Risk management - Schedule of encumbered assets and collateral received and matching liabilities (Details) - Encumbered assets - Liquidity risk € in Millions	Dec. 31, 2025 EUR (€)
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Matching liabilities, contingent liabilities or securities lent	€ 472,045
Assets, collateral received and own debt securities issued other than covered bonds and ABSs encumbered	€ 491,519

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

No definition available.

Name:	ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration