Quarterly report pursuant to Section 13 or 15(d)

SHAREHOLDERS' EQUITY Schedule of Shareholders' Equity (Details)

v3.3.0.814
SHAREHOLDERS' EQUITY Schedule of Shareholders' Equity (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Dec. 31, 2014
Dec. 31, 2013
Stockholders' Equity Attributable to Parent $ (1,932.0)   $ (1,932.0)   $ (1,431.3)  
Stockholders' Equity Attributable to Noncontrolling Interest 172.5   172.5   (303.0)  
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest (1,759.5) $ (177.3) (1,759.5) $ (177.3) (1,734.3) $ 6,884.3
NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS 10.6 (5,879.6) (689.0) (5,939.0)    
INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST (4.6) (1,007.6) (1.5) (1,004.4)    
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest 6.0 (6,887.2) (690.5) (6,943.4)    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 14.4 (5,960.8) (468.3) (5,927.5)    
Other Comprehensive Income (Loss), Net of Tax 4.5 (80.7) 211.4 13.1    
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST (0.7) (0.5) 9.3 (1.6)    
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest     (479.1) (6,930.3)    
Deconsolidation, Gain (Loss), Amount     (528.2)      
Stock and Other Incentive Plans     6.0 (3.4)    
Preferred share dividends     (38.4) (107.9)    
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders     (40.7)      
Undistributed Gains To Noncontrolling Interest     (1.2) (20.0)    
Cliffs Shareholders Equity [Member]            
Stockholders' Equity Attributable to Parent (1,932.0) 30.7 (1,932.0) 30.7 (1,431.3) 6,069.5
NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS     (689.0) (5,939.0)    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent     220.7 11.5    
Comprehensive Income (Loss), Net of Tax, Attributable to Parent     (468.3) (5,927.5)    
Deconsolidation, Gain (Loss), Amount     0.0      
Stock and Other Incentive Plans     6.0 (3.4)    
Preferred share dividends     (38.4) (107.9)    
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders     0.0      
Undistributed Gains To Noncontrolling Interest     0.0 0.0    
Noncontrolling Interest [Member]            
Stockholders' Equity Attributable to Noncontrolling Interest $ 172.5 $ (208.0) 172.5 (208.0) $ (303.0) $ 814.8
INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST     (1.5) (1,004.4)    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest     (9.3) 1.6    
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST     (10.8) (1,002.8)    
Deconsolidation, Gain (Loss), Amount     (528.2)      
Stock and Other Incentive Plans     0.0 0.0    
Preferred share dividends     0.0 0.0    
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders     (40.7)      
Undistributed Gains To Noncontrolling Interest     $ (1.2) $ (20.0)