Insurance (Guarantees Related to Annuity Contracts) (Details) - Variable Annuity Guarantees - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 104,271	$ 96,865
Separate account value	99,385	91,837
Net amount at risk	$ 6,671	$ 11,073
Average attained age of contractholders	68 years	68 years
Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 59,859	$ 55,967
Separate account value	58,694	54,731
Net amount at risk	$ 4,750	$ 4,128
Average attained age of contractholders	68 years	68 years