Revenue - Additional Information (Detail) € in Millions	12 Months Ended
Dec. 31, 2018 EUR (€) Segments
Disclosure of disaggregation of revenue from contracts with customers [line items]
Number of operating segments \| Segments	6
Europe heavyside and americas materials [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue yet to be recognised from fixed-price long term construction contracts \| €	€ 1,848

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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