Goodwill and Acquired Intangible Assets Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Finite-Lived Intangible Assets [Abstract]
Cost	$ 665	$ 670
Accumulated amortization	(621)	(583)
Acquired intangible assets, net	$ 44	$ 87
Weighted average life in years	6 years	5 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2016	$ 21
2017	14
2018	6
2019	3
2020	0
Thereafter	0
Acquired intangible assets, net	44	$ 87
Customer Lists
Finite-Lived Intangible Assets [Abstract]
Cost	241	243
Accumulated amortization	(240)	(239)
Acquired intangible assets, net	$ 1	$ 4
Weighted average life in years	5 years	5 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 1	$ 4
Purchased Technology
Finite-Lived Intangible Assets [Abstract]
Cost	369	371
Accumulated amortization	(329)	(294)
Acquired intangible assets, net	$ 40	$ 77
Weighted average life in years	6 years	5 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 40	$ 77
Trade Names and Logos
Finite-Lived Intangible Assets [Abstract]
Cost	23	24
Accumulated amortization	(23)	(23)
Acquired intangible assets, net	0	$ 1
Weighted average life in years		4 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	0	$ 1
Covenants Not to Compete or Sue
Finite-Lived Intangible Assets [Abstract]
Cost	32	32
Accumulated amortization	(29)	(27)
Acquired intangible assets, net	$ 3	$ 5
Weighted average life in years	9 years	9 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 3	$ 5