Investments - Available-for-Sale Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 41,726	$ 39,533
Debt Securities, Available-for-sale, Allowance for Credit Loss	(21)	(12)	$ (1)	$ (23)
Gross Unrealized Gains, fixed maturities, available-for-sale	418	152
Gross Unrealized Losses, fixed maturities, available-for-sale	(2,305)	(3,442)
Total fixed maturities	39,818	36,231
Amortized Cost
One year or less	1,526	1,417
Over one year through five years	9,670	8,340
Over five years through ten years	6,568	7,259
Over ten years	9,370	9,532
Subtotal	27,134	26,548
Mortgage-backed and asset-backed securities	14,592	12,985
Fair Value
One year or less	1,501	1,396
Over one year through five years	9,433	7,930
Over five years through ten years	6,211	6,485
Over ten years	8,851	8,462
Subtotal	25,996	24,273
Mortgage-backed and asset-backed securities	13,822	11,958
ABS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,347	2,016
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	18	0
Gross Unrealized Losses, fixed maturities, available-for-sale	(45)	(75)
Total fixed maturities	3,320	1,941
CLO
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,104	3,040
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	3	3
Gross Unrealized Losses, fixed maturities, available-for-sale	(17)	(102)
Total fixed maturities	3,090	2,941
CMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	3,466	3,715
Debt Securities, Available-for-sale, Allowance for Credit Loss	(12)	(10)	0
Gross Unrealized Gains, fixed maturities, available-for-sale	19	21
Gross Unrealized Losses, fixed maturities, available-for-sale	(348)	(358)
Total fixed maturities	3,125	3,368
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	18,691	16,794
Debt Securities, Available-for-sale, Allowance for Credit Loss	(9)	(2)	(1)	$ (23)
Gross Unrealized Gains, fixed maturities, available-for-sale	197	33
Gross Unrealized Losses, fixed maturities, available-for-sale	(1,013)	(1,592)
Total fixed maturities	17,866	15,233
Foreign government/government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	583	596
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	$ 0
Gross Unrealized Gains, fixed maturities, available-for-sale	6	0
Gross Unrealized Losses, fixed maturities, available-for-sale	(27)	(49)
Total fixed maturities	562	547
Municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	6,207	6,718
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	131	93
Gross Unrealized Losses, fixed maturities, available-for-sale	(299)	(515)
Total fixed maturities	6,039	6,296
Residential mortgage-backed securities ("RMBS")
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	4,675	4,214
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	18	2
Gross Unrealized Losses, fixed maturities, available-for-sale	(406)	(508)
Total fixed maturities	4,287	3,708
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	1,653	2,440
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Gross Unrealized Gains, fixed maturities, available-for-sale	26	0
Gross Unrealized Losses, fixed maturities, available-for-sale	(150)	(243)
Total fixed maturities	$ 1,529	$ 2,197