Financial instruments fair value risk - Summary of Reconciliation of Movements in Level 3 Valuations (Details) - At fair value - Level 3 - EUR (€) € in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of Fair Value Measurement of Assets [Line Items] | ||
| Assets and liabilities at beginning of period | € 962 | € 684 |
| Gains/(losses) recognised in income statement | (46) | (58) |
| Gains/(losses) recognised in other comprehensive income | (22) | 67 |
| Purchases and new issues | 30 | 135 |
| Sales and settlements | (80) | 134 |
| Assets and liabilities at end of period | € 844 | € 962 |