Quarterly report [Sections 13 or 15(d)]

EARNINGS PER SHARE - Earnings Per Share Computation (Details)

v3.26.1
EARNINGS PER SHARE - Earnings Per Share Computation (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Earnings Per Share [Abstract]    
Loss from continuing operations $ (226) $ (486)
Net income attributable to noncontrolling interests (8) (12)
Loss from continuing operations (234) (498)
Loss from discontinued operations, net of tax (3) 0
Net loss $ (237) $ (498)
Weighted average number of shares:    
Basic (in shares) 570 495
Employee stock plans (in shares) 0 0
Diluted (in shares) 570 495
Earnings Per Share, Basic [Abstract]    
Continuing operations $ (0.42) $ (1.01)
Discontinued operations 0 0
Earnings Per Share, Basic, Total (0.42) (1.01)
Loss per common share attributable to Cliffs shareholders - diluted    
Continuing operations (0.42) (1.01)
Discontinued operations 0 0
Earnings Per Share, Diluted, Total $ (0.42) $ (1.01)