Annual report pursuant to Section 13 and 15(d)

SEGMENT REPORTING SEGMENT REPORTING (Revenue from External Customers by Products and Services) (Details)

v3.6.0.2
SEGMENT REPORTING SEGMENT REPORTING (Revenue from External Customers by Products and Services) (Details) - Sales Revenue, Net [Member] - Product Concentration Risk [Member]
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Revenue from External Customer [Line Items]      
Concentration Risk, Percentage 100.00% 100.00% 100.00%
Iron Ore Revenue [Member]      
Revenue from External Customer [Line Items]      
Concentration Risk, Percentage 91.00% 91.00% 92.00%
Freight and Venture Partners' Cost Reimbursements [Member]      
Revenue from External Customer [Line Items]      
Concentration Risk, Percentage 9.00% 9.00% 8.00%