Annual report pursuant to Section 13 and 15(d)

EARNINGS PER SHARE - Earnings Per Share Computation (Details)

v3.20.4
EARNINGS PER SHARE - Earnings Per Share Computation (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Earnings Per Share [Abstract]      
Income (loss) from continuing operations $ (82.0) $ 295.0 $ 1,040.0
Net Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest 41.0 0.0 0.0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent (123.0) 295.0 1,040.0
Income (loss) from discontinued operations, net of tax 1.0 (2.0) 88.0
Net Income (Loss) Attributable to Parent $ (122.0) $ 293.0 $ 1,128.0
Weighted average number of shares:      
Basic 379.0 277.0 297.0
Convertible senior notes 0.0 4.0 3.0
Employee stock plans 0.0 3.0 4.0
Diluted 379.0 284.0 304.0
Earnings (loss) per common share attributable to Cliffs common shareholders - basic:      
Continuing operations $ (0.32) $ 1.07 $ 3.50
Discontinued operations 0 (0.01) 0.30
Earnings (loss) per common share attributable to Cliffs common shareholders - basic (0.32) 1.06 3.80
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted:      
Continuing operations (0.32) 1.04 3.42
Discontinued operations 0 (0.01) 0.29
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted $ (0.32) $ 1.03 $ 3.71