Accumulated Other Comprehensive Income (Loss) (AOCI) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	$ (205)
Other comprehensive (loss) income before reclassifications	25
Amounts reclassified from AOCI	(8)
Net current period other comprehensive (loss) income	17
Accumulated other comprehensive income (loss), ending balance	(188)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	(224)
Other comprehensive (loss) income before reclassifications	37
Amounts reclassified from AOCI	0
Net current period other comprehensive (loss) income	37
Accumulated other comprehensive income (loss), ending balance	(187)
Changes in Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	6
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified from AOCI	(6)
Net current period other comprehensive (loss) income	(6)
Accumulated other comprehensive income (loss), ending balance	0
Changes in Fair Value of Effective Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	13
Other comprehensive (loss) income before reclassifications	(12)
Amounts reclassified from AOCI	(2)
Net current period other comprehensive (loss) income	(14)
Accumulated other comprehensive income (loss), ending balance	$ (1)