Retirement benefits - Actuarial assumptions (Details) |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Pension defined benefit plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Discount rate, benefit obligations | 5.01% | 4.83% |
| Future compensation rate increase, benefit obligations | 3.67% | 3.66% |
| Discount rate, benefit expense | 4.83% | 4.69% |
| Future compensation rate increase, benefit expense | 3.66% | 3.62% |
| Other Post-Employment Defined Benefit Plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Discount rate, benefit obligations | 4.99% | 4.78% |
| Discount rate, benefit expense | 4.78% | 4.69% |