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Subsequent Events - Additional Information (Detail) - Major business combination [member] - EUR (€) € in Millions | Feb. 20, 2019 | Jan. 10, 2019
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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 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 -URIDate 2018-03-16 + Details
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