Quarterly report pursuant to Section 13 or 15(d)

EARNINGS PER SHARE (Earnings Per Share Computation) (Details)

v3.10.0.1
EARNINGS PER SHARE (Earnings Per Share Computation) (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Earnings Per Share [Abstract]        
Income from Continuing Operations $ 229.4 $ 83.8 $ 216.0 $ 5.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST 0.0 1.7 0.0 3.4
Net Income from Continuing Operations Attributable to Cliffs Shareholders 229.4 85.5 216.0 8.7
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX (64.3) (53.7) (135.2) (5.0)
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 165.1 $ 31.8 $ 80.8 $ 3.7
Weighted Average Number of Shares:        
Basic 297,618 296,100 297,442 280,617
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements 3,700 4,600 3,700 4,600
Diluted 301,275 300,700 301,143 285,247
Income (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic:        
Continuing operations (in dollars per share) $ 0.77 $ 0.28 $ 0.73 $ 0.03
Discontinued operations (in dollars per share) (0.22) (0.18) (0.46) (0.01)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share) 0.55 0.10 0.27 0.02
Income (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted:        
Continuing operations (in dollars per share) 0.76 0.28 0.72 0.03
Discontinued operations (in dollars per share) (0.21) (0.18) (0.45) (0.02)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share) $ 0.55 $ 0.10 $ 0.27 $ 0.01