Stockholders' Equity - Summary of Activities Related to Dividends on Common Stock (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Jan. 29, 2016	Jan. 23, 2015	Jan. 29, 2016	Jan. 23, 2015
Dividends, Common Stock [Abstract]
Dividends per share declared	$ 0.180	$ 0.165	$ 0.540	$ 0.495
Dividend payments			$ 159	$ 157
Additional Paid-in Capital
Dividends, Common Stock [Abstract]
Dividend payments			84	52
Retained Earnings
Dividends, Common Stock [Abstract]
Dividend payments			$ 75	$ 105