09-041999-02-28United Kingdom / GlobalRisk and Insurance Services; ConsultingUSD 2,200 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Sedgwick Group plc acquired for ~$2.2B cash; offer declared unconditional 1998-11-03, compulsory acquisition completed Feb 1999. No employee headcount disclosed for acquired workforce.
1998-12-31restructuringannounced1001999-01-311999-12-31GlobalJ&H and MMC integrationrestructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Subsequent event: final group of nearly 100 redundant employees severed in January 1999 under J&H and MMC integration plans.
1998-12-31restructuringcompleted1996-01-011998-12-31United KingdomLondon back-office operationsUSD 15 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Remaining $15M severance reserve from 1996 London restructuring reversed in 1998 because staff reduction plan could no longer be executed following Sedgwick acquisition. No positions eliminated under this reversal.
1998-12-31restructuringcompleted4501997-03-271999-03-31WorldwideRisk and Insurance Services; ConsultingUSD 168 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		MMC Plan: 450 terminations in 1998. Total plan targeted 1,300 positions. Charge of $168 million recorded in 1997.
1998-12-31restructuringcompleted2501997-03-271999-03-31WorldwideRisk and Insurance ServicesUSD 143 (millions)restructuring_footnote
f5-10k / Qwen3.6-27B-Q8_0		J&H Plan: 250 terminations in 1998. Total plan targeted 900 positions. Charge of $143 million allocated to acquisition cost.
1998-12-31acquisition_additioncompleted1998-11-031998-12-31WorldwideRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10k / Qwen3.6-27B-Q8_0		Acquisition of Sedgwick Group plc completed in late 1998. Headcount not explicitly disclosed in filing.
1998-09-30acquisition_additionannounced16,0001998-11-03United Kingdom and worldwideRisk and Insurance ServicesUSD 2,100 (millions)subsequent_events
f5-10q / GLM-5.3-flash-fp4-HTML		Sedgwick Group plc acquisition became wholly unconditional on 1998-11-03; Company acquired ~88% of issued share capital for ~$2.1 billion. Sedgwick employed approximately 16,000 employees at December 31, 1997.
1998-09-30acquisition_additioncompleted16,0001998-08-251998-11-03United Kingdom / globalRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Offer announced during Q3 1998 (Form 8-K dated 1998-08-25); became unconditional 1998-11-03 with ~88% of shares acquired. Headcount of approximately 16,000 is as of 1997-12-31 per Sedgwick's reported figures; not reflected in this filing's results.
1998-09-30acquisition_additioncompleted1998-06-301998-06-30United StatesRisk and Insurance Services / employee benefit administrationbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of insurance and health benefit program administrator; headcount added not disclosed.
1998-09-30acquisition_additioncompleted1998-03-241998-03-24MexicoRisk and Insurance Services / employee benefit consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase completed within year-to-date period; headcount added not disclosed.
1998-09-30acquisition_additioncompleted16,0001998-09-30United KingdomRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Sedgwick Group plc acquisition announced Q3 1998; 16,000 employees at Dec 31, 1997.
1998-09-30acquisition_additioncompleted1998-06-30United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquisition of Kirke-Van Orsdel, Inc. on June 30, 1998.
1998-09-30acquisition_additioncompleted1998-03-24MexicoRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquisition of Brockman y Schuh Group on March 24, 1998.
1998-06-30restructuringin_progress1997-03-27Primarily United StatesRisk and Insurance ServicesMD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Ongoing integration of Johnson & Higgins; during Q2 1998 the Company realized additional savings from elimination of redundant personnel and consolidation of offices, primarily in the United States. No employee count or charge amount quantified.
1998-06-30acquisition_additioncompleted1998-06-301998-06-30United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Acquired Kirke-Van Orsdel, Inc., an administrator of insurance and health benefit programs; headcount added not disclosed.
1998-06-30acquisition_additioncompleted1998-03-241998-03-24MexicoRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Acquired Brockman y Schuh Group, a risk and insurance services and employee benefit consulting firm; headcount added not disclosed.
1998-06-30acquisition_additioncompleted1998-06-30United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of Kirke-Van Orsdel, Inc., an administrator of insurance and health benefit programs; headcount added not disclosed
1998-06-30acquisition_additioncompleted1998-03-24MexicoRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of Brockman y Schuh Group, a risk and insurance services and employee benefit consulting firm; headcount added not disclosed
1998-06-30restructuringin_progressUnited StatesRisk and Insurance ServicesMD&A
f5-10q / Qwen3.6-27B-Q8_0		Elimination of redundant personnel and consolidation of offices primarily in the U.S. as part of J&H integration.
1998-06-30acquisition_additioncompleted1998-06-30United StatesRisk and Insurance ServicesUSD 313 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Purchase of Kirke-Van Orsdel, Inc., an administrator of insurance and health benefit programs.
