Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Carrying Amount Asset	$ 62,727	$ 56,649
Maximum Exposure to Loss	68,004	61,057
Tax Credits Guaranteed By Third Parties Amount That Reduces Maximum Exposure To Loss Related To Other Invested Assets	12	94
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount Asset	6,357	5,641
Maximum Exposure to Loss	11,498	9,888
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,528	1,906
Maximum Exposure to Loss	1,662	2,063
Other
Variable Interest Entity [Line Items]
Carrying Amount Asset	428	296
Maximum Exposure to Loss	430	300
Structured securities (RMBS, CMBS, and ABS)
Variable Interest Entity [Line Items]
Carrying Amount Asset	52,710	47,874
Maximum Exposure to Loss	52,710	47,874
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,568	932
Maximum Exposure to Loss	1,568	932
Foreign government
Variable Interest Entity [Line Items]
Carrying Amount Asset	136	0
Maximum Exposure to Loss	$ 136	$ 0