Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Carrying Amount Asset	$ 62,481	$ 56,649
Maximum Exposure to Loss	67,996	61,057
Tax Credits Guaranteed By Third Parties Amount That Reduces Maximum Exposure To Loss Related To Other Invested Assets	6	94
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount Asset	6,674	5,641
Maximum Exposure to Loss	12,016	9,888
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,495	1,906
Maximum Exposure to Loss	1,621	2,063
Other
Variable Interest Entity [Line Items]
Carrying Amount Asset	450	296
Maximum Exposure to Loss	497	300
Structured Products (RMBS, CMBS, and ABS)
Variable Interest Entity [Line Items]
Carrying Amount Asset	51,962	47,874
Maximum Exposure to Loss	51,962	47,874
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,764	932
Maximum Exposure to Loss	1,764	932
Foreign government
Variable Interest Entity [Line Items]
Carrying Amount Asset	136	0
Maximum Exposure to Loss	$ 136	$ 0