Insurance (Guarantees Related to Annuity Contracts) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Variable Annuity Guarantees: | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 59,965	$ 64,506
Separate account value (1)	38,210	41,305
Net amount at risk	$ 2,199	$ 1,572
Average attained age of contractholders	67 years	67 years
Variable Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 22,146	$ 24,036
Separate account value (1)	20,440	22,291
Net amount at risk	$ 823	$ 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	$ 5,201	$ 5,671
Net amount at risk	$ 392	$ 408
Average attained age of contractholders	51 years	51 years