Property and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Property, Plant and Equipment [Line Items]
Land classified as capital in progress	$ 18
Land	17	2
Capital in progress	86	36
Total property plant and equipment, gross	1,492	1,524
Less accumulated depreciation and amortization	(925)	(963)
Total property and equipment, net	567	561
Capitalized computer software, additions	51	99	56
Capitalized labor costs	30	35	28
Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment	410	531
Property, plant and equipment, estimated useful lives	3-5
Software [Member]
Property, Plant and Equipment [Line Items]
Computer software	505	478
Property, plant and equipment, estimated useful lives	3-6
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Furniture and fixtures	60	61
Property, plant and equipment, estimated useful lives	5
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements	223	229
Property, plant and equipment, estimated useful lives	2-16
Building [Member]
Property, Plant and Equipment [Line Items]
Buildings	$ 191	$ 187
Property, plant and equipment, estimated useful lives	5-30