Quarterly report [Sections 13 or 15(d)]

EARNINGS PER SHARE - Earnings Per Share Computation (Details)

v3.25.2
EARNINGS PER SHARE - Earnings Per Share Computation (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Earnings Per Share [Abstract]        
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest $ (470) $ 9 $ (953) $ (44)
Net income attributable to noncontrolling interests (13) (7) (25) (21)
Net income (loss) attributable to Cliffs shareholders $ (483) $ 2 $ (978) $ (65)
Weighted average number of shares:        
Basic (in shares) 495 473 495 483
Employee stock plans (in shares) 0 1 0 0
Diluted (in shares) 495 474 495 483
Earnings (loss) per common share attributable to Cliffs shareholders:        
Income (Loss) from Continuing Operations, Per Basic Share $ (0.97) $ 0.00 $ (1.97) $ (0.13)
Earnings Per Share, Diluted [Abstract]        
Continuing operations (in dollars per share) $ (0.97) $ 0.00 $ (1.97) $ (0.13)