Income Taxes - Components of Income Tax Expense (Recovery) Recognized in Equity (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Major components of tax expense (income) [abstract]
Current income tax expense (recovery)	$ 25	$ 5
Deferred income tax expense (recovery)	$ (25)	(6)
Total income tax recognized directly in equity		$ (1)

The aggregate current and deferred tax relating to particular items that are charged or credited directly to equity, for example: (a) an adjustment to the opening balance of retained earnings resulting from either a change in accounting policy that is applied retrospectively or the correction of an error; and (b) amounts arising on initial recognition of the equity component of a compound financial instrument. [Refer: Deferred tax relating to items credited (charged) directly to equity; Retained earnings; Financial instruments, class [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2020-01-01
-Paragraph 81
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_a&doctype=Standard
-URIDate 2020-01-01

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- Definition

The amount of current tax relating to particular items that are charged or credited directly to equity, for example: (a) an adjustment to the opening balance of retained earnings resulting from either a change in accounting policy that is applied retrospectively or the correction of an error; and (b) amounts arising on initial recognition of the equity component of a compound financial instrument. [Refer: Retained earnings; Financial instruments, class [member]]

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- Definition

The amount of deferred tax related to items credited (charged) directly to equity. [Refer: Deferred tax expense (income)]

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- References

No definition available.

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