Stockholders' Equity - Stock-Based Compensation Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 30, 2015	Oct. 24, 2014	Oct. 30, 2015	Oct. 24, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 59	$ 68	$ 136	$ 130
Cost of Product Revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1	2	3	3
Cost of Hardware Maintenance and Other Services Revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	4	3	10	8
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	26	30	57	57
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	18	22	44	43
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 10	$ 11	$ 22	$ 19