Investment in Equity Investees (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended	33 Months Ended			1 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Cost of Sales [Member]	Jun. 30, 2013 Cost of Sales [Member]	Jun. 30, 2014 Cost of Sales [Member]	Jun. 30, 2013 Cost of Sales [Member]	Jun. 30, 2014 Other Income (Expense) [Member]	Jun. 30, 2013 Other Income (Expense) [Member]	Jun. 30, 2014 Other Income (Expense) [Member]	Jun. 30, 2013 Other Income (Expense) [Member]	Jun. 30, 2014 Combined Metals of Chicago, LLC [Member]	Jun. 30, 2014 Magnetation LLC [Member]	Jun. 30, 2014 Magnetation LLC [Member]	Oct. 04, 2011 Magnetation LLC [Member]	Jun. 30, 2014 Rockport Roll Shop LLC [Member]	Jul. 31, 2014 Subsequent Event [Member] Magnetation LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage													40.00%	49.90%	49.90%		50.00%
Income (Loss) from Equity Method Investments					$ 2.9	$ 2.4	$ 5.1	$ 4.1	$ (2.5)	$ (1.2)	$ (3.8)	$ 1.1
Revenue	85.3	74.3	157.7	143.9
Gross profit	23.6	26.4	48.1	51.5
Net income	5.0	5.4	10.5	16.5
Other Commitment																297.5		10.0
Payments to Acquire Equity Method Investments														45.0	242.5			45.0
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity														$ 106.9	$ 106.9