Net Income Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 28, 2011	Oct. 29, 2010	Oct. 28, 2011	Oct. 29, 2010
Net Income Per Share [Line Items]
Net income	$ 165.6	$ 175.4	$ 305.1	$ 326.1
Shares used in basic computation	361.5	359.1	365.9	355.8
Dilutive potential shares related to employee equity award plans	7.8	15.9	9.8	15.7
Dilutive impact of assumed conversion of Notes	6.7	12.4	11.1	9.4
Dilutive impact of warrants	0	4.3	4.0	2.1
Shares used in diluted computation	376.0	391.7	390.8	383.0
Net Income per Share: Basic	$ 0.46	$ 0.49	$ 0.83	$ 0.92
Net Income per Share: Diluted	$ 0.44	$ 0.45	$ 0.78	$ 0.85
Percentage of reduction in dilutive effect of notes when stock price increases			80.00%
Debt instrument convertible conversion price	$ 31.85		$ 31.85
Options And Restricted Stock Units [Member]
Net Income Per Share [Line Items]
Options and RSUs	15.6	2.1	9.6	3.7