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FINANCIAL INSTRUMENTS - Additional Information (Details) - Fair value - Level 1 € in Millions | Jun. 30, 2020 EUR (€)
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Constellium SE (Issued May 2014, due 2024) |
Disclosure of detailed information about financial instruments [line items] |
Percentage of fair value senior notes issued | 100.50%
Senior notes issued | € 359
Constellium N.V. Senior Unsecured Notes (Issued February 2017, due 2025) |
Disclosure of detailed information about financial instruments [line items] |
Percentage of fair value senior notes issued | 101.60%
Senior notes issued | € 589
Constellium N.V. EUR and USD Senior Unsecured Notes (Issued November 2017, due 2026) |
Disclosure of detailed information about financial instruments [line items] |
Percentage of fair value senior notes issued | 99.70%
Senior notes issued | € 844
Constellium SE (Issued June 2020, due 2028) |
Disclosure of detailed information about financial instruments [line items] |
Percentage of fair value senior notes issued | 99.80%
Senior notes issued | € 289

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