Investments (Available-For-Sale Securities By Contractual Maturities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	$ 98,817	$ 94,295
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	113,519	105,200
Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Due in one year or less	3,141
Due after one year through five years	14,427
Due after five years through ten years	18,607
Due after ten years	52,892
Amortized Cost	98,817	94,295
Available-for-sale Securities, Debt Maturities, Fair Value
Due in one year or less	3,171
Due after one year through five years	15,168
Due after five years through ten years	20,579
Due after ten years	64,387
Fair Value	113,519	$ 105,200
Fixed Maturity AFS Securities [Member] \| Fixed maturity AFS securities other than structured securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	89,067
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	103,305
Fixed Maturity AFS Securities [Member] \| Structured securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	9,750
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	$ 10,214

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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