Derivatives - Designated Hedge Gain (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Reclassified from AOCI to Earnings	$ 41	$ 9	$ 92	$ 52
Effective Portion Recognized in Other Comprehensive Income	(36)	(39)	(52)	(88)
Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Reclassified from AOCI to Earnings	0	(19)	0	(19)
Effective Portion Recognized in Other Comprehensive Income	0	21	0	23
Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion Reclassified from AOCI to Earnings	41	28	92	71
Effective Portion Recognized in Other Comprehensive Income	$ (36)	$ (60)	$ (52)	$ (111)