Annual report pursuant to Section 13 and 15(d)

Uncategorized Items - clf-20181231.xml

v3.10.0.1
Label Element Value
Capital Addition Purchase Commitments [Member]  
Recorded Unconditional Purchase Obligation us-gaap_RecordedUnconditionalPurchaseObligation $ 580,000,000
Common Stock [Member]  
Common Stock, New Shares, Issued clf_CommonStockNewSharesIssued 44,400,000
Common Stock, New Shares, Issued clf_CommonStockNewSharesIssued 63,300,000