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. 26, 2018	Oct. 27, 2017	Oct. 26, 2018	Oct. 27, 2017
Dividends, Common Stock [Abstract]
Dividends per share declared	$ 0.40	$ 0.20	$ 0.80	$ 0.40
Dividend payments			$ 207	$ 108
Additional Paid-in Capital
Dividends, Common Stock [Abstract]
Dividend payments			207	0
Retained Earnings (Accumulated Deficit)
Dividends, Common Stock [Abstract]
Dividend payments			$ 0	$ 108