Post-employment benefits - Sensitivity of key assumptions (Detail) - EUR (€) € in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Post-employment benefits [Line Items] | ||
| Percentage of reasonably possible decrease in actuarial assumption | 1.00% | |
| Bottom of range | ||
| Post-employment benefits [Line Items] | ||
| Increase in actuarial assumption of life expectancy after retirement | 6 months | |
| Top of range | ||
| Post-employment benefits [Line Items] | ||
| Increase in actuarial assumption of life expectancy after retirement | 1 year | |
| Discount rate (1% movement) | ||
| Post-employment benefits [Line Items] | ||
| Increase | € (80) | € (123) |
| Decrease | 98 | 150 |
| Pension increase (1% movement) | ||
| Post-employment benefits [Line Items] | ||
| Increase | 54 | 60 |
| Decrease | (47) | (52) |
| Salary increase (1% movement) | ||
| Post-employment benefits [Line Items] | ||
| Increase | 12 | 14 |
| Decrease | (11) | (12) |
| Longevity | ||
| Post-employment benefits [Line Items] | ||
| Increase | 26 | 34 |
| Decrease | € (21) | € (24) |
| Percentage of reasonably possible decrease in actuarial assumption | 10.00% |