Stockholders' Equity (Stock-Based Compensation Expense) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 27, 2012	Apr. 29, 2011	Apr. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 257.6	$ 175.2	$ 159.8
Cost Of Product Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	5.4	3.6	4.0
Cost Of Service Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	17.8	14.4	14.3
Sales And Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	126.0	81.5	73.7
Research And Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	74.1	44.5	38.5
General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 34.3	$ 31.2	$ 29.3