Investments (Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Unrealized Gains (Losses)	$ 1,648	$ 2,256
Equity securities	988	1,269
Common Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	550	784
Equity Securities, FV-NI, Unrealized Gains (Losses)	272	295
Equity securities	822	1,079
Non-redeemable Preferred Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	169	189
Equity Securities, FV-NI, Unrealized Gains (Losses)	(3)	1
Equity securities	166	190
Equity Securities
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	719	973
Equity Securities, FV-NI, Unrealized Gains (Losses)	269	296
Equity securities	$ 988	$ 1,269