v3.26.3
EARNINGS PER SHARE - Earnings Per Share Computation (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Earnings Per Share [Abstract]        
Income (loss) from continuing operations $ 167 $ (231) $ (191) $ (1,190)
Net income attributable to noncontrolling interests (13) (17) (32) (42)
Income (loss) from continuing operations 154 (248) (223) (1,232)
Loss from discontinued operations, net of tax (2) (3) (7) (3)
Net income (loss) $ 152 $ (251) $ (230) $ (1,235)
Weighted average number of shares:        
Basic (in shares) 572 495 571 495
Employee stock plans (in shares) 2 0 0 0
Diluted (in shares) 574 495 571 495
Earnings Per Share, Basic [Abstract]        
Continuing operations $ 0.27 $ (0.51) $ (0.39) $ (2.49)
Discontinued operations 0 0 (0.01) 0
Earnings Per Share, Basic, Total 0.27 (0.51) (0.40) (2.49)
Earnings (loss) per common share attributable to Cliffs shareholders - diluted        
Continuing operations 0.26 (0.51) (0.39) (2.49)
Discontinued operations 0 0 (0.01) 0
Earnings Per Share, Diluted, Total $ 0.26 $ (0.51) $ (0.40) $ (2.49)