Inventories - Summary of Inventories (Parenthetical) (Detail) - EUR (€) € in Millions	Dec. 31, 2018	Dec. 31, 2017
Classes of inventories [line items]
Work-in-progress	€ 109	€ 92
Construction contracts [member]
Classes of inventories [line items]
Work-in-progress	€ 3	€ 2

A classification of current inventory representing the amount of assets currently in production, which require further processes to be converted into finished goods or services. [Refer: Current finished goods; Inventories]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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