Employee Benefit Plans (Summary Of Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 27, 2018	Jan. 28, 2017	Jan. 27, 2018	Jan. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 399	$ 352	$ 797	$ 724
Income tax benefit for share-based compensation	96	102	271	207
Cost of sales—product
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	23	19	46	40
Cost of sales—service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	31	34	65	67
Share-based compensation expense in cost of sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	54	53	111	107
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	134	129	270	255
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	135	125	270	265
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	64	45	128	94
Restructuring and other charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	12	0	18	3
Share-based compensation expense in operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 345	$ 299	$ 686	$ 617