Fair Value Measurements (Tables)

3 Months Ended

Dec. 31, 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
December 31, 2020:
Derivative instruments:
Assets:
Commodity contracts	$	60	$	111	$	—	$	171
Foreign currency contracts	$	—	$	14	$	—	$	14
Liabilities:
Commodity contracts	$	(58)	$	(14)	$	—	$	(72)
Foreign currency contracts	$	—	$	(25)	$	—	$	(25)
Interest rate contracts	$	—	$	(50)	$	—	$	(50)
Non-qualified supplemental postretirement grantor trust investments (a)	$	46	$	—	$	—	$	46
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
December 31, 2019:
Derivative instruments:
Assets:
Commodity contracts	$	26	$	20	$	—	$	46
Foreign currency contracts	$	—	$	40	$	—	$	40
Interest rate contracts	$	—	$	3	$	—	$	3
Liabilities:
Commodity contracts	$	(77)	$	(110)	$	—	$	(187)
Foreign currency contracts	$	—	$	(4)	$	—	$	(4)
Interest rate contracts	$	—	$	(7)	$	—	$	(7)
Non-qualified supplemental postretirement grantor trust investments (a)	$	42	$	—	$	—	$	42

(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:

	December 31, 2020		September 30, 2020		December 31, 2019
Carrying amount	$	6,078	$	6,081	$	5,906
Estimated fair value	$	6,581	$	6,504	$	6,249