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OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES - Supplemental Statement of Cash Flows Information (Details) - USD ($) $ in Millions | 9 Months Ended
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Sep. 30, 2024 | Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract] |  |
Cash Paid for Interest – Net of Amounts Capitalized | $ 59.5 | $ 64.8
Cash Paid for Income Taxes – Net | 7.0 | 14.1
Noncash Investing and Financing Activities |  |
Increase in Accounts Payable for Capital Additions to Property, Plant and Equipment | 13.5 | 11.8
Capitalized Asset Retirement Costs | 51.0 | 2.4
AFUDC–Equity | $ 4.0 | $ 2.5

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