INCOME TAXES (Components of Net Deferred Income Tax Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
INCOME TAXES [Abstract]
Employee benefits	$ 14.2	$ 11.8
Incentive compensation	62.1	62.5
Asset retirement obligations & other reserves	82.5	77.9
State net operating losses	86.3	95.0
State bonus depreciation	41.4	30.1
Operating lease liabilities	149.7	176.7
Other	72.0	59.1
Total gross deferred tax assets	508.2	513.1
Valuation allowance	(76.8)	(65.7)
Total net deferred tax asset	431.4	447.4
Property, plant & equipment	889.4	824.4
Goodwill/other intangible assets	379.2	380.2
Operating lease right-of-use assets	143.6	176.7
Other	92.0	72.0
Total deferred tax liabilities	1,504.2	1,453.3
Net deferred tax liability	$ 1,072.8	$ 1,005.9