Commitments and Contingencies - Summary of Commitments through Purchase and Sale Transactions of Investments (Detail) - EUR (€) € in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure of purchase and sale transactions of investments [line items] | |||
| Purchase | € 82 | € 8 | € 253 |
| Sale | 756 | 37 | € 12 |
| Mortgage loans [member] | |||
| Disclosure of purchase and sale transactions of investments [line items] | |||
| Purchase | 85 | 189 | |
| Sale | 0 | ||
| Private loans [member] | |||
| Disclosure of purchase and sale transactions of investments [line items] | |||
| Purchase | 356 | 291 | |
| Sale | 0 | ||
| Other [member] | |||
| Disclosure of purchase and sale transactions of investments [line items] | |||
| Purchase | 921 | € 1,205 | |
| Sale | € 0 | ||