Derivative Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Cash Flow Hedging [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI	$ 4.7	$ (9.8)	$ 5.8	$ (9.8)
Net Investment Hedging [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI	0	(1.7)	0	(0.8)
Net Sales [Member] | Cash Flow Hedging [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) reclassified from AOCI into income	(2.8)	0.5	(8.1)	4.4
Net Sales [Member] | Not designated as hedges [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	2.8	(5.3)	3.5	(4.6)
Cost of Sales [Member] | Not designated as hedges [Member] | Commodity derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.7)	4.7	(2.0)	5.0
Other Income [Member] | Fair Value Hedging [Member] | Interest Rate Swap [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.4)	(0.8)	0.5	1.9
Other Income [Member] | Not designated as hedges [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.5)	(1.1)	(1.6)	(0.5)
Interest Expense [Member] | Fair Value Hedging [Member] | Interest Rate Swap [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	$ 0.9		$ 1.8