Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) - Secondary Guarantees [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Universal Life [Member]
Net Amount at Risk by Product and Guarantee [Line Items]
Net Amount At Risk By Product And Guarantee General And Separate Account Value	$ 5,772	$ 5,957
Net Amount at Risk by Product and Guarantee, Net Amount at Risk	$ 69,083	$ 71,124
Net Amount at Risk by Product and Guarantee, Weighted Average Attained Age	67 years	66 years
Variable Life [Member]
Net Amount at Risk by Product and Guarantee [Line Items]
Net Amount At Risk By Product And Guarantee General And Separate Account Value	$ 3,926	$ 3,526
Net Amount at Risk by Product and Guarantee, Net Amount at Risk	$ 19,909	$ 21,325
Net Amount at Risk by Product and Guarantee, Weighted Average Attained Age	51 years	50 years