Additional Financial Information (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Oct. 01, 2011	Oct. 02, 2010	Oct. 01, 2011	Oct. 02, 2010
Cash Interest and Taxes
Cash paid for interest	$ 2.2	$ 1.9	$ 7.1	$ 2.8
Cash paid for income taxes	13.9	89.0	25.3	123.9
Additional Financial Information (Textuals) [Abstract]
Capitalization of fixed assets and recognition of related obligations, net			$ 60.3	$ 20.3
Number of Class B common shares converted into Class A common shares				11.3