GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Schedule Of Goodwill) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Beginning Balance	$ 2.0	$ 74.5
Impairment	0.0	(73.5)
Impact of foreign currency translation	0.0	1.0
Ending Balance	2.0	2.0
Accumulated goodwill impairment loss	(73.5)	(73.5)
U.S. Iron Ore [Member]
Goodwill [Roll Forward]
Beginning Balance	2.0	2.0
Impairment	0.0	0.0
Impact of foreign currency translation	0.0	0.0
Ending Balance	2.0	2.0
Accumulated goodwill impairment loss	0.0	0.0
Asia Pacific Iron Ore [Member]
Goodwill [Roll Forward]
Beginning Balance	0.0	72.5
Impairment	0.0	(73.5)
Impact of foreign currency translation	0.0	1.0
Ending Balance	0.0	0.0
Accumulated goodwill impairment loss	$ (73.5)	$ (73.5)