REGULATORY ASSETS AND LIABILITIES - PLANT RETIREMENTS (Details) - USD ($) $ in Millions |
Jun. 30, 2024 |
Dec. 31, 2023 |
|---|---|---|
| Oak Creek Power Plant Units 5 and 6 | ||
| Regulatory assets | $ 3,435.0 | $ 3,274.7 |
| Regulatory liability | 3,894.6 | 3,745.2 |
| Removal costs | ||
| Oak Creek Power Plant Units 5 and 6 | ||
| Regulatory liability | 1,401.5 | 1,329.9 |
| Plant retirement related items | ||
| Oak Creek Power Plant Units 5 and 6 | ||
| Regulatory assets | 824.6 | $ 646.2 |
| Oak Creek Power Plant Units 5 and 6 | ||
| Oak Creek Power Plant Units 5 and 6 | ||
| Deferred tax liabilities | 9.4 | |
| Oak Creek Power Plant Units 5 and 6 | Removal costs | ||
| Oak Creek Power Plant Units 5 and 6 | ||
| Regulatory liability | 43.9 | |
| Oak Creek Power Plant Units 5 and 6 | Plant retirement related items | ||
| Oak Creek Power Plant Units 5 and 6 | ||
| Regulatory assets | $ 78.3 |