Capital Management and Solvency - Composition of Total Capitalization and Calculation of Gross Financial Leverage Ratio (Parenthetical) (Detail) - EUR (€) € in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
||
|---|---|---|---|---|
| Disclosure of capital management and solvency [line items] | ||||
| Senior debt for the gross financial leverage | [1] | € 1,389 | € 1,507 | |
| Currency swap contract [member] | ||||
| Disclosure of capital management and solvency [line items] | ||||
| Senior debt for the gross financial leverage | € (7) | € (26) | ||
| ||||