Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	$ (1,071)
Balance at end of the period	(1,029)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(1,008)	$ (1,025)
Other comprehensive income (loss) before reclassification adjustments	32	69
Net other comprehensive income (loss)	32	69
Balance at end of the period	(976)	(956)
Deferred Gain (Loss) on Hedging Activities
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(7)	(29)
Other comprehensive income (loss) before reclassification adjustments	12	2
Amount reclassified from accumulated OCI	2	22
Tax (provision) benefit	(5)	(7)
Net other comprehensive income (loss)	9	17
Balance at end of the period	2	(12)
Pension and Postretirement Adjustment
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(56)	(47)
Other comprehensive income (loss) before reclassification adjustments	1	(5)
Amount reclassified from accumulated OCI	(1)	1
Tax (provision) benefit		1
Net other comprehensive income (loss)		(3)
Balance at end of the period	(56)	(50)
Unrealized Gain on Investment
Accumulated Other Comprehensive Loss
Balance at the beginning of the period		(1)
Other comprehensive income (loss) before reclassification adjustments	1
Net other comprehensive income (loss)	1
Balance at end of the period	1	(1)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss
Balance at the beginning of the period	(1,071)	(1,102)
Other comprehensive income (loss) before reclassification adjustments	46	66
Amount reclassified from accumulated OCI	1	23
Tax (provision) benefit	(5)	(6)
Net other comprehensive income (loss)	42	83
Balance at end of the period	$ (1,029)	$ (1,019)