Insurance (Guarantees Related to Annuity Contracts) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Variable Annuity Guarantees: | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 63,915	$ 65,044
Separate account value (1)	42,206	42,585
Net amount at risk	$ 1,682	$ 1,579
Average attained age of contractholders	68 years	68 years
Variable Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 23,656	$ 24,170
Separate account value (1)	21,910	22,370
Net amount at risk	$ 549	$ 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	$ 5,802	$ 6,030
Net amount at risk	$ 440	$ 459
Average attained age of contractholders	51 years	50 years