Derivative Financial Instruments (Details) (USD $) In Millions	3 Months Ended
	Jul. 31, 2011
Commodity derivatives [Member] | Not designated as hedges [Member] | Other Current Assets [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	$ 3.1
Fair value of derivatives in a loss position	(0.5)
Currency Derivatives [Member] | Cash Flow Hedging [Member] | Accrued Expenses [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	0.6
Fair value of derivatives in a loss position	(17.7)
Currency Derivatives [Member] | Cash Flow Hedging [Member] | Other Liabilities [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	0.3
Fair value of derivatives in a loss position	(4.1)
Currency Derivatives [Member] | Not designated as hedges [Member] | Accrued Expenses [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	2.4
Fair value of derivatives in a loss position	(0.4)
Interest Rate Swap [Member] | Net Investment Hedging [Member] | Other Current Assets [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	2.8
Fair value of derivatives in a loss position	0
Interest Rate Swap [Member] | Net Investment Hedging [Member] | Other Assets [Member]
Fair values of derivative instruments
Fair value of derivatives in a gain position	1.9
Fair value of derivatives in a loss position	$ 0