Segment Information and Concentrations - Revenue and Operating Income By Segments (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment	3
Revenue by segment	$ 1,478	$ 1,444
Income from operations	117	101
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue by segment	1,478	1,444
Operating income by segment	160	139
Operating Segments [Member] | Software
Segment Reporting Information [Line Items]
Revenue by segment	452	419
Operating income by segment	125	115
Operating Segments [Member] | Services
Segment Reporting Information [Line Items]
Revenue by segment	557	543
Operating income by segment	45	34
Operating Segments [Member] | Hardware (1)
Segment Reporting Information [Line Items]
Revenue by segment	469	482
Operating income by segment	(10)	(10)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other adjustments	43	38
Transformation / restructuring costs	13	4
Acquisition-related amortization of intangible assets	29	32
Acquisition-related costs	$ 1	$ 2