Investments (Unconsolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Carrying Amount Asset	$ 71,802	$ 71,339
Carrying Amount Liability	77,812	77,008
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount Asset	5,938	6,208
Carrying Amount Liability	11,408	11,282
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount Asset	2,262	2,261
Carrying Amount Liability	2,783	2,837
Other
Variable Interest Entity [Line Items]
Carrying Amount Asset	375	252
Carrying Amount Liability	394	271
Structured securities (RMBS, CMBS, and ABS)
Variable Interest Entity [Line Items]
Carrying Amount Asset	60,301	59,773
Carrying Amount Liability	60,301	59,773
U.S. corporate and foreign corporate securities
Variable Interest Entity [Line Items]
Carrying Amount Asset	2,926	2,845
Carrying Amount Liability	$ 2,926	$ 2,845