Changes in Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Changes in Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (68)	$ (24)	$ (68)	$ (24)	$ (73)	$ (38)	$ (22)	$ (16)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	204	86	204	86	247	219	114	141
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(32)	(20)	(32)	(20)	(32)	(37)	(20)	(19)
Accumulated Other Comprehensive Income (Loss), Net of Tax	104	42	104	42	$ 142	$ 144	$ 72	$ 106
Cumulative Translation Adjustment, Net of Tax, Period Increase (Decrease)	5	(2)	(30)	(8)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Before Reclassifications, Net of Tax	(8)	(13)	51	(27)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	0	0	(3)	(1)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(3)	(15)	18	(36)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Reclassified from OCI, Net of Tax	(35)	(15)	(66)	(28)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	0		8
Other Comprehensive Income (Loss), Reclassifications out of OCI, Net of Tax	(35)	(15)	(58)	(28)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	5	(2)	(30)	(8)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(43)	(28)	(15)	(55)
Net change in certain retirement plans	0	0	5	(1)
Other Comprehensive Income (Loss), Net of Tax	(38)	(30)	(40)	(64)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	5	7	(28)	13
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising Reclassed from OCI, Tax	$ 19	$ 8	$ 37	$ 16