Fair Value Measurements (Details 3) - USD ($)	3 Months Ended	12 Months Ended
	Apr. 30, 2015	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Goodwill, impairment loss		$ 114,000,000	$ 0
Goodwill		1,266,000,000	1,323,000,000	$ 1,282,000,000
Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments		1,079,000,000		657,000,000
Consumer Tax
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Goodwill, impairment loss		0
Goodwill		18,000,000	$ 17,000,000	18,000,000
Consumer Ecosystem | Consumer Tax
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Goodwill, impairment loss	$ 263,000,000
Goodwill	$ 211,000,000
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments		$ 15,000,000		$ 15,000,000