1998-06-30acquisition_additioncompleted1998-03-24MexicoRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Purchase of Brockman y Schuh Group, a risk and insurance services and employee benefit consulting firm.
1998-03-31acquisition_additioncompleted1998-03-241998-03-24MexicoRisk and Insurance Services / Employee Benefit ConsultingUSD 100 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Purchase of Brockman y Schuh Group, a risk and insurance services and employee benefit consulting firm, for approximately $100 million; headcount added not quantified
1998-03-31restructuringin_progress1997-03-27Primarily United StatesRisk and Insurance ServicesMD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Integration of Johnson & Higgins: elimination of redundant personnel and consolidation of offices, primarily in the US; integration savings realized during the quarter; affected headcount not quantified
1998-03-31acquisition_additioncompleted1998-03-24MexicoRisk and Insurance Services; Employee Benefit Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Headcount added through the acquisition not disclosed; purchase price approximately $100 million.
1998-03-31restructuringin_progressPrimarily United StatesRisk and Insurance ServicesMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Ongoing Johnson & Higgins integration actions; no employee count or charge amount disclosed in this filing.
1998-03-31acquisition_additioncompleted1998-03-24MexicoRisk and Insurance Services; Employee Benefit ConsultingUSD 100 (millions)business_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Purchase of Brockman y Schuh Group for approx. $100 million. Headcount not disclosed.
1998-03-31restructuringin_progressUnited StatesRisk and Insurance ServicesMD&A
f5-10q / Qwen3.6-27B-Q8_0		Integration savings realized from elimination of redundant personnel and consolidation of offices. Specific headcount or charges not disclosed.
1997-12-31acquisition_additioncompleted1997-03-271997-03-27GlobalRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Johnson & Higgins completed 1997-03-27; headcount added not separately disclosed
1997-12-31restructuringin_progress2,2001997-03-271999-12-31Primarily United StatesRisk and Insurance ServicesUSD 120 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Approximately 2,200 positions eliminated as part of J&H integration; $119.9M severance charge; substantially all severance expected paid by 1998-06-30; $51.8M remitted in 1997
1997-12-31acquisition_additioncompleted1997-01-011997-01-31FranceRisk and Insurance ServicesItem_1_Business
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Acquisition of CECAR SA, a French insurance broker, in January 1997; headcount added not disclosed
1997-12-31plant_closurein_progress1997-01-01London, United KingdomRisk and Insurance ServicesUSD 69 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		London real estate charge for consolidating back-office operations and razing/redeveloping London building; associated headcount impact not separately quantified
1997-12-31restructuringin_progress2,2001997-03-271999-12-31WorldwideRisk and Insurance ServicesUSD 120 (millions)MD&A
f5-10k / Qwen3.6-27B-Q8_0		Related to the combination with Johnson & Higgins. Charge reflects severance and associated benefits for staff reductions and relocations. Substantially all severance expected to be paid no later than June 30, 1998. Gross annual integration savings of approx $200 million expected by end of 1999.
1997-12-31restructuringin_progress1,3001997-03-271998-12-31WorldwideMarsh & McLennan Companies (all segments)USD 117 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Severance and related benefits for planned reduction of approximately 1,300 positions; 800 terminations completed in 1997, 500 remaining at year-end. Part of $167.5M special charge.
1997-12-31restructuringin_progress9001997-03-271998-12-31WorldwideJohnson & Higgins (acquired operations)USD 74 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Reduction of over 900 J&H positions; 600 completed in 1997, 300 remaining at year-end. Costs allocated to the $1.8 billion J&H acquisition cost rather than expensed.
1997-12-31restructuringin_progress1997-03-271998-12-31Primarily United StatesMarsh & McLennan Companies (facilities)USD 38 (millions)restructuring_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Planned consolidation of approximately 30 offices; 10 completed in 1997, 20 remaining. Charge represents future rent under noncancellable leases net of sublease income and lease terminations.
1997-12-31restructuringin_progress1997-03-271998-12-31Primarily United StatesJohnson & Higgins (facilities)USD 69 (millions)business_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Planned consolidation of approximately 50 J&H offices; 10 completed in 1997, 40 remaining. Allocated to acquisition cost.
1997-12-31plant_closurein_progress1997-10-01United Kingdom (London)Risk and Insurance Services — London operationsUSD 61 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Fourth-quarter 1997 charge for consolidating offices, vacating leased locations, and razing/redeveloping the company-owned London building; $34.7M building demolition, $26.6M lease abandonment. No employee count disclosed.
1997-12-31restructuringannounced6001996-01-011998-12-31United Kingdom (London)Insurance and reinsurance back office operationsUSD 27 (millions)MD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Charge and plan originated in 1996 (over 600 employees); execution delayed in 1997 by the J&H acquisition, with the company restating commitment to act in 1998. Charge not counted in FY1997 activity.
