Investments - Schedule of Net Appreciation (Decline) Recognized in Net Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 125	$ (13)	$ 235	$ 98
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Total	107	(32)	170	31
Limited partnership interests carried at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 18	$ 19	$ 65	$ 67