Investments - Amortized Cost and Fair Value of Fixed Maturity Available-for-Sale Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, Amortized Cost	$ 703	$ 536
Due after one year through five years, Amortized Cost	4,320	3,288
Due after five years through ten years, Amortized Cost	3,195	2,171
Due after ten years, Amortized Cost	15,453	14,503
Subtotal, Amortized Cost	23,671	20,498
Other securities which provide for periodic payments, Amortized Cost	21,935	17,210
Due in one year or less, Fair Value	687	527
Due after one year through five years, Fair Value	4,209	3,089
Due after five years through ten years, Fair Value	3,048	1,939
Due after ten years, Fair Value	13,183	11,457
Subtotal, Fair Value	21,127	17,012
Other securities which provide for periodic payments, Fair Value	21,246	16,083
Amortized Cost	45,606	37,708
Fair Value	42,373	33,095
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	14,631	12,209
Other securities which provide for periodic payments, Fair Value	14,342	11,467
Amortized Cost	14,631	12,209
Fair Value	14,342	11,467
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	4,797	3,337
Other securities which provide for periodic payments, Fair Value	4,475	3,063
Amortized Cost	4,797	3,337
Fair Value	4,475	3,063
Structured hybrids
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost		26
Other securities which provide for periodic payments, Fair Value		26
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Other securities which provide for periodic payments, Amortized Cost	2,507	1,638
Other securities which provide for periodic payments, Fair Value	$ 2,429	$ 1,527

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3