Investments - Investments - Available-for-Sale Securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 42,946	$ 41,726
Allowance for credit losses, fixed maturity, AFS	(18)	(21)	$ (17)	$ (12)
Gross Unrealized Gains, fixed maturities, available-for-sale	311	418
Gross Unrealized Losses, fixed maturities, available-for-sale	(2,399)	(2,305)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	40,840	39,818
ABS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,527	3,347
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	15	18
Gross Unrealized Losses, fixed maturities, available-for-sale	(43)	(45)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,499	3,320
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,168	3,104
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	5	3
Gross Unrealized Losses, fixed maturities, available-for-sale	(5)	(17)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,168	3,090
CMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,345	3,466
Allowance for credit losses, fixed maturity, AFS	(12)	(12)	(11)	(10)
Gross Unrealized Gains, fixed maturities, available-for-sale	20	19
Gross Unrealized Losses, fixed maturities, available-for-sale	(303)	(348)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	3,050	3,125
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	19,598	18,691
Allowance for credit losses, fixed maturity, AFS	(6)	(9)	$ (6)	$ (2)
Gross Unrealized Gains, fixed maturities, available-for-sale	144	197
Gross Unrealized Losses, fixed maturities, available-for-sale	(1,079)	(1,013)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	18,657	17,866
Foreign Govt./Govt. Agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	574	583
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	4	6
Gross Unrealized Losses, fixed maturities, available-for-sale	(30)	(27)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	548	562
Municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	6,175	6,207
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	101	131
Gross Unrealized Losses, fixed maturities, available-for-sale	(335)	(299)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	5,941	6,039
RMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	4,889	4,675
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	10	18
Gross Unrealized Losses, fixed maturities, available-for-sale	(426)	(406)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	4,473	4,287
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	1,670	1,653
Allowance for credit losses, fixed maturity, AFS	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	12	26
Gross Unrealized Losses, fixed maturities, available-for-sale	(178)	(150)
Fixed maturities, available-for-sale, at fair value (amortized cost of $54,478 and $53,805)	$ 1,504	$ 1,529