MODERNIZATION - Schedule of Rollforward of Reserves (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Modernization Reserve Rollforward [Roll Forward] | ||||
| Modernization expenses | $ 6 | $ 53 | $ 32 | $ 97 |
| SBO Initiatives | ||||
| Modernization Reserve Rollforward [Roll Forward] | ||||
| Other | (4) | |||
| SBO Initiatives | ||||
| Modernization Reserve Rollforward [Roll Forward] | ||||
| Beginning balance | 26 | |||
| Modernization expenses | 36 | |||
| Cash payments | (40) | |||
| Ending balance | $ 18 | $ 18 | ||