Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 15,497
Amortized Cost, Due after one year through five years	49,042
Amortized Cost, Due after five years through ten years	56,906
Amortized Cost, Due after ten years	123,620
Amortized Cost, Structured Securities	57,631
Amortized Cost, net of ACL	302,696
Estimated Fair Value, Due in one year or less	15,676
Estimated Fair Value, Due after one year through five years	51,166
Estimated Fair Value, Due after five years through ten years	63,218
Estimated Fair Value, Due after ten years	150,473
Estimated Fair Value, Structured Securities	59,472
Estimated Fair Value of Fixed Maturity Securities AFS	$ 340,005	$ 327,820