Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net income	$ 1,093	$ 1,079
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation of fixed assets	44	38
Amortization and impairment of intangible assets	16	25
Share-based compensation expense	130	127
Deferred income taxes	(76)	(70)
Other, net	(82)	0
Change in assets and liabilities:
Receivables, net	(826)	(664)
Accounts payable and accrued liabilities	(343)	(443)
Accelerating Aon United Program liabilities	34	0
Current income taxes	163	126
Pension, other postretirement and postemployment liabilities	(12)	(9)
Other assets and liabilities	168	234
Cash provided by operating activities	309	443
Cash flows from investing activities
Proceeds from investments	118	13
Purchases of investments	(56)	(11)
Net sales (purchases) of short-term investments - non fiduciary	(5,046)	280
Acquisition of businesses, net of cash and funds held on behalf of clients	(4)	(2)
Sale of businesses, net of cash and funds held on behalf of clients	75	1
Capital expenditures	(48)	(76)
Cash provided by (used for) investing activities	(4,961)	205
Cash flows from financing activities
Share repurchase	(250)	(550)
Proceeds from issuance of shares	25	25
Cash paid for employee taxes on withholding shares	(130)	(157)
Commercial paper issuances, net of repayments	(591)	(173)
Issuance of debt	5,942	744
Increase in fiduciary liabilities, net of fiduciary receivables	394	636
Cash dividends to shareholders	(123)	(115)
Noncontrolling interests and other financing activities	(6)	(6)
Cash provided by financing activities	5,261	404
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(146)	58
Net increase in cash and cash equivalents and funds held on behalf of clients	463	1,110
Cash, cash equivalents and funds held on behalf of clients at beginning of period	7,722	7,076
Cash, cash equivalents and funds held on behalf of clients at end of period	8,185	8,186
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	995	1,119
Cash and cash equivalents and funds held on behalf of clients classified as held for sale	73	0
Funds held on behalf of clients	7,117	7,067
Total cash and cash equivalents and funds held on behalf of clients	8,185	8,186
Supplemental disclosures:
Interest paid	95	79
Income taxes paid, net of refunds	$ 244	$ 206