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Summary of Significant Accounting Policies - Average Depreciation, Depletion and Amortization Rates (Details) - uSDollarsPerMCFE | 12 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Exploration And Production Operations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Depreciation, depletion and amortization rate (in dollars per Mcfe of production) | [1] | 0.61 | 0.69 | 0.63
Integrated Upstream and Gathering Other Operations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Average depreciation, depletion and amortization rates |  | 3.60% | 3.60% | 3.50%
Pipeline and Storage |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Average depreciation, depletion and amortization rates |  | 2.60% | 2.70% | 2.60%
Utility |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Average depreciation, depletion and amortization rates |  | 2.80% | 2.80% | 2.70%
All Other and Corporate |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Average depreciation, depletion and amortization rates |  | 3.70% | 3.00% | 2.90%
[1] | Amounts represents depletion of exploration and production properties.

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- Definition The reporting period depletion average rate on long-lived physical assets used in the normal conduct of business and not intended for resale. + References No definition available. + Details
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Balance Type: | na
Period Type: | duration

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- Definition The reporting period depreciation, depletion and amortization average rate on long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include land, buildings and production equipment. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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