Derivative Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Cash Flow Hedging [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) recognized in AOCI	$ (4.4)	$ 7.9	$ (5.8)	$ 13.7
Net Sales [Member] | Cash Flow Hedging [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) reclassified from AOCI into income	(1.4)	0.5	(0.7)	(7.7)
Net Sales [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.6)	5.4	(1.6)	8.9
Interest Expense [Member] | Fair Value Hedging [Member] | Interest rate swaps [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	0.3	0.7	0.8	2.5
Other Income [Member] | Fair Value Hedging [Member] | Interest rate swaps [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(0.3)	(0.6)	(0.5)	(0.1)
Other Income [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	0.9	0	(0.7)	(1.6)
Cost of Sales [Member] | Not designated as hedges [Member] | Commodity derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	$ 0	$ (0.8)	$ 3.9	$ (2.8)