Derivatives - Value of Derivatives held as Net Investment Hedges (Detail) - Derivatives held as net investment hedges - EUR (€) € in Millions	Dec. 31, 2025	Dec. 31, 2024
Value of Derivatives held as Net Investment Hedges [Line Items]
Assets	€ 709	€ 189
Liabilities	102	1,595
Nominal amount	41,875	45,517
Fair Value changes used for hedge effectiveness	€ 3,572	€ (2,442)

The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [domain]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Name:	ifrs-full_HedgingInstrumentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant