XML 77 R56.htm IDEA: XBRL DOCUMENT v3.10.0.1
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Revenue Reimbursement) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Freight and Reimbursement Revenue $ 160.1 $ 221.4 $ 174.8
Mining and Pelletizing [Member]      
Freight and Reimbursement Revenue 160.1 221.4 174.8
Mining and Pelletizing [Member] | Freight Revenue [Member]      
Freight and Reimbursement Revenue 160.1 166.7 106.8
Mining and Pelletizing [Member] | Co-venturer [Member]      
Freight and Reimbursement Revenue 0.0 $ 54.7 $ 68.0
Calculated under Revenue Guidance in Effect before Topic 606 [Member]      
Freight and Reimbursement Revenue $ 156.2