Investments - Net appreciation (decline) recognized in net income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt and Equity Securities, FV-NI [Line Items]
Total	$ (245)	$ 117	$ (763)	$ 585
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Total	(209)	(20)	(771)	170
Limited partnership interests carried at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total	$ (36)	$ 137	$ 8	$ 415