Insurance (Guarantees Related to Annuity Contracts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Variable Annuity Guarantees: | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 65,044	$ 64,506
Separate account value (1)	42,585	41,305
Net amount at risk	$ 1,579	$ 1,572
Average attained age of contractholders	68 years	67 years
Variable Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 24,170	$ 24,036
Separate account value (1)	22,370	22,291
Net amount at risk	$ 614	$ 584
Average attained age of contractholders	66 years	65 years
Other Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 6,030	$ 5,671
Net amount at risk	$ 459	$ 408
Average attained age of contractholders	50 years	51 years