Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

When an investment contract or contracts have a range of settlement dates, the latest settlement date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

When an investment contract or contracts have a range of settlement dates, the earliest settlement date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226016-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=d3e41678-113959

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- Definition

The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Derivative Instruments and Hedging Activities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) MMBTU MW t lb	Mar. 31, 2016 EUR (€) MMBTU MW t lb	Dec. 31, 2015 EUR (€) MMBTU MW t lb
Natural Gas [Member]
Derivative [Line Items]
Beginning Settlement Date	Apr. 01, 2016
Ending Settlement Date	Dec. 31, 2017
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (21.1)
Zinc [Member]
Derivative [Line Items]
Beginning Settlement Date	Apr. 01, 2016
Ending Settlement Date	Dec. 31, 2017
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (5.9)
Iron Ore [Member]
Derivative [Line Items]
Beginning Settlement Date	Apr. 01, 2016
Ending Settlement Date	Nov. 30, 2017
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (5.5)
Electricity [Member]
Derivative [Line Items]
Beginning Settlement Date	Apr. 01, 2016
Ending Settlement Date	Dec. 31, 2017
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (3.8)
Commodity Contract [Member] \| Nickel [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives \| lb	99,400	99,400	164,800
Commodity Contract [Member] \| Natural Gas [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives \| MMBTU	31,907,500	31,907,500	36,972,500
Commodity Contract [Member] \| Zinc [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives \| lb	41,634,300	41,634,300	54,173,800
Commodity Contract [Member] \| Iron Ore [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives \| t	2,260,000	2,260,000	2,795,000
Commodity Contract [Member] \| Electricity [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives \| MW	1,098,000	1,098,000	1,386,400
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount \| €		€ 32,125,000	€ 55,500,000
Other Current Assets [Member]
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 11.1