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Fair Value Measurements: Schedule of Fair Values (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative Liability, Statement of Financial Position [Extensible Enumeration] | Derivative Liability, Current | Derivative Liability, Current
Contract Subject to Master Netting |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative Asset, Fair Value, Gross Asset | $ 5.6 | $ 1.9
Derivative Liability, Fair Value, Gross Liability | 1.1 | 3.3
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 | (5.6) | (1.9)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset | (1.1) | (3.3)
Fair Value, Measurements, Recurring | Fair Value |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative Assets, Fair Value Disclosure | 0.0 | 0.0
Derivative, Liabilities, Fair Value Disclosure | 4.6 | 6.8
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 | 5.6 | 1.9
Derivative, Liabilities, Fair Value Disclosure | 5.7 | 10.1
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 | (5.6) | (1.9)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset | (1.1) | (3.3)
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 | 0.0 | 0.0
Derivative, Liabilities, Fair Value Disclosure | 4.6 | 6.8
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 | 5.6 | 1.9
Derivative, Liabilities, Fair Value Disclosure | 5.7 | 10.1
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

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