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v3.25.3

Financial Instruments - Narrative (Details) Bcf in Billions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Sep. 30, 2025 USD ($) counterparty Bcf | Sep. 30, 2024 USD ($) | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($)
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Foreign currency forward contracts duration maximum | 5 years |  |  |
After tax net hedging gains in accumulated other comprehensive income (loss) | $ 19,900,000 |  |  |
After tax net hedging gains reclassified within twelve months | 35,700,000 |  |  |
Fair market value of derivative liability with a credit-risk related contingency | 1,900,000 |  |  |
Hedging collateral deposits | 0 | $ 0 | $ 0 | $ 91,670,000
Foreign Currency Contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Hedging notional amount of forecasted transportation costs | $ 44,100,000 |  |  |
Over the Counter Swaps, No Cost Collars and Foreign Currency Forward Contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Number of counterparties in which the company holds over-the-counter swap positions | counterparty | 18 |  |  |
Number of counterparties in net gain position | counterparty | 13 |  |  |
Credit risk exposure per counterparty | $ 3,000,000 |  |  |
Maximum credit risk exposure per counterparty | 8,700,000 |  |  |
Collateral received by company | $ 0 |  |  |
Cash Flow Hedges |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Hedge duration | 5 years |  |  |
Cash Flow Hedges | Natural Gas Bcf |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Nonmonetary notional amount of price risk cash flow hedge derivatives, natural gas (in Bcf) | Bcf | 414.3 |  |  |

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