Insurance (Guarantees Related to Annuity Contracts) (Details) - Variable Annuity Guarantees - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value (3)	$ 96,451	$ 100,034
Separate account value	91,617	95,430
Net amount at risk	$ 8,000	$ 6,617
Average attained age of contract holders	70 years	69 years
Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value (3)	$ 53,870	$ 57,069
Separate account value	52,745	56,027
Net amount at risk	$ 7,515	$ 4,495
Average attained age of contract holders	70 years	69 years