Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 166		$ 167
Foreign currency translation adjustment	3		1
Changes in postretirement benefit plans	(7)	0	(7)	0
Tax on changes in postretirement benefit plans	2		2
Income tax expense on amortization of postretirement benefit plan items	(1)		(2)
Reclassification of unrealized gain (loss) on foreign exchange agreements	(7)		(8)
Ending balance	158		158
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	349		351
Foreign currency translation adjustment	3		1
Changes in postretirement benefit plans	0		0
Tax on changes in postretirement benefit plans	0		0
Income tax expense on amortization of postretirement benefit plan items	0		0
Reclassification of unrealized gain (loss) on foreign exchange agreements	0		0
Ending balance	352		352
Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(184)		(186)
Foreign currency translation adjustment	0		0
Changes in postretirement benefit plans	(7)		(7)
Tax on changes in postretirement benefit plans	2		2
Income tax expense on amortization of postretirement benefit plan items	(1)		(2)
Reclassification of unrealized gain (loss) on foreign exchange agreements	0		0
Ending balance	(187)		(187)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1		2
Foreign currency translation adjustment	0		0
Changes in postretirement benefit plans	0		0
Tax on changes in postretirement benefit plans	0		0
Income tax expense on amortization of postretirement benefit plan items	0		0
Reclassification of unrealized gain (loss) on foreign exchange agreements	(7)		(8)
Ending balance	(7)		(7)
Cost of revenue
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	1		2
Reclassification of unrealized gain (loss) on foreign exchange agreements	(1)
Cost of revenue | Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	0		0
Reclassification of unrealized gain (loss) on foreign exchange agreements	0
Cost of revenue | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	1		2
Reclassification of unrealized gain (loss) on foreign exchange agreements	0
Cost of revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	0		0
Reclassification of unrealized gain (loss) on foreign exchange agreements	(1)
Selling, general and administrative expenses
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	2		4
Selling, general and administrative expenses | Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	0		0
Selling, general and administrative expenses | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	2		4
Selling, general and administrative expenses | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Amortization of net actuarial loss on postretirement benefit plans into:	0		0
Revenue
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements			1
Revenue | Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements			0
Revenue | Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements			0
Revenue | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of unrealized gain (loss) on foreign exchange agreements			$ 1