Fair Value Measurement (Tables)

12 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities 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 described in Note 2, as of September 30, 2015 and 2014:

	Asset (Liability)
	Level 1			Level 2			Level 3		Total
September 30, 2015:
Derivative instruments:
Assets:
Commodity contracts	$	17.4		$	11.6		$	—	$	29.0
Foreign currency contracts	$	—		$	29.1		$	—	$	29.1
Cross-currency swaps	$	—		$	0.4		$	—	$	0.4
Interest rate contracts	$	—		$	—		$	—	$	—
Liabilities:
Commodity contracts	$	(70.0	)	$	(99.0	)	$	—	$	(169.0	)
Foreign currency contracts	$	—		$	(0.1	)	$	—	$	(0.1	)
Interest rate contracts	$	—		$	(10.8	)	$	—	$	(10.8	)
Non-qualified supplemental postretirement grantor trust investments (a)	$	30.3		$	—		$	—	$	30.3
September 30, 2014
Derivative instruments:
Assets:
Commodity contracts	$	10.6		$	19.8		$	—	$	30.4
Foreign currency contracts	$	—		$	12.8		$	—	$	12.8
Cross-currency swaps	$	—		$	2.1		$	—	$	2.1
Interest rate contracts	$	—		$	0.1		$	—	$	0.1
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

(a) Consists primarily of mutual fund investments held in grantor trusts associated with non-qualified supplemental retirement plans (see Note 8).