Goodwill and Purchased Intangible Assets - Schedule of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill	$ 2,755	$ 2,750
Accumulated Impairment Losses	(23)	(23)
Total	2,727
Additions	0
Impairment	0
Other	5
Total	2,732
Software
Goodwill [Roll Forward]
Goodwill	1,935	1,930
Accumulated Impairment Losses	(7)	(7)
Total	1,923
Additions	0
Impairment	0
Other	5
Total	1,928
Services
Goodwill [Roll Forward]
Goodwill	658	658
Accumulated Impairment Losses	0	0
Total	658
Additions	0
Impairment	0
Other	0
Total	658
Hardware (1)
Goodwill [Roll Forward]
Goodwill	162	162
Accumulated Impairment Losses	(16)	$ (16)
Total	146
Additions	0
Impairment	0
Other	0
Total	$ 146