Insurance (Guarantees Related to Annuity Contracts) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Variable Annuity Guarantees: | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 62,462	$ 65,044
Separate account value (1)	41,617	42,585
Net amount at risk	$ 1,631	$ 1,579
Average attained age of contractholders	69 years	68 years
Variable Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 23,049	$ 24,170
Separate account value (1)	21,380	22,370
Net amount at risk	$ 519	$ 614
Average attained age of contractholders	67 years	66 years
Other Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 5,009	$ 6,030
Net amount at risk	$ 193	$ 459
Average attained age of contractholders	56 years	50 years