Financial Instruments Carried at Fair Value - Recognitions of Trade Date Profit (Detail) - EUR (€) € in Millions |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
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| Financial Instruments carried at Fair Value [Abstract] | |||||||
| Balance, beginning of year | € 691 | € 577 | |||||
| New trades during the period | 513 | 343 | |||||
| Amortization | (223) | (141) | |||||
| Matured trades | (71) | (53) | |||||
| Subsequent move to observability | [1] | (38) | (36) | [2] | |||
| Exchange rate changes | (5) | 1 | |||||
| Balance, end of year | € 866 | € 691 | |||||
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