Employee Benefits, Net Periodic Benefit Costs and Charges Relating To Other Benefit Plans(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Periodic Benefit Costs and Charges Relating to Other Benefit Plans [Line Items]
Non-cash net periodic benefit costs (income)	$ (11.5)	$ (5.7)	$ 5.1
Deferred compensation plan	0.9	0.2	1.3
Defined contribution plans	7.6	7.1	6.5
Total	(3.0)	1.6	13.1
Fabricated Products
Net Periodic Benefit Costs and Charges Relating to Other Benefit Plans [Line Items]
Total	7.4	6.4	6.4
All Other
Net Periodic Benefit Costs and Charges Relating to Other Benefit Plans [Line Items]
Total	(10.4)	(4.8)	6.7
Canadian pension plan
Net Periodic Benefit Costs and Charges Relating to Other Benefit Plans [Line Items]
Non-cash net periodic benefit costs (income)	0.4	0.3	0.2
VEBAs
Net Periodic Benefit Costs and Charges Relating to Other Benefit Plans [Line Items]
Non-cash net periodic benefit costs (income)	$ (11.9)	$ (6.0)	$ 5.1