Fundies. English
Segment disclosures
Company overviewMarsh & McLennan Companies, Inc.
Each reported dimension combination stays separate. Revenue and operating income are shown as reported, with their dates and sources.
Revenue · Reported segment facts
85 dimension combinations 543 retained observations 23 reported periods
Counts describe retained dimensioned rows only. Periods and members can change across reports, and this view does not infer missing values or expected segment totals.
Intersegment Elimination · Consulting Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 20000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 53000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 18000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 33000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 15000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 60000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 18000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 44000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 13000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 26000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 13000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 56000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 14000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 40000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 13000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 26000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 59000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Intersegment Elimination · Riskand Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-01-01 – 2024-09-30 | 5000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 4000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 5000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 5000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 5000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 5000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
Intersegment Elimination · Risk And Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-09-30 | 5000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 4000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 5000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 5000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 4000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 5000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Intersegment Elimination · Consulting Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 17000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 29000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-03-31 | 12000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 73000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 18000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 33000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 15000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 60000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 56000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Intersegment Elimination · Risk And Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 4000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 4000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 4000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 5000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Operating Segments · Career · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-01-01 – 2024-12-31 | 1059000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 1019000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 962000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Career · Consulting Segment · Mercer Consulting Group
Consolidation Items · Product Or Service · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 218000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 307000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 742000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 220000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 435000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 215000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 294000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 731000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 219000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 437000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
Operating Segments · Career · Mercer Consulting Group · Consulting Segment
Consolidation Items · Product Or Service · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:CareerMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 319000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 756000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 219000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 437000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 307000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 742000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 220000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 435000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Health · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-01-01 – 2024-12-31 | 2100000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2061000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 2017000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Health · Consulting Segment · Mercer Consulting Group
Consolidation Items · Product Or Service · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 608000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 520000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 1605000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 538000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 496000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 1559000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
Operating Segments · Health · Mercer Consulting Group · Consulting Segment
Consolidation Items · Product Or Service · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:HealthMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 555000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 1757000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 594000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1202000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 520000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 1605000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 547000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1085000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Wealth · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-01-01 – 2024-12-31 | 2584000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2507000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 2366000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Wealth · Consulting Segment · Mercer Consulting Group
Consolidation Items · Product Or Service · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 670000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 625000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 1909000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 612000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1284000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 672000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 635000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 1853000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 637000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 1218000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
Operating Segments · Wealth · Mercer Consulting Group · Consulting Segment
Consolidation Items · Product Or Service · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mmc:WealthMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 705000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2060000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 685000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1355000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 625000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 1909000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 612000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1284000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Career · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mrsh:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 248000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 1087000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 218000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 1059000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 1019000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Health · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mrsh:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 661000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 2284000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 608000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 2100000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2061000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Wealth · Consulting Segment
Consolidation Items · Product Or Service · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=mrsh:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 752000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 2819000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 670000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 2584000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2507000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Consulting Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 2465000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 7150000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 2371000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 4685000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 2314000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 9133000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 2262000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 6692000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 2216000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 4430000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 2214000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 8709000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 2206000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 6409000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 2172000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 4203000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 8139000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Consulting Segment · Health · Mercer Consulting Group
Consolidation Items · Statement Business Segments · Product Or Service · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;srt:ProductOrServiceAxis=mmc:HealthMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-04-01 – 2024-06-30 | 547000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1085000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 518000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 1063000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
Operating Segments · Consulting Segment · Mercer Consulting Group
Consolidation Items · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 1496000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 5743000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 1452000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 4256000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 1379000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 2804000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 1425000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 5587000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 1425000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 4143000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 1374000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 2718000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 5345000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Consulting Segment · Oliver Wyman Group Consulting Group
