Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2022

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:

	Asset (Liability)
	Level 1		Level 2		Level 3		Total
March 31, 2022:
Derivative instruments:
Assets:
Commodity contracts	$	823	$	1,146	$	—	$	1,969
Foreign currency contracts	$	—	$	35	$	—	$	35
Interest rate contracts	$	—	$	31	$	—	$	31
Liabilities:
Commodity contracts	$	(308)	$	(13)	$	—	$	(321)
Foreign currency contracts	$	—	$	(2)	$	—	$	(2)
Interest rate contracts	$	—	$	(1)	$	—	$	(1)
Non-qualified supplemental postretirement grantor trust investments (a)	$	50	$	—	$	—	$	50
September 30, 2021:
Derivative instruments:
Assets:
Commodity contracts	$	641	$	1,008	$	—	$	1,649
Foreign currency contracts	$	—	$	38	$	—	$	38
Liabilities:
Commodity contracts	$	(264)	$	(16)	$	—	$	(280)
Foreign currency contracts	$	—	$	(8)	$	—	$	(8)
Interest rate contracts	$	—	$	(29)	$	—	$	(29)
Non-qualified supplemental postretirement grantor trust investments (a)	$	53	$	—	$	—	$	53
March 31, 2021:
Derivative instruments:
Assets:
Commodity contracts	$	73	$	162	$	—	$	235
Foreign currency contracts	$	—	$	25	$	—	$	25
Liabilities:
Commodity contracts	$	(63)	$	(9)	$	—	$	(72)
Foreign currency contracts	$	—	$	(12)	$	—	$	(12)
Interest rate contracts	$	—	$	(39)	$	—	$	(39)
Non-qualified supplemental postretirement grantor trust investments (a)	$	40	$	—	$	—	$	40

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

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:

	March 31, 2022		September 30, 2021		March 31, 2021
Carrying amount	$	6,559	$	6,491	$	6,046
Estimated fair value	$	6,543	$	6,996	$	6,362