Goodwill and Purchased Intangible Assets, Net - Purchased Intangible Assets, Net (Detail) - USD ($) $ in Millions	Jan. 26, 2018	Apr. 28, 2017
Acquired Finite Lived Intangible Assets [Line Items]
Gross Assets	$ 216	$ 200
Accumulated Amortization	(110)	(69)
Net Assets	106	131
Developed Technology
Acquired Finite Lived Intangible Assets [Line Items]
Gross Assets	164	148
Accumulated Amortization	(71)	(44)
Net Assets	93	104
Customer Contracts/Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Gross Assets	43	43
Accumulated Amortization	(30)	(19)
Net Assets	13	24
Other Purchased Intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Gross Assets	9	9
Accumulated Amortization	(9)	(6)
Net Assets	$ 0	$ 3