Fair Value Measurements (Tables)

9 Months Ended

Jun. 30, 2021

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, 2021:
Derivative instruments:
Assets:
Commodity contracts	$	241	$	396	$	—	$	637
Foreign currency contracts	$	—	$	24	$	—	$	24
Liabilities:
Commodity contracts	$	(136)	$	(9)	$	—	$	(145)
Foreign currency contracts	$	—	$	(13)	$	—	$	(13)
Interest rate contracts	$	—	$	(35)	$	—	$	(35)
Non-qualified supplemental postretirement grantor trust investments (a)	$	42	$	—	$	—	$	42
September 30, 2020:
Derivative instruments:
Assets:
Commodity contracts	$	68	$	39	$	—	$	107
Foreign currency contracts	$	—	$	32	$	—	$	32
Liabilities:
Commodity contracts	$	(54)	$	(64)	$	—	$	(118)
Foreign currency contracts	$	—	$	(14)	$	—	$	(14)
Interest rate contracts	$	—	$	(55)	$	—	$	(55)
Non-qualified supplemental postretirement grantor trust investments (a)	$	42	$	—	$	—	$	42
June 30, 2020:
Derivative instruments:
Assets:
Commodity contracts	$	39	$	29	$	—	$	68
Foreign currency contracts	$	—	$	49	$	—	$	49
Liabilities:
Commodity contracts	$	(58)	$	(114)	$	—	$	(172)
Foreign currency contracts	$	—	$	(7)	$	—	$	(7)
Interest rate contracts	$	—	$	(59)	$	—	$	(59)
Non-qualified supplemental postretirement grantor trust investments (a)	$	41	$	—	$	—	$	41

(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:

	June 30, 2021		September 30, 2020		June 30, 2020
Carrying amount	$	5,890	$	6,081	$	6,036
Estimated fair value	$	6,314	$	6,504	$	6,208