Investments (Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Unrealized Gains (Losses)	$ 2,160	$ 2,388
Equity securities	747	712
Common Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	454	451
Equity Securities, FV-NI, Unrealized Gains (Losses)	185	167
Equity securities	639	618
Non-redeemable preferred Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	111	93
Equity Securities, FV-NI, Unrealized Gains (Losses)	(3)	1
Equity securities	108	94
Equity Securities
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	565	544
Equity Securities, FV-NI, Unrealized Gains (Losses)	182	168
Equity securities	$ 747	$ 712