Annual report pursuant to Section 13 and 15(d)

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

betfred games-free to play_FAIR VALUE OF FINANCIAL v2.4.1.9
Betfred
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross $ 2,217.7us-gaap_PropertyPlantAndEquipmentGross $ 13,570.9us-gaap_PropertyPlantAndEquipmentGross  
Accumulated Depreciation and Depletion, Property, Plant and Equipment 802.8clf_AccumulatedDepreciationandDepletionPropertyPlantandEquipment 2,417.5clf_AccumulatedDepreciationandDepletionPropertyPlantandEquipment  
Property, plant and equipment, net 1,414.9us-gaap_PropertyPlantAndEquipmentNet 11,153.4us-gaap_PropertyPlantAndEquipmentNet 11,207.3us-gaap_PropertyPlantAndEquipmentNet
Land Rights And Mineral Rights [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 590.2us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MiningPropertiesAndMineralRightsMember
7,819.6us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MiningPropertiesAndMineralRightsMember
 
Office And Information Technology [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 75.5us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ComputerEquipmentMember
125.7us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ComputerEquipmentMember
 
Buildings [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 65.6us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingMember
255.2us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingMember
 
Mining Equipment [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 732.6us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_EquipmentMember
1,819.3us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_EquipmentMember
 
Processing Equipment [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 567.4us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OtherMachineryAndEquipmentMember
2,148.6us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OtherMachineryAndEquipmentMember
 
Electric Power Facilities [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 48.8us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ElectricGenerationEquipmentMember
114.3us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ElectricGenerationEquipmentMember
 
Land Improvements [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 25.5us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandImprovementsMember
69.3us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandImprovementsMember
 
Other Assets [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 60.8us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OtherAssetsMember
227.6us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OtherAssetsMember
 
Construction in Progress [Member]      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross $ 51.3us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
$ 991.3us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember