Financing Arrangements (Amount Of Interest Expense Recognized) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 27, 2012	Jan. 28, 2011	Jan. 27, 2012	Jan. 28, 2011
Financing Arrangements [Abstract]
Contractual coupon interest expense	$ 5.5	$ 5.5	$ 16.5	$ 16.5
Amortization of debt discount	13.0	12.2	38.4	36.1
Amortization of debt issuance costs	1.1	1.1	3.3	3.1
Less capitalized interest	(0.9)	0	(4.3)	0
Total interest expense related to Notes	$ 18.7	$ 18.8	$ 53.9	$ 55.7