Investments (Equity Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Unrealized Gains (Losses)	$ 1,589	$ 562
Equity securities	757	1,684
Common Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	424	1,347
Equity Securities, FV-NI, Unrealized Gains (Losses)	239	195
Equity securities	663	1,542
Non-redeemable Preferred Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	90	148
Equity Securities, FV-NI, Unrealized Gains (Losses)	4	(6)
Equity securities	94	142
Equity Securities
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	514	1,495
Equity Securities, FV-NI, Unrealized Gains (Losses)	243	189
Equity securities	$ 757	$ 1,684