Annual report pursuant to Section 13 and 15(d)

DEBT AND CREDIT FACILITIES - Other Financing Arrangements (Details)

v3.20.4
DEBT AND CREDIT FACILITIES - Other Financing Arrangements (Details)
$ in Millions
Dec. 31, 2020
USD ($)
Debt Instrument [Line Items]  
Debt Instrument, Par Value $ 5,595
AK Steel [Member]  
Debt Instrument [Line Items]  
Debt Instrument, Par Value 132
Cleveland-Cliffs Inc. [Member] | EDC Revolving Credit Facility  
Debt Instrument [Line Items]  
Line of Credit Facility, Maximum Borrowing Capacity 40
Credit facility, amount outstanding 18
Unsecured Industrial Revenue Bonds | AK Steel [Member]  
Debt Instrument [Line Items]  
Debt Instrument, Par Value $ 66
Debt, Weighted Average Interest Rate 6.86%
Secured Industrial Revenue Bonds | AK Steel [Member]  
Debt Instrument [Line Items]  
Debt Instrument, Par Value $ 26