Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 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	20	46
Amounts reclassified from accumulated other comprehensive loss	1	(1)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(366)	(256)
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	20	48
Amounts reclassified from accumulated other comprehensive loss	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(333)	(225)
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	0	(2)
Amounts reclassified from accumulated other comprehensive loss	1	(1)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (33)	$ (31)