v3.26.3
Other comprehensive income (loss) information - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - CAD ($)
$ in Millions
9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
At beginning of period $ 22,254  
At end of period 24,467 $ 23,684
Accumulated Defined Benefit Plans Adjustment Attributable to Parent    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
At beginning of period (14) (214)
Current period change excluding amounts reclassified from accumulated other comprehensive income 9 12
Amounts reclassified from accumulated other comprehensive income 4 15
At end of period $ (1) $ (187)