Revenue - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Jan. 25, 2019	Jan. 26, 2018
Disaggregation Of Revenue [Line Items]
Revenue recognized	$ 1,410	$ 1,466
Transaction price allocated to remaining performance obligations	$ 3,357
Minimum
Disaggregation Of Revenue [Line Items]
Deferred sales commissions amortization period	1 year
Maximum
Disaggregation Of Revenue [Line Items]
Deferred sales commissions amortization period	3 years