REGULATORY MATTERS (Roadrunner Reserve II) (Details) - USD ($) $ in Thousands |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Public Utilities, General Disclosures [Line Items] | ||
| Plant in Service | $ 9,580,229 | $ 9,000,669 |
| Roadrunner Reserve II | ||
| Public Utilities, General Disclosures [Line Items] | ||
| Plant in Service | $ 360,000 |