DERIVATIVE INSTRUMENTS - GAINS (LOSSES) AND NOTIONAL VOLUMES (Details) MWh in Millions, MMBTU in Millions, $ in Millions	3 Months Ended
Mar. 31, 2024 USD ($) MWh MMBTU	Mar. 31, 2023 USD ($) MWh MMBTU
Realized gains and losses
Gains (losses)	$ (55.3)	$ (74.9)
Natural gas contracts
Realized gains and losses
Gains (losses)	$ (56.9)	$ (75.3)
Notional sales volumes
Notional sales volumes \| MMBTU	67.8	58.7
FTRs and TCRs
Realized gains and losses
Gains (losses)	$ 1.6	$ 0.4
Notional sales volumes
Notional sales volumes \| MWh	7.6	7.3
Non-Utility Energy Infrastructure
Realized gains and losses
Realized gains and losses on derivatives income statement location	Total operating revenues	Total operating revenues
Utility operations
Realized gains and losses
Realized gains and losses on derivatives income statement location	Cost of sales	Cost of sales

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A

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Indicates line item in statement of income or comprehensive income that includes gain (loss) from derivative.

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Nominal energy measure used to calculate payments on a derivative instrument.

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