MODERNIZATION - Schedule of Rollforward of Reserves (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Modernization Reserve Rollforward [Roll Forward] | ||||
| Modernization expenses | $ 10 | $ 34 | $ 26 | $ 44 |
| SBO Initiatives | ||||
| Modernization Reserve Rollforward [Roll Forward] | ||||
| Beginning balance | 26 | |||
| Modernization expenses | 26 | |||
| Cash payments | (27) | |||
| Ending balance | $ 25 | $ 25 | ||