Investments - Investment Gains (Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investment Gains (Losses) [Abstract]
Investment gains (losses)	$ (53)	$ (199)	$ 660
Net gain related to the expected novation of a coinsurance agreement		18
Gain (loss) on fixed maturity securities related to funds with held liability		62
Loss on embedded derivative		44
Nonredeemable Preferred Stock
Investment Gains (Losses) [Abstract]
Investment gains (losses)	14	(75)	2
Altium Packaging LLC
Investment Gains (Losses) [Abstract]
Investment gains (losses)			555
Fixed maturity securities
Investment Gains (Losses) [Abstract]
Gross gains	75	120	186
Gross losses	(166)	(261)	(90)
Investment gains (losses)	(91)	(141)	96
Equity securities
Investment Gains (Losses) [Abstract]
Investment gains (losses)	4	(116)	4
Derivative instruments
Investment Gains (Losses) [Abstract]
Investment gains (losses)	(1)	64	6
Short-term investments and other
Investment Gains (Losses) [Abstract]
Investment gains (losses)	(11)	(6)	(1)
Joint venture
Investment Gains (Losses) [Abstract]
Investment gains (losses)	$ 46