Investments (Available-For-Sale Securities By Contractual Maturities) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	$ 105,866	$ 104,174
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	117,313	123,044
Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	105,866	104,174
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	117,313	$ 123,044
Fixed Maturity AFS Securities [Member] \| Fixed maturity AFS securities other than structured securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Due in one year or less	3,198
Due after one year through five years	15,156
Due after five years through ten years	19,308
Due after ten years	56,040
Amortized Cost	93,702
Available-for-sale Securities, Debt Maturities, Fair Value
Due in one year or less	3,219
Due after one year through five years	16,072
Due after five years through ten years	20,949
Due after ten years	64,484
Fair Value	104,724
Fixed Maturity AFS Securities [Member] \| Structured securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Amortized Cost	12,164
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	$ 12,589

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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