Quarterly report [Sections 13 or 15(d)]

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details)

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BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details) - Nov. 01, 2024 - Stelco Holdings Inc
$ / shares
shares
$ / shares
Business Acquisition [Line Items]    
Price per share (in dollars per share) | (per share) $ 60.00 $ 13.27
Shares of Cliffs common shares issued to Stelco Holdings stockholders (in shares) | shares 25,862,021  
Stelco Holdings Inc    
Business Acquisition [Line Items]    
Price per share (in dollars per share) | $ / shares $ 60.00