SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION (Deferred Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract with Customer, Liability, Revenue Recognized	$ 38.5	$ 51.3
Other Current Liabilities [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract with Customer, Liability, Current	22.1	21.0	$ 23.8
Contract With Customer, Liability, Period Increase (Decrease)	1.1	(2.8)
Contract with Customer, Liability	12.8	12.8
Other Noncurrent Liabilities [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred Revenue (Long-Term)	25.7	38.5	$ 51.4
Contract With Customer, Liability, Period Increase (Decrease)	(12.8)	(12.9)
Take or Pay Contracts [Member] | Other Current Liabilities [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract with Customer, Liability	$ 9.3	$ 8.2