Financial and Other Derivative Instruments (Cumulative Gross Volume of Derivative Contracts Outstanding) (Details) - 12 months ended Dec. 31, 2023	CAD ($) MWh MMBTU T gal	USD ($)
Natural gas (MMBtu)
Derivative [Line Items]
Notional amount, energy measure | MMBTU	2,201,557,616
Electricity (MWh)
Derivative [Line Items]
Notional amount, energy measure | MWh	40,542,536
Oil (Gallons)
Derivative [Line Items]
Notional amount, volume measure | gal	4,272,000
Foreign currency exchange ($ CAD)
Derivative [Line Items]
Notional amount, monetary measure | $	$ 127,326,648
FTR (MWh)
Derivative [Line Items]
Notional amount, energy measure | MWh	66,064
Renewable Energy Certificates (MWh)
Derivative [Line Items]
Notional amount, energy measure | MWh	10,242,908
Carbon emissions (Metric Ton)
Derivative [Line Items]
Notional amount, mass measure | T	746,400
Interest rate contracts ($ USD)
Derivative [Line Items]
Notional amount, monetary measure | $		$ 1,200,000,000
Treasury Lock ($ USD)
Derivative [Line Items]
Notional amount, monetary measure | $		$ 500,000,000