Fair Value Measurement (Tables)

6 Months Ended

Mar. 31, 2012

Fair Value Measurements [Abstract]

Financial assets and financial liabilities that are measured at fair value on a recurring basis

	Asset (Liability)
	Quoted Prices
	in Active			Significant
	Markets for			Other
	Identical Assets			Observable			Unobservable
	and Liabilities			Inputs			Inputs
	(Level 1)			(Level 2)			(Level 3)		Total
March 31, 2012:
Assets:
Derivative financial instruments:
Commodity contracts	$	9.8		$	1.2		$	—	$	11.0
Foreign currency contracts	$	—		$	3.1		$	—	$	3.1
Liabilities:
Derivative financial instruments:
Commodity contracts	$	(41.1	)	$	(42.2	)	$	—	$	(83.3	)
Interest rate contracts	$	—		$	(53.2	)	$	—	$	(53.2	)
September 30, 2011:
Assets:
Derivative financial instruments:
Commodity contracts	$	3.5		$	3.3		$	—	$	6.8
Foreign currency contracts	$	—		$	5.3		$	—	$	5.3
Liabilities:
Derivative financial instruments:
Commodity contracts	$	(28.1	)	$	(16.1	)	$	—	$	(44.2	)
Foreign currency contracts	$	—		$	(3.3	)	$	—	$	(3.3	)
Interest rate contracts	$	—		$	(44.4	)	$	—	$	(44.4	)
March 31, 2011:
Assets:
Derivative financial instruments:
Commodity contracts	$	2.6		$	12.1		$	—	$	14.7
Foreign currency contracts	$	—		$	0.3		$	—	$	0.3
Interest rate contracts	$	—		$	13.0		$	—	$	13.0
Liabilities:
Derivative financial instruments:
Commodity contracts	$	(10.6	)	$	(9.8	)	$	—	$	(20.4	)
Foreign currency contracts	$	—		$	(4.0	)	$	—	$	(4.0	)
Interest rate contracts	$	—		$	(0.2	)	$	—	$	(0.2	)