Stockholders' Equity - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 103	$ 98	$ 321	$ 303
Software and Software Development Costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capitalized computer software, gross	1	1	3	3
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	15	15	44	44
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	27	23	86	78
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	36	32	111	101
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 25	$ 28	$ 80	$ 80