INCOME TAXES - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Operating lease liabilities	$ 145.9	$ 140.8
Asset retirement obligations & other reserves	96.7	86.6
State net operating losses	62.8	74.7
Incentive compensation	55.3	52.4
Capitalized research expenditures	0.0	39.7
Foreign net operating losses	35.1	28.9
Employee benefits	23.8	22.2
Other	40.6	52.9
Total gross deferred tax assets	460.2	498.2
Valuation allowance	(86.3)	(87.7)
Total net deferred tax asset	373.9	410.5
Property, plant & equipment	1,177.3	1,189.1
Goodwill/other intangible assets	315.6	323.2
Operating lease right-of-use assets	134.6	129.8
Other	104.7	104.9
Total deferred tax liabilities	1,732.2	1,747.0
Deferred Income Tax Liabilities, Net	$ 1,358.3	$ 1,336.5