The amount of revenue arising from construction contracts. Construction contracts are contracts specifically negotiated for the construction of an asset or a combination of assets that are closely interrelated or interdependent in terms of their design, technology and function or their ultimate purpose or use. [Refer: Revenue]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2016-01-13
-Paragraph 39
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2016-03-30&anchor=para_39_a&doctype=Standard
-URIDate 2016-03-31

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 18
-IssueDate 2016-01-13
-Paragraph 35
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=18&date=2016-03-30&anchor=para_35_b&doctype=Standard
-URIDate 2016-03-31

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2016-01-13
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_112_c&doctype=Standard
-URIDate 2016-03-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRIC
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-IssueDate 2016-01-13
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-Subparagraph b
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Name:	ifrs-full_RevenueFromConstructionContracts
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Segment Information - Additional Information (Detail) € in Millions	12 Months Ended
	Dec. 31, 2017 EUR (€) Country Segments	Dec. 31, 2016 EUR (€)	Dec. 31, 2015 EUR (€)
Disclosure of operating segments [Line Items]
Number of operating segments \| Segments	6
Number of business operating countries	32
Revenue from construction contracts \| €	€ 5,236	€ 5,102	€ 4,523
Europe Heavyside [member]
Disclosure of operating segments [Line Items]
Number of business operating countries	19
Europe Lightside [member]
Disclosure of operating segments [Line Items]
Number of business operating countries	17
Overseas [Member] \| Minimum [member]
Disclosure of operating segments [Line Items]
Percentage of limit of external group revenue	10.00%