Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Amortized cost, due in one year or less	$ 4,123
Amortized cost, due after one year through five years	19,430
Amortized cost, due after five years through ten years	13,040
Amortized cost, due after ten years	28,394
Amortized cost, Structured Securities	21,071
Fixed maturity securities, amortized cost	86,058	$ 86,565
Estimated fair value, due in one year or less	4,098
Estimated fair value, due after one year through five years	19,009
Estimated fair value, due after five years through ten years	12,085
Estimated fair value, due after ten years	24,530
Estimated fair value, Structured Securities	20,007
Fixed maturity securities, estimated fair value	$ 79,729	$ 79,129