Quarterly report pursuant to Section 13 or 15(d)

ACQUISITIONS - Narrative (Details)

v3.21.2
ACQUISITIONS - Narrative (Details)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Dec. 09, 2020
USD ($)
Mar. 13, 2020
USD ($)
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Dec. 31, 2020
business
Business Acquisition [Line Items]              
Number of businesses acquired | business             2
Acquisition-related costs     $ (4) $ (7) $ (18) $ (68)  
Other Operating Income (Expense)              
Business Acquisition [Line Items]              
Equity interest loss         (18)    
ArcelorMittal USA              
Business Acquisition [Line Items]              
Acquisition-related costs     $ (1)   $ (3)    
Consideration transferred $ 2,604            
AK Steel              
Business Acquisition [Line Items]              
Exchange ratio   0.400          
Consideration transferred   $ 1,535