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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 |

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