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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, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | € 498 | € 448 | € 398
Metal price lag |  | 22 | 4
Start-up and development costs | (21) | (17) | (25)
Manufacturing system and process transformation costs |  | (2) | (5)
Wise integration and acquisition costs |  |  | (2)
Wise one-time costs |  |  | (20)
Wise purchase price adjustment |  |  | 20
Share-based compensation costs | (12) | (8) | (6)
Gains on pension plan amendments | 36 | 20 |
Depreciation and amortization | (197) | (171) | (155)
Restructuring costs | (1) | (4) | (5)
Unrealized (losses) / gains on derivatives | (84) | 57 | 71
Unrealized exchange (losses) / gains from the remeasurement of monetary assets and liabilities-net |  | (4) | 3
Gains / (losses) on disposals | 186 | (3) | (10)
Other | (1) |  | (1)
(Loss) / Income from operations | 404 | 338 | 267
Finance costs-net | (149) | (260) | (188)
Share of loss of joint-ventures | (33) | (29) | (14)
Income before income tax | 222 | 49 | 65
Income tax (expense) / benefit | (32) | (80) | (69)
Net income / (loss) | 190 | (31) | (4)
P&ARP [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 243 | 204 | 204
A&T [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 152 | 146 | 118
AS&I [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | 125 | 120 | 104
Start-up and development costs | 21 | 16 |
Holdings & Corporate [member] |  |  |
Disclosure of segment adjusted EBITDA and reconciliation of adjusted EBITDA to net income [line items] |  |  |
Adjusted EBITDA | € (22) | € (22) | € (28)

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