Deferred Income Tax - Additional Information (Detail) - EUR (€) € in Billions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of income taxes [abstract]
Amount of tax losses	€ 1.5	€ 1.5
Deferred tax assets expiration year	2023	2022

The amount of unused tax losses for which no deferred tax asset is recognised in the statement of financial position. [Refer: Unused tax losses [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_e&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant