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Annual report pursuant to Section 13 and 15(d)

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Schedule Of Subsidiaries) (Details)

v2.4.0.8
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Schedule Of Subsidiaries) (Details)
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Northshore [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Minnesota Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
United Taconite [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Minnesota Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Wabush [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Newfoundland and Labrador/ Quebec, Canada Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Bloom Lake [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Quebec, Canada Ìý
Noncontrolling Interest, Ownership Percentage by Parent 82.80% 75.00%
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Tilden [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Michigan Ìý
Noncontrolling Interest, Ownership Percentage by Parent 85.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Empire [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Michigan Ìý
Noncontrolling Interest, Ownership Percentage by Parent 79.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Koolyanobbing [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Western Australia Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Iron Ore Ìý
Pinnacle [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province West Virginia Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Coal Ìý
Oak Grove [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province Alabama Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Coal Ìý
CLCC [Member]
 Ìý Ìý
Related Party Transaction [Line Items] Ìý Ìý
Entity Address, State or Province West Virginia Ìý
Noncontrolling Interest, Ownership Percentage by Parent 100.00% Ìý
Segment Reporting Information, Description of Products and Services Coal Ìý