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COMMITMENTS AND CONTINGENT LIABILITIES - LEGAL PROCEEDINGS (Details) - USD ($) $ in Thousands | 9 Months Ended |
--- | --- | ---
Jun. 30, 2025 | Sep. 30, 2024
Site Contingency [Line Items] |  |
Manufactured gas plant remediation | $ 155,861 | $ 161,650
Recovery from third party of environmental remediation cost, period | 7 years |
Regulatory assets | $ 615,859 | $ 609,192
Expended, net of recoveries |  |
Site Contingency [Line Items] |  |
Regulatory assets | 70,500 |
Minimum |  |
Site Contingency [Line Items] |  |
Product liability contingency, loss exposure in excess of accrual, best estimate | 130,900 |
Maximum |  |
Site Contingency [Line Items] |  |
Product liability contingency, loss exposure in excess of accrual, best estimate | $ 194,600 |

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