Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (375)
Foreign currency translation adjustment	(78)	$ 29
Ending balance	(461)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(103)	(121)
Foreign currency translation adjustment	(77)	29
Tax on foreign currency translation adjustment	(13)	(4)
Ending balance	(193)	(96)
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(269)	(214)
Income tax impact on amortization of postretirement benefit plan items	(1)	(1)
Ending balance	(266)	(213)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(3)	(1)
Unrealized loss on derivative hedge agreements	(2)	(9)
Income tax benefit on unrealized loss on derivative hedge agreements		1
Ending balance	(2)	(7)
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(375)	(336)
Foreign currency translation adjustment	(77)	29
Tax on foreign currency translation adjustment	(13)	(4)
Income tax impact on amortization of postretirement benefit plan items	(1)	(1)
Unrealized loss on derivative hedge agreements	(2)	(9)
Income tax benefit on unrealized loss on derivative hedge agreements		1
Ending balance	(461)	(316)
Other non-operating income | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of prior service cost and net actuarial loss on postretirement benefit plans into other non-operating income (expense), net	4	2
Other non-operating income | Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of prior service cost and net actuarial loss on postretirement benefit plans into other non-operating income (expense), net	4	2
Revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements	2	1
Revenue | Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements	2	1
Cost of Revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements	1	1
Cost of Revenue | Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements	$ 1	$ 1