XML 100 R83.htm IDEA: XBRL DOCUMENT
v3.4.0.3

DISCONTINUED OPERATIONS PreTax Exit Costs (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2016 | Mar. 31, 2015
PreTax Exit Costs [Line Items] |  |
Deconsolidation, Gain (Loss), Amount |  | $ (528.2)
Canadian Entities [Member] |  |
PreTax Exit Costs [Line Items] |  |
Investment Impairment of Deconsolidation | $ (3.8) | 476.0
Deconsolidation, Gain (Loss), Amount | (3.8) | 818.7
Bloom Lake Group [Member] |  |
PreTax Exit Costs [Line Items] |  |
Contingent Liabilities of Deconsolidated Entities | $ 0.0 | $ (342.7)

X
- Definition Contingent Liabilities of Deconsolidated Entities + References No definition available. + Details
Name: | clf_ContingentLiabilitiesofDeconsolidatedEntities
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investment Impairment of Deconsolidation + References No definition available. + Details
Name: | clf_InvestmentImpairmentofDeconsolidation
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition [Line Items] for PreTax Exit Costs [Table] + References No definition available. + Details
Name: | clf_PreTaxExitCostsLineItems
Namespace Prefix: | clf_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the gain (loss) recognized by the parent and included in its attributable portion of net income for the period due to deconsolidation of a subsidiary or derecognition of a group of assets. The gain (loss) recognized and included in the net income attributable to the parent for the period is generally computed as the difference between: (a) the aggregate of: (1) the fair value of any consideration received; (2) the fair value of any retained noncontrolling investment in the former subsidiary at the date the subsidiary was deconsolidated; and (3) the carrying amount of any noncontrolling interest in the former subsidiary (including any accumulated other comprehensive income attributable to the noncontrolling interest) at the date the subsidiary was deconsolidated and (b) the carrying amount of the former subsidiary's assets and liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4582445-111684 + Details
Name: | us-gaap_DeconsolidationGainOrLossAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=clf_CanadianEntitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=clf_BloomLakeGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |