XML 99 R77.htm IDEA: XBRL DOCUMENT
v3.22.2

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2022 | Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract] |  |
Reclassification from environmental obligations | $ 63 | $ 0
Loss Contingency, Estimate of Possible Loss | $ 3 |

X
- Definition Asset Retirement Obligation, Reclassification + References No definition available. + Details
Name: | clf_AssetRetirementObligationReclassification
Namespace Prefix: | clf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant