Dividends paid and proposed - Additional Information (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Dividend Payable [Abstract]
Dividends paid, ordinary shares	€ 24	€ 36

The amount of dividends paid by the entity on ordinary shares. [Refer: Ordinary shares [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 34
-IssueDate 2025-01-01
-Paragraph 16A
-Subparagraph f
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=34&code=ifrs-tx-2025-en-r&anchor=para_16A_f&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 246
-Subparagraph f
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_246_f&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 246
-Subparagraph f
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_246_f&doctype=Standard
-URIDate 2025-03-27

Name:	ifrs-full_DividendsPaidOrdinaryShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration