Goodwill and Purchased Intangible Assets, Net - Amortization Expense for Purchased Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 25, 2019	Oct. 26, 2018	Oct. 25, 2019	Oct. 26, 2018
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 11	$ 12	$ 22	$ 25
Cost of revenues | Developed Technology
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	11	9	22	18
Operating expenses | Customer Contracts/Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 0	$ 3	$ 0	$ 7