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Operating Segment Information - Summary of Segment adjusted EBITDA and reconciliation of Adjusted EBITDA to Net Income (Detail) - EUR (€) € in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | € 431 | € 377 | € 343
Metal price lag | 22 | 4 | (34)
Start-up and development costs | (17) | (25) | (21)
Manufacturing system and process transformation costs | (2) | (5) | (11)
Wise integration and acquisition costs |  | (2) | (14)
Wise one-time costs |  | (20) | (38)
Wise purchase price adjustment |  | 20 |
Share based compensation costs | (8) | (6) | (7)
Gains / (Losses) on pension plan amendments | 20 |  | (5)
Depreciation and amortization | (171) | (155) | (140)
Impairment |  |  | (457)
Restructuring costs | (4) | (5) | (8)
Unrealized gains on derivatives | 57 | 71 | (20)
Unrealized exchange (losses) /gains from the remeasurement of monetary assets and liabilities - net | (4) | 3 | (3)
Losses on disposals | (3) | (10) | (5)
Other |  | (1) | (6)
Income / (loss) from operations | 321 | 246 | (426)
Finance costs - net | (243) | (167) | (155)
Share of loss of joint-ventures | (29) | (14) | (3)
Income / (Loss) before income tax | 49 | 65 | (584)
Income tax (expense) / benefit | (80) | (69) | 32
Net loss | (31) | (4) | (552)
P&ARP [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 202 | 201 | 183
A&T [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 133 | 103 | 103
Holdings & Corporate [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | (23) | (29) | (23)
AS&I [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 119 | € 102 | € 80
Start-up and development costs | € (16) |  |

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