Investments - Net Realized 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
Investments, Debt and Equity Securities [Abstract]
Gross realized gains on sales of available-for-sale securities	$ 7	$ 0	$ 19	$ 0
Gross realized losses on sales available-for-sale securities	(6)	(21)	(15)	(23)
Net foreign currency gains (losses)	0	(3)	0	(3)
Change in allowance for credit losses and intent to sell	(10)	(4)	(15)	(9)
Other net realized gains (losses)	0	0	0	10
Net realized investment gains (losses)	$ (9)	$ (28)	$ (11)	$ (25)