Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) - Universal and Variable Life Contracts - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Secondary Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value (1), (3)	$ 11,841	$ 11,937
Net amount at risk (7)	$ 82,915	$ 86,221
Average attained age of policyholders	54 years	53 years
Paid-Up Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value (1), (3)	$ 2,872	$ 2,940
Net amount at risk (7)	$ 14,021	$ 14,500
Average attained age of policyholders	65 years	65 years