Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - CAD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets and liabilities [abstract]
Deferred tax assets	$ 5,254	$ 4,842
Deferred tax liability	(2,769)	(2,614)
Net deferred tax assets (liabilities)	$ 2,485	$ 2,228	$ 2,602

The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]

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