Employee Benefit Plans (Summary of Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,529	$ 1,458	$ 1,440
Income tax benefit for share-based compensation	451	429	373
Cost of sales—product
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	85	70	50
Cost of sales—service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	134	142	157
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	219	212	207
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	529	470	448
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	542	545	559
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	236	205	228
Restructuring and other charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3	26	(2)
Operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,310	$ 1,246	$ 1,233