Segment Information - Revenue and Operating Income By Segments (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment									3
Revenue by segment	$ 1,802	$ 1,677	$ 1,620	$ 1,444	$ 1,680	$ 1,613	$ 1,604	$ 1,476	$ 6,543	$ 6,373	$ 6,591
Income from operations	$ 146	$ 189	$ 163	$ 101	$ 138	$ 168	$ (266)	$ 95	599	135	353
Restructuring and other asset-related charges											160
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue by segment									6,543	6,373	6,591
Operating income by segment									840	820	817
Operating Segments [Member] | Software Segment [Domain]
Segment Reporting Information [Line Items]
Revenue by segment									1,841	1,747	1,748
Operating income by segment									577	539	526
Operating Segments [Member] | Services Segment [Domain]
Segment Reporting Information [Line Items]
Revenue by segment									2,306	2,218	2,272
Operating income by segment									201	194	165
Operating Segments [Member] | Hardware Segment [Domain]
Segment Reporting Information [Line Items]
Revenue by segment									2,396	2,408	2,571
Operating income by segment									62	87	126
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other adjustments									241	685	464
Pension mark-to-market adjustments									85	454	149
Restructuring and other asset-related charges									26	74
Acquisition Related Amortization Costs Included in Other Adjustments									123	125	119
Acquisiton Related Costs Included In Other Adjustments									7	11	27
Acquisition Related Purchase Price Adjustments									0	0	6
Legal Costs for OFAC and FCPA Investigations									0	1	3
Reserve related to subcontract in Middle East Africa									$ 0	$ 20	$ 0