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Property Plant and Equipment - Additional Information (Detail) - Muscle shoals [member] € in Millions	12 Months Ended
	Dec. 31, 2015 EUR (€)
Disclosure of detailed information about property, plant and equipment [line items]
Discount rate applied to cash flows projection description	11.00%
Growth rate for extrapolate the cash flows beyond the projection period	0.00%
Recoverable value lower than the carrying value	€ 400
Impairment charge	400
Constellium Valais cash-generating units [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment charge	€ 49

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Amount by which units recoverable lower than carrying amount.

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The discount rate applied to cash flow projections for a cash-generating unit (group of units). [Refer: Cash-generating units [member]]

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

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