Net Income (Loss) per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Jul. 31, 2015	Jul. 25, 2014
Net income per share:
Net income (loss)	$ (30)	$ 88
Shares used in basic computation	304	323
Dilutive impact of employee equity award plans	0	6
Shares used in diluted computation	304	329
Basic	$ (0.10)	$ 0.27
Diluted	$ (0.10)	$ 0.27