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Details of Selected Financial Statement Captions - Deferred Credits and Other Liabilities (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Sep. 30, 2024
--- | --- | ---
Balance Sheet Related Disclosures [Abstract] |  |
Pension and postretirement liabilities | $ 68,398 | $ 67,322
Operating lease liabilities (See Note 7) | 262,549 | 224,498
Customer advances for construction | 9,573 | 7,973
Other regulatory liabilities (See Note 3) | 332,017 | 279,979
Asset retirement obligation | 7,428 | 7,942
Liabilities from risk management activities | 146 | 313
APT annual adjustment mechanism | 31,299 | 37,195
Unrecognized tax benefits (See Note 15) | 50,210 | 46,174
Other | 22,702 | 20,536
Total | $ 784,322 | $ 691,932

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