BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Investments In Unconsolidated Ventures) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Investment	$ 68.7		$ 108.4
Amapa [Member] | Investments In Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest, equity method investment	30.00%
Total percentage of Amapa sold	100.00%
Investment	29.4		101.9
Cockatoo [Member] | Other Liabilities [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest, equity method investment	0.00%	[1]	50.00%	[1]
Investment			(25.3)	[1]
Hibbing [Member] | Investments In Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Investment	6.4	[2]
Hibbing [Member] | Other Liabilities [Member]
Schedule of Equity Method Investments [Line Items]
Investment			(2.1)	[2]
Other Equity Investees [Member] | Investments In Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Investment	$ 32.9		$ 33.9
Hibbing [Member] | Hibbing [Member] | Investments In Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest, equity method investment	23.00%	[2]

[1] At December 31, 2012 our ownership interest percentage for Cockatoo was 50 percent.

[2] At December 31, 2012 the classification for Hibbing was Other liabilities.