Trade and Other Receivables - Summary of Trade and Other Receivables (Parenthetical) (Detail) - EUR (€) € in Millions	Dec. 31, 2017	Dec. 31, 2016
Trade and other receivables [Abstract]
Unbilled revenue from construction contracts	€ 176	€ 149
Retentions held by customers in respect of construction contracts	€ 154	€ 167

The amount of progress billings on construction contracts that are not paid until the conditions specified in the contract for the payment of such amounts have been satisfied or until defects have been rectified. [Refer: Progress billings]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2016-01-13
-Paragraph 40
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2016-03-30&anchor=para_40_c&doctype=Standard
-URIDate 2016-03-31

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