Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Apr. 24, 2015	Apr. 25, 2014	Apr. 26, 2013	Apr. 27, 2012
Income Tax Contingency [Line Items]
Deferred tax assets, increase/decrease in valuation allowance	$ 8,100,000	$ 9,800,000
Operating loss and credit carryforwards, expiration dates range, minimum	2018
Operating loss and credit carryforwards, expiration dates range, maximum	2035
Gross unrecognized tax benefits	271,900,000	235,900,000	189,600,000	161,000,000
Unrecognized tax benefits included in other long-term liabilities	213,600,000
Unrecognized tax benefits that would affect provision for income taxes	167,500,000
Tax penalties and interest on unrecognized tax benefits	3,600,000	2,200,000	1,200,000
Accrued tax penalties and interest on unrecognized tax benefits	8,600,000	5,000,000
Resolution of income tax examinations	46,400,000	0	100,000
Expected refund, excluding interest from fiscal 2005 to 2007 income tax audit	8,000,000
Estimated potential decrease in unrecognized tax benefit balance	95,400,000
Accumulated unremitted earnings from foreign subsidiaries	3,300,000,000
Estimated unrecognized deferred tax liability on unremitted earnings of foreign subsidiaries	1,000,000,000
United Kingdom
Income Tax Contingency [Line Items]
Resolution of income tax examinations	(1,000,000)
Federal Income Tax
Income Tax Contingency [Line Items]
Operating loss carry forwards	21,700,000
Tax credit carry forward amount	117,000,000
Resolution of income tax examinations	47,400,000
State and Local Income Tax
Income Tax Contingency [Line Items]
Operating loss carry forwards	85,400,000
Tax credit carry forward amount	145,500,000
Additional Paid-in Capital
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 122,000,000