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Fair Value Measurements - Unobservable Inputs for Level 3 Natural Gas Supply Contracts (Details) - Natural gas supply contracts
Jun. 30, 2026
$ / MMBTU
Forward natural gas price per MMBtu | Minimum | Discounted cash flow  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 2.07
Forward natural gas price per MMBtu | Maximum | Discounted cash flow  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 5.37
Forward natural gas price per MMBtu | Arithmetic average | Discounted cash flow  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 3.47
Volatility | Minimum | Option pricing model  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 0.192
Volatility | Maximum | Option pricing model  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 0.663
Volatility | Arithmetic average | Option pricing model  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Derivative, measurement input 0.282