v3.24.0.1
Employee Future Benefits - Schedule of Net Benefit Costs (Details) - CAD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Pension Plans    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]    
Service costs $ 62 $ 106
Interest costs 159 114
Expected return on plan assets (202) (194)
Amortization of actuarial (gains) losses (9) 4
Amortization of past service credits/plan amendments (1) (1)
Regulatory adjustments 12 (10)
Net Benefit Cost 21 19
OPEB Plans    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]    
Service costs 22 35
Interest costs 30 21
Expected return on plan assets (22) (23)
Amortization of actuarial (gains) losses (19) (10)
Amortization of past service credits/plan amendments (1) (1)
Regulatory adjustments 5 4
Net Benefit Cost $ 15 $ 26