Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Amortized cost, due in one year or less	$ 2,137
Amortized cost, due after one year through five years	16,689
Amortized cost, due after five years through ten years	15,126
Amortized cost, due after ten years	29,947
Amortized cost, Structured Securities	21,454
Fixed maturity securities, amortized cost	85,353	$ 83,395
Estimated fair value, due in one year or less	2,093
Estimated fair value, due after one year through five years	15,810
Estimated fair value, due after five years through ten years	13,015
Estimated fair value, due after ten years	24,340
Estimated fair value, Structured Securities	19,313
Fixed maturity securities, estimated fair value	$ 74,571	$ 74,757