Shareholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Apr. 28, 2018	Mar. 15, 2017	Oct. 20, 2015
Class of Stock [Line Items]
Treasury stock repurchased, shares	0	0
Treasury stock, shares	39,716,000	39,558,000	39,585,000
Treasury stock, at cost	$ 1,122,435,000	$ 1,121,526,000	$ 1,121,724,000
Maximum
Class of Stock [Line Items]
Number of shares authorized to be repurchase				$ 50,000,000	$ 50,000,000
Stock Repurchase Program
Class of Stock [Line Items]
Treasury stock, shares	39,716,411,000
Treasury stock, at cost	$ 1,087,778,000
New Stock Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, remaining authorized repurchase amount	$ 50,000,000