Derivatives (Hedges of Net Investments in Foreign Operations) (Details) - Foreign Operations Hedges [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) Deferred in AOCI (Effective Portion)	$ (33)	$ (250)	$ (359)	$ (649)
Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) Deferred in AOCI (Effective Portion)	(31)	(104)	(126)	(335)
Currency options
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) Deferred in AOCI (Effective Portion)	$ (2)	$ (146)	$ (233)	$ (314)