Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (387)	$ (301)
Other comprehensive income before reclassifications, net of tax	63	23
Amounts reclassified from accumulated other comprehensive loss	(1)	0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(325)	(278)
Net Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(353)	(273)
Other comprehensive income before reclassifications, net of tax	62	24
Amounts reclassified from accumulated other comprehensive loss	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(291)	(249)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(34)	(28)
Other comprehensive income before reclassifications, net of tax	1	(1)
Amounts reclassified from accumulated other comprehensive loss	(1)	0
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (34)	$ (29)