Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Operating Activities
Net income (loss)	$ 3,161	$ 3,377
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net realized (gains) losses	(433)	(361)
Equity in net (income) or loss of investments accounted for using the equity method and other income or loss	(265)	(336)
Amortization of intangible assets	146	136
Share-based compensation	124	100
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expenses recoverable	2,020	2,447
Unearned premiums, net of ceded unearned premiums	17	956
Premiums receivable	(693)	(1,504)
Deferred acquisition costs	33	(166)
Reinsurance balances payable	456	589
Deferred income tax assets, net	155	61
Other items, net	47	(199)
Net cash provided by operating activities	4,768	5,100
Investing Activities
Purchases of fixed maturity investments	(28,187)	(21,559)
Purchases of equity securities	(1,264)	(932)
Purchases of other investments	(1,745)	(1,898)
Proceeds from sales of fixed maturity investments	22,258	16,447
Proceeds from sales of equity securities	1,324	673
Proceeds from sales, redemptions and maturities of other investments	1,427	1,024
Proceeds from redemptions and maturities of fixed maturity investments	1,801	1,270
Net settlements of derivative instruments	275	127
Net (purchases) sales of short-term investments	530	(818)
Acquisitions, net of cash	0	852
Purchases of fixed assets	(33)	(38)
Other	(5)	(29)
Net cash used for investing activities	(3,619)	(4,881)
Financing Activities
Purchases of common shares under share repurchase program	(1,091)	0
Proceeds from common shares issued, net	20	(2)
Common dividends paid	(7)	0
Preferred dividends paid	(30)	(30)
Other	(4)	(3)
Net cash used for financing activities	(1,112)	(35)
Effects of exchange rate changes on foreign currency cash and restricted cash	57	30
Increase (decrease) in cash and restricted cash	94	214
Cash and restricted cash, beginning of year	1,760	1,498
Cash and restricted cash, end of period	1,854	1,712
Income taxes paid (received)	315	221
Interest paid	$ 64	$ 63