Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Oct. 29, 2011	Apr. 30, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents, assets	$ 37.9	$ 188.2
Derivative instruments, assets	1.1	5.5
Total assets	39.0	193.7
Derivative instruments, liabilities	1.1	5.6
Quoted Prices In Active Markets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents, assets	37.9	188.2
Derivative instruments, assets	0	0
Total assets	37.9	188.2
Derivative instruments, liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents, assets	0	0
Derivative instruments, assets	1.1	5.5
Total assets	1.1	5.5
Derivative instruments, liabilities	1.1	5.6
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents, assets	0	0
Derivative instruments, assets	0	0
Total assets	0	0
Derivative instruments, liabilities	$ 0	$ 0