EMPLOYEE BENEFITS - AMOUNTS RECOGNIZED ON THE BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension and OPEB assets	$ 260.7	$ 159.2
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and OPEB assets	92.9	7.6
Other long-term liabilities	6.6	7.5
Total net assets	86.3	0.1
OPEB Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and OPEB assets	167.8	151.6
Other long-term liabilities	11.1	11.8
Total net assets	$ 156.7	$ 139.8