Annual report pursuant to Section 13 and 15(d)

DEBT AND CREDIT FACILITIES - Schedule Of Long-Term Debt (Details)

v3.20.4
DEBT AND CREDIT FACILITIES - Schedule Of Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Jun. 19, 2020
Apr. 24, 2020
Apr. 17, 2020
Mar. 16, 2020
Mar. 13, 2020
Dec. 31, 2019
Debt Instrument [Line Items]              
Debt Instrument, Par Value $ 5,595            
Total Debt 5,424            
Long-term Debt, Current Maturities 34            
Long-term debt $ 5,390           $ 2,114
Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 3.25%            
Cleveland-Cliffs Inc. [Member] | ABL Facility [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 2.15%            
Debt Instrument, Par Value             450
Line of Credit Facility, Maximum Borrowing Capacity $ 3,500            
Credit facility, amount outstanding 1,510           $ 0
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            
AK Steel [Member]              
Debt Instrument [Line Items]              
Debt Instrument, Par Value 132            
AK Steel [Member] | Industrial Revenue Bonds [Member]              
Debt Instrument [Line Items]              
Debt Instrument, Par Value 92            
Unamortized Debt Issuance Expense 0            
Total Debt 94            
Debt Instrument, Unamortized Premium $ 2            
4.875% 2024 Senior Secured Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 5.00%           5.00%
Debt Instrument, Par Value $ 395           $ 400
Unamortized Debt Issuance Expense (3)           (5)
Debt Instrument, Unamortized Discount 1           2
Total Debt $ 391           $ 393
9.875% 2025 Senior Secured Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 10.57%            
Debt Instrument, Par Value $ 955   $ 555 $ 400      
Unamortized Debt Issuance Expense (8)            
Debt Instrument, Unamortized Discount 25            
Total Debt $ 922            
6.75% 2026 Senior Secured Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.99%            
Debt Instrument, Par Value $ 845 $ 120       $ 725  
Unamortized Debt Issuance Expense (20)            
Debt Instrument, Unamortized Discount 9            
Total Debt $ 816            
7.625% 2021 AK Senior Notes | AK Steel [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 7.33%            
Debt Instrument, Par Value $ 34            
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 0            
Total Debt $ 34            
7.50% 2023 AK Senior Notes [Member] | AK Steel [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.17%            
Debt Instrument, Par Value $ 13            
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 0            
Total Debt $ 13            
6.375% 2025 Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 8.11%            
Debt Instrument, Par Value $ 64       $ 232    
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 4            
Total Debt $ 60            
6.375% 2025 AK Senior Notes | AK Steel [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 8.11%            
Debt Instrument, Par Value $ 29            
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 2            
Total Debt $ 27            
1.50% 2025 Convertible Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.26%           6.26%
Debt Instrument, Par Value $ 296           $ 316
Unamortized Debt Issuance Expense (4)           (4)
Debt Instrument, Unamortized Discount 49           65
Total Debt $ 243           $ 247
5.75% 2025 Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.01%           6.01%
Debt Instrument, Par Value $ 396           $ 473
Unamortized Debt Issuance Expense (3)           (3)
Debt Instrument, Unamortized Discount 4           6
Total Debt $ 389           $ 464
7.00% 2027 Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 9.24%            
Debt Instrument, Par Value $ 73       $ 335    
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 8            
Total Debt $ 65            
7.00% 2027 AK Senior Notes | AK Steel [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 9.24%            
Debt Instrument, Par Value $ 56            
Unamortized Debt Issuance Expense 0            
Debt Instrument, Unamortized Discount 6            
Total Debt $ 50            
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.49%           6.49%
Debt Instrument, Par Value $ 556           $ 750
Unamortized Debt Issuance Expense (4)           (6)
Debt Instrument, Unamortized Discount 18           27
Total Debt $ 534           $ 717
6.25% 2040 Senior Notes | Cleveland-Cliffs Inc. [Member]              
Debt Instrument [Line Items]              
Imputed interest rate 6.34%           6.34%
Debt Instrument, Par Value $ 263           $ 298
Unamortized Debt Issuance Expense (2)           (2)
Debt Instrument, Unamortized Discount 3           3
Total Debt $ 258           $ 293