Intangible assets - Additional information (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Goodwill impairment	€ 0	€ 0
VIU calculation period	3 years
Percentage decrease in available cash flow	10.00%
Change in discount rate assumption	1.00%
Change in future growth rate assumption	0.00%
Software \| Internally generated
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Intangible assets other than goodwill	€ 956	€ 768

The amount of identifiable non-monetary assets without physical substance. This amount does not include goodwill. [Refer: Goodwill]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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