Investment in Equity Investees (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended							30 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Cost of Sales [Member]	Mar. 31, 2013 Cost of Sales [Member]	Mar. 31, 2014 Other Income (Expense) [Member]	Mar. 31, 2013 Other Income (Expense) [Member]	Mar. 31, 2014 Combined Metals of Chicago, LLC [Member]	Mar. 31, 2014 Magnetation LLC [Member]	Oct. 04, 2011 Magnetation LLC [Member]	Mar. 31, 2014 Rockport Roll Shop LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage							40.00%	49.90%		50.00%
Income (Loss) from Equity Method Investments			$ 2.2	$ 1.7	$ (1.3)	$ 2.3
Revenue	72.4	69.5
Gross profit	24.5	25.2
Net income	5.5	11.1
Other Commitment								100.0	297.5
Payments to Acquire Equity Method Investments								197.5
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity								$ 95.2