Inventories - Summary of Inventories (Parenthetical) (Detail) - EUR (€) € in Millions	Dec. 31, 2017	Dec. 31, 2016
Classes of inventories [Line Items]
Work-in-progress	€ 92	€ 94
Construction contracts [member]
Classes of inventories [Line Items]
Work-in-progress	€ 2	€ 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
-Name IAS
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-IssueDate 2016-01-13
-Paragraph 37
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2016-03-30&anchor=para_37&doctype=Standard
-URIDate 2016-03-31

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
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-IssueDate 2016-01-13
-Paragraph 78
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_78_c&doctype=Standard
-URIDate 2016-03-31

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant