Investments - Investments - Available-for-Sale Securities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 41,723		$ 39,533
Allowance for credit losses, fixed maturity, AFS	(20)	$ (18)	(12)	$ (15)	$ (13)	$ (1)
Gross Unrealized Gains, fixed maturities, available-for-sale	74		152
Gross Unrealized Losses, fixed maturities, available-for-sale	(3,815)		(3,442)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	37,962		36,231
ABS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,216		2,016
Allowance for credit losses, fixed maturity, AFS	0		0
Gross Unrealized Gains, fixed maturities, available-for-sale	0		0
Gross Unrealized Losses, fixed maturities, available-for-sale	(86)		(75)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,130		1,941
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,066		3,040
Allowance for credit losses, fixed maturity, AFS	0		0
Gross Unrealized Gains, fixed maturities, available-for-sale	3		3
Gross Unrealized Losses, fixed maturities, available-for-sale	(26)		(102)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,043		2,941
CMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,548		3,715
Allowance for credit losses, fixed maturity, AFS	(12)	(12)	(10)	(7)	(1)	0
Gross Unrealized Gains, fixed maturities, available-for-sale	19		21
Gross Unrealized Losses, fixed maturities, available-for-sale	(431)		(358)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,124		3,368
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	18,377		16,794
Allowance for credit losses, fixed maturity, AFS	(8)	$ (6)	(2)	(8)	(8)	(1)
Gross Unrealized Gains, fixed maturities, available-for-sale	13		33
Gross Unrealized Losses, fixed maturities, available-for-sale	(1,731)		(1,592)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	16,651		15,233
Foreign Govt./Govt. Agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	614		596
Allowance for credit losses, fixed maturity, AFS	0		0	$ 0	$ (4)	$ 0
Gross Unrealized Gains, fixed maturities, available-for-sale	0		0
Gross Unrealized Losses, fixed maturities, available-for-sale	(47)		(49)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	567		547
Municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	6,292		6,718
Allowance for credit losses, fixed maturity, AFS	0		0
Gross Unrealized Gains, fixed maturities, available-for-sale	39		93
Gross Unrealized Losses, fixed maturities, available-for-sale	(645)		(515)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	5,686		6,296
RMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	4,403		4,214
Allowance for credit losses, fixed maturity, AFS	0		0
Gross Unrealized Gains, fixed maturities, available-for-sale	0		2
Gross Unrealized Losses, fixed maturities, available-for-sale	(576)		(508)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,827		3,708
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	2,207		2,440
Allowance for credit losses, fixed maturity, AFS	0		0
Gross Unrealized Gains, fixed maturities, available-for-sale	0		0
Gross Unrealized Losses, fixed maturities, available-for-sale	(273)		(243)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	$ 1,934		$ 2,197