Statements of Cash Flows Additional Information - Supplemental Cash Flows and Non Cash Investing Activities (Detail) - USD ($) $ in Millions	6 Months Ended
	Oct. 30, 2015	Oct. 24, 2014
Non-cash Investing Activities:
Capital expenditures incurred but not paid	$ 15	$ 9
Acquisition of software through long-term financing	0	12
Supplemental Cash Flow Information:
Income taxes paid, net of refunds	94	69
Interest paid	$ 20	$ 12