Investments (Available-For-Sale Securities By Contractual Maturities) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	$ 101,885	$ 94,295
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	118,252	105,200
Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Due in one year or less	3,450
Due after one year through five years	14,509
Due after five years through ten years	19,004
Due after ten years	54,263
Amortized Cost	101,885	94,295
Available-for-sale Securities, Debt Maturities, Fair Value
Due in one year or less	3,485
Due after one year through five years	15,370
Due after five years through ten years	21,265
Due after ten years	66,909
Fair Value	118,252	$ 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	91,226
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	107,029
Fixed Maturity AFS Securities [Member] \| Structured securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	10,659
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	$ 11,223

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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