Risk management - Reconciliation of model (reportable) ECL to total ECL (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Disclosure of financial assets [line items]
Unweighted ECL for all collective provisioned clients in upside scenario	€ 2,938
Unweighted ECL for all collective provisioned clients in baseline scenario	3,232
Unweighted ECL for all collective provisioned clients in down scenario	3,993
Accumulated impairments
Disclosure of financial assets [line items]
Financial assets	6,101	€ 6,049
Total reportable collective provisions \| Accumulated impairments
Disclosure of financial assets [line items]
Financial assets	3,168	2,975
ECL from individually assessed impairments \| Accumulated impairments
Disclosure of financial assets [line items]
Financial assets	2,750	2,871
ECL from management adjustments \| Accumulated impairments
Disclosure of financial assets [line items]
Financial assets	183	€ 203
Excluding all managment adjustments
Disclosure of financial assets [line items]
Total model ECL	€ 3,326

The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Classes of financial instruments [domain]; Financial liabilities]

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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