Property and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Property, Plant and Equipment [Line Items]
Land	$ 6	$ 17
Capital in progress	92	79
Total property plant and equipment, gross	1,500	1,395
Less accumulated depreciation and amortization	(945)	(852)
Total property and equipment, net	555	543
Land classified as capital in progress	35
Capitalized computer software, additions	66	51	99
Capitalized labor costs	56	30	35
Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment	388	370
Property, plant and equipment, estimated useful lives	3-5
Software [Member]
Property, Plant and Equipment [Line Items]
Computer software	489	466
Property, plant and equipment, estimated useful lives	3-6
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Furniture and fixtures	72	59
Property, plant and equipment, estimated useful lives	5
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements	262	213
Property, plant and equipment, estimated useful lives	2-16
Building [Member]
Property, Plant and Equipment [Line Items]
Buildings	$ 191	$ 191
Property, plant and equipment, estimated useful lives	5-30
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	2 years
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Minimum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	2 years
Minimum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	30 years
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	16 years
Maximum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	30 years
Computer Software, Intangible Asset [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Computer Software, Intangible Asset [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	6 years