Investments (Amortized Cost and Fair Value of Fixed Maturities by Contractual Maturities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Available For Sale Securities Debt Maturities Amortized Cost
Due in one year or less	$ 1,453
Due after one year through five years	8,028
Due after five year through ten years	10,013
Due after ten years	20,799
Asset and mortgage-backed securities	6,610
Total	46,903	$ 46,753
Available For Sale Securities Debt Maturities Fair Value
Due in one year or less	1,454
Due after one year through five years	8,412
Due after five year through ten years	10,979
Due after ten years	24,854
Asset and mortgage-backed securities	6,647
Total	$ 52,346	$ 51,121

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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