Stockholders' Equity Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 71	$ 65	$ 241	$ 197
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	2	2	6	6
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	19	18	66	55
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	24	21	89	63
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 26	$ 24	$ 80	$ 73