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Derivatives Instruments (Notional Volumes of Commodity Swaps and Forward Contracts Designated for Regulatory Deferral) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 CAD ($) MMBTU MWh
Commodity swaps and forwards | Natural gas | 2023
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh	18
Commodity swaps and forwards | Natural gas | 2024
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh	12
Commodity swaps and forwards | Power | 2023
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh | MWh	1
Commodity swaps and forwards | Power | 2024
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh | MWh	1
Physical natural gas purchases | Natural gas | 2023
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh	6
Physical natural gas purchases | Natural gas | 2024
Derivative [Line Items]
Natural Gas (Mmbtu) / Power (MWh) | MWh	0
Foreign Exchange Swaps and Forward Contracts | 2023
Derivative [Line Items]
Notional volumes of outstanding derivatives designated as cash flow hedges that are expected to settle | $	$ 206
Weighted average rate	1.2832
% of USD requirements	0.50%
Foreign Exchange Swaps and Forward Contracts | 2024
Derivative [Line Items]
Notional volumes of outstanding derivatives designated as cash flow hedges that are expected to settle | $	$ 123
Weighted average rate	1.3064
% of USD requirements	0.28%

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- Definition

Average contractual rate at which a foreign currency can be purchased or sold.

+ References

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- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

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- Definition

The percentage of expected requirements covered by the aggregate notional amount of derivative contracts expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract as a percentage of expected need.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

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