Derivative Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Cash Flow Hedging [Member] | Currency derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI	$ 12.6	$ 1.1
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	(5.3)
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	2.4	0.7
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	3.9	(1.2)
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		0.9
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	(3.8)	(1.2)
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	$ 0.3	$ 0.9