Investments - Investment Gains (Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investment Gains (Losses) [Abstract]
Investment gains (losses)	$ (199)	$ 660	$ (1,246)
Net gain related to the expected novation of a coinsurance agreement	18
Gain on embedded derivative	62
Loss on fixed maturity securities supporting the funds withheld liability	(44)
Nonredeemable Preferred Stock
Investment Gains (Losses) [Abstract]
Investment gains (losses)	(75)	2	(3)
Altium Packaging LLC
Investment Gains (Losses) [Abstract]
Investment gains (losses)		555
Diamond Offshore Drilling Inc.
Investment Gains (Losses) [Abstract]
Investment gains (losses)		(15)	(1,211)
Fixed maturity securities
Investment Gains (Losses) [Abstract]
Gross gains	120	186	220
Gross losses	(261)	(90)	(220)
Investment gains (losses)	(141)	96	0
Equity securities
Investment Gains (Losses) [Abstract]
Investment gains (losses)	(116)	4	(3)
Derivative instruments
Investment Gains (Losses) [Abstract]
Investment gains (losses)	64	6	(10)
Short term investments and other
Investment Gains (Losses) [Abstract]
Investment gains (losses)	$ (6)	$ 14	$ (22)