Gain (Loss) on Consolidation of Business

No definition available.

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- Definition

Interest income earned on both U.S. and foreign fiduciary funds held in trust.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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- Definition

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 5,876	$ 5,379	$ 11,800	$ 10,928
Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	5,894	5,397	11,831	10,956
Risk and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	3,722	3,313	7,628	6,862
Fiduciary interest income	108	13	199	17
Risk and Insurance Services \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	3,722	3,313	7,628	6,862
Fiduciary interest income	108	13	199	17
Loss on consolidation of business				27
Risk and Insurance Services \| Total International
Disaggregation of Revenue [Line Items]
Revenue	1,352	1,245	2,711	2,512
Risk and Insurance Services \| EMEA
Disaggregation of Revenue [Line Items]
Revenue	858	780	1,790	1,649
Risk and Insurance Services \| Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue	357	347	669	641
Risk and Insurance Services \| Latin America
Disaggregation of Revenue [Line Items]
Revenue	137	118	252	222
Risk and Insurance Services \| U.S./Canada
Disaggregation of Revenue [Line Items]
Revenue	1,686	1,533	3,071	2,812
Consulting
Disaggregation of Revenue [Line Items]
Revenue	2,172	2,084	4,203	4,094
Consulting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	2,172	2,084	4,203	4,094
Consulting \| Wealth
Disaggregation of Revenue [Line Items]
Revenue	637	597	1,218	1,214
Consulting \| Health
Disaggregation of Revenue [Line Items]
Revenue	518	587	1,063	1,111
Consulting \| Career
Disaggregation of Revenue [Line Items]
Revenue	219	205	437	407
Oliver Wyman Group \| Operating Segments
Disaggregation of Revenue [Line Items]
Loss on consolidation of business				12
Small Individual Financial Advisory Business \| Operating Segments
Disaggregation of Revenue [Line Items]
Pre-tax gain (loss) on sale			(17)
Mercer U.S. Affinity Business \| Operating Segments
Disaggregation of Revenue [Line Items]
Pre-tax gain (loss) on sale		112		112
Marsh & Guy Carpenter \| Risk and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	3,614	3,300	7,429	6,845
Marsh \| Risk and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	3,038	2,778	5,782	5,324
Marsh \| Risk and Insurance Services \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	3,103	2,787	5,903	5,336
Guy Carpenter \| Risk and Insurance Services
Disaggregation of Revenue [Line Items]
Revenue	576	522	1,647	1,521
Guy Carpenter \| Risk and Insurance Services \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	619	526	1,725	1,526
Mercer \| Consulting
Disaggregation of Revenue [Line Items]
Revenue	1,374	1,389	2,718	2,732
Mercer \| Consulting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	1,374	1,389	2,718	2,732
Oliver Wyman Group \| Consulting
Disaggregation of Revenue [Line Items]
Revenue	798	695	1,485	1,362
Oliver Wyman Group \| Consulting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	$ 798	$ 695	$ 1,485	$ 1,362