Business Segments (Details) $ in Millions	3 Months Ended
Mar. 31, 2016 USD ($) segment	Mar. 31, 2015 USD ($)
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Number of business segments \| segment	2
Segment Reporting Information [Line Items]
Sales	$ 757.5	$ 1,125.5
Operating profit (loss):	(80.5)	66.1
LIFO and net realizable value reserves	0.0	0.0
Corporate expenses	(11.0)	(12.8)
Closed company and other expenses	(3.5)	(6.0)
Restructuring charges	(9.0)	0.0
Interest expense, net	(28.3)	(26.7)
Income (loss) before income tax provision (benefit)	(132.3)	20.6
Restructuring Reserve	14.0
High Performance Materials & Components
Segment Reporting Information [Line Items]
Operating profit (loss):	$ 29.1	72.9
Flat Rolled Products
Segment Reporting Information [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated	250
Operating profit (loss):	$ (109.6)	(6.8)
Operating Segments
Segment Reporting Information [Line Items]
Sales	789.1	1,169.6
Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	507.9	564.9
Operating Segments \| Flat Rolled Products
Segment Reporting Information [Line Items]
Sales	281.2	604.7
Internal Customers \| Operating Segments
Segment Reporting Information [Line Items]
Sales	31.6	44.1
Internal Customers \| Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	14.9	22.1
Internal Customers \| Operating Segments \| Flat Rolled Products
Segment Reporting Information [Line Items]
Sales	16.7	22.0
External Customers \| Operating Segments
Segment Reporting Information [Line Items]
Sales	757.5	1,125.5
External Customers \| Operating Segments \| High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales	493.0	542.8
External Customers \| Operating Segments \| Flat Rolled Products
Segment Reporting Information [Line Items]
Sales	$ 264.5	$ 582.7

corporate office expenses not allocable to business segments

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Restructuring and other charges

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Staff Accounting Bulletin (SAB)
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(a))
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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