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Operations and Significant Accounting Policies - Other Current Liabilities (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
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Organization, Consolidation and Presentation of Financial Statements [Abstract] |  |
PSAs | $ 6.0 | $ 6.0
Customer Deposits | 5.7 | 7.4
Provision for Interim Rate Refund | 5.5 | 0.0
Operating Lease Liabilities | 3.1 | 3.0
Finance Lease Liabilities | 0.4 | 0.4
Other | 59.5 | 75.1
Total Other Current Liabilities | $ 80.2 | $ 91.9

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