INCOME TAXES (Details 3) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Pension and postretirement benefits	$ 181.9	$ 190.6
Environmental reserves	36.3	34.5
Asset retirement obligations	16.4	13.2
Accrued liabilities	54.1	38.6
Lease liabilities	87.4	90.0
Tax credits	49.8	25.1
Net operating losses	141.0	70.0
Capital loss carryforward	0.9	0.9
Interest deduction limitation	7.0	41.8
Other miscellaneous items	0.0	20.2
Total deferred tax assets	574.8	524.9
Valuation allowance	239.6	182.1	$ 147.4
Net deferred tax assets	335.2	342.8
Deferred tax liabilities:
Property, plant and equipment	530.4	525.0
Right-of-use lease assets	86.2	88.8
Intangible amortization	40.0	54.6
Inventory and prepaids	17.4	20.6
Partnerships	80.9	67.3
Taxes on unremitted earnings	6.1	5.7
Other miscellaneous items	6.2	0.0
Total deferred tax liabilities	767.2	762.0
Net deferred tax liability	$ (432.0)	$ (419.2)