v3.25.4
Employee retirement benefits - Components of Net Periodic Benefit Cost and Changes in Amounts Recorded in Accumulated Other Comprehensive Income (Detail) - CAD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Changes in amounts recorded in accumulated other comprehensive income      
Total recorded in other comprehensive income $ (265) $ (613) $ 218
Pension benefits      
Components of net periodic benefit cost      
Service cost 186 186 162
Interest cost 369 365 373
Expected return on plan assets (395) (454) (373)
Amortization of prior service cost 27 27 19
Amortization of actuarial loss (gain) 11 48 44
Net pension and other post retirement benefit enhancement 19 0 0
Net periodic benefit cost 217 172 225
Changes in amounts recorded in accumulated other comprehensive income      
Net actuarial loss (gain) (197) (439) 102
Amortization of net actuarial (loss) gain included in net periodic benefit cost (11) (48) (44)
Prior service cost 0 0 184
Amortization of prior service cost included in net periodic benefit cost (27) (27) (19)
Total recorded in other comprehensive income (235) (514) 223
Total recorded in net periodic benefit cost and other comprehensive income, before-tax (18) (342) 448
Other postretirement benefits      
Components of net periodic benefit cost      
Service cost 4 13 12
Interest cost 22 25 28
Expected return on plan assets 0 0 0
Amortization of prior service cost (5) 0 0
Amortization of actuarial loss (gain) (8) (8) (9)
Net pension and other post retirement benefit enhancement 1 0 0
Net periodic benefit cost 14 30 31
Changes in amounts recorded in accumulated other comprehensive income      
Net actuarial loss (gain) (43) (29) (14)
Amortization of net actuarial (loss) gain included in net periodic benefit cost 8 8 9
Prior service cost 0 (78) 0
Amortization of prior service cost included in net periodic benefit cost 5 0 0
Total recorded in other comprehensive income (30) (99) (5)
Total recorded in net periodic benefit cost and other comprehensive income, before-tax $ (16) $ (69) $ 26