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 before non-controlling interests	$ 569	$ 553
Adjustments to reconcile net income before non-controlling interests to net cash provided by operating activities:
Amortization	103	86
Depreciation	23	21
Non-cash stock-based compensation	52	52
Change in estimated acquisition earn-out payables	7	(2)
Deferred income taxes	(2)	(3)
Net loss/(gain) on sales/disposals of investments, businesses, fixed assets and customer accounts	2	(29)
Payments on acquisition earn-outs in excess of original estimated payables	(1)	(31)
Other	2	2
Changes in operating assets and liabilities, net of effect from acquisitions and divestitures:
Commissions, fees and other receivables (increase) decrease	(139)	(140)
Reinsurance recoverable (increase) decrease	1,142	26
Prepaid reinsurance premiums (increase) decrease	(9)	(21)
Other assets (increase) decrease	(11)	(80)
Losses and loss adjustment reserve increase (decrease)	(1,143)	(23)
Unearned premiums increase (decrease)	55	140
Accounts payable increase (decrease)	5	(54)
Accrued expenses and other liabilities increase (decrease)	(132)	(109)
Other liabilities increase (decrease)	15	(15)
Net cash provided by operating activities	538	373
Cash flows from investing activities:
Additions to fixed assets	(32)	(39)
Payments for businesses acquired, net of cash acquired	(161)	(98)
Proceeds from sales of businesses, fixed assets and customer accounts	10	58
Other investing activities	(4)	2
Net cash used in investing activities	(187)	(77)
Cash flows from financing activities:
Fiduciary receivables and liabilities, net	119	248
Payments on acquisition earn-outs	(45)	(65)
Proceeds from long-term debt	4,192	599
Payments on long-term debt	(188)	(175)
Deferred debt issuance costs	(36)	(5)
Borrowings on revolving credit facility	150	150
Payments on revolving credit facility	(400)	(250)
Proceeds from issuance of common stock, net of expenses	4,315
Repurchase shares to fund tax withholdings for non-cash stock-based compensation	(41)	(54)
Cash dividends paid	(86)	(75)
Other financing activities	1	2
Net cash provided by financing activities	7,981	375
Effect of foreign exchange rate changes on cash and cash equivalents inclusive of fiduciary cash	85	0
Net increase in cash and cash equivalents inclusive of fiduciary cash	8,417	671
Cash and cash equivalents inclusive of fiduciary cash at beginning of period	2,502	2,303
Cash and cash equivalents inclusive of fiduciary cash at end of period	$ 10,919	$ 2,974