Property and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Property, Plant and Equipment [Line Items]
Land	$ 6	$ 6
Capital in progress	130	92
Total property plant and equipment, gross	1,593	1,500
Less accumulated depreciation and amortization	(987)	(945)
Total property and equipment, net	606	555
Capitalized computer software, additions	82	66	51
Capitalized labor costs	48	56	30
Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment	402	388
Property, plant and equipment, estimated useful lives	3-5
Computer Software, Intangible Asset [Member]
Property, Plant and Equipment [Line Items]
Computer software	509	489
Property, plant and equipment, estimated useful lives	3-6
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Furniture and fixtures	72	72
Property, plant and equipment, estimated useful lives	5
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements	282	262
Property, plant and equipment, estimated useful lives	2-16
Building [Member]
Property, Plant and Equipment [Line Items]
Buildings	$ 192	$ 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