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OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES - Other Current Liabilities (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
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Organization, Consolidation and Presentation of Financial Statements [Abstract] |  |
Provision for Interim Rate Refund | $ 17.0 | $ 0.0
Customer Deposits | 9.2 | 7.4
PSAs | 5.9 | 6.0
Operating Lease Liabilities | 3.4 | 3.0
Finance Lease Liabilities | 0.4 | 0.4
Other | 66.6 | 75.1
Total Other Current Liabilities | $ 102.5 | $ 91.9

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