Other Net Investment Result - Summary of Other Net Investment Result (Detail) - EUR (€) € in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Profit or loss [abstract] | |||
| Interest revenue on financial instruments calculated using the effective interest method | € 636 | € 605 | € 599 |
| Interest revenue on financial instruments measured at FVPL | 217 | 186 | 89 |
| Other investment income | 825 | 729 | 550 |
| Results from financial transactions | 10,065 | 7,634 | 6,929 |
| Impairment (losses) / reversals | (22) | (47) | (33) |
| Investment contract income / (expenses) | (11,372) | (8,781) | (7,851) |
| Interest expense | (18) | (32) | (45) |
| For the year ended December 31 | € 331 | € 294 | € 238 |