Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Apr. 27, 2012	Apr. 29, 2011
Income Taxes [Abstract]
Reserves and accruals	$ 70.2	$ 56.8
Acquisition intangibles	6.7	0
Net operating loss and credit carryforwards	97.7	120.3
Stock-based compensation	78.7	74.1
Deferred revenue	262.0	176.2
Other	15.1	17.4
Gross deferred tax assets	530.4	444.8
Valuation allowance	(32.4)	(45.5)
Deferred tax assets, net of valuation allowance	498.0	399.3
Reserves and accruals	4.7	0
Acquisition intangibles	2.2	7.4
Property and equipment	67.9	11.9
1.75% Convertible Senior Notes Due 2013	15.2	28.2
Other	2.6	(1.9)
Total deferred tax liabilities	92.6	45.6
Deferred tax assets, net of valuation allowance and deferred tax liabilities	$ 405.4	$ 353.7