Fair Value Measurement - Fair Value Level 3 Rollforward Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
FG VIEs’ Assets
Fair Value Level 3 Rollforward
Fair value at beginning of period	$ 188	$ 223	$ 204	$ 260
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	1	3	0	0
Other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	(9)	(16)	(24)	(50)
Consolidations	0			15
Deconsolidations	0		0	(15)
Transfers out of Level 3	0		0
Fair value at end of period	180	210	180	210
Change in unrealized gains/(losses) related to financial instruments held	0	3	(3)	1
Consolidated Investment Vehicles | Equity securities and warrants
Fair Value Level 3 Rollforward
Fair value at beginning of period	290	258	297
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	5	(11)	45
Other comprehensive income (loss)	0	0	0
Purchases	3	52	41
Sales	(4)	(2)	(89)
Settlements	0	0	0
Consolidations	0
Deconsolidations	219		219
Transfers out of Level 3	0		0
Fair value at end of period	75	297	75	297
Change in unrealized gains/(losses) related to financial instruments held	6	(11)	6
Consolidated Investment Vehicles | Equity Securities
Fair Value Level 3 Rollforward
Fair value at beginning of period				239
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)				15
Other comprehensive income (loss)				0
Purchases				57
Sales				(14)
Settlements				0
Consolidations				0
Deconsolidations				0
Fair value at end of period		297		297
Change in unrealized gains/(losses) related to financial instruments held				7
Consolidated Investment Vehicles | Corporate securities
Fair Value Level 3 Rollforward
Fair value at beginning of period	84	90	96	91
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	0	(2)	(3)	4
Other comprehensive income (loss)	0	0	0	0
Purchases	0	1	6	2
Sales	0	(2)	(15)	(10)
Settlements	0	0	0	0
Consolidations	0			0
Deconsolidations	84		84	0
Transfers out of Level 3	0		0
Fair value at end of period	0	87	0	87
Change in unrealized gains/(losses) related to financial instruments held	0	(2)	0	3
Consolidated Investment Vehicles | Structured products
Fair Value Level 3 Rollforward
Fair value at beginning of period	0	38	46	0
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	7	(3)	9	(6)
Other comprehensive income (loss)	0	0	0	0
Purchases	0	8	0	50
Sales	0	0	(48)	(21)
Settlements	0	0	0	0
Consolidations	0			0
Deconsolidations	(166)		(166)	20
Transfers out of Level 3	0		0
Fair value at end of period	173	43	173	43
Change in unrealized gains/(losses) related to financial instruments held	7	(3)	7	(6)
Other
Fair Value Level 3 Rollforward
Fair value at beginning of period	33	37	50	27
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	(20)	1	(33)	12
Other comprehensive income (loss)	0	0	0	(1)
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	(4)	0
Consolidations	0			0
Deconsolidations	0		0	0
Transfers out of Level 3	0		0
Fair value at end of period	13	38	13	38
Change in unrealized gains/(losses) related to financial instruments held	(20)	1	(33)	12
Other | Other Comprehensive Income (Loss)
Total pre-tax realized and unrealized gains (losses) recorded in:
Change in unrealized gains/(losses) related to financial instruments held	0	0	0	(1)
Financial Guaranty Variable Interest Entities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at start of period	(699)	(282)	(715)	(289)
Total Pretax Realized And Unrealized Gains (Losses) Recorded As Liabilities [Abstract]
Net income (loss)	17	8	18	34
Other comprehensive income (loss)	13	(4)	14	(1)
Issuances		0		0
Sales		0		0
Settlements	127	27	141	92
Consolidations				(102)
Deconsolidations	0	0	0	15
Fair value at end of period	(542)	(251)	(542)	(251)
Change in unrealized gains/(losses) included in earnings related to financial instruments	9	8	11	57
Change in unrealized gains/(losses) included in OCI related to financial instruments	13	(4)	14	(1)
Liabilities of CIVs
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at start of period	(4,199)	(3,987)	(4,154)	(3,705)
Total Pretax Realized And Unrealized Gains (Losses) Recorded As Liabilities [Abstract]
Net income (loss)	0	(31)	(45)	264
Other comprehensive income (loss)	0	41	(13)	97
Issuances		(8)		(1,416)
Sales		2		2
Settlements	0	0	13	401
Consolidations				(26)
Deconsolidations	4,199	(26)	4,199	374
Fair value at end of period	0	(4,009)	0	(4,009)
Change in unrealized gains/(losses) included in earnings related to financial instruments	0	(13)	0	289
Change in unrealized gains/(losses) included in OCI related to financial instruments	0	41	0	97
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale
Fair Value Level 3 Rollforward
Fair value at beginning of period	46	51	47	72
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	0	0	1	0
Other comprehensive income (loss)	(3)	(3)	(3)	(11)
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	(1)	0	(3)	(13)
Consolidations	0			0
Deconsolidations	0		0	0
Transfers out of Level 3	(40)		(40)
Fair value at end of period	2	48	2	48
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss)
Total pre-tax realized and unrealized gains (losses) recorded in:
Change in unrealized gains/(losses) related to financial instruments held	0	(3)	0	(13)
RMBS | Fixed-maturity securities, available-for-sale
Fair Value Level 3 Rollforward
Fair value at beginning of period	162	184	179	216
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	4	3	11	13
Other comprehensive income (loss)	(6)	(8)	(14)	(27)
Purchases	0	22	0	22
Sales	0	0	0	0
Settlements	(7)	(9)	(23)	(32)
Consolidations	0			0
Deconsolidations	0		0	0
Transfers out of Level 3	0		0
Fair value at end of period	153	192	153	192
RMBS | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss)
Total pre-tax realized and unrealized gains (losses) recorded in:
Change in unrealized gains/(losses) related to financial instruments held	(6)	(8)	(13)	(25)
Asset-backed securities | Fixed-maturity securities, available-for-sale
Fair Value Level 3 Rollforward
Fair value at beginning of period	800	805	794	863
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	13	2	13	2
Other comprehensive income (loss)	(2)	1	(10)	(36)
Purchases	0	4	23	39
Sales	0	(1)	(2)	(13)
Settlements	(15)	(5)	(22)	(49)
Consolidations	0			0
Deconsolidations	0		0	0
Transfers out of Level 3	0		0
Fair value at end of period	796	806	796	806
Asset-backed securities | Fixed-maturity securities, available-for-sale | Other Comprehensive Income (Loss)
Total pre-tax realized and unrealized gains (losses) recorded in:
Change in unrealized gains/(losses) related to financial instruments held	3	1	0	(35)
Credit Risk Contract
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair value at start of period	(57)	(147)	(162)	(154)
Total pre-tax realized and unrealized gains (losses) recorded in:
Net income (loss)	9	(48)	115	(42)
Other comprehensive income (loss)	0	0	0	0
Issuances		0		0
Sales		0		0
Settlements	(1)	1	(2)	2
Consolidations				0
Deconsolidations	0	0	0	0
Fair value at end of period	(49)	(194)	(49)	(194)
Change in unrealized gains/(losses) included in earnings related to financial instruments	$ 9	$ (46)	$ 114	$ (41)