Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS - Fair Value of Pension Assets (Details)

v3.22.0.1
BENEFIT PLANS - Fair Value of Pension Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]      
Hedge funds, minimum number of days notice prior to redemption 30 days    
Hedge funds, maximum number of days notice prior to redemption 90 days    
Private Equity Commitments      
Defined Benefit Plan Disclosure [Line Items]      
Commitments related to investments $ 17.5 $ 21.9  
Real Asset Commitments      
Defined Benefit Plan Disclosure [Line Items]      
Commitments related to investments 0.3 0.1  
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 600.5 638.4 $ 603.2
U.S. Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 44.8 38.5  
International Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 36.5 42.4  
Fixed Income | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 475.8 489.8  
Private Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 16.1 9.8  
Hedge Funds | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.1 15.3  
Real Assets | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4.4 16.3  
Cash | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 22.8 26.3  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 67.6 64.8  
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 44.8 38.5  
Quoted Prices in Active Markets for Identical Assets (Level 1) | International Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Income | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Private Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Hedge Funds | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real Assets | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 22.8 26.3  
Significant Other Observable Inputs (Level 2) | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 512.3 532.2  
Significant Other Observable Inputs (Level 2) | U.S. Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Other Observable Inputs (Level 2) | International Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 36.5 42.4  
Significant Other Observable Inputs (Level 2) | Fixed Income | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 475.8 489.8  
Significant Other Observable Inputs (Level 2) | Private Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Other Observable Inputs (Level 2) | Hedge Funds | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Other Observable Inputs (Level 2) | Real Assets | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Other Observable Inputs (Level 2) | Cash | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Unobservable Inputs (Level 3) | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 20.6 41.4  
Significant Unobservable Inputs (Level 3) | U.S. Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Unobservable Inputs (Level 3) | International Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Unobservable Inputs (Level 3) | Fixed Income | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.0 0.0  
Significant Unobservable Inputs (Level 3) | Private Equity | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 16.1 9.8  
Significant Unobservable Inputs (Level 3) | Hedge Funds | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0.1 15.3  
Significant Unobservable Inputs (Level 3) | Real Assets | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4.4 16.3  
Significant Unobservable Inputs (Level 3) | Cash | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 0.0 $ 0.0