Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share (Earnings Per Share Computation) (Detail)

v2.4.0.6
Earnings Per Share (Earnings Per Share Computation) (Detail) (USD $)
In Millions, except Share data in Thousands, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Earnings Per Share [Abstract]        
Net income from continuing operations attributable to Cliffs shareholders $ 87.8 $ 618.0 $ 713.9 $ 1,429.9
Income (loss) from discontinued operations (2.7) (16.8) 5.1 3.7
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 85.1 $ 601.2 $ 719.0 $ 1,433.6
Weighted average number of shares:        
Basic (in shares) 142,396 144,203 142,332 139,563
Employee stock plans (in shares) 499 786 448 758
Diluted (in shares) 142,895 144,989 142,780 140,321
Earnings Per Share, Basic [Abstract]        
Continuing operations (in usd per share) $ 0.62 $ 4.29 $ 5.02 $ 10.24
Discontinued operations (in usd per share) $ (0.02) $ (0.12) $ 0.04 $ 0.03
Earnings per common share attributable to Cliffs shareholders - Basic (in usd per share) $ 0.60 $ 4.17 $ 5.06 $ 10.27
Earnings Per Share, Diluted [Abstract]        
Continuing operations (in usd per share) $ 0.61 $ 4.27 $ 5.00 $ 10.19
Discontinued operations (in usd per share) $ (0.02) $ (0.12) $ 0.04 $ 0.03
Earnings per common share attributable to Cliffs shareholders - Diluted (in usd per share) $ 0.59 $ 4.15 $ 5.04 $ 10.22