Employee Benefit Plans - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 25, 2020	Jan. 26, 2019	Jan. 25, 2020	Jan. 26, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 384	$ 395	$ 782	$ 803
Income tax benefit for share-based compensation	109	126	240	291
Share-based compensation expense in cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	59	53	116	109
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	146	133	292	263
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	119	125	246	262
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	55	65	115	127
Restructuring and other charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	5	19	13	42
Share-based compensation expense in operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	325	342	666	694
Product | Share-based compensation expense in cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	23	22	46	45
Service | Share-based compensation expense in cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 36	$ 31	$ 70	$ 64