Stockholders' Equity - Share-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 435	$ 401	$ 382
Income tax benefit	(173)	(200)	(199)
Decrease in net income	262	201	183
Software and Software Development Costs
Decrease in net income per share:
Share-based compensation expense	$ 3	$ 4	$ 3
Share Based Compensation Expense
Decrease in net income per share:
Basic (in dollars per share)	$ 1.00	$ 0.77	$ 0.71
Diluted (in dollars per share)	$ 0.99	$ 0.76	$ 0.70
Cost of product revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1	$ 1	$ 3
Cost of service and other revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	59	57	40
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	116	103	101
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	151	136	133
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	108	104	105
Total share-based compensation expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 435	$ 401	$ 382

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