Changes in Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Changes in Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (57)	$ (80)	$ (57)	$ (80)	$ (59)	$ (54)	$ (68)	$ (38)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	(32)	177	(32)	177	(1)	152	204	219
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(10)	(16)	(10)	(16)	(10)	(10)	(32)	(37)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(99)	81	(99)	81	$ (70)	$ 88	$ 104	$ 144
Cumulative Translation Adjustment, Net of Tax, Period Increase (Decrease)	2	(12)	(3)	(42)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Before Reclassifications, Net of Tax	(14)	8	(115)	59
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	(1)	(2)	(4)	(7)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(13)	(6)	(122)	10
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Reclassified from OCI, Net of Tax	(17)	(35)	(69)	(101)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	1	18	4	28
Other Comprehensive Income (Loss), Reclassifications out of OCI, Net of Tax	(16)	(17)	(65)	(73)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	2	(12)	(3)	(42)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(31)	(27)	(184)	(42)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	0	(16)	0	(21)
Net change in certain retirement plans, net of tax		10		15
Other Comprehensive Income (Loss), Net of Tax	(29)	(23)	(187)	(63)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	8	(5)	65	(33)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising Reclassed from OCI, Tax	$ 10	$ 19	$ 38	$ 57