Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 8,543
Amortized Cost, Due after one year through five years	56,031
Amortized Cost, Due after five years through ten years	57,297
Amortized Cost, Due after ten years	130,770
Amortized Cost, Structured Securities	57,295
Amortized Cost, net of ACL	309,936
Estimated Fair Value, Due in one year or less	8,702
Estimated Fair Value, Due after one year through five years	58,669
Estimated Fair Value, Due after five years through ten years	63,388
Estimated Fair Value, Due after ten years	150,695
Estimated Fair Value, Structured Securities	59,584
Estimated Fair Value of Fixed Maturity Securities AFS	$ 341,038	$ 354,809