Derivatives and hedge accounting - Net investment hedge accounting - impact on statement of profit or loss and other comprehensive income (Details) - EUR (€) € in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Investment in foreign operations
Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [line items]
Change in value of hedged item used for calculating hedge ineffectiveness for the period	€ (816)	€ 295
Carrying amount net investment hedge reserve at the end of the reporting period	488	(95)
Hedged item affected statement of profit or loss
Change in value of hedging instrument recognised in OCI	816	(295)
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-)
Discontinued hedges
Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [line items]
Change in value of hedged item used for calculating hedge ineffectiveness for the period
Carrying amount net investment hedge reserve at the end of the reporting period	535	302
Hedged item affected statement of profit or loss
Change in value of hedging instrument recognised in OCI
Hedge ineffectiveness recognised in the statement of profit or loss, gain (+) / loss (-)

The amount of reclassification adjustments related to hedges of net investments in foreign operations, net of tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Other comprehensive income]