Investments - Credit Loss Expense Incurred (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		$ (1,091)	$ 0	$ 0
Total credit loss benefit (expense)		(22)	(15)	(11)
Fortitude Re
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments	$ 335
Corporate bonds
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(941)	0	0
Total credit loss benefit (expense)		(24)	(5)	(10)
State and municipal bonds
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(48)	0	0
RMBS
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(28)	0	0
Total credit loss benefit (expense)		1	(6)	0
CMBS
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(36)	0	0
ABS
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(37)	0	0
Total credit loss benefit (expense)		1	(4)	0
Hybrid and redeemable preferred securities
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Line Items]
Total intent to sell impairments		(1)	0	0
Total credit loss benefit (expense)		$ 0	$ 0	$ (1)