Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Carrying Amount Asset	$ 60,843	$ 56,649
Maximum Exposure to Loss	65,993	61,057
Tax Credits Guaranteed By Third Parties Amount That Reduces Maximum Exposure To Loss Related To Other Invested Assets	73	94
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount Asset	5,997	5,641
Maximum Exposure to Loss	11,020	9,888
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,762	1,906
Maximum Exposure to Loss	1,875	2,063
Other
Variable Interest Entity [Line Items]
Carrying Amount Asset	412	296
Maximum Exposure to Loss	426	300
Structured securities (RMBS, CMBS, and ABS)
Variable Interest Entity [Line Items]
Carrying Amount Asset	51,175	47,874
Maximum Exposure to Loss	51,175	47,874
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Carrying Amount Asset	1,358	932
Maximum Exposure to Loss	1,358	932
Foreign government
Variable Interest Entity [Line Items]
Carrying Amount Asset	139	0
Maximum Exposure to Loss	$ 139	$ 0