Investments - Net appreciation (decline) recognized in net income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Total	$ (54)	$ 266
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Total	(92)	125
Limited partnership interests carried at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 38	$ 141