Supplemental Financial Information - Product Warranty Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
	Jul. 27, 2018	Jul. 28, 2017	Jul. 27, 2018	Apr. 27, 2018
Movement In Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 40	$ 50
Expense accrued during the period	4	1
Warranty costs incurred	(6)	(7)
Balance at end of period	38	44
Standard Product Warranty Accrual, Balance Sheet Classification [Abstract]
Accrued expenses			$ 25	$ 25
Other long-term liabilities			13	15
Total warranty liabilities	$ 40	$ 50	$ 38	$ 40