Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Apr. 25, 2014	Apr. 26, 2013
Components of Deferred Tax Assets and Liabilities [Abstract]
Reserves and accruals	$ 89.3	$ 83.5
Acquired intangibles	22.3	12.3
Net operating loss and credit carryforwards	87.6	76.5
Stock-based compensation	73.3	81.9
Deferred revenue	318.9	311.6
Other	19.8	20.7
Gross deferred tax assets	611.2	586.5
Valuation allowance	(49.6)	(39.8)
Deferred tax assets, net of valuation allowance	561.6	546.7
Reserves and accruals	3.9	7.7
Acquired intangibles	10.0	6.0
Property and equipment	30.8	71.5
Convertible Notes	0	4.4
Other	2.6	4.1
Total deferred tax liabilities	47.3	93.7
Deferred tax assets, net of valuation allowance and deferred tax liabilities	$ 514.3	$ 453.0