Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Amortized cost, due in one year or less	$ 3,837
Amortized cost, due after one year through five years	19,627
Amortized cost, due after five years through ten years	13,501
Amortized cost, due after ten years	28,494
Amortized cost, Structured Securities	21,106
Fixed maturity securities, amortized cost	86,565	$ 86,129
Estimated fair value, due in one year or less	3,821
Estimated fair value, due after one year through five years	19,066
Estimated fair value, due after five years through ten years	12,266
Estimated fair value, due after ten years	24,148
Estimated fair value, Structured Securities	19,828
Fixed maturity securities, estimated fair value	$ 79,129	$ 80,085