Stockholders' Equity - Summary of Activities Related to Dividends on Common Stock (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Oct. 30, 2015	Oct. 24, 2014	Oct. 30, 2015	Oct. 24, 2014
Dividends, Common Stock [Abstract]
Dividends per share declared	$ 0.180	$ 0.165	$ 0.360	$ 0.330
Dividend payments			$ 107	$ 105
Additional Paid-in Capital
Dividends, Common Stock [Abstract]
Dividend payments			84	52
Retained Earnings
Dividends, Common Stock [Abstract]
Dividend payments			$ 23	$ 53