Investments - Realized Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Investments [Abstract]
Net realized investment gains (losses), excluding credit (loss)/recovery and other investment write-downs	$ 13	$ 31	$ 7	$ (20)
Credit (loss)/recovery and other investment write-downs	(61)	(5)	(1,891)	(10)
Net realized investment (losses) gains, before income taxes	$ (48)	$ 26	$ (1,884)	$ (30)