Goodwill and Acquired Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
Finite-Lived Intangible Assets [Abstract]
Cost	$ 751	$ 648
Accumulated amortization	(552)	(499)
Acquired intangible assets, net	199	149
Weighted average life in years	6 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015	67
2016	55
2017	36
2018	25
2019	15
Thereafter	1
Total expected future amortization expense	199	149
Customer Lists [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	318	306
Accumulated amortization	(261)	(249)
Acquired intangible assets, net	57	57
Weighted average life in years	6 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Total expected future amortization expense	57	57
Purchased Technology [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	366	277
Accumulated amortization	(242)	(207)
Acquired intangible assets, net	124	70
Weighted average life in years	5 years	6 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Total expected future amortization expense	124	70
Trade Names [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	33	32
Accumulated amortization	(23)	(20)
Acquired intangible assets, net	10	12
Weighted average life in years	6 years	6 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Total expected future amortization expense	10	12
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	34	33
Accumulated amortization	(26)	(23)
Acquired intangible assets, net	8	10
Weighted average life in years	8 years	9 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Total expected future amortization expense	$ 8	$ 10