Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 14,784
Amortized Cost, Due after one year through five years	49,294
Amortized Cost, Due after five years through ten years	59,170
Amortized Cost, Due after ten years	130,773
Amortized Cost, Structured Securities	56,709
Amortized Cost, net of ACL	310,730
Estimated Fair Value, Due in one year or less	14,935
Estimated Fair Value, Due after one year through five years	52,294
Estimated Fair Value, Due after five years through ten years	67,613
Estimated Fair Value, Due after ten years	160,503
Estimated Fair Value, Structured Securities	59,464
Estimated Fair Value of Fixed Maturity Securities AFS	$ 354,809	$ 327,820