v3.26.1
Variable Interest Entity - Schedule of consolidated VIE's assets and liabilities (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
ASSETS      
Cash and cash equivalents $ 343.4 $ 134.2  
Accounts receivable - net 136.2 109.9  
Inventories 582.9 519.6  
Prepaid and other current assets 31.4 24.4  
Total current assets 1,401.6 1,031.3 $ 807.4
Property, plant and equipment - net 1,253.0 1,167.6 1,150.8
Other assets 172.1 70.4 70.6
Total assets 2,875.1 2,269.3 2,142.3
LIABILITIES      
Accounts payable, trade 216.6 187.2  
Accrued compensation and benefits 77.1 74.4 45.2
Accrued and other current liabilities 43.6 35.6 48.0
Total current liabilities 509.4 523.6 447.5
Accrued benefits costs - less current portion 92.1 97.7 142.3
Other liabilities 114.3 104.9  
Asset retirement obligations - less current portion 74.3 75.3 82.5
Total noncurrent liabilities 831.2 815.8 $ 847.4
Variable Interest Entity, Primary Beneficiary      
ASSETS      
Cash and cash equivalents 2.1 4.6  
Accounts receivable - net 0.2 0.1  
Inventories 112.3 116.6  
Prepaid and other current assets 12.8 8.9  
Total current assets 127.4 130.2  
Property, plant and equipment - net 447.4 426.3  
Other assets 12.3 12.0  
Total assets 587.1 568.5  
LIABILITIES      
Accounts payable, trade 55.1 49.0  
Accrued compensation and benefits 12.9 11.7  
Accrued and other current liabilities 6.0 8.2  
Total current liabilities 102.2 86.2  
Accrued benefits costs - less current portion 28.0 32.2  
Other liabilities 62.9 62.1  
Asset retirement obligations - less current portion 52.4 46.6  
Total noncurrent liabilities 143.3 140.9  
TOTAL 245.5 227.1  
Variable Interest Entity, Primary Beneficiary | Related Party      
LIABILITIES      
Due to affiliates $ 28.2 $ 17.3