Commitments and Contingencies - Summary of Other Commitments and Contingencies (Detail) - EUR (€) € in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Disclosure Of Other Commitments And Contingencies [abstract] | ||
| Guarantees | € 864 | € 918 |
| Other guarantees | € 0 | € 6 |