Investments - Schedule of Net Appreciation (Decline) Recognized in Net Income for Assets that are Still Held (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 236	$ (471)	$ 812
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Total	151	(466)	377
Limited partnership interests carried at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 85	$ (5)	$ 435