Consolidation Items · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:OliverWymanGroupConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 818000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 3390000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 810000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 2436000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 837000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1626000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 789000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 3122000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 781000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 2266000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 798000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 1485000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 2794000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Riskand Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 4762000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 15395000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 3453000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 11748000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 4022000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 8295000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 4273000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 14089000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 3190000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 10818000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 3722000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 7628000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 12645000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Risk And Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 3907000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 13294000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 4625000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 9387000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 3453000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 11748000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 4022000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 8295000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Riskand Insurance Services Segment · Guy Carpenter Reinsurance Group
Consolidation Items · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mmc:GuyCarpenterReinsuranceGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 1242000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 2544000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 430000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 2302000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 1192000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2432000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 408000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 2133000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 2060000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Riskand Insurance Services Segment · Marsh Insurance Group
Consolidation Items · Statement Business Segments · Subsegments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mmc:MarshInsuranceGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-03-31 | 3520000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 12851000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 3023000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 9446000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 3342000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 6423000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-03-31 | 3081000000 | USD | 2025-04-17 · 20:09:17.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 11657000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
| 2023-07-01 – 2023-09-30 | 2782000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-01-01 – 2023-09-30 | 8685000000 | USD | 2024-10-17 · 20:17:43.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 3103000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 5903000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2022-01-01 – 2022-12-31 | 10585000000 | USD | 2025-02-10 · 21:05:24.000Z | Open filing evidence |
Operating Segments · Consulting Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 2602000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 5160000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-03-31 | 2558000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 9794000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 2371000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 4685000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 2314000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 9133000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 8709000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Riskand Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-12-31 | 17265000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 15395000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 14089000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Risk And Insurance Services Segment
Consolidation Items · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 4823000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 9874000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-03-31 | 5051000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 4625000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 9387000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 4762000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
Operating Segments · Guy Carpenter Reinsurance Group · Riskand Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mmc:GuyCarpenterReinsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2024-04-01 – 2024-06-30 | 680000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1872000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-04-01 – 2023-06-30 | 619000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
| 2023-01-01 – 2023-06-30 | 1725000000 | USD | 2024-07-18 · 20:18:20.000Z | Open filing evidence |
Operating Segments · Guy Carpenter Reinsurance Group · Risk And Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mmc:GuyCarpenterReinsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 435000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2387000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 710000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1952000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 430000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 2302000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 680000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1872000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Marsh Insurance Group · Risk And Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mmc:MarshInsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 3472000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 10907000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 3915000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 7435000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 3023000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 9446000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 3342000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 6423000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Mercer Consulting Group · Consulting Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 1579000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 4573000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 1498000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 2994000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 1452000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 4256000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 1379000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 2804000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Oliver Wyman Group Consulting Group · Consulting Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mmc:OliverWymanGroupConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-07-01 – 2025-09-30 | 886000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2577000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 873000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1691000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-07-01 – 2024-09-30 | 810000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-01-01 – 2024-09-30 | 2436000000 | USD | 2025-10-16 · 11:39:00.000Z | Open filing evidence |
| 2024-04-01 – 2024-06-30 | 837000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
| 2024-01-01 – 2024-06-30 | 1626000000 | USD | 2025-07-17 · 11:51:39.000Z | Open filing evidence |
Operating Segments · Guy Carpenter Reinsurance Group · Riskand Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:GuyCarpenterReinsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-12-31 | 2635000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 2544000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 2432000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Guy Carpenter Reinsurance Group · Risk And Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:GuyCarpenterReinsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 1269000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 1242000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
Operating Segments · Marsh Insurance Group · Riskand Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:MarshInsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2025-01-01 – 2025-12-31 | 14630000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 12851000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 11657000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Marsh Insurance Group · Risk And Insurance Services Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:MarshInsuranceGroupMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 3782000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 3520000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
Operating Segments · Marsh Management Consulting · Consulting Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:MarshManagementConsultingMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 897000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 3604000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 818000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 3390000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 3122000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Operating Segments · Mercer Consulting Group · Consulting Segment
Consolidation Items · Subsegments · Statement Business Segments
Source dimensions
srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:SubsegmentsAxis=mrsh:MercerConsultingGroupMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-01-01 – 2026-03-31 | 1661000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2025-01-01 – 2025-12-31 | 6190000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2025-01-01 – 2025-03-31 | 1496000000 | USD | 2026-04-16 · 12:11:18.000Z | Open filing evidence |
| 2024-01-01 – 2024-12-31 | 5743000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
| 2023-01-01 – 2023-12-31 | 5587000000 | USD | 2026-02-09 · 21:02:58.000Z | Open filing evidence |
Career · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
srt:ProductOrServiceAxis=mmc:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 247000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 606000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 189000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 359000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 170000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 812000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 235000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 576000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 177000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 732000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Defined Benefit Consulting Administration · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
