Quarterly report pursuant to Section 13 or 15(d)

DISCONTINUED OPERATIONS Schedule of Disposal Groups, including Discontinued Operations, Income Statement - Canadian Entities (Details)

v2.4.1.9
DISCONTINUED OPERATIONS Schedule of Disposal Groups, including Discontinued Operations, Income Statement - Canadian Entities (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
LOSS FROM DISCONTINUED OPERATIONS, net of tax $ (928.5)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax $ (140.4)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Canadian Entities [Member]    
Disposal Group, Including Discontinued Operation, Revenue 11.3us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
158.3us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Disposal Group, Including Discontinued Operation, Costs of Goods Sold (11.1)us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(208.0)us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Eliminations with Continuing Operations 0clf_EliminationswithContinuingOperations
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(28.7)clf_EliminationswithContinuingOperations
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Disposal Group, Including Discontinued Operation, Gross Profit (Loss) 0.2us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(78.4)us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Disposal Group, Including Discontinued Operation, Operating Expense (33.3)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(58.6)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Disposal Group, Including Discontinued Operation, Other Expense (1.0)us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(1.4)us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax (34.1)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
(138.4)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Business Exit Costs (818.7)us-gaap_BusinessExitCosts1
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
0us-gaap_BusinessExitCosts1
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
Discontinued Operation, Tax Effect of Discontinued Operation 0us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
44.3us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
LOSS FROM DISCONTINUED OPERATIONS, net of tax $ (852.8)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember
$ (94.1)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= clf_CanadianEntitiesMember