Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS - Fair Value of Postretirement Assets (Details)

v3.25.0.1
BENEFIT PLANS - Fair Value of Postretirement Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   $ 363.5  
U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   40.9  
International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   35.6  
Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   243.3  
Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   13.8  
Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   4.8  
Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   25.1  
Other Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 10.7 10.7 $ 10.7
Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10.7    
Other Benefits | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   1.2  
Other Benefits | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   1.0  
Other Benefits | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   7.2  
Other Benefits | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.4  
Other Benefits | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.1  
Other Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.8  
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 8.5    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | U.S. Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1.1    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | International Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.5    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | Fixed Income | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 6.2    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | Private Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.4    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | Real Assets | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.2    
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Other Benefits | Cash | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.1    
Quoted Prices in Active Markets for Identical Assets (Level 1)      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   25.1  
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   25.1  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.8  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.1    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | U.S. Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | International Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Fixed Income | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Private Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Real Assets | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.8  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Benefits | Cash | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.1    
Significant Other Observable Inputs (Level 2)      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   319.8  
Significant Other Observable Inputs (Level 2) | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   40.9  
Significant Other Observable Inputs (Level 2) | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   35.6  
Significant Other Observable Inputs (Level 2) | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   243.3  
Significant Other Observable Inputs (Level 2) | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Other Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   9.4  
Significant Other Observable Inputs (Level 2) | Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 7.8    
Significant Other Observable Inputs (Level 2) | Other Benefits | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   1.2  
Significant Other Observable Inputs (Level 2) | Other Benefits | U.S. Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1.1    
Significant Other Observable Inputs (Level 2) | Other Benefits | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   1.0  
Significant Other Observable Inputs (Level 2) | Other Benefits | International Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.5    
Significant Other Observable Inputs (Level 2) | Other Benefits | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   7.2  
Significant Other Observable Inputs (Level 2) | Other Benefits | Fixed Income | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 6.2    
Significant Other Observable Inputs (Level 2) | Other Benefits | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Other Benefits | Private Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Other Observable Inputs (Level 2) | Other Benefits | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Other Benefits | Real Assets | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Other Observable Inputs (Level 2) | Other Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Other Observable Inputs (Level 2) | Other Benefits | Cash | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Unobservable Inputs (Level 3)      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   18.6  
Significant Unobservable Inputs (Level 3) | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 13.3 13.8 13.1
Significant Unobservable Inputs (Level 3) | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4.5 4.8 $ 4.8
Significant Unobservable Inputs (Level 3) | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Other Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.5  
Significant Unobservable Inputs (Level 3) | Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.6    
Significant Unobservable Inputs (Level 3) | Other Benefits | U.S. Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Other Benefits | U.S. Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Unobservable Inputs (Level 3) | Other Benefits | International Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Other Benefits | International Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Unobservable Inputs (Level 3) | Other Benefits | Fixed Income      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.0  
Significant Unobservable Inputs (Level 3) | Other Benefits | Fixed Income | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Significant Unobservable Inputs (Level 3) | Other Benefits | Private Equity      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.4  
Significant Unobservable Inputs (Level 3) | Other Benefits | Private Equity | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.4    
Significant Unobservable Inputs (Level 3) | Other Benefits | Real Assets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   0.1  
Significant Unobservable Inputs (Level 3) | Other Benefits | Real Assets | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.2    
Significant Unobservable Inputs (Level 3) | Other Benefits | Cash      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets   $ 0.0  
Significant Unobservable Inputs (Level 3) | Other Benefits | Cash | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0    
Investments measured at net asset value | Other Benefits | Fair Value      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 2.2