Fair Value Measurements (Tables)

3 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Schedule of 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
December 31, 2022:
Derivative instruments:
Assets:
Commodity contracts	$	345	$	329	$	—	$	674
Foreign currency contracts	$	—	$	35	$	—	$	35
Interest rate contracts	$	—	$	63	$	—	$	63
Liabilities:
Commodity contracts	$	(297)	$	(152)	$	—	$	(449)
Foreign currency contracts	$	—	$	(4)	$	—	$	(4)
Non-qualified supplemental postretirement grantor trust investments (a)	$	46	$	—	$	—	$	46
September 30, 2022:
Derivative instruments:
Assets:
Commodity contracts (b)	$	938	$	1,268	$	27	$	2,233
Foreign currency contracts	$	—	$	119	$	—	$	119
Interest rate contracts	$	—	$	66	$	—	$	66
Liabilities:
Commodity contracts (b)	$	(377)	$	(136)	$	—	$	(513)
Foreign currency contracts	$	—	$	(2)	$	—	$	(2)
Non-qualified supplemental postretirement grantor trust investments (a)	$	43	$	—	$	—	$	43
December 31, 2021:
Derivative instruments:
Assets:
Commodity contracts	$	411	$	711	$	—	$	1,122
Foreign currency contracts	$	—	$	29	$	—	$	29
Interest rate contracts	$	—	$	5	$	—	$	5
Liabilities:
Commodity contracts	$	(160)	$	(18)	$	—	$	(178)
Foreign currency contracts	$	—	$	(7)	$	—	$	(7)
Interest rate contracts	$	—	$	(17)	$	—	$	(17)
Non-qualified supplemental postretirement grantor trust investments (a)	$	52	$	—	$	—	$	52

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

(b)Includes derivative assets and liabilities held-for-sale associated with the October 2022 sale of the U.K. energy marketing business (see Note 5).

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, 2022		September 30, 2022		December 31, 2021
Carrying amount	$	6,759	$	6,665	$	6,580
Estimated fair value	$	6,350	$	6,189	$	7,048