srt:ProductOrServiceAxis=mmc:DefinedBenefitConsultingAdministrationMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-12-31 | 1279000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 300000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 959000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 320000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 659000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 1381000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Health · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
srt:ProductOrServiceAxis=mmc:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 441000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 1341000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 458000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 900000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 442000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 1735000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 415000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 1286000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 429000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 1648000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Investment Management Related Services · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
srt:ProductOrServiceAxis=mmc:InvestmentManagementRelatedServicesMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-12-31 | 906000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 225000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 683000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 232000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 458000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 767000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Wealth · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
srt:ProductOrServiceAxis=mmc:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 592000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 1748000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 613000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1156000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 543000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 2185000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 525000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 1642000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 552000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 1117000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 2148000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Career · Consulting Segment · Operating Segments
Product Or Service · Statement Business Segments · Consolidation Items
Source dimensions
srt:ProductOrServiceAxis=mrsh:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 247000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 495000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 219000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 437000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Health · Consulting Segment · Operating Segments
Product Or Service · Statement Business Segments · Consolidation Items
Source dimensions
srt:ProductOrServiceAxis=mrsh:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 611000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 1272000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 594000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1202000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Wealth · Consulting Segment · Operating Segments
Product Or Service · Statement Business Segments · Consolidation Items
Source dimensions
srt:ProductOrServiceAxis=mrsh:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 740000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 1492000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 685000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1355000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
International · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=mmc:InternationalMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 888000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 2823000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 1059000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1935000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 876000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 3215000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 704000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 2403000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 808000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 1699000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 3082000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
United Statesand Canada · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=mmc:UnitedStatesandCanadaMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 1014000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 2972000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
Americas · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=srt:AmericasMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-04-01 – 2019-06-30 | 1097000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1958000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 861000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 3662000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 926000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 2670000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 941000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 1744000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 3322000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Asia Pacific · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=srt:AsiaPacificMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 242000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 698000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 291000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 456000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 165000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 683000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 167000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 514000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 183000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 347000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 645000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Latin America · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=srt:LatinAmericaMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 110000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 304000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 116000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 194000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 78000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 400000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 96000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 279000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 99000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 183000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 404000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
EMEA · Riskand Insurance Services Segment
Statement Geographical · Statement Business Segments
Source dimensions
srt:StatementGeographicalAxis=us-gaap:EMEAMember;us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 536000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 1821000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 652000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1285000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 633000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 2132000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 441000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 1610000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 526000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 1169000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 2033000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Career · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
us-gaap:ProductOrServiceAxis=mmc:CareerMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 164000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Defined Benefit Consulting Administration · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
us-gaap:ProductOrServiceAxis=mmc:DefinedBenefitConsultingAdministrationMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 339000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Health · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
us-gaap:ProductOrServiceAxis=mmc:HealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 442000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Investment Management Related Services · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
us-gaap:ProductOrServiceAxis=mmc:InvestmentManagementRelatedServicesMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 226000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Wealth · Consulting Segment
Product Or Service · Statement Business Segments
Source dimensions
us-gaap:ProductOrServiceAxis=mmc:WealthMember;us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 565000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Consulting Segment
Statement Business Segments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 1785000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 5258000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 1800000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 3473000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 1673000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 6779000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 1656000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 4974000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 1650000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 3318000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 1668000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 6444000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Consulting Segment · Mercer Consulting Group
Statement Business Segments · Subsegments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:MercerConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 1280000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 3695000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 1260000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 2415000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 1155000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 4732000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 1175000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 3504000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 1158000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 2329000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 1171000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 4528000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Consulting Segment · Oliver Wyman Group Consulting Group
Statement Business Segments · Subsegments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mmc:OliverWymanGroupConsultingGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 505000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 1563000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 540000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1058000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 518000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 2047000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 481000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 1470000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 492000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 989000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 497000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 1916000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Riskand Insurance Services Segment
