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Subsequent Events - Additional Information (Detail) - Major business combination [member] - EUR (€) € in Millions	Feb. 20, 2019	Jan. 10, 2019
Top of range [member] | Pan US ABL Facility [member]
Disclosure of non-adjusting events after reporting period [line items]
Increase in commitments	€ 350
Constellium-Bowling Green [member]
Disclosure of non-adjusting events after reporting period [line items]
Percentage of voting equity interest acquired		49.00%

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- Definition

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+ References

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- Definition

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+ References

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- Definition

The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_c&doctype=Appendix&seq=2
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