Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 10,526
Amortized Cost, Due after one year through five years	52,424
Amortized Cost, Due after five years through ten years	57,986
Amortized Cost, Due after ten years	129,880
Amortized Cost, Structured Securities	56,187
Amortized Cost, net of ACL	307,003
Estimated Fair Value, Due in one year or less	10,670
Estimated Fair Value, Due after one year through five years	55,246
Estimated Fair Value, Due after five years through ten years	64,867
Estimated Fair Value, Due after ten years	151,302
Estimated Fair Value, Structured Securities	58,610
Estimated Fair Value of Fixed Maturity Securities AFS	$ 340,695	$ 354,809