Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Jan. 01, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (336)
Cumulative effect of change in accounting principle				$ (3)	$ (7)
Foreign currency translation adjustment	28	$ (85)	$ 79
Amortization of prior service credit cost	(4)	(4)	(3)
Foreign currency translation adjustment for postretirement benefit plans	(3)	15	(18)
Unrealized (loss) gain	(14)	(8)	9
Reclassification of unrealized gain on derivative hedge agreements into revenue	12	4	(5)
Ending Balance	(375)	(336)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(336)	(210)	(318)
Cumulative effect of change in accounting principle		(17)		$ (17)
Foreign currency translation adjustment	27	(83)	79
Income tax impact on foreign currency translation adjustment	(9)	(12)	46
Amortization of prior service credit cost	(83)	(36)	(18)
Income tax expense on changes in postretirement benefit plans		5	7
Foreign currency translation adjustment for postretirement benefit plans	(3)	15	(18)
Income tax expense on changes in postretirement benefit plans, including settlement	16
Income tax impact on amortization of postretirement benefit plan items	(2)	(3)	(3)
Unrealized (loss) gain			9
Ending Balance	(375)	(336)	(210)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(121)	(15)	(140)
Cumulative effect of change in accounting principle		(11)
Foreign currency translation adjustment	27	(83)	79
Income tax impact on foreign currency translation adjustment	(9)	(12)	46
Ending Balance	(103)	(121)	(15)
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(214)	(198)	(177)
Cumulative effect of change in accounting principle		(6)
Amortization of prior service credit cost	(83)	(36)	(18)
Income tax expense on changes in postretirement benefit plans		5	7
Foreign currency translation adjustment for postretirement benefit plans	(3)	15	(18)
Income tax expense on changes in postretirement benefit plans, including settlement	16
Income tax impact on amortization of postretirement benefit plan items	(2)	(3)	(3)
Ending Balance	(269)	(214)	(198)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1)	3	(1)
Unrealized (loss) gain	(14)	(8)	9
Ending Balance	(3)	(1)	3
Nonoperating Income (Expense) | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Income tax impact on amortization of postretirement benefit plan items	8	9	11
Nonoperating Income (Expense) | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Income tax impact on amortization of postretirement benefit plan items	8	9	11
Cost of Revenue | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Unrealized (loss) gain			1
Reclassification of unrealized gain on derivative hedge agreements into revenue	5
Cost of Revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Unrealized (loss) gain			1
Reclassification of unrealized gain on derivative hedge agreements into revenue	5
Revenue | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Unrealized (loss) gain			(6)
Reclassification of unrealized gain on derivative hedge agreements into revenue	7
Revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Unrealized (loss) gain			$ (6)
Reclassification of unrealized gain on derivative hedge agreements into revenue	7
Other Expense [Member] | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Settlement charge released into other non-operating income (expense), net	9
Other Expense [Member] | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Settlement charge released into other non-operating income (expense), net	$ 9
Cross Currency Swaps | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain on derivative hedge agreements into revenue		4
Cross Currency Swaps | Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain on derivative hedge agreements into revenue
Cross Currency Swaps | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain on derivative hedge agreements into revenue		$ 4