Derecognition of Financial Assets - Summary of Carrying Amount of Transferred Assets Do Not Qualify for Derecognition and Associated Liabilities (Detail) - Securitisations [member] - CAD ($) $ in Millions	Jul. 31, 2021	Apr. 30, 2021	Oct. 31, 2020
Disclosure of transferred financial assets that are not derecognised in their entirety [line items]
Carrying value of associated liabilities	$ 25,667	$ 27,595	$ 27,819
Residential mortgage loans [member]
Disclosure of transferred financial assets that are not derecognised in their entirety [line items]
Carrying value of assets	17,145	18,338	20,586
Other related assets [member]
Disclosure of transferred financial assets that are not derecognised in their entirety [line items]
Carrying value of assets	$ 10,131	$ 11,009	$ 9,548