Segment Information, Net Sales by Product Categories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net Sales:
Net sales	$ 335.1	$ 337.4
Aero/HS products
Net Sales:
Net sales	163.6	179.6
GE products
Net Sales:
Net sales	112.2	105.8
Automotive Extrusions
Net Sales:
Net sales	40.8	30.8
Other products
Net Sales:
Net sales	$ 18.5	$ 21.2