Derivatives - Value of Derivatives held as Cash Flow Hedges (Detail) - Derivatives held as cash flow hedges - EUR (€) € in Millions	Dec. 31, 2025	Dec. 31, 2024
Value of Derivatives held as Cash Flow Hedges [line items]
Assets	€ 240	€ 58
Liabilities	354	183
Nominal amount	98,862	109,671
Fair Value changes used for hedge effectiveness	€ (50)	€ (229)

The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [domain]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 60
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60_a&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 60
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60_a&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2025-01-01
-Paragraph 24A
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24A_a&doctype=Standard
-URIDate 2025-03-27

Name:	ifrs-full_HedgingInstrumentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant