v3.25.1
Fair Value Measurements
 6 Months Ended
Mar. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value Measurements
Note 11 — Fair Value Measurements

Recurring Fair Value Measurements

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 1Level 2Level 3Total
March 31, 2025:
Derivative instruments:
Assets:
Commodity contracts$213 $28 $— $241 
Foreign currency contracts$— $14 $— $14 
Interest rate contracts$— $1 $— $1 
Liabilities:
Commodity contracts$(150)$(9)$— $(159)
Foreign currency contracts$— $(1)$— $(1)
Interest rate contracts$— $(11)$— $(11)
Non-qualified supplemental postretirement grantor trust investments (a)$32 $— $— $32 
September 30, 2024:
Derivative instruments:
Assets:
Commodity contracts$106 $27 $— $133 
Foreign currency contracts$— $6 $— $6 
Interest rate contracts$— $1 $— $1 
Liabilities:
Commodity contracts$(120)$(32)$— $(152)
Foreign currency contracts$— $(9)$— $(9)
Interest rate contracts$— $(22)$— $(22)
Non-qualified supplemental postretirement grantor trust investments (a)$43 $— $— $43 
March 31, 2024:
Derivative instruments:
Assets:
Commodity contracts$107 $39 $— $146 
Foreign currency contracts$— $16 $— $16 
Interest rate contracts$— $11 $— $11 
Liabilities:
Commodity contracts$(184)$(38)$— $(222)
Foreign currency contracts$— $(1)$— $(1)
Interest rate contracts$— $(3)$— $(3)
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.
The fair values of our Level 1 exchange-traded commodity futures and option contracts and non-exchange-traded commodity futures and forward contracts are based upon actively quoted market prices for identical assets and liabilities. Substantially all of the remaining derivative instruments are designated as Level 2. The fair values of certain non-exchange-traded commodity derivatives designated as Level 2 are based upon indicative price quotations available through brokers, industry price publications or recent market transactions and related market indicators. The fair values of our Level 2 interest rate contracts and foreign currency contracts are based upon third-party quotes or indicative values based on recent market transactions. The fair values of investments held in grantor trusts are derived from quoted market prices as substantially all of the investments in these trusts have active markets.

Other Financial Instruments

The carrying amounts of other financial instruments included in current assets and current liabilities (except for current maturities of long-term debt) approximate their fair values because of their short-term nature. We estimate the fair value of long-term debt by using current market rates and by discounting future cash flows using rates available for similar type debt (Level 2). 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, 2025September 30, 2024March 31, 2024
Carrying amount$6,670 $6,733 $6,826 
Estimated fair value$6,642 $6,663 $6,647 

Financial instruments other than derivative instruments, such as short-term investments and trade accounts receivable, could expose us to concentrations of credit risk. We limit credit risk from short-term investments by investing only in investment-grade commercial paper, money market mutual funds, securities guaranteed by the U.S. Government or its agencies and FDIC insured bank deposits. The credit risk arising from concentrations of trade accounts receivable is limited because we have a large customer base that extends across many different U.S. markets and a number of foreign countries. For information regarding concentrations of credit risk associated with our derivative instruments, see Note 12.