Hedging derivatives - Narrative (Details) - EUR (€) € in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of detailed information about hedges [abstract]
Macro cash flows hedge, position	€ 5,000
Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, assets	€ 227	€ 775	€ 1,006

The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial asset measured at amortised cost and has ceased to be adjusted for hedging gains and losses. [Refer: Financial assets at amortised cost; Hedged items [domain]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2025-01-01
-Paragraph 24B
-Subparagraph a
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_a_v&doctype=Standard
-URIDate 2025-03-27

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