Fair Value Measurements (Tables)

9 Months Ended

Jun. 30, 2020

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:

	Asset (Liability)
	Level 1		Level 2		Level 3		Total
June 30, 2020:
Derivative instruments:
Assets:
Commodity contracts	$	38.3	$	29.3	$	—	$	67.6
Foreign currency contracts	$	—	$	49.0	$	—	$	49.0
Liabilities:
Commodity contracts	$	(57.7)	$	(114.2)	$	—	$	(171.9)
Foreign currency contracts	$	—	$	(7.0)	$	—	$	(7.0)
Interest rate contracts	$	—	$	(59.0)	$	—	$	(59.0)
Non-qualified supplemental postretirement grantor trust investments (a)	$	41.4	$	—	$	—	$	41.4
September 30, 2019:
Derivative instruments:
Assets:
Commodity contracts	$	32.0	$	10.1	$	—	$	42.1
Foreign currency contracts	$	—	$	59.0	$	—	$	59.0
Liabilities:
Commodity contracts	$	(62.3)	$	(112.7)	$	—	$	(175.0)
Foreign currency contracts	$	—	$	(4.3)	$	—	$	(4.3)
Interest rate contracts	$	—	$	(12.3)	$	—	$	(12.3)
Non-qualified supplemental postretirement grantor trust investments (a)	$	39.7	$	—	$	—	$	39.7
June 30, 2019:
Derivative instruments:
Assets:
Commodity contracts	$	30.1	$	24.3	$	—	$	54.4
Foreign currency contracts	$	—	$	29.5	$	—	$	29.5
Liabilities:
Commodity contracts	$	(44.8)	$	(62.4)	$	—	$	(107.2)
Foreign currency contracts	$	—	$	(5.2)	$	—	$	(5.2)
Interest rate contracts	$	—	$	(7.8)	$	—	$	(7.8)
Non-qualified supplemental postretirement grantor trust investments (a)	$	40.8	$	—	$	—	$	40.8

(a)Consists primarily of mutual fund investments held in grantor trusts associated with non-qualified supplemental retirement plans (see Note 12)

Schedule of Carrying Amount and Estimated Fair Value of Long-term Debt

The carrying amounts and estimated fair values of our long-term debt (including current maturities but excluding unamortized debt issuance costs) were as follows:

	June 30, 2020		September 30, 2019		June 30, 2019
Carrying amount	$	6,036.2	$	5,856.6	$	4,347.1
Estimated fair value	$	6,208.1	$	6,189.3	$	4,571.3