Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Amortized cost, due in one year or less	$ 4,199
Amortized cost, due after one year through five years	19,642
Amortized cost, due after five years through ten years	12,425
Amortized cost, due after ten years	28,185
Amortized cost, Structured Securities	21,211
Fixed maturity securities, amortized cost	85,662	$ 86,565
Estimated fair value, due in one year or less	4,176
Estimated fair value, due after one year through five years	19,334
Estimated fair value, due after five years through ten years	11,800
Estimated fair value, due after ten years	24,261
Estimated fair value, Structured Securities	20,260
Fixed maturity securities, estimated fair value	$ 79,831	$ 79,129