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Subsidiaries and Operating Segments - Summary of Group's Affiliates are Included in Consolidated Financial Statements (Detail) | 12 Months Ended
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Dec. 31, 2017
Cross operating segment [member] | Constellium Singen GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
Cross operating segment [member] | Constellium Valais S.A. [member] |
Disclosure of subsidiaries [line items] |
Country | Switzerland
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Automotive USA, LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Engley (Changchun) Automotive Structures Co Ltd. [member] |
Disclosure of subsidiaries [line items] |
Country | China
Percentage Group Interest | 54.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions Decin S.r.o. [member] |
Disclosure of subsidiaries [line items] |
Country | Czech Republic
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions Deutschland GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions Landau GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions Burg GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions France S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Extrusions Levice S.r.o. [member] |
Disclosure of subsidiaries [line items] |
Country | Slovakia
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Automotive Mexico, S. DE R.L. DE C.V. [member] |
Disclosure of subsidiaries [line items] |
Country | Mexico
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Constellium Automotive Mexico Trading, S. DE R.L. DE C.V [member] |
Disclosure of subsidiaries [line items] |
Country | Mexico
Percentage Group Interest | 100.00%
Consolidation Method | Full
AS&I [member] | Astrex Inc [member] |
Disclosure of subsidiaries [line items] |
Country | Canada
Percentage Group Interest | 50.00%
Consolidation Method | Full
AS&I [member] | Constellium Automotive Zilina S.r.o. [member] |
Disclosure of subsidiaries [line items] |
Country | Slovakia
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Issoire [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Montreuil Juigne [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium China [member] |
Disclosure of subsidiaries [line items] |
Country | China
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Italy S.p.A [member] |
Disclosure of subsidiaries [line items] |
Country | Italy
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Japan KK [member] |
Disclosure of subsidiaries [line items] |
Country | Japan
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Rolled Products Ravenswood, LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Southeast Asia PTE LTD [member] |
Disclosure of subsidiaries [line items] |
Country | Singapore
Percentage Group Interest | 100.00%
Consolidation Method | Full
A&T [member] | Constellium Ussel S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium Deutschland GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium Rolled Products Singen GmbH KG [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium Property and Equipment Company LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium Neuf Brisach [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Wise Metals Group LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Wise Alloys, LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Wise Alloys Funding LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Wise Alloys Funding II LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Listerhill total maintenance cetter LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium Metal Procurement LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
P&ARP [member] | Constellium-UACJ ABS LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 51.00%
Consolidation Method | Equity
P&ARP [member] | Rhenaroll [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 50.00%
Consolidation Method | Equity
Holdings & Corporate [member] | C-TEC Constellium Technology Center [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Finance S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium France III [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium France Holdco S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium International [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Paris S.A.S [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Germany Holdco GmbH & Co. KG [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Germany Verwaltungs GmbH [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Holdco II B.V. [member] |
Disclosure of subsidiaries [line items] |
Country | Netherlands
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium UK Limited [member] |
Disclosure of subsidiaries [line items] |
Country | United Kingdom
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium U.S. Holdings I, LLC [member] |
Disclosure of subsidiaries [line items] |
Country | U.S.
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Switzerland AG [member] |
Disclosure of subsidiaries [line items] |
Country | Switzerland
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium W S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Constellium Treuhand UG [member] |
Disclosure of subsidiaries [line items] |
Country | Germany
Percentage Group Interest | 100.00%
Consolidation Method | Full
Holdings & Corporate [member] | Engineered Products International S.A.S. [member] |
Disclosure of subsidiaries [line items] |
Country | France
Percentage Group Interest | 100.00%
Consolidation Method | Full

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