Statements of Cash Flows Additional Information - Supplemental Cash Flows and Non Cash Investing Activities (Detail) - USD ($) $ in Millions	3 Months Ended
	Jul. 31, 2015	Jul. 25, 2014
Non-cash Investing Activities:
Capital expenditures incurred but not paid	$ 13	$ 12
Supplemental Cash Flow Information:
Income taxes paid, net of refunds	40	68
Interest paid	$ 20	$ 12