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EARNINGS PER SHARE EARNINGS PER SHARE (Narrative Details) (Details)
In Millions, unless otherwise specified |
3 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
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Dec. 31, 2014
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Mar. 31, 2013
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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| Earnings Per Share [Abstract] | |||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 25.2us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | 12.9us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | 25.2us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | ||
| Antidilutive Incremental Common Shares Excluded and Attributable to Share-based Payment Arrangements | 0.7clf_AntidilutiveIncrementalCommonSharesExcludedandAttributabletoSharebasedPaymentArrangements | 0clf_AntidilutiveIncrementalCommonSharesExcludedandAttributabletoSharebasedPaymentArrangements | 0.5clf_AntidilutiveIncrementalCommonSharesExcludedandAttributabletoSharebasedPaymentArrangements | ||
| X | ||||||||||
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- Definition
Antidilutive Incremental Common Shares Excluded and Attributable to Share-based Payment Arrangements No definition available.
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| X | ||||||||||
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- Definition
Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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