Financial Instruments - Summary of Offsetting Risk Management Positions (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Offsetting Of Financial Assets Liabilities [Abstract]
Gross Amount, Risk Management Asset	$ 70	$ 13
Amount Offset, Risk Management Asset	(65)	(8)
Net Amount per Consolidated Financial Statements, Risk Management Asset	5	5
Gross Amount, Risk Management Liabilities	123	10
Amount Offset, Risk Management Liabilities	(65)	(8)
Net Amount per Consolidated Financial Statements, Risk Management Liabilities	58	2
Gross Amount, Risk Management Net	(53)	3
Net Amount per Consolidated Financial Statements, Risk Management Net	$ (53)	$ 3

Disclosure of offsetting of financial assets liabilities abstract.

No definition available.

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- Definition

Gross financial assets liabilities net subject to offsetting enforceable master netting arrangements or similar agreements.

+ References

No definition available.

+ Details

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- Definition

Net financial assets liabilities net subject to offsetting enforceable master netting arrangements or similar agreements.

+ References

No definition available.

+ Details

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- Definition

The amount of financial assets set off against financial liabilities when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis, or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 13C
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_b&doctype=Standard
-URIDate 2020-01-01

+ Details

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- Definition

The gross amount of recognised financial assets that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 13C
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_a&doctype=Standard
-URIDate 2020-01-01

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- Definition

The amount of financial liabilities set off against financial assets when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]

+ References

+ Details

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- Definition

The gross amount of recognised financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial liabilities]

+ References

+ Details

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- Definition

The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial assets, from the net amount of financial assets subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 13C
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_e&doctype=Standard
-URIDate 2020-01-01

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- Definition

The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial liabilities, from the net amount of financial liabilities subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position.

+ References

+ Details

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