Financial Risks - Summary of Credit Quality of Gross Positions of Reinsurance Assets (Detail) - Carrying value [member] - EUR (€) € in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Disclosure of detailed information about credit rating [line items] | ||
| Reinsurance contract assets | € 16,958 | € 15,719 |
| AA [member] | ||
| Disclosure of detailed information about credit rating [line items] | ||
| Reinsurance contract assets | 1,008 | 1,087 |
| A [member] | ||
| Disclosure of detailed information about credit rating [line items] | ||
| Reinsurance contract assets | 14,832 | 14,041 |
| Below A [member] | ||
| Disclosure of detailed information about credit rating [line items] | ||
| Reinsurance contract assets | 208 | 3 |
| Not rated [member] | ||
| Disclosure of detailed information about credit rating [line items] | ||
| Reinsurance contract assets | € 910 | € 587 |