Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 767,583	$ 740,463
Maximum Exposure to Loss	74,826	67,996
Tax Credits Guaranteed By Third Parties Amount That Reduces Maximum Exposure To Loss Related To Other Invested Assets	5	6
Structured Securities
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	57,150	51,962
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	2,036	1,764
Foreign government
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	134	136
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	68,015	62,481
Variable Interest Entity, Not Primary Beneficiary | Structured Securities
Variable Interest Entity [Line Items]
Assets	57,150	51,962
Variable Interest Entity, Not Primary Beneficiary | U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Assets	2,036	1,764
Variable Interest Entity, Not Primary Beneficiary | Foreign government
Variable Interest Entity [Line Items]
Assets	134	136
Variable Interest Entity, Not Primary Beneficiary | Other limited partnership interests
Variable Interest Entity [Line Items]
Assets	6,770	6,674
Variable Interest Entity, Not Primary Beneficiary | Other invested assets
Variable Interest Entity [Line Items]
Assets	1,388	1,495
Variable Interest Entity, Not Primary Beneficiary | Other
Variable Interest Entity [Line Items]
Assets	537	450
Other
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	584	497
Other invested assets
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	1,491	1,621
Other limited partnership interests
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	$ 13,431	$ 12,016