Stockholders' Equity Share-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 65	$ 56	$ 132	$ 113
Income tax benefit	(20)	(18)	(40)	(36)
Decrease in net income or increase in net loss from continuing operations	$ 45	$ 38	$ 92	$ 77
Earnings Per Share, Increase (Decrease)
Basic (dollars per share)	$ 0.17	$ 0.13	$ 0.34	$ 0.27
Diluted (dollars per share)	$ 0.17	$ 0.13	$ 0.34	$ 0.27
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 2	$ 1	$ 4	$ 2
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	18	17	37	33
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	21	18	42	37
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 24	$ 20	$ 49	$ 41