Investments (Amortized Cost and Fair Value of Fixed Maturities by Contractual Maturities) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Available For Sale Securities Debt Maturities Amortized Cost
Due in one year or less	$ 1,143
Due after one year through five years	8,350
Due after five year through ten years	10,565
Due after ten years	26,175
Asset and mortgage-backed securities	6,564
Total	52,797	$ 49,548
Available For Sale Securities Debt Maturities Fair Value
Due in one year or less	1,150
Due after one year through five years	8,887
Due after five year through ten years	11,518
Due after ten years	30,004
Asset and mortgage-backed securities	6,728
Total	$ 58,287	$ 56,735

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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