Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS - Reconciliation of Beginning and Ending Balances for Plan Assets Valued using Significant Unobservable Inputs (Details)

v3.20.4
BENEFIT PLANS - Reconciliation of Beginning and Ending Balances for Plan Assets Valued using Significant Unobservable Inputs (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Private Equity    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Roll Forward]    
Beginning balance $ 12.9 $ 18.6
Return on plan assets:    
Unrealized (0.1) 0.0
Realized (1.0) (2.0)
Purchases 0.1 0.5
Sales (2.1) (4.2)
Ending balance 9.8 12.9
Hedge Funds    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Roll Forward]    
Beginning balance 36.3 34.3
Return on plan assets:    
Unrealized 0.0 2.3
Realized (1.3) (0.3)
Purchases 0.0 0.0
Sales (19.7) 0.0
Ending balance 15.3 36.3
Real Assets    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Roll Forward]    
Beginning balance 18.9 19.9
Return on plan assets:    
Unrealized (0.1) 0.7
Realized 0.1 (0.6)
Purchases 0.1 0.1
Sales (2.7) (1.2)
Ending balance $ 16.3 $ 18.9