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PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Narrative) (Details) - USD ($) |  | 12 Months Ended
--- | --- | ---
Oct. 01, 2018 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items] |  |  |
Labor Agreement, Contract Term | 4 years |  |
401(k) contribution match |  | $ 0.60 |
Defined Benefit Plan, Accumulated Benefit Obligation |  | 1,010,000,000.0 | $ 896,800,000
Reserve for investment commitments |  | 37,100,000 |
Early Termination Fees for Pension Benefits |  | 14,900,000 |
Early Termination Fees for Other Postretirement Benefits |  | $ 3,000,000.0 |
Structured Finance [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Redemption request notice period, days |  | 90 days |
Real Estate [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Redemption request notice period, days |  | 45 days |
Withdrawal request notice period, days |  | 95 days |
Pension Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Participant contributions |  | $ 0 | 0
Other Postretirement Benefits Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Participant contributions |  | 5,800,000 | $ 5,600,000
Prior To Age65 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Annual limit on medical coverage for each participant |  | $ 7,000 |

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