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Operating Segment Information - Summary of Revenue by Product Lines (Detail) - EUR (€) € in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure of products and services [line items] |  |  |
Revenue | € 5,237 | € 4,743 | € 5,153
Packaging rolled products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 2,146 | 2,003 | 2,205
Automotive rolled products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 483 | 319 | 275
Specialty and other thin-rolled products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 176 | 160 | 262
Aerospace rolled products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 760 | 795 | 861
Transportation, Industry and other rolled products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 541 | 484 | 487
Automotive extruded products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 614 | 537 | 544
Other extruded products [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | 504 | 456 | 490
Other [member] |  |  |
Disclosure of products and services [line items] |  |  |
Revenue | € 13 | € (11) | € 29

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