v3.26.1
Other employee benefits (Schedule of other employee benefit plan, assumptions used (Details) - Other employee benefits [Member] - Year
Dec. 31, 2025
Dec. 31, 2024
Defined benefit cost [Member]    
Other Employee Benefits [Line Items]    
Discount rate 4.74% 4.64%
Defined benefit cost [Member] | Initial [Member]    
Other Employee Benefits [Line Items]    
Weighted average health care trend rate 5.67% 5.82%
Defined benefit cost [Member] | Ultimate [Member]    
Other Employee Benefits [Line Items]    
Weighted average health care trend rate 4.00% 4.00%
Defined benefit cost [Member] | Males [Member]    
Other Employee Benefits [Line Items]    
Average longevity at retirement age for current pensioners (years) 20.6 20.5
Defined benefit cost [Member] | Females [Member]    
Other Employee Benefits [Line Items]    
Average longevity at retirement age for current pensioners (years) 24 23.9
Defined benefit obligation [Member]    
Other Employee Benefits [Line Items]    
Discount rate 5.05% 4.74%
Defined benefit obligation [Member] | Initial [Member]    
Other Employee Benefits [Line Items]    
Weighted average health care trend rate 5.59% 5.67%
Defined benefit obligation [Member] | Ultimate [Member]    
Other Employee Benefits [Line Items]    
Weighted average health care trend rate 4.00% 4.00%
Defined benefit obligation [Member] | Males [Member]    
Other Employee Benefits [Line Items]    
Average longevity at retirement age for current pensioners (years) 20.7 20.6
Average longevity at retirement age for current employees (future pensioners) (years) 22.5 22.5
Defined benefit obligation [Member] | Females [Member]    
Other Employee Benefits [Line Items]    
Average longevity at retirement age for current pensioners (years) 24 24
Average longevity at retirement age for current employees (future pensioners) (years) 25.7 25.6