Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash flows from operating activities
Net income	$ 1,576	$ 1,631
Adjustments to reconcile net income to cash provided by operating activities:
Gain from sales of businesses	0	(257)
Depreciation of fixed assets	93	89
Amortization and impairment of intangible assets	400	144
Share-based compensation expense	266	247
Deferred income taxes	(242)	(122)
Other, net	(111)	(112)
Change in assets and liabilities:
Receivables, net	(902)	(959)
Accounts payable and accrued liabilities	(738)	(251)
Accelerating Aon United Program liabilities	15	61
Current income taxes	(73)	60
Pension, other postretirement and postemployment liabilities	(12)	(17)
Other assets and liabilities	664	308
Cash provided by operating activities	936	822
Cash flows from investing activities
Proceeds from investments	71	146
Purchases of investments	(42)	(91)
Net purchases (sales) of short-term investments - non fiduciary	(153)	189
Acquisition of businesses, net of cash and funds held on behalf of clients	(143)	(2,780)
Sale of businesses, net of cash and funds held on behalf of clients	119	352
Capital expenditures	(120)	(101)
Cash used for investing activities	(268)	(2,285)
Cash flows from financing activities
Share repurchase	(500)	(500)
Proceeds from issuance of shares	33	27
Cash paid for employee taxes on withholding shares	(194)	(176)
Commercial paper issuances, net of repayments	480	(591)
Issuance of debt	0	7,926
Repayment of debt	(300)	(4,328)
Increase in fiduciary liabilities, net of fiduciary receivables	569	283
Cash dividends to shareholders	(308)	(269)
Redeemable and nonredeemable noncontrolling interests, and other financing activities	(153)	(108)
Cash provided by (used for) financing activities	(373)	2,264
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	696	(202)
Net increase in cash and cash equivalents and funds held on behalf of clients	991	599
Cash, cash equivalents and funds held on behalf of clients at beginning of period	8,333	7,722
Cash, cash equivalents and funds held on behalf of clients at end of period	9,324	8,321
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	1,008	974
Cash and cash equivalents and funds held on behalf of clients classified as held for sale	1	38
Funds held on behalf of clients	8,315	7,309
Total cash and cash equivalents and funds held on behalf of clients	9,324	8,321
Supplemental disclosures:
Interest paid	416	256
Income taxes paid, net of refunds	$ 692	$ 553