Fair Value Measurement (Tables)

6 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Financial Assets and Financial Liabilities that are Measured at Fair Value on a Recurring Basis

The following table presents on a gross basis our financial assets and liabilities including both current and noncurrent portions, that are measured at fair value on a recurring basis within the fair value hierarchy, as of March 31, 2015, September 30, 2014 and March 31, 2014:

	Asset (Liability)
	Level 1			Level 2			Level 3		Total
March 31, 2015:
Derivative instruments:
Assets:
Commodity contracts	$	13.9		$	8.3		$	—	$	22.2
Foreign currency contracts	$	—		$	35.8		$	—	$	35.8
Interest rate contracts	$	—		$	0.1		$	—	$	0.1
Cross-currency swaps	$	—		$	9.7		$	—	$	9.7
Liabilities:
Commodity contracts	$	(64.0	)	$	(104.3	)	$	—	$	(168.3	)
Interest rate contracts	$	—		$	(12.5	)	$	—	$	(12.5	)
Non-qualified supplemental postretirement grantor trust investments (a)	$	31.8		$	—		$	—	$	31.8
September 30, 2014:
Derivative instruments:
Assets:
Commodity contracts	$	10.6		$	19.8		$	—	$	30.4
Foreign currency contracts	$	—		$	12.8		$	—	$	12.8
Interest rate contracts	$	—		$	0.1		$	—	$	0.1
Cross-currency swaps	$	—		$	2.1		$	—	$	2.1
Liabilities:
Commodity contracts	$	(21.2	)	$	(32.9	)	$	—	$	(54.1	)
Foreign currency contracts	$	—		$	(0.1	)	$	—	$	(0.1	)
Interest rate contracts	$	—		$	(21.0	)	$	—	$	(21.0	)
Non-qualified supplemental postretirement grantor trust investments (a)	$	30.0		$	—		$	—	$	30.0
March 31, 2014 (b):
Derivative instruments:
Assets:
Commodity contracts	$	17.5		$	14.0		$	—	$	31.5
Foreign currency contracts	$	—		$	0.1		$	—	$	0.1
Liabilities:
Commodity contracts	$	(10.0	)	$	(19.7	)	$	—	$	(29.7	)
Foreign currency contracts	$	—		$	(5.6	)	$	—	$	(5.6	)
Interest rate contracts	$	—		$	(27.8	)	$	—	$	(27.8	)
Cross-currency swaps	$	—		$	(2.2	)	$	—	$	(2.2	)
Non-qualified supplemental postretirement grantor trust investments (a)	$	29.8		$	—		$	—	$	29.8

(a) Consists primarily of mutual fund investments held in grantor trusts associated with non-qualified supplemental retirement plans.

(b) Certain immaterial amounts have been revised to correct the classification of derivatives.