XML 71 R58.htm IDEA: XBRL DOCUMENT
v3.19.2

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Narrative) (Details) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 USD ($) | Jun. 30, 2018 USD ($) | Jun. 30, 2019 USD ($) | Jun. 30, 2018 USD ($) | Dec. 31, 2018 USD ($)
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Par Value | $ 2,238.0 |  | $ 2,238.0 |  |
Extinguishment of Debt, Amount | 714.0 | $ 15.5 | 724.0 | $ 15.5 |
$750 Million 5.875% 2027 Senior Notes [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Par Value | $ 750.0 |  | $ 750.0 |  |
Debt issuance, discount rate | 96.125% |  | 96.125% |  |
Repurchase price if triggering event occurs |  |  | 1.01 |  |
Debt Issuance Costs, Gross | $ 6.8 |  | $ 6.8 |  |
$1.075 Billion 5.75% 2025 Senior Notes [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Par Value | 473.3 |  | 473.3 |  | $ 1,073.3
Extinguishment of Debt, Amount | $ 600.0 | $ 1.7 | $ 600.0 | $ 1.7 |

X
- Definition Debt issuance, discount rate + References No definition available. + Details
Name: | clf_Debtissuancediscountrate
Namespace Prefix: | clf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Repurchase price if triggering event occurs + References No definition available. + Details
Name: | clf_Repurchasepriceiftriggeringeventoccurs
Namespace Prefix: | clf_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399 + Details
Name: | us-gaap_DeferredFinanceCostsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Gross amount of debt extinguished. + References No definition available. + Details
Name: | us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=clf_A750Million5.8752027SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=clf_A1.075Billion5.752025SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |