Quarterly report pursuant to Section 13 or 15(d)

SHAREHOLDERS' EQUITY Narrative (Details)

v2.4.1.9
SHAREHOLDERS' EQUITY Narrative (Details)
Mar. 31, 2015
Empire [Member]  
Noncontrolling Interest, Ownership Percentage by Parent 79.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ clf_NameofOperationAxis
= clf_EmpireMember
Tilden [Member]  
Noncontrolling Interest, Ownership Percentage by Parent 85.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ clf_NameofOperationAxis
= clf_TildenMember
Bloom Lake [Member]  
Noncontrolling Interest, Ownership Percentage by Parent 82.80%us-gaap_MinorityInterestOwnershipPercentageByParent
/ clf_NameofOperationAxis
= clf_BloomLakeMember