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Income Taxes - Summary of Components of Deferred Income Tax Balances (Detail) - CAD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Oct. 31, 2025 | Oct. 31, 2024 | Oct. 31, 2023
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | $ 3,023 | $ 3,404 |
Benefit (expense) to Income statement | (12) | (153) |
Benefit (expense) to equity | (312) | (295) |
Translation and other | 32 | 67 |
Ending balance of net asset | 2,731 | 3,023 |
Comprising |  |  |
Deferred tax assets | 2,732 | 3,024 | $ 3,420
Deferred tax liabilities | (1) | (1) | (16)
Net deferred tax assets (liabilities) | 2,731 | 3,023 | $ 3,404
Allowance for credit losses [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 1,343 | 893 |
Benefit (expense) to Income statement | (56) | 449 |
Benefit (expense) to equity | 0 |  |
Translation and other | 5 | 1 |
Ending balance of net asset | 1,292 | 1,343 |
Employee future benefits [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 282 | 264 |
Benefit (expense) to Income statement | 23 | 3 |
Benefit (expense) to equity | (6) | 15 |
Translation and other | 0 |  |
Ending balance of net asset | 299 | 282 |
Deferred compensation benefits [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 749 | 783 |
Benefit (expense) to Income statement | 308 | (35) |
Benefit (expense) to equity | 0 |  |
Translation and other | 2 | 1 |
Ending balance of net asset | 1,059 | 749 |
Other comprehensive income [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 224 | 522 |
Benefit (expense) to Income statement | 0 |  |
Benefit (expense) to equity | (261) | (298) |
Translation and other | 0 |  |
Ending balance of net asset | (37) | 224 |
Premises and equipment [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | (480) | (343) |
Benefit (expense) to Income statement | (19) | (136) |
Benefit (expense) to equity | 0 |  |
Translation and other | 1 | (1) |
Ending balance of net asset | (498) | (480) |
Pension benefits [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | (338) | (395) |
Benefit (expense) to Income statement | 13 | 73 |
Benefit (expense) to equity | (47) | (16) |
Translation and other | 2 |  |
Ending balance of net asset | (370) | (338) |
Goodwill and intangible assets [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | (805) | (913) |
Benefit (expense) to Income statement | 36 | 107 |
Benefit (expense) to equity | 0 |  |
Translation and other | (6) | 1 |
Ending balance of net asset | (775) | (805) |
Securities [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 867 | 987 |
Benefit (expense) to Income statement | (294) | (119) |
Benefit (expense) to equity | 0 |  |
Translation and other | 5 | (1) |
Ending balance of net asset | 578 | 867 |
Deferred Tax Asset Liability Other [member] |  |  |
Disclosure of components of deferred tax assets and liabilities [line items] |  |  |
Beginning balance of net asset | 1,181 | 1,606 |
Benefit (expense) to Income statement | (23) | (495) |
Benefit (expense) to equity | 2 | 4 |
Translation and other | 23 | 66 |
Ending balance of net asset | $ 1,183 | $ 1,181 |

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