Annual report pursuant to Section 13 and 15(d)

Acquisitions And Other Investments (Spider Purchase Price Allocation) (Details)

v2.4.0.6
Acquisitions And Other Investments (Spider Purchase Price Allocation) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2010
Spider [Member]
Scenario, Previously Reported [Member]
Dec. 31, 2010
Spider [Member]
Scenario, Adjustment [Member]
Jul. 06, 2010
Spider [Member]
Scenario, Adjustment [Member]
Dec. 31, 2010
Spider [Member]
Scenario, Change [Member]
Business Acquisition [Line Items]            
Cash     $ 56.9 $ 56.9 $ 56.9  
Fair value of total consideration transferred     56.9 56.9    
Fair value of Cliffs' ownership interest in subsidiary held prior to acquisition of remaining interest     4.9 4.9    
Total net assets acquired   1.7 61.8 61.8    
Cash     9.0 9.0    
Other current assets     4.5 4.5    
Mineral rights     31.0 35.3   4.3
Total identifiable assets acquired     44.5 48.8   4.3
Other current liabilities     (5.2) (5.2)    
Long-term deferred tax liabilities (1,041.8)   (2.7) (5.1)   (2.4)
Total identifiable liabilities assumed     (7.9) (10.3)   (2.4)
Total identifiable net assets acquired     36.6 38.5   1.9
Goodwill     77.1 75.2   (1.9)
Noncontrolling interest in subsidiary (1,075.4)   (51.9) (51.9)    
Total net assets acquired   $ 1.7 $ 61.8 $ 61.8