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Supplementary Information for Exploration and Production Activities - Results of Operations for Producing Activities (Details) - USD ($) | 12 Months Ended
--- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022
Reserve Quantities [Line Items] |  |  |  |
Operating Revenues | [1] | $ 741,076,000 | $ 1,038,760,000 | $ 1,881,680,000
Production/Lifting Costs |  | 270,927,000 | 253,555,000 | 283,914,000
Franchise/Ad Valorem Taxes |  | 13,468,000 | 17,532,000 | 25,112,000
Purchased Emission Allowance Expense |  | 0 | 0 | 1,305,000
Accretion Expense |  | 5,992,000 | 5,673,000 | 7,530,000
Depreciation, Depletion and Amortization ($0.69, $0.63 and $0.57 per Mcfe of production, respectively) |  | 270,648,000 | 235,694,000 | 202,418,000
Impairment of Exploration and Production Properties |  | 463,692,000 | 0 | 0
Income Tax Expense (Benefit) |  | (76,983,000) | 145,574,000 | 368,925,000
Results of Operations for Producing Activities (excluding corporate overheads and interest charges) |  | (206,668,000) | 380,732,000 | 992,476,000
Revenues from sales to affiliates |  | 0 | 0 | 0
Transfers to operations |  | 1,557,000 | 1,957,000 | 5,696,000
Depreciation, Depletion and Amortization (per Mcfe of production) |  | 0.69 | 0.63 | 0.57
Gas |  |  |  |
Reserve Quantities [Line Items] |  |  |  |
Gas (includes transfers to operations of $1,557, $1,957, and $5,696, respectively) | [2] | 738,778,000 | 1,036,499,000 | 1,730,723,000
Oil, Condensate and Other Liquids |  |  |  |
Reserve Quantities [Line Items] |  |  |  |
Operating Revenues |  | $ 2,298,000 | $ 2,261,000 | $ 150,957,000
[1] | Exclusive of hedging gains and losses. See further discussion in Note J — Financial Instruments.
[2] | There were no revenues from sales to affiliates for all years presented.

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- Definition Depreciation, depletion and amortization associated with oil and gas producing activities, calculated as total depreciation, depletion and amortization during the period divided by the volume of oil and gas produced for the period. + References No definition available. + Details
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