Quarterly report pursuant to Section 13 or 15(d)

DEBT AND CREDIT FACILITIES - Debt Redemption (Details)

v3.21.1
DEBT AND CREDIT FACILITIES - Debt Redemption (Details) - Cleveland-Cliffs Inc.
3 Months Ended
Mar. 31, 2021
4.625% 2029 Senior Notes  
Debt Instrument, Redemption [Line Items]  
Repurchase price if triggering event occurs 101.00%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 104.625%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period One  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 100.00%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Two  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 102.313%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Three  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 101.156%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Four  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 100.00%
4.875% 2031 Senior Notes  
Debt Instrument, Redemption [Line Items]  
Repurchase price if triggering event occurs 101.00%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 104.875%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period One  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 100.00%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Two  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 102.438%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Three  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 101.625%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Four  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 100.813%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Five  
Debt Instrument, Redemption [Line Items]  
Debt Instrument, Redemption Price, Percentage 100.00%