v3.26.3
DERIVATIVE INSTRUMENTS - DERIVATIVE ASSETS AND LIABILITIES (Details)
$ in Millions
Sep. 30, 2026
USD ($)
Instruments
Dec. 31, 2025
USD ($)
Instruments
Derivative assets    
Current derivative assets $ 34.0 $ 26.2
Long-term derivative assets 0.2 0.1
Total derivative assets $ 34.2 $ 26.3
Current derivative assets balance sheet location Other Other
Long-term derivative assets balance sheet location Other Assets, Noncurrent Other Assets, Noncurrent
Derivative liabilities    
Current derivative liabilities $ 55.2 $ 30.8
Long-term derivative liabilities 2.0 1.7
Total derivative liabilities $ 57.2 $ 32.5
Current derivative liabilities balance sheet location Other Liabilities, Current Other Liabilities, Current
Long-term derivative liabilities balance sheet location Other noncurrent liabilities Other noncurrent liabilities
Natural gas contracts    
Derivative assets    
Current derivative assets $ 19.3 $ 19.7
Derivative liabilities    
Current derivative liabilities 55.2 30.0
FTRs    
Derivative assets    
Current derivative assets 14.7 6.5
Derivative liabilities    
Current derivative liabilities $ 0.0 $ 0.8
Designated as hedging instrument    
Derivative instruments    
Number of derivative instruments | Instruments 0 0