PROPERTY, PLANT AND EQUIPMENT PROPERTY, PLANT AND EQUIPMENT (Book Value of Land and Mineral Rights Disclosure) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Land Rights	$ 31.9us-gaap_Land	$ 46.3us-gaap_Land
Mineral Rights [Abstract]
Mineral Properties, Gross	558.3us-gaap_MineralPropertiesGross	7,773.3us-gaap_MineralPropertiesGross
Mineral Properties, Accumulated Depletion	(101.3)	(942.6)
Mineral Properties, Net	$ 457.0us-gaap_MineralPropertiesNet	$ 6,830.7us-gaap_MineralPropertiesNet

Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 4

-Subparagraph (e)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Subparagraph (SX 210.5-02.13)

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- Definition

The accumulated decrease in the carrying value of the mineral properties as a result of mine or mineral production.

+ References

No definition available.

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- Definition

Carrying amount at the balance sheet date of mineral properties, gross of adjustments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Mineral properties, net of adjustments.

+ References

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