Restructuring and Other Charges - Activities Related to Restructuring Reserves (Detail) - USD ($) $ in Millions	3 Months Ended
	Jul. 31, 2015	Jul. 25, 2014
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	$ 0
Net charges	27	$ 0
Cash payments	(11)
Balance at end of period	16
Employee Severance Related Costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	0
Net charges	26
Cash payments	(11)
Balance at end of period	15
Other
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	0
Net charges	1
Cash payments	0
Balance at end of period	$ 1