Amount of curtailment.

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- Definition

Charge related to European commission announcement.

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- Definition

Due from third parties.

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No definition available.

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- Definition

Establishment reserves.

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No definition available.

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- Definition

Loss contingency, recovery from third party.

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Number of installments.

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No definition available.

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- Definition

Number of plants.

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No definition available.

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- Definition

Payment for litigation settlement installment amount.

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No definition available.

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- Definition

Period Of Operation Under Power Supply Structure

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No definition available.

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- Definition

Write-off of receivable.

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No definition available.

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- Definition

Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Name Accounting Standards Codification

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-Section S99

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-Subparagraph (SX 210.5-02.25)

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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.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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The estimated maximum amount of possible loss from the contingency.

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The estimated minimum amount of possible loss from the contingency.

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- Definition

Amount of receivable related to a loss contingency accrual. For example, an insurance recovery receivable.

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-Name Accounting Standards Codification

-Topic 460

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-Section 50

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- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (g)

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Cumulative provision for contract losses not offset against related costs accumulated on the balance sheet.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

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Contingencies and Commitments - Additional Information (Detail)		1 Months Ended			9 Months Ended	15 Months Ended
	Nov. 19, 2009 EUR (€) Plant	Jul. 31, 2014 Plant	Jun. 30, 2012 EUR (€) Installment	Jun. 30, 2012 USD ($)	Sep. 30, 2015 EUR (€)	Dec. 31, 2013 EUR (€)	Dec. 31, 2013 USD ($)	Sep. 30, 2015 USD ($)	Jun. 05, 2015 USD ($)	Feb. 21, 2013 EUR (€)	Feb. 21, 2013 USD ($)	Dec. 31, 2012 t	Jun. 30, 2012 USD ($) Installment	Mar. 26, 2012 EUR (€)	Mar. 26, 2012 USD ($)	Sep. 30, 2010 t	Nov. 19, 2009 USD ($)
Loss Contingencies [Line Items]
Claimed obligation, minimum			€ 159,000,000										$ 178,000,000
Claimed obligation, maximum			303,000,000										340,000,000
Management estimate for maximum exposure from class action														€ 85,000,000	$ 110,000,000
Number of smelters \| Plant		2
Recovery amount			303,000,000	$ 375,000,000
Reduction in recovery amount			53,000,000										$ 65,000,000
Payments to Italian Government			€ 250,000,000	$ 310,000,000
Payments to Italian Government, installments amount						€ 50,000,000	$ 69,000,000
Number of installments, litigation payment \| Installment			5										5
Litigation reserve			€ 159,000,000										$ 178,000,000
Amount of curtailment, metric-tons-per-year \| t																44,000
Minimum [Member]
Loss Contingencies [Line Items]
Provision for contract losses											$ 0
Maximum [Member]
Loss Contingencies [Line Items]
Provision for contract losses										€ 76,000,000	97,000,000
Italy [Member]
Loss Contingencies [Line Items]
Number of years operating under a power supply structure					10 years
Charge related to European Commission announcement	€ 173,000,000																$ 250,000,000
Number of smelters \| Plant	2
Write-off of receivable	€ 14,000,000																20,000,000
Establishment reserve	€ 159,000,000																$ 230,000,000
Portovesme [Member]
Loss Contingencies [Line Items]
Amount of curtailment, metric-tons-per-year \| t												150,000
Alcoa [Member]
Loss Contingencies [Line Items]
Reduction in recovery amount					€ 53,000,000			$ 59,000,000
Noncurrent asset					€ 91,000,000			$ 103,000,000
Alcoa Trasformazioni [Member]
Loss Contingencies [Line Items]
Management estimate for maximum exposure from class action										€ 76,000,000	$ 97,000,000
Lockheed Martin [Member] \| Pending Litigation [Member]
Loss Contingencies [Line Items]
Claimed obligation, minimum									$ 0
Claimed obligation, maximum									$ 76,000,000