Segment Information and Concentrations - Revenue and Operating Income By Segments (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment	3
Revenues	$ 1,517	$ 1,478
Income from operations	109	115
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	1,517	1,478
Operating income by segment	148	158
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Transformation costs	16	13
Acquisition-related amortization of intangible assets	23	29
Acquisition-related costs	0	1
Other adjustments	39	43
ATM [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	195	209
SCO [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	77	101
POS [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	184	154
IPS [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	5
Software license [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	70	85
Software Maintenance [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	91	92
Cloud [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	155	142
Professional Services [Domain] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	144	133
Software | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	460	452
Operating income by segment	109	124
Services | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	601	557
Operating income by segment	62	44
Hardware | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	456	469
Operating income by segment	$ (23)	$ (10)