Stockholders' Equity - Stock-Based Compensation Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Apr. 26, 2019	Apr. 27, 2018	Apr. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 158	$ 161	$ 195
Income tax benefit for stock-based compensation	15	29	41
Cost of Product Revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	4	3	4
Cost of Hardware Maintenance and Other Services Revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	10	10	13
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	67	68	84
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	48	49	59
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 29	$ 31	$ 35