Financial Risk Management Objectives and Policies - Schedule of Aggregate Net Foreign Exchange Gains/ Losses Recognized in Profit or Loss (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financial Risk Management Objectives And Policies [Abstract]
Net foreign exchange gain included in main currencies	€ (29)	€ 2	€ 3
Net foreign exchange gain/ (loss) included in other currencies	3	(1)	2
Net foreign exchange gain included in foreign exchange transactions	10	4	8
Total	€ (16)	€ 5	€ 13

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Classes of financial instruments [domain]]

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