Goodwill and Acquired Intangible Assets Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Finite-Lived Intangible Assets [Abstract]
Cost	$ 670	$ 635
Accumulated amortization	(583)	(502)
Acquired intangible assets, net	$ 87	$ 133
Weighted average life in years	5 years	6 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2016	$ 37
2017	24
2018	16
2019	7
2020	3
Thereafter	0
Acquired intangible assets, net	87	$ 133
Customer Lists
Finite-Lived Intangible Assets [Abstract]
Cost	243	244
Accumulated amortization	(239)	(231)
Acquired intangible assets, net	$ 4	$ 13
Weighted average life in years	5 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 4	$ 13
Purchased Technology
Finite-Lived Intangible Assets [Abstract]
Cost	371	336
Accumulated amortization	(294)	(227)
Acquired intangible assets, net	$ 77	$ 109
Weighted average life in years	5 years	5 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 77	$ 109
Trade Names and Logos
Finite-Lived Intangible Assets [Abstract]
Cost	24	23
Accumulated amortization	(23)	(19)
Acquired intangible assets, net	$ 1	$ 4
Weighted average life in years	4 years	8 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 1	$ 4
Covenants Not to Compete or Sue
Finite-Lived Intangible Assets [Abstract]
Cost	32	32
Accumulated amortization	(27)	(25)
Acquired intangible assets, net	$ 5	$ 7
Weighted average life in years	9 years	8 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 5	$ 7