1997-12-31acquisition_additioncompleted1997-03-271997-03-27WorldwideRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Total consideration approximately $1.8 billion; acquired headcount not disclosed. Results included from Q2 1997.
1997-12-31acquisition_additioncompleted1997-01-011997-01-31FranceRisk and Insurance ServicesMD&A
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Compagnie Europeenne De Courtage d'Assurances et de Reassurances acquired for approximately $200 million; acquired headcount not disclosed.
1997-12-31divestiture_reductioncompleted1997-01-011997-12-31Not disclosedInsurance program management and consulting operationsdiscontinued_operations_footnote
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Two businesses sold during 1997 with $13.2 million pretax gain; headcount removed not disclosed.
1997-09-30acquisition_additioncompleted1997-03-271997-03-27GlobalRisk and Insurance Services; Consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Business combination with Johnson & Higgins, a privately held insurance broking and employee benefit consulting firm; no employee count disclosed. Results included in operations beginning Q2 1997.
1997-09-30acquisition_additioncompleted1997-011997-01FranceRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of CECAR, a French insurance broker, for approximately $200 million; no employee count disclosed.
1997-09-30acquisition_additioncompleted1997-051997-05United StatesRisk and Insurance Services — Insurance Program ManagementMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Acquisition of Albert H. Wohlers & Co. cited as a driver of insurance program management revenue growth; no employee count disclosed.
1997-06-30acquisition_additioncompleted1997-03-27Risk and Insurance ServicesUSD 1,800 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Business combination with Johnson & Higgins, an insurance broking and employee benefits consulting firm, for approximately $1.8 billion in cash and stock; headcount added not disclosed.
1997-06-30acquisition_additioncompleted1997-01FranceRisk and Insurance ServicesUSD 200 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Purchase of CECAR, a French insurance broker, for approximately $200 million; headcount added not disclosed.
1997-06-30divestiture_reductioncompleted1997-05Risk and Insurance Services — Insurance Program ManagementUSD 10 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Disposition of Trust Consultants Inc. in May 1997 generated a $10 million gain; headcount removed not disclosed.
1997-06-30acquisition_additioncompleted1997-03-27United StatesRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Strategic business combination with Johnson & Higgins closed March 27, 1997; total consideration approx. $1.8 billion (cash and stock). No employee headcount added disclosed. Related Form 8-K filed April 7, 1997.
1997-06-30acquisition_additioncompleted1997-01FranceRisk and Insurance Servicesbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of French insurance broker CECAR for approximately $200 million in January 1997; no headcount added disclosed.
1997-06-30divestiture_reductioncompleted1997-05Risk and Insurance Services — Insurance Program ManagementMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Disposition of Trust Consultants Inc. (TCI) in May 1997 with a $10 million gain; no headcount removed disclosed.
1997-03-31acquisition_additioncompleted1997-03-121997-03-27Insurance ServicesUSD 1,800 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Strategic business combination with Johnson & Higgins, a privately-held insurance broking and employee benefit consulting firm, consummated March 27, 1997; total consideration approximately $1.8 billion (~$600 million cash plus ~9.8 million common shares). No employee headcount figures disclosed.
1997-03-31acquisition_additioncompleted1997-01-011997-01-31FranceInsurance ServicesUSD 200 (millions)business_combinations_footnote
f5-10q / GLM-5.3-flash-fp4-HTML		Purchase of Compagnie Europeenne De Courtage d'Assurances et de Reassurances (CECAR), a French insurance broker, for approximately $200 million in January 1997. No employee headcount figures disclosed.
1997-03-31divestiture_reductioncompletedInsurance Program ManagementMD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of Frizzell drove a 44% decline in insurance program management revenue; Seabury & Smith represents the whole of program management subsequent to the sale. No employee headcount figures disclosed.
1997-03-31acquisition_additioncompleted1997-05-011997-05-01Insurance Program Management (Seabury & Smith)other
f5-10q / GLM-5.3-flash-fp4-HTML		Subsequent event: on May 1, 1997, wholly-owned subsidiary Seabury & Smith acquired all capital stock of Albert H. Wohlers & Co. in exchange for 471,625 shares of Company common stock. No employee headcount figures disclosed.
1997-03-31acquisition_additioncompleted1997-03-121997-03-27GlobalInsurance services / consultingbusiness_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Strategic combination with Johnson & Higgins for approximately $1.8 billion; no employee count disclosed. Results reflected in operations beginning Q2 1997.
1997-03-31acquisition_additioncompleted1997-01-31FranceInsurance services (insurance broking)business_combinations_footnote
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Purchase of CECAR, a French insurance broker, for approximately $200 million in January 1997; no employee count disclosed. Exact January date not specified.
