XML 95 R72.htm IDEA: XBRL DOCUMENT
v3.21.2

FAIR VALUE MEASUREMENTS - Carrying Value And Fair Value Of Financial Instruments Disclosure (Details) - USD ($) $ in Millions | Jun. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Carrying Value |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | $ 5,368 | $ 5,424
Fair Value |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 6,266 | 6,065
Senior Notes | Carrying Value | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 3,548 | 3,802
Senior Notes | Fair Value | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 4,446 | 4,446
Industrial Revenue Bonds | Carrying Value | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 94 | 94
Industrial Revenue Bonds | Fair Value | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 94 | 91
Line of Credit | Carrying Value | Level 2 | ABL Facility |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 1,670 | 1,510
Line of Credit | Carrying Value | Level 2 | EDC Revolving Facilities - outstanding balance |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 56 | 18
Line of Credit | Fair Value | Level 2 | ABL Facility |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | 1,670 | 1,510
Line of Credit | Fair Value | Level 2 | EDC Revolving Facilities - outstanding balance |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total long-term debt | $ 56 | $ 18

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=clf_IndustrialRevenueBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=clf_EDCRevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |