FAIR VALUE MEASUREMENTS (Measured on Recurring Basis) (Details) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022 |
Other Assets | Pension Benefits | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Defined Benefit Plan, Plan Assets, Amount | $ 18.8 | $ 18.6 |
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 | 49.4 | 35.6 |
Derivative, Collateral, Right to Reclaim Cash | (49.4) | (35.6) |
Derivative Liability | 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 | 13.4 | 20.6 |
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 | 36 | 11.8 |
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 | 3.2 |
Fair Value, Measurements, Recurring | Catalyst financing arrangements | | |
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 | 2.7 | 4 |
Fair Value, Measurements, Recurring | Catalyst financing arrangements | 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 | Catalyst financing arrangements | Level 2 | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Obligations, Fair Value Disclosure | 2.7 | 4 |
Fair Value, Measurements, Recurring | Catalyst financing arrangements | Level 3 | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Obligations, Fair Value Disclosure | 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 |
Obligations, Fair Value Disclosure | 792.3 | 1,361.1 |
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 |
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 | 792.3 | 1,361.1 |
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 |
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 | 29.4 | 147.3 |
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 | 29.4 | 147.3 |
Fair Value, Measurements, Recurring | Money market funds | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and cash equivalents | 125.4 | 106.5 |
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 | 125.4 | 106.5 |
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 |
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 |
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 | 66 | 49.5 |
Derivative assets, Effect of Counter-party Netting | (49.4) | (35.6) |
Derivative assets, Net Carrying Value on Balance Sheet | 16.6 | 13.9 |
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 | 20.3 | 33.8 |
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 | 33.8 | 15.7 |
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 | 11.9 | 0 |
Fair Value, Measurements, Recurring | Derivatives included within inventory intermediation agreement obligations | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative Asset, Fair Value, Amount Not Offset Against Collateral | 16.6 | 25.1 |
Derivative assets, Effect of Counter-party Netting | 0 | 0 |
Derivative assets, Net Carrying Value on Balance Sheet | 16.6 | 25.1 |
Fair Value, Measurements, Recurring | Derivatives included within inventory intermediation agreement obligations | Level 1 | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative Asset, Fair Value, Amount Not Offset Against Collateral | 0 | 0 |
Fair Value, Measurements, Recurring | Derivatives included within inventory intermediation agreement obligations | Level 2 | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivative Asset, Fair Value, Amount Not Offset Against Collateral | 16.6 | 25.1 |
Fair Value, Measurements, Recurring | Derivatives included within inventory intermediation agreement obligations | 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 |