1997-03-31divestiture_reductioncompletedUnited KingdomInsurance Program ManagementMD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale of Frizzell cited as the cause of a 44% decline in program management revenue; no headcount or transaction date disclosed in this filing.
1997-03-31acquisition_additionannounced1997-05-011997-05-01United StatesInsurance Program Management (Seabury & Smith)other
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Subsequent-event acquisition of Albert H. Wohlers & Co. for 471,625 shares; no employee count disclosed.
1997-03-31acquisition_additioncompleted1997-03-27GlobalInsurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Acquisition of Johnson & Higgins, a privately-held insurance broking and employee benefit consulting firm. Headcount not explicitly disclosed.
1997-03-31acquisition_additioncompleted1997-01-01FranceInsurance Servicesbusiness_combinations_footnote
f5-10q / Qwen3.6-27B-Q8_0		Purchase of Compagnie Europeenne De Courtage d'Assurances et de Reassurances (CECAR). Headcount not explicitly disclosed.
1996-12-31divestiture_reductioncompleted1996United KingdomInsurance Services (insurance program management, personal financial planning, consumer finance)Item_1_Business
f5-10k / GLM-5.3-flash-HTML		The Frizzell Group Limited and its subsidiaries were sold during fiscal 1996; affected employee count not disclosed. Exact sale date within 1996 not specified.
1996-12-31acquisition_additioncompleted1997-01FranceInsurance Services (insurance broking)Item_1_Business
f5-10k / GLM-5.3-flash-HTML		Subsequent event to FY1996: CECAR SA, a French insurance broker, acquired in January 1997, making the registrant the largest insurance broker in France; employee count not disclosed.
1996-12-31acquisition_additioncompleted1997-03-121997-03-27Worldwide (headquartered in New York)Insurance Services and employee benefit consultingItem_1_Business
f5-10k / GLM-5.3-flash-HTML		Subsequent event to FY1996: Stock Purchase Agreement dated March 12, 1997; J&H became a subsidiary on March 27, 1997 (actual closing date shown in expected_completion_date). J&H 1996 revenues were $1.2 billion; employee count not disclosed and FY1996 disclosures exclude J&H.
1996-12-31divestiture_reductioncompletedUnited KingdomInsurance servicesItem_1_Business
f5-10k / MiMo-V2.6-Flash-fp8-HTML		The Frizzell Group Limited and subsidiaries were sold in 1996; no employee count disclosed
1996-12-31acquisition_additioncompleted1997-03-121997-03-27United StatesInsurance servicesItem_1_Business
f5-10k / MiMo-V2.6-Flash-fp8-HTML		Johnson & Higgins became a subsidiary on 1997-03-27 (subsequent event); 1996 revenues of $1.2 billion; no employee count disclosed
1996-12-31acquisition_additioncompleted1997-01-31FranceInsurance servicesItem_1_Business
f5-10k / MiMo-V2.6-Flash-fp8-HTML		CECAR SA, a French insurance broker, acquired in January 1997 (subsequent event); no employee count disclosed
1996-09-30divestiture_reductioncompleted1996-06-30United KingdomInsurance Services — Insurance Program ManagementUSD 33 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Sale of The Frizzell Group Limited completed June 1996 for approximately $290 million; $33.2 million pretax gain offset by $33.4 million of non-recurring charges. No employee headcount figures disclosed for the divested operation.
1996-09-30divestiture_reductioncompleted1996-06-301996-06-30United KingdomInsurance Services (reinsurance broking / insurance program management)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Sale completed June 1996; filing discloses no headcount removed. Related non-recurring charges of $33.4M (London market provision, goodwill write-off, real estate) are not identified as workforce/severance charges. Announcement date approximated to completion month (June 1996) as no separate announcement date is given.
1996-06-30divestiture_reductioncompleted1996-06-051996-06-30United KingdomInsurance Program Management (The Frizzell Group Limited)USD 33 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Company completed sale of The Frizzell Group Ltd. for approximately $290 million in June 1996; second quarter includes a $33.2 million pretax gain on the sale. No headcount figure disclosed for the divested business.
1996-03-31divestiture_reductionannounced1996-02-071996-06-30United KingdomInsurance Program Management — Frizzell GroupUSD 289 (millions)MD&A
f5-10q / GLM-5.3-flash-fp4-HTML		Agreement signed to sell the Frizzell Group for approximately $289 million; transaction subject to regulatory and other approvals; headcount impact not quantified
1996-03-31divestiture_reductionannounced1996-02-071996-06-30United KingdomInsurance Program Management (Frizzell Group)MD&A
f5-10q / MiMo-V2.6-Flash-fp8-HTML		Agreement signed February 7, 1996 to sell the Frizzell Group for approximately $289 million, subject to regulatory approvals, expected to close by end of Q2 1996; no employee count disclosed for the divested workforce.