Segment Information and Concentrations - Revenue and Operating Income By Segments (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Revenue related to IPS divestiture		$ 52		$ 124
Number of Reportable Segments | segment			3
Revenues	$ 1,593	1,620	$ 3,071	3,064
Income from operations	178	163	295	264
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	1,593	1,620	3,071	3,064
Operating income by segment	215	207	375	346
Operating Segments [Member] | Software
Segment Reporting Information [Line Items]
Revenues	464	452	916	871
Operating income by segment	128	144	253	259
Operating Segments [Member] | Services
Segment Reporting Information [Line Items]
Revenues	588	574	1,145	1,117
Operating income by segment	75	49	120	83
Operating Segments [Member] | Hardware (1)
Segment Reporting Information [Line Items]
Revenues	541	594	1,010	1,076
Operating income by segment	12	14	2	4
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Transformation / restructuring costs	8	11	21	15
Acquisition-related amortization of intangible assets	28	32	57	64
Acquisition-related costs	1	1	2	3
Other adjustments	$ 37	$ 44	$ 80	$ 82