Investments - Investment Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	$ 14	$ (59)	$ (21)	$ (70)
Joint Venture
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	46		46
Nonredeemable Preferred Stock
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	3	(70)	0	(108)
Fixed maturity securities
Investment Gains (Losses) [Abstract]
Gross gains	8	45	43	71
Gross losses	(35)	(60)	(92)	(88)
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	(27)	(15)	(49)	(17)
Equity securities
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	3	(71)	(11)	(109)
Derivative instruments
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022		26		55
Short term investments and other
Investment Gains (Losses) [Abstract]
Investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock included within equity securities held as of June 30, 2023 and 2022	$ (8)	$ 1	$ (7)	$ 1