v3.25.2
Fair Value Measurements: Schedule of Fair Values (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Contract Subject to Master Netting    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Fair Value, Gross Asset $ 1.0 $ 2.2
Derivative Liability, Fair Value, Gross Liability 0.2 0.6
Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset (1.0) (2.2)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset (0.2) (0.6)
Fair Value, Measurements, Recurring | Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 0.3 0.0
Derivative, Liabilities, Fair Value Disclosure 1.7 4.2
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 0.0 0.0
Derivative, Liabilities, Fair Value Disclosure 0.0 0.0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 1.3 2.2
Derivative, Liabilities, Fair Value Disclosure 1.9 4.8
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 0.0 0.0
Derivative, Liabilities, Fair Value Disclosure 0.0 0.0
Fair Value, Measurements, Recurring | Gas Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset (1.0) (2.2)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset (0.2) (0.6)
Fair Value, Measurements, Recurring | Gas Utilities | Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 0.3 0.0
Derivative, Liabilities, Fair Value Disclosure $ 1.7 $ 4.2
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Derivative Liability, Current Derivative Liability, Current
Fair Value, Measurements, Recurring | Gas Utilities | Fair Value, Inputs, Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure $ 0.0 $ 0.0
Derivative, Liabilities, Fair Value Disclosure 0.0 0.0
Fair Value, Measurements, Recurring | Gas Utilities | Fair Value, Inputs, Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 1.3 2.2
Derivative, Liabilities, Fair Value Disclosure 1.9 4.8
Fair Value, Measurements, Recurring | Gas Utilities | Fair Value, Inputs, Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Assets, Fair Value Disclosure 0.0 0.0
Derivative, Liabilities, Fair Value Disclosure $ 0.0 $ 0.0