SEGMENT REPORTING (Narrative) (Details) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2015
USD ($)
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Sep. 30, 2015
USD ($)
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Jun. 30, 2015
USD ($)
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Mar. 31, 2015
USD ($)
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Dec. 31, 2014
USD ($)
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Sep. 30, 2014
USD ($)
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Jun. 30, 2014
USD ($)
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Mar. 31, 2014
USD ($)
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Dec. 31, 2015
USD ($)
customer
Facility
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Dec. 31, 2014
USD ($)
customer
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Dec. 31, 2013
USD ($)
customer
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| Segment Reporting Information [Line Items] | |||||||||||
| Asset Impairment Charges | $ 3.3 | $ 635.5 | $ 14.3 | ||||||||
| Revenues | $ 476.0 | $ 593.2 | $ 498.1 | $ 446.0 | $ 1,030.3 | $ 979.7 | $ 747.7 | $ 615.5 | $ 2,013.3 | 3,373.2 | 3,890.8 |
| U.S. Iron Ore [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Number Of Mines | Facility | 5 | ||||||||||
| Revenues | $ 1,525.4 | 2,506.5 | 2,667.9 | ||||||||
| Asia Pacific Iron Ore [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Number Of Mines | Facility | 1 | ||||||||||
| Revenues | $ 487.9 | $ 866.7 | $ 1,224.3 | ||||||||
| North American Coal [Member] | Low Volatile Metallurgical Coal Mines [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Number Of Mines | Facility | 2 | ||||||||||
| Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Number of Customers | customer | 3 | 1,000,000 | 1,000,000 | ||||||||
| Concentration Risk, Percentage | 10.00% | 10.00% | 10.00% | ||||||||
| Revenues | $ 1,300.0 | $ 1,900.0 | $ 1,900.0 | ||||||||
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- Definition Number of Customers No definition available.
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- Definition Number of mines No definition available.
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- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). 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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