Basis of Preparation and Summary of Material Accounting Policies - Disclosure of the Balance Sheet as a Result of the Retrospective Application of IFRS 17 (Detail) - CAD ($) $ in Millions	Oct. 31, 2024	Oct. 31, 2023	[1]	Oct. 31, 2022
Disclosure of initial application of standards or interpretations [line items]
Deferred tax assets	$ 821	$ 647		$ 500
Other assets	30,862	27,659		35,153
Liabilities and equity
Other liabilities	30,155	26,653		28,104
Retained earnings	$ 33,471	$ 30,352		28,767
Increase (decrease) due to changes in accounting policy [member] | IFRS 17 [member]
Disclosure of initial application of standards or interpretations [line items]
Deferred tax assets				20
Other assets				(44)
Liabilities and equity
Other liabilities				32
Retained earnings				(56)
Previously stated [member]
Disclosure of initial application of standards or interpretations [line items]
Deferred tax assets				480
Other assets				35,197
Liabilities and equity
Other liabilities				28,072
Retained earnings				$ 28,823

[1] Certain comparative amounts have been restated to reflect the adoption of IFRS 17 in the first quarter of 2024. See Note 1 to the consolidated financial statements for additional details.