INCOME TAXES (Details 3) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets [Abstract]
Pension and postretirement benefits	$ 93.3	$ 48.4
Environmental reserves	60.5	66.5
Asset retirement obligations	28.6	28.5
Accrued liabilities	43.1	42.4
Tax credits	10.8	10.2
Federal and state net operating losses	6.7	5.7
Capital loss carryforward	15.5	15.0
Other miscellaneous items	5.3	13.7
Total deferred tax assets	263.8	230.4
Valuation allowance	(21.1)	(24.1)
Net deferred tax assets	242.7	206.3
Deferred tax liabilities [Abstract]
Property, plant and equipment	178.9	147.8
Intangible amortization	8.8	10.5
Inventory and prepaids	0	4.3
Partnerships	95.0	92.4
Total deferred tax liabilities	282.7	255.0
Net deferred tax (liability) asset	$ (40.0)	$ (48.7)