Revenue (Tables)

12 Months Ended

Dec. 31, 2024

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

The following table disaggregates various components of the Company's revenue:

For the Years Ended December 31,
(In millions)	2024		2023		2022
Marsh:
EMEA	$	3,530	$	3,262	$	2,997
Asia Pacific	1,414		1,295		1,215
Latin America	575		559		502
Total International	5,519		5,116		4,714
U.S./Canada	7,017		6,262		5,791
Total Marsh	12,536		11,378		10,505
Guy Carpenter (a)	2,362		2,258		2,020
Subtotal	14,898		13,636		12,525
Fiduciary interest income	497		453		120
Total Risk and Insurance Services	$	15,395	$	14,089	$	12,645
Mercer:
Wealth (b) (c)	$	2,584	$	2,507	$	2,366
Health (b) (d)	2,100		2,061		2,017
Career	1,059		1,019		962
Total Mercer	5,743		5,587		5,345
Oliver Wyman Group (e)	3,390		3,122		2,794
Total Consulting	$	9,133	$	8,709	$	8,139

(a)Revenue in 2023 includes a gain from a legal settlement with a competitor of $58 million, excluding legal fees.

(b)Revenue in 2024 includes a net gain of $35 million from the sale of the U.K. pension administration and U.S.health and benefits administration businesses, that comprised of a $70 million gain in Wealth, offset by a $35 million loss in Health.

(c)Revenue in 2023 includes the loss on sale of an individual financial advisory business in Canada of $17 million.

(d)Revenue in 2022 includes a net gain from the sale of the Mercer U.S. affinity business of $112 million.

(e)Revenue in 2024 includes a gain of $20 million from the sale of a business in Oliver Wyman Group.

Schedule of Contract Assets and Liabilities

The following table provides contract assets and contract liabilities information from contracts with customers:

December 31, (In millions)	2024		2023		2022
Contract assets	$	473	$	357	$	335
Contract liabilities	$	866	$	869	$	837

Details of the change in Contract Assets and Contract Liabilities for 2024 and 2023 are as follows:

For the Years Ended December 31,
(In millions)	2024		2023
Contract Assets
Balance at January 1,	$	357	$	335
Additions (a)	963		825
Transfers to accounts receivable (b)	(844)		(805)
Effect of foreign exchange rate changes	(3)		2
Balance at December 31,	$	473	$	357
Contract Liabilities
Balance at January 1,	$	869	$	837
Cash received for performance obligations not yet fulfilled	847		822
Revenue recognized	(835)		(799)
Effect of foreign exchange rate changes	(15)		9
Balance at December 31,	$	866	$	869

(a)Includes $69 million from the acquisition of McGriff in 2024.

(b)Amounts transferred to accounts receivable as the rights to bill and collect became unconditional.