Goodwill and Acquired Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2011 Years percentage segments	Jul. 31, 2010 Years
Finite-Lived Intangible Assets [Abstract]
Cost	$ 925	$ 923
Accumulated amortization	(745)	(667)
Acquired intangible assets, net	180	256
Weighted average life in years	7	7
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2012	57
2013	33
2014	30
2015	25
2016	19
Thereafter	16
Total expected future amortization expense	180
Customer Lists [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	433	438
Accumulated amortization	(371)	(328)
Acquired intangible assets, net	62	110
Weighted average life in years	7	6
Purchased Technology [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	422	414
Accumulated amortization	(329)	(301)
Acquired intangible assets, net	93	113
Weighted average life in years	7	7
Trade Names [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	35	35
Accumulated amortization	(25)	(21)
Acquired intangible assets, net	10	14
Weighted average life in years	7	7
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Abstract]
Cost	35	36
Accumulated amortization	(20)	(17)
Acquired intangible assets, net	$ 15	$ 19
Weighted average life in years	8	8