Stockholders' Equity - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 111	$ 105
Software and Software Development Costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capitalized computer software, gross	1	1
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	15	14
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	30	30
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	38	35
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 28	$ 26