Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME/(LOSS)		$ 877	$ (1,336)
Adjustments to reconcile net income to total net cash from operating activities:
Depreciation		167	176
Amortization		144	176
Impairment		0	1,042
Non-cash restructuring charges		0	17
Non-cash lease expense		71	76
Net periodic cost/(benefit) of defined benefit pension plans		100	(15)
Provision for doubtful receivables from clients		8	13
Benefit from deferred income taxes		(62)	(379)
Share-based compensation		104	85
(Gain)/loss on disposal of operations		(40)	1,190
Non-cash foreign exchange loss/(gain)		30	(25)
Other, net		34	32
Changes in operating assets and liabilities, net of effects from purchase of subsidiaries:
Accounts receivable		382	271
Other assets		(142)	(299)
Other liabilities		(689)	(159)
Provisions		20	48
Net cash from operating activities		1,004	913
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software		(166)	(189)
Acquisitions of operations, net of cash acquired		(14)	(28)
Contributions to investments in associates		(16)	0
Net proceeds from sale of operations		870	0
Cash and fiduciary funds transferred in sale of operations		(54)	0
Net purchases of held-to-maturity securities		(50)	0
Net purchases of available-for-sale securities		(40)	(13)
Net cash from/(used in) investing activities		530	(230)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Senior notes issued		0	746
Debt issuance costs		0	(9)
Repayments of debt		(4)	(653)
Repurchase of shares		(1,300)	(506)
Net proceeds from fiduciary funds held for clients		343	934
Payments of deferred and contingent consideration related to acquisitions		(19)	(2)
Cash paid for employee taxes on withholding shares		(53)	(30)
Dividends paid		(269)	(265)
Acquisitions of and dividends paid to non-controlling interests		(9)	(10)
Net cash (used in)/from financing activities		(1,311)	205
INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	[1]	223	888
Effect of exchange rate changes on cash, cash equivalents and restricted cash		202	32
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD	[1]	4,998	3,792
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD	[1]	$ 5,423	$ 4,712

[1] The amounts of cash, cash equivalents and restricted cash, their respective classification on the condensed consolidated balance sheets as well as their respective portions of the increase or decrease in cash, cash equivalents and restricted cash for each of the periods presented have been included in Note 19 — Supplemental Disclosures of Cash Flow Information.