Quarterly report pursuant to Section 13 or 15(d)

SHAREHOLDERS' EQUITY Schedule of Shareholders' Equity (Details)

v2.4.0.8
SHAREHOLDERS' EQUITY Schedule of Shareholders' Equity (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Jun. 30, 2014
Jun. 30, 2013
Dec. 31, 2013
Dec. 31, 2012
Stockholders' Equity Attributable to Parent $ 6,027.6   $ 6,027.6   $ 6,069.5  
Stockholders' Equity Attributable to Noncontrolling Interest 802.0   802.0   814.8  
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest 6,829.6 6,783.8 6,829.6 6,783.8 6,884.3 5,760.9
NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS 10.9 146.0 (59.4) 253.0    
INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST 3.6 (4.7) 3.2 9.1    
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest 14.5 141.3 (56.2) 262.1    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 45.8 (42.2) 33.3 69.0    
Other Comprehensive Income (Loss), Net of Tax 35.5 (187.1) 93.8 (181.7)    
OTHER COMPREHENSIVE INCOME ATTRIBUTABLE TO THE NONCONTROLLING INTEREST (0.6) (1.1) (1.1) (2.3)    
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest     37.6 80.4    
Stock and Other Incentive Plans     (3.1) 3.7    
Common and preferred share dividends     (72.1) (68.9)    
Undistributed Gains To Noncontrolling Interest     (17.1)      
Capital Contribution By Noncontrolling Interest       13.0    
Cliffs Shareholders Equity [Member]
            
Stockholders' Equity Attributable to Parent 6,027.6 5,631.2 6,027.6 5,631.2 6,069.5 4,632.7
NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS     (59.4) 253.0    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent     92.7 (184.0)    
Comprehensive Income (Loss), Net of Tax, Attributable to Parent     33.3 69.0    
Stock and Other Incentive Plans     (3.1) 3.7    
Common and preferred share dividends     (72.1) (68.9)    
Undistributed Gains To Noncontrolling Interest     0      
Capital Contribution By Noncontrolling Interest       0    
Noncontrolling Interest [Member]
            
Stockholders' Equity Attributable to Noncontrolling Interest 802.0 1,152.6 802.0 1,152.6 814.8 1,128.2
INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST     3.2 9.1    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest     1.1 2.3    
OTHER COMPREHENSIVE INCOME ATTRIBUTABLE TO THE NONCONTROLLING INTEREST     4.3 11.4    
Stock and Other Incentive Plans     0 0    
Common and preferred share dividends     0 0    
Undistributed Gains To Noncontrolling Interest     (17.1)      
Capital Contribution By Noncontrolling Interest       13.0    
Common Stock [Member]
            
Stock Issued During Period, Value, New Issues       263.4    
Common Stock [Member] | Cliffs Shareholders Equity [Member]
            
Stock Issued During Period, Value, New Issues       263.4    
Common Stock [Member] | Noncontrolling Interest [Member]
            
Stock Issued During Period, Value, New Issues       0    
Preferred Class A [Member]
            
Stock Issued During Period, Value, New Issues       731.3    
Preferred Class A [Member] | Cliffs Shareholders Equity [Member]
            
Stock Issued During Period, Value, New Issues       731.3    
Preferred Class A [Member] | Noncontrolling Interest [Member]
            
Stock Issued During Period, Value, New Issues       $ 0