Statement Business Segments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 2206000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 7203000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 2574000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 4997000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 2423000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 8228000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 1863000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 6303000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 2096000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 4440000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 2344000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 7630000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Riskand Insurance Services Segment · International
Statement Business Segments · Statement Geographical
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:StatementGeographicalAxis=mmc:InternationalMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 891000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Riskand Insurance Services Segment · Americas
Statement Business Segments · Statement Geographical
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:StatementGeographicalAxis=us-gaap:AmericasMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 803000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Riskand Insurance Services Segment · Asia Pacific
Statement Business Segments · Statement Geographical
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:StatementGeographicalAxis=us-gaap:AsiaPacificMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 164000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Riskand Insurance Services Segment · EMEA
Statement Business Segments · Statement Geographical
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:StatementGeographicalAxis=us-gaap:EMEAMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 643000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Riskand Insurance Services Segment · Latin America
Statement Business Segments · Statement Geographical
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:StatementGeographicalAxis=us-gaap:LatinAmericaMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2018-01-01 – 2018-03-31 | 84000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
Riskand Insurance Services Segment · Guy Carpenter Reinsurance Group
Statement Business Segments · Subsegments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mmc:GuyCarpenterReinsuranceGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 273000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 1328000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 392000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 1055000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 663000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 1286000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 215000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 1184000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 332000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 969000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 637000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 1187000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Riskand Insurance Services Segment · Marsh Guy Carpenter
Statement Business Segments · Subsegments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mmc:MarshGuyCarpenterMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 2175000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 7123000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 2548000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 4948000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 2400000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 8163000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 1845000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 6257000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 2081000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 4412000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 2331000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 7591000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Riskand Insurance Services Segment · Marsh Insurance Group
Statement Business Segments · Subsegments
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mmc:RiskandInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mmc:MarshInsuranceGroupMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2019-07-01 – 2019-09-30 | 1902000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-01-01 – 2019-09-30 | 5795000000 | USD | 2019-10-30 · 12:08:40.000Z | Open filing evidence |
| 2019-04-01 – 2019-06-30 | 2156000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-06-30 | 3893000000 | USD | 2019-08-02 · 12:18:35.000Z | Open filing evidence |
| 2019-01-01 – 2019-03-31 | 1737000000 | USD | 2019-04-26 · 13:34:14.000Z | Open filing evidence |
| 2018-01-01 – 2018-12-31 | 6877000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
| 2018-07-01 – 2018-09-30 | 1630000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-01-01 – 2018-09-30 | 5073000000 | USD | 2018-10-26 · 12:33:30.000Z | Open filing evidence |
| 2018-04-01 – 2018-06-30 | 1749000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-06-30 | 3443000000 | USD | 2018-07-27 · 13:26:03.000Z | Open filing evidence |
| 2018-01-01 – 2018-03-31 | 1694000000 | USD | 2018-04-27 · 20:03:05.000Z | Open filing evidence |
| 2017-01-01 – 2017-12-31 | 6404000000 | USD | 2019-02-21 · 21:24:23.000Z | Open filing evidence |
Consulting Segment · Intersegment Elimination
Statement Business Segments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 22000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 51000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 20000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 53000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Operating Segments
Statement Business Segments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 2685000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 7845000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 2465000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 7150000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Health And Benefits · Operating Segments
Statement Business Segments · Product Or Service · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ProductOrServiceAxis=mrsh:HealthAndBenefitsMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 578000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 1850000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 555000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 1757000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Investments And Retirement · Operating Segments
Statement Business Segments · Product Or Service · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ProductOrServiceAxis=mrsh:InvestmentsAndRetirementMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 762000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 2254000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 705000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2060000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Workforce And Rewards · Operating Segments
Statement Business Segments · Product Or Service · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;srt:ProductOrServiceAxis=mrsh:WorkforceAndRewardsMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 332000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 827000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 319000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 756000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Management Consulting · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mrsh:ManagementConsultingMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 1013000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 2914000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 886000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2577000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Consulting Segment · Marsh Management Consulting · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mrsh:MarshManagementConsultingMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 1004000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 1901000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 873000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1691000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Consulting Segment · Mercer Consulting Group · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mrsh:MercerConsultingGroupMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 1598000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 3259000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 1498000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 2994000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Consulting Segment · People And Investments · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:ConsultingSegmentMember;us-gaap:SubsegmentsAxis=mrsh:PeopleAndInvestmentsMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 1672000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 4931000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 1579000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 4573000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Risk And Insurance Services Segment · Intersegment Elimination
Statement Business Segments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 1000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 5000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 5000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Risk And Insurance Services Segment · Operating Segments
Statement Business Segments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 4200000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 14074000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 3907000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 13294000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Risk And Insurance Services Segment · Guy Carpenter Reinsurance Group · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mrsh:GuyCarpenterReinsuranceGroupMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 692000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 1961000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 710000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 1952000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Risk And Insurance Services Segment · Marsh Insurance Group · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mrsh:MarshInsuranceGroupMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-04-01 – 2026-06-30 | 4131000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2026-01-01 – 2026-06-30 | 7913000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-04-01 – 2025-06-30 | 3915000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
| 2025-01-01 – 2025-06-30 | 7435000000 | USD | 2026-07-21 · 12:13:36.000Z | Open filing evidence |
Risk And Insurance Services Segment · Reinsurance · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mrsh:ReinsuranceMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 404000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 2365000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 435000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 2387000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
Risk And Insurance Services Segment · Risk · Operating Segments
Statement Business Segments · Subsegments · Consolidation Items
Source dimensions
us-gaap:StatementBusinessSegmentsAxis=mrsh:RiskAndInsuranceServicesSegmentMember;us-gaap:SubsegmentsAxis=mrsh:RiskMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember| Period | Value | Unit | Filed | Evidence |
|---|---|---|---|---|
| 2026-07-01 – 2026-09-30 | 3796000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2026-01-01 – 2026-09-30 | 11709000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-07-01 – 2025-09-30 | 3472000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |
| 2025-01-01 – 2025-09-30 | 10907000000 | USD | 2026-10-15 · 16:16:49.000Z | Open filing evidence |