Derivative Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2012	Jan. 31, 2011
Cash Flow Hedging [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI	$ 7.9	$ 1.5	$ 13.7	$ (8.3)
Net Investment Hedging [Member] | Currency Derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI				(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	0.5	(2.0)	(7.7)	2.4
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	5.4		8.9	(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	(0.8)	2.0	(2.8)	7.0
Other Income [Member] | Fair Value Hedging [Member] | Interest Rate Swaps [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.6)	0.3	(0.1)	2.2
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		(0.9)	(1.6)	(1.4)
Interest Expense [Member] | Fair Value Hedging [Member] | Interest Rate Swaps [Member]
Fair values of derivative instruments affecting statements of operations
Gain (loss) on derivative instruments recognized in income	$ 0.7	$ 0.6	$ 2.5	$ 1.6