Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) - Secondary Guarantees [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
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	$ 5,957	$ 6,099
Net Amount at Risk by Product and Guarantee, Net Amount at Risk	$ 71,124	$ 73,131
Net Amount at Risk by Product and Guarantee, Weighted Average Attained Age	66 years	65 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	$ 3,526	$ 3,230
Net Amount at Risk by Product and Guarantee, Net Amount at Risk	$ 21,325	$ 23,004
Net Amount at Risk by Product and Guarantee, Weighted Average Attained Age	50 years	50 years