ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Reclassifications Out of Accumulated Other Comprehensive Loss (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	$ 3.7
Prior service cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total net periodic benefit cost, before tax	(0.1)
Recognized actuarial loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total net periodic benefit cost, before tax	5.1
Pension and other postretirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total net periodic benefit cost, before tax	5.0
Total net periodic benefit cost, tax benefit	(1.3)
Amounts reclassified from accumulated other comprehensive income (loss)	$ 3.7