FAIR VALUE MEASUREMENTS (Measured on Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, Effect of Counter-party Netting	$ (22.3)	$ (23.7)
Derivative, Collateral, Obligation to Return Cash	22.3	23.7
Payment for Contingent Consideration Liability, Operating Activities	18.8
Other Assets | Pension Benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Plan Assets, Amount	19.3	18.8
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	33.6	46.9
Derivative, Collateral, Right to Reclaim Cash	(26.7)	(46.9)
Derivative Liability	6.9	0.0
Fair Value, Measurements, Recurring | Commodity contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	31.5	46.9
Fair Value, Measurements, Recurring | Commodity contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	2.1	0.0
Fair Value, Measurements, Recurring | Commodity contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0.0	0.0
Fair Value, Measurements, Recurring | Renewable energy credit and emissions obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Obligations, Fair Value Disclosure	428.9	429.8
Fair Value, Measurements, Recurring | Renewable energy credit and emissions obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure	0.0	0.0
Fair Value, Measurements, Recurring | Renewable energy credit and emissions obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure	428.9	429.8
Fair Value, Measurements, Recurring | Renewable energy credit and emissions obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure	0.0	0.0
Fair Value, Measurements, Recurring | Contingent consideration obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Collateral, Right to Reclaim Cash		0.0
Obligations, Fair Value Disclosure		21.6
Fair Value, Measurements, Recurring | Contingent consideration obligation | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure		0.0
Fair Value, Measurements, Recurring | Contingent consideration obligation | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure		0.0
Fair Value, Measurements, Recurring | Contingent consideration obligation | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Obligations, Fair Value Disclosure		21.6
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	12.4	130.3
Fair Value, Measurements, Recurring | Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	12.4	130.3
Fair Value, Measurements, Recurring | Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0.0	0.0
Fair Value, Measurements, Recurring | Money market funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0.0	0.0
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	26.7	80.1
Derivative assets, Effect of Counter-party Netting	(26.7)	(46.9)
Derivative assets, Net Carrying Value on Balance Sheet	0.0	33.2
Derivative, Collateral, Obligation to Return Cash	26.7	46.9
Fair Value, Measurements, Recurring | Commodity contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	23.8	80.1
Fair Value, Measurements, Recurring | Commodity contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	2.9	0.0
Fair Value, Measurements, Recurring | Commodity contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	$ 0.0	$ 0.0