Financial Instrument Risk Management - Narrative (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Disclosure of financial assets [line items]
Percent of debt security portfolio considered investment grade	99.00%	99.00%
Available- for-sale
Disclosure of financial assets [line items]
Impairment loss on available-for-sale assets	$ 8	$ 11
Reversal of impairment	$ 0	$ 0

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- Definition

The amount of impairment loss on financial assets. [Refer: Financial assets; Impairment loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The amount recognised as an increase of the carrying amount of an asset or cash-generating unit to its recoverable amount when an impairment loss had been previously recognised. [Refer: Impairment loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-IssueDate 2022-03-24
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Risk Exposure Associated With Instruments Sharing Characteristic, Concentration Percentage

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