Employee Benefit Plans - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 1,569	$ 1,591	$ 1,599
Income tax benefit for share-based compensation	452	542	558
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	237	220	227
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	592	540	538
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	500	519	555
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	215	250	246
Restructuring and other charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	25	62	33
Share-based compensation expense in operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	1,332	1,371	1,372
Product | Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	93	90	94
Service | Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 144	$ 130	$ 133