Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) by Component Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 26, 2018	Jan. 27, 2017	Jan. 26, 2018	Jan. 27, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 2,780
Other comprehensive income, net of tax	$ (23)	$ 4	(13)	$ (6)
Ending balance	2,176		2,176
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(29)
Other comprehensive income, net of tax			3
Ending balance	(26)		(26)
Defined Benefit Obligation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			0
Other comprehensive income, net of tax			(1)
Ending balance	(1)		(1)
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			0
Other comprehensive income, net of tax			(15)
Ending balance	(15)		(15)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(29)
Other comprehensive income, net of tax			(13)
Ending balance	$ (42)		$ (42)