BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details)	3 Months Ended							3 Months Ended	12 Months Ended			12 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Empire [Member]	Mar. 31, 2013 Black Label And Black Thor Chromite Deposits [Member]	Mar. 31, 2013 Big Daddy Chromite Deposit [Member]	Mar. 31, 2013 CLCC [Member]	Mar. 31, 2013 Wabush [Member]	Mar. 31, 2013 Bloom Lake [Member]	Mar. 31, 2013 Asia Pacific Iron Ore [Member] Cockatoo [Member] USD ($)	Dec. 31, 2012 Asia Pacific Iron Ore [Member] Cockatoo [Member] AUD	Mar. 31, 2013 Equity Method Investments [Member] Amapa [Member]	Mar. 31, 2013 Other Liabilities [Member] Cockatoo [Member]	Dec. 31, 2012 Sonoma [Member] Asia Pacific Coal [Member] AUD	Jul. 10, 2012 Sonoma [Member] Asia Pacific Coal [Member]
Related Party Transaction [Line Items]
Current Fiscal Year End Date	--12-31
Ownership Interest		79.00%	100.00%	70.00%	100.00%	100.00%	75.00%						45.00%
Ownership interest, equity method investment										30.00%	50.00%
Total percentage of Amapa sold										100.00%
Proceeds from sale of economic interest (in AUD)									4.00			141,000,000
Estimated rehabilitation costs								$ 24,000,000