| Line Item | Jun 30, 2026 | Mar 31, 2026 | Dec 31, 2025 | Sep 30, 2025 | Jun 30, 2025 | Mar 31, 2025 | Dec 31, 2024 | Sep 30, 2024 | Jun 30, 2024 | Mar 31, 2024 | Dec 31, 2023 | Sep 30, 2023 | Jun 30, 2023 | Mar 31, 2023 | Dec 31, 2022 | Sep 30, 2022 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OPERATING REVENUES: | ||||||||||||||||
| YoY growth | +22.5% | +8.8% | +3.2% | +3.3% | ||||||||||||
| OPERATING EXPENSES: | ||||||||||||||||
| Operation and maintenance | ||||||||||||||||
| Administrative and general | ||||||||||||||||
| Depreciation and amortization | ||||||||||||||||
| Taxes other than income taxes | ||||||||||||||||
| Operating expenses | ||||||||||||||||
| Operating income | ||||||||||||||||
| % of revenue | 41.7% | 31.6% | 33.0% | 38.9% | ||||||||||||
| OTHER INCOME (EXPENSES): | ||||||||||||||||
| Interest on debt | ||||||||||||||||
| Allowance for funds used during construction | ||||||||||||||||
| Other pension costs | ||||||||||||||||
| Other income (expenses), net | ||||||||||||||||
| Other income (expenses) | ||||||||||||||||
| Income before income taxes | ||||||||||||||||
| Income tax expense (benefit) | ||||||||||||||||
| Net Income | ||||||||||||||||
| % of revenue | 32.4% | 24.0% | 26.5% | 30.5% | ||||||||||||
| Basic Earnings Per Share (in Dollars per share) | — | |||||||||||||||
| Diluted Earnings Per Share (in Dollars per share) | — |