Cleveland-Cliffs Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details)

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,872.0us-gaap_PropertyPlantAndEquipmentGross	$ 1,870.2us-gaap_PropertyPlantAndEquipmentGross
Accumulated Depreciation and Depletion, Property, Plant and Equipment	(824.8)	(799.7)
Property, plant and equipment, net	1,047.2us-gaap_PropertyPlantAndEquipmentNet	1,070.5us-gaap_PropertyPlantAndEquipmentNet
Land Rights And Mineral Rights [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	500.5	500.5
Office And Information Technology [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	69.7	73.7
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	59.8	59.8
Mining Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	584.9	585.1
Processing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	512.7	510.2
Electric Power Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	44.2	46.8
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	24.8	24.7
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	54.7	55.0
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 20.7	$ 14.4