Investments (Equity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Unrealized Gains (Losses)	$ 2,001	$ 1,589
Equity securities	746	757
Common Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	453	424
Equity Securities, FV-NI, Unrealized Gains (Losses)	193	239
Equity securities	646	663
Non-redeemable preferred Stock
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	100	90
Equity Securities, FV-NI, Unrealized Gains (Losses)	0	4
Equity securities	100	94
Equity Securities
Debt and Equity Securities, FV-NI [Line Items]
Equity Securities, FV-NI, Cost	553	514
Equity Securities, FV-NI, Unrealized Gains (Losses)	193	243
Equity securities	$ 746	$ 757