Goodwill and Acquired Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Finite-Lived Intangible Assets [Abstract]
Cost	$ 1,017	$ 925
Accumulated amortization	(804)	(745)
Acquired intangible assets, net	213	180
Weighted average life in years	7 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2013	56
2014	45
2015	39
2016	30
2017	22
Thereafter	21
Acquired intangible assets, net	213	180
Customer Lists [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	487	433
Accumulated amortization	(397)	(371)
Acquired intangible assets, net	90	62
Weighted average life in years	6 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	90	62
Purchased Technology [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	450	422
Accumulated amortization	(356)	(329)
Acquired intangible assets, net	94	93
Weighted average life in years	6 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	94	93
Trade Names [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	44	35
Accumulated amortization	(28)	(25)
Acquired intangible assets, net	16	10
Weighted average life in years	6 years	7 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	16	10
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	36	35
Accumulated amortization	(23)	(20)
Acquired intangible assets, net	13	15
Weighted average life in years	8 years	8 years
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Acquired intangible assets, net	$ 13	$ 15