PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Additional Information) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Pension Benefits [Member] | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Effect of change in mine ownership & noncontrolling interest | $ 14.2 | $ 48.4 | $ 51.2 |
| Actual return on plan assets | 54.8 | (6.4) | 59.1 |
| Other Benefits [Member] | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Effect of change in mine ownership & noncontrolling interest | 5.9 | 5.5 | 5.9 |
| Actual return on plan assets | $ 16.0 | $ (3.9) | $ 31.9 |
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- Definition This element represents the effect of change in mine ownership & noncontrolling interest No definition available.
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- Definition The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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