Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Net cash flows provided by (used in) operating activities			$ (1,794)	$ (949)
Fixed-maturity securities, available-for-sale:
Purchases			(180)	(788)
Sales	$ 296	$ 106	353	226
Maturities and paydowns			389	499
Short-term investments with original maturities of over three months:
Purchases			(28)	0
Maturities and paydowns			9	30
Net sales (purchases) of short-term investments with original maturities of less than three months			379	(267)
Sales of fixed-maturity securities, trading			68	0
Paydowns of financial guaranty variable interest entities’ assets			44	27
Purchases of other invested assets			(8)	(35)
Return of capital from and sales of other invested assets			34	54
Other			(2)	(2)
Net cash flows provided by (used in) investing activities			1,058	(256)
Cash flows from financing activities:
Dividends paid			(33)	(35)
Repurchases of common shares			(303)	(165)
Net paydowns of financial guaranty variable interest entities’ liabilities			(65)	(23)
Issuance of long-term debt, net of issuance costs			0	495
Paydown of long-term debt			0	(1)
Other			(7)	6
Cash flows from consolidated investment vehicles:
Proceeds from issuance of collateralized loan obligations			1,372	1,132
Repayment of collateralized loan obligations			(372)	(2)
Proceeds from issuance of warehouse financing debt			791	546
Repayment of warehouse financing debt			(744)	(750)
Borrowings under credit facilities			1	0
Contributions from noncontrolling interests to consolidated investment vehicles			35	8
Distributions to noncontrolling interests from consolidated investment vehicles			(16)	(8)
Net cash flows provided by (used in) financing activities			659	1,203
Effect of foreign exchange rate changes			(2)	0
Increase (decrease) in cash and cash equivalents and restricted cash			(79)	(2)
Cash and cash equivalents and restricted cash at beginning of period			342	298	$ 298
Cash and cash equivalents and restricted cash at end of period	263	296	263	296	342
Supplemental cash flow information
Income taxes paid (received)			97	0
Interest paid on long-term debt			38	40
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			183	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			26	1
Distributions to noncontrolling interests			20	1
Reconciliation of cash and cash equivalents and restricted cash to the condensed consolidated balance sheets:
Cash	138	144	138	144	120
Restricted cash (included in other assets)	0	4	0	4
Cash and cash equivalents of consolidated investment vehicles (Note 8)	125	148	125	148
Cash and cash equivalents and restricted cash at end of period	$ 263	$ 296	$ 263	$ 296	$ 342