Investments - Amortized Cost and Fair Value of Fixed Maturity by Contractual Maturity (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	$ 170	$ 124
Due after one year through five years, Amortized Cost	2,853	2,193
Due after five years through ten years, Amortized Cost	1,922	1,840
Due after ten years, Amortized Cost	14,893	14,417
Subtotal	19,838	18,574
Other securities which provide for periodic payments, Amortized Cost	18,388	17,149
Amortized Cost	38,226	35,723
Due in one year or less, Fair Value	166	123
Due after one year through five years, Fair Value	2,724	2,059
Due after five years through ten years, Fair Value	1,750	1,633
Due after ten years, Fair Value	12,329	11,379
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value, Total	16,969	15,194
Other securities which provide for periodic payments, Fair Value	17,228	16,024
Total fixed maturity available-for-sale securities	34,197	31,218
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	12,620	12,209
Amortized Cost	12,620	12,209
Other securities which provide for periodic payments, Fair Value	11,892	11,467
Total fixed maturity available-for-sale securities	11,892	11,467
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	4,004	3,309
Amortized Cost	4,004	3,309
Other securities which provide for periodic payments, Fair Value	3,672	3,036
Total fixed maturity available-for-sale securities	3,672	3,036
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	1,764	1,631
Other securities which provide for periodic payments, Fair Value	$ 1,664	$ 1,521