DERIVATIVE INSTRUMENTS - GAINS (LOSSES) AND NOTIONAL VOLUMES (Details) MWh in Millions, MMBTU in Millions, $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
Sep. 30, 2026
USD ($)
MMBTU
MWh
|
Sep. 30, 2025
USD ($)
MWh
MMBTU
|
Sep. 30, 2026
USD ($)
MWh
MMBTU
|
Sep. 30, 2025
USD ($)
MMBTU
MWh
|
|
| Realized gains and losses | ||||
| Realized gains and losses on derivatives income statement location | Cost of sales | Cost of sales | Cost of sales | Cost of sales |
| Gains (losses) | $ 10.8 | $ (2.7) | $ 18.5 | $ 5.7 |
| Natural gas contracts | ||||
| Realized gains and losses | ||||
| Gains (losses) | $ (8.4) | $ (5.7) | $ (4.4) | $ 0.4 |
| Notional volumes | ||||
| Notional volumes | MMBTU | 15.2 | 14.2 | 51.8 | 51.5 |
| FTRs | ||||
| Realized gains and losses | ||||
| Gains (losses) | $ 19.2 | $ 3.0 | $ 22.9 | $ 5.3 |
| Notional volumes | ||||
| Notional volumes | MWh | 4.3 | 4.5 | 12.4 | 13.8 |