Goodwill and Purchased Intangible Assets, Net - Amortization Expense for Purchased Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Jul. 28, 2017	Jul. 29, 2016
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 13	$ 11
Cost of revenues | Developed Technology
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	8	6
Operating expenses | Customer Contracts/Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	4	4
Operating expenses | Other Purchased Intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1	$ 1