Investments - Schedule of Gross Realized Gains (Losses) on Sales of Fixed Income Securities (Details) - Fixed income securities - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Debt Securities, Available-for-Sale [Line Items]
Gross realized gains	$ 33	$ 28	$ 74	$ 74
Gross realized losses	$ (124)	$ (153)	$ (270)	$ (326)