ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplementary Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Paid (Received) for:
Interest, Net of Capitalized Amounts	$ 1,837.8	$ 1,673.5	$ 1,286.3
Income Taxes	133.4	78.4	116.8
Sale of Transferable Tax Credits	(202.0)	(102.0)	0.0
Noncash Investing and Financing Activities:
Acquisitions Under Finance Leases	29.5	48.7	31.8
Construction Expenditures Included in Current Liabilities as of December 31,	1,312.0	842.4	1,258.9
Acquisition of Nuclear Fuel Included in Current Liabilities as of December 31,	23.5	24.2	0.0
Noncash Increase in Noncurrent Assets from the Sale of the Competitive Contracted Renewables Portfolio	$ 0.0	$ 74.7	$ 0.0