Quarterly report pursuant to Section 13 or 15(d)

SEGMENT REPORTING - Segment Assets (Details)

v3.20.2
SEGMENT REPORTING - Segment Assets (Details) - USD ($)
$ in Millions
Jun. 30, 2020
Dec. 31, 2019
Segment Reporting Information [Line Items]    
Total assets $ 8,490.7 $ 3,503.8
Corporate and Other [Member]    
Segment Reporting Information [Line Items]    
Total assets 604.0 947.1
Operating Segments [Member]    
Segment Reporting Information [Line Items]    
Total assets 7,886.7 2,556.7
Operating Segments [Member] | Steel and Manufacturing [Member]    
Segment Reporting Information [Line Items]    
Total assets 6,201.6 913.6
Operating Segments [Member] | Mining and Pelletizing [Member]    
Segment Reporting Information [Line Items]    
Total assets $ 1,685.1 $ 1,643.1