Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Activities
Net income (loss)	$ 2,109	$ 620
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net realized (gains) losses	367	742
Equity in net (income) or loss of investment funds accounted for using the equity method and other income or loss	(104)	107
Amortization of intangible assets	71	80
Share-based compensation	73	80
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expenses recoverable	1,604	1,554
Unearned premiums, net of ceded unearned premiums	1,111	1,125
Premiums receivable	(1,333)	(1,096)
Deferred acquisition costs	(190)	(242)
Reinsurance balances payable	692	128
Other items, net	(316)	(264)
Net cash provided by operating activities	4,084	2,834
Investing Activities
Purchases of fixed maturity investments	(13,024)	(13,065)
Purchases of equity securities	(176)	(787)
Purchases of other investments	(1,112)	(1,270)
Proceeds from sales of fixed maturity investments	9,655	9,990
Proceeds from sales of equity securities	216	1,540
Proceeds from sales, redemptions and maturities of other investments	345	1,075
Proceeds from redemptions and maturities of fixed maturity investments	589	578
Net settlements of derivative instruments	(69)	(106)
Net (purchases) sales of short-term investments	(323)	(152)
Purchases of fixed assets	(37)	(37)
Other	0	128
Net cash used for investing activities	(3,936)	(2,106)
Financing Activities
Purchases of common shares under share repurchase program	0	(586)
Proceeds from common shares issued, net	5	(3)
Change in third party investment in redeemable noncontrolling interests	(22)	0
Other	(5)	(85)
Preferred dividends paid	(30)	(30)
Net cash used for financing activities	(52)	(704)
Effects of exchange rate changes on foreign currency cash and restricted cash	(14)	(80)
Increase (decrease) in cash and restricted cash	82	(56)
Cash and restricted cash, beginning of year	1,273	1,314
Cash and restricted cash, end of period	$ 1,355	$ 1,258