Derivative Financial Instruments (Tables)

3 Months Ended

Jul. 31, 2013

Derivative Financial Instruments [Abstract]

Fair value of derivative instruments

	July 31, 2013				April 30, 2013
	Other Current Assets		Other Current Liabilities		Other Current Assets		Other Current Liabilities
Derivatives designated as hedging instruments:
Commodity contracts	$	0.8	$	1.3	$	2.1	$	2.0
Derivatives not designated as hedging instruments:
Commodity contracts	$	4.3	$	2.5	$	3.6	$	2.3
Foreign currency exchange contracts		0.8		0.3		0.7		0.2
Total derivatives not designated as hedging instruments	$	5.1	$	2.8	$	4.3	$	2.5
Total derivative instruments	$	5.9	$	4.1	$	6.4	$	4.5

Commodity contracts gains and losses recognized on derivatives designated as cash flow hedges

	Three Months Ended July 31,
	2013		2012
Losses recognized in other comprehensive loss (effective portion)	$	(6.0)	$	(2.2)
Losses reclassified from accumulated other comprehensive loss to cost of products sold (effective portion)		(8.8)		(6.5)
Change in accumulated other comprehensive loss	$	2.8	$	4.3
Losses recognized in cost of products sold (ineffective portion)	$	—	$	(0.1)

Net realized and unrealized gains and losses recognized in cost of products sold on derivatives not designated as qualified hedging instruments

	Three Months Ended July 31,
	2013		2012
Unrealized gains on commodity contracts	$	4.5	$	19.6
Unrealized gains on foreign currency exchange contracts		0.1		0.1
Total unrealized gains recognized in cost of products sold	$	4.6	$	19.7
Realized losses on commodity contracts	$	(6.4)	$	(7.8)
Realized gains on foreign currency exchange contracts		1.0		0.1
Total realized losses recognized in cost of products sold	$	(5.4)	$	(7.7)
Total (losses) gains recognized in cost of products sold	$	(0.8)	$	12.0

Outstanding derivative contracts

	July 31, 2013		April 30, 2013
Commodity contracts	$	315.6	$	347.6
Foreign currency exchange contracts		68.3		56.8