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v3.22.2.2

Segment Information (Selected Information And Details For MMC's Operating Segments) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Mar. 31, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | $ 4,770 |  | $ 4,583 | $ 15,698 | $ 14,683
Operating Income (Loss) | 791 |  | 740 | 3,600 | 3,326
Loss on deconsolidation of russian businesses |  | $ 39 |  | 39 | 0
Risk and Insurance Services |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | 2,838 |  | 2,670 | 9,700 | 9,036
Interest on fiduciary funds | 40 |  | 4 | 57 | 12
Consulting |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | 1,951 |  | 1,925 | 6,045 | 5,690
Operating Segments |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | 4,789 |  | 4,595 | 15,745 | 14,726
Operating Income (Loss) | 879 |  | 807 | 3,834 | 3,522
Operating Segments | Risk and Insurance Services |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | 2,838 |  | 2,670 | 9,700 | 9,036
Operating Income (Loss) | 529 |  | 403 | 2,617 | 2,413
Interest on fiduciary funds | 40 |  | 4 | 57 | 12
Equity method income (loss) |  |  | 8 | 9 | 25
Gain (loss) on consolidation of business |  |  |  |  | 52
Loss on deconsolidation of russian businesses |  |  |  | 27 |
Operating Segments | Consulting |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | 1,951 |  | 1,925 | 6,045 | 5,690
Operating Income (Loss) | 350 |  | 404 | 1,217 | 1,109
Loss on deconsolidation of russian businesses |  |  |  | 12 |
Corporate/Eliminations |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | (19) |  | (12) | (47) | (43)
Operating Income (Loss) | (88) |  | (67) | (234) | (196)
Intersegment Eliminations | Risk and Insurance Services |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue |  |  |  | 5 | 5
Intersegment Eliminations | Consulting |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Revenue | $ 19 |  | $ 11 | 42 | $ 38
Gain on disposal |  |  |  | $ 112 |

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