XML 98 R77.htm IDEA: XBRL DOCUMENT
v3.10.0.1

DEBT AND CREDIT FACILITIES (Debt Extinguishment/Restructuring) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Extinguishment of Debt [Line Items] |  |  |  |
Gain (loss) on extinguishment of debt |  | $ (6.8) | $ (165.4) | $ 166.3
$544.2 Million 7.75% 2020 Second Lien Notes |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 114.1
Debt Instrument, Face Amount Received in Debt Exchange of $544M 7.75% Notes |  |  |  | 57.0
Debt, carrying value |  |  |  | 77.5
Gain (loss) on extinguishment of debt |  |  | (104.5) | 6.9
$500 Million 3.95% 2018 Senior Notes [Member] |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 17.6
Debt Instrument, Face Amount Received in Debt Exchange of $500M 3.95% Notes |  |  |  | 11.4
Debt, carrying value |  |  |  | 15.5
Gain (loss) on extinguishment of debt | $ 19.9 |  |  | 1.8
$400 Million 5.90% 2020 Senior Notes |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 65.1
Debt Instrument, Face Amount Received in Debt Exchange of $400M 5.90% Notes |  |  |  | 26.0
Debt Instrument, Par Value |  |  | 88.9 |
Debt, carrying value |  |  |  | 35.4
Gain (loss) on extinguishment of debt |  | (3.3) | (7.8) | 28.3
$500 Million 4.80% 2020 Senior Notes |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 44.7
Debt Instrument, Face Amount Received in Debt Exchange of $500M 4.80% Notes |  |  |  | 17.9
Debt Instrument, Par Value |  |  | 122.4 |
Debt, carrying value |  |  |  | 24.4
Gain (loss) on extinguishment of debt |  | (3.7) | (1.9) | 19.5
$700 Million 4.875% 2021 Senior Notes |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 76.3
Debt instrument, Face Amount Received in Debt Exchange of $700M 4.875% Notes |  |  |  | 30.5
Debt Instrument, Par Value |  | 124.0 | 138.4 |
Debt, carrying value |  |  |  | 41.5
Gain (loss) on extinguishment of debt |  | 0.1 | (2.8) | 33.3
$800 Million 6.25% 2040 Senior Notes [Member] |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 194.4
Debt Instrument, Face Amount Received in Debt Exchange of $800M 6.25% Notes |  |  |  | 75.7
Debt Instrument, Par Value |  | $ 298.4 | 298.4 |
Debt, carrying value |  |  |  | 103.0
Gain (loss) on extinguishment of debt |  |  |  | 84.5
$218.5 Million 8.00% 2020 1.5 Lien Notes |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |
Debt Instrument, Face Amount Exchanged |  |  |  | 512.2
Debt Instrument, Par Value |  |  |  | 218.5
Debt, carrying value |  |  |  | 297.3
Gain (loss) on extinguishment of debt |  |  | $ 45.1 | $ 174.3

X
- Definition Debt Instrument, Face Amount Exchanged + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountExchanged
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Face Amount Received in Debt Exchange of $400M 5.90% Notes + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountReceivedinDebtExchangeof400M5.90Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Face Amount Received in Debt Exchange of $500M 3.95% Notes + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountReceivedinDebtExchangeof500M3.95Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Face Amount Received in Debt Exchange of $500M 4.80% Notes + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountReceivedinDebtExchangeof500M4.80Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Face Amount Received in Debt Exchange of $544.2M 7.75% Notes + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountReceivedinDebtExchangeof544M7.75Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Face Amount Received in Debt Exchange of $800M 6.25% Notes + References No definition available. + Details
Name: | clf_DebtInstrumentFaceAmountReceivedinDebtExchangeof800M6.25Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Par Value + References No definition available. + Details
Name: | clf_DebtInstrumentParValue
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Debt, carrying value + References No definition available. + Details
Name: | clf_Debtcarryingvalue
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt instrument, Face Amount Received in Debt Exchange of $700M 4.875% Notes + References No definition available. + Details
Name: | clf_DebtinstrumentFaceAmountReceivedinDebtExchangeof700M4.875Notes
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_ExtinguishmentOfDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=114001942&loc=d3e12355-112629 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114001942&loc=d3e12317-112629 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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

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

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

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

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

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