Property and Equipment (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Property, Plant and Equipment [Line Items]
Equipment		$ 533	$ 447
Computer software		619	552
Furniture and fixtures		73	71
Leasehold improvements		296	286
Land		60	7
Buildings		403	192
Capital in progress		256	188
Total property plant and equipment, gross		2,240	1,743
Less accumulated depreciation and amortization		(1,209)	(1,061)
Total property and equipment, net		1,031	682
Capitalized computer software, additions		103	116	$ 80
Capitalized labor costs		$ 80	89	$ 46
Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		2 years
Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		30 years
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		5 years
Computer software | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		3 years
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		6 years
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		5 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		5 years
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		2 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		16 years
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		5 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)		30 years
Land and Buildings
Property, Plant and Equipment [Line Items]
Capital in progress		$ 172	$ 100
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, additions	$ 262