Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Net cash flows provided by (used in) operating activities				$ (1,848)	$ (1,792)
Fixed-maturity securities, available-for-sale:
Purchases				(279)	(1,025)
Sales	$ 207		$ 0	560	222
Maturities and paydowns				585	757
Short-term investments with original maturities of over three months:
Purchases				(42)	0
Maturities and paydowns				23	32
Net sales (purchases) of short-term investments with original maturities of less than three months				64	125
Sales of fixed-maturity securities, trading				121	0
Paydowns of financial guaranty variable interest entities’ assets				74	45
Purchases of other invested assets				(11)	(44)
Return of capital from and sales of other invested assets				35	61
Other				(2)	(4)
Net cash flows provided by (used in) investing activities				1,128	169
Cash flows from financing activities:
Dividends paid				(49)	(51)
Repurchases of common shares				(400)	(305)
Net paydowns of financial guaranty variable interest entities’ liabilities				(92)	(38)
Issuance of long-term debt, net of issuance costs				0	889
Redemptions and purchases of debt, including make-whole				0	(620)
Other				(6)	7
Cash flows from consolidated investment vehicles:
Proceeds from issuance of collateralized loan obligations				1,372	2,079
Repayment of collateralized loan obligations				(373)	(365)
Proceeds from issuance of warehouse financing debt				882	1,008
Repayment of warehouse financing debt				(758)	(1,061)
Borrowings under credit facilities				46	0
Contributions from noncontrolling interests to consolidated investment vehicles				52	33
Distributions to noncontrolling interests from consolidated investment vehicles				(19)	(10)
Net cash flows provided by (used in) financing activities				655	1,566
Effect of foreign exchange rate changes				(6)	(1)
Increase (decrease) in cash and cash equivalents and restricted cash				(71)	(58)
Cash and cash equivalents and restricted cash at beginning of period		$ 240		342	298	$ 298
Cash and cash equivalents and restricted cash at end of period	271	342	240	271	240	342
Supplemental cash flow information
Income taxes paid (received)				97	1
Interest paid on long-term debt				47	50
Supplemental disclosure of non-cash activities:
Fixed-maturity securities, available-for-sale, received as salvage				610	0
Fixed-maturity securities, available-for-sale, ceded to a reinsurer				27	0
Fixed-maturity securities, trading, received as salvage				550	0
Fixed-maturity securities, trading, ceded to a reinsurer				6	0
Debt securities of financial guaranty variable interest entities received as salvage				54	0
Contributions from noncontrolling interests				32	1
Distributions to noncontrolling interests				53	1
Reconciliation of cash and cash equivalents and restricted cash to the condensed consolidated balance sheets:
Cash	131	120	101	131	101	120
Restricted cash (included in other assets)	1		1	1	1
Cash and cash equivalents of consolidated investment vehicles (Note 8)	139		138	139	138
Cash and cash equivalents and restricted cash at end of period	$ 271	$ 342	$ 240	$ 271	$ 240	$ 342