Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Carrying Amount Asset	$ 71,339	$ 76,597
Carrying Amount Liability	77,008	79,059
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount Asset	6,208	5,186
Carrying Amount Liability	11,282	7,074
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount Asset	2,261	1,604
Carrying Amount Liability	2,837	2,161
Other
Variable Interest Entity [Line Items]
Carrying Amount Asset	252	722
Carrying Amount Liability	271	739
Structured securities (RMBS, CMBS, and ABS)
Variable Interest Entity [Line Items]
Carrying Amount Asset	59,773	65,824
Carrying Amount Liability	59,773	65,824
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Carrying Amount Asset	2,845	3,261
Carrying Amount Liability	$ 2,845	$ 3,261