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SHARE OF INCOME / (LOSS) OF JOINT-VENTURES - Amounts Included in Consolidated Financial Statements in Accordance with Group Accounting Principles (Details) - EUR (€) € in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of investments accounted for using equity method [line items] |  |  |
Revenue | € 4,883 | € 5,907 | € 5,686
Cost of sales | (4,393) | (5,305) | (5,148)
Selling and administrative expenses | (237) | (276) | (247)
Income from operations | 125 | 255 | 404
Finance costs | (159) | (175) | (156)
Net (loss) / income | € (17) | € 64 | 190
Gain related shareholders loan facilities modification |  |  | 11
Constellium-UACJ ABS LLC |  |  |
Disclosure of investments accounted for using equity method [line items] |  |  |
Revenue |  |  | 262
Cost of sales |  |  | (309)
Selling and administrative expenses |  |  | (10)
Income from operations |  |  | (57)
Finance costs |  |  | (7)
Net (loss) / income |  |  | € (64)

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