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Commitments, Guarantees, Pledged Assets, Provisions and Contingent Liabilities - Summary of Changes In Provision Balance (Detail) - CAD ($) $ in Millions | 12 Months Ended
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Oct. 31, 2025 | Oct. 31, 2024
Disclosure of Commitments Pledged Assets Provisions and Contingent Liabilities [Line Items] |  |
Balance at beginning of year | $ 259 | $ 1,578
Additional provisions/increase in provisions | 159 | 168
Provisions utilized | (208) | (229)
Amounts reversed | (41) | (1,255)
Foreign exchange and other | 2 | (3)
Balance at end of year | 171 | 259
Restructuring and severance [member] |  |
Disclosure of Commitments Pledged Assets Provisions and Contingent Liabilities [Line Items] |  |
Balance at beginning of year | 164 | 335
Additional provisions/increase in provisions | 125 | 101
Provisions utilized | (129) | (210)
Amounts reversed | (36) | (59)
Foreign exchange and other |  | (3)
Balance at end of year | 124 | 164
Legal [member] |  |
Disclosure of Commitments Pledged Assets Provisions and Contingent Liabilities [Line Items] |  |
Balance at beginning of year | 95 | 1,243
Additional provisions/increase in provisions | 34 | 67
Provisions utilized | (79) | (19)
Amounts reversed | (5) | (1,196)
Foreign exchange and other | 2 |
Balance at end of year | $ 47 | $ 95

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- Definition The increase in existing other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2024-01-01 -Paragraph 84 -Subparagraph b -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2024-en-r&anchor=para_84_b&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The increase (decrease) in other provisions resulting from foreign currency exchange rate changes on provisions measured in a currency different from the entity's presentation currency. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 37 -IssueDate 2024-01-01 -Paragraph 84 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2024-en-r&anchor=para_84&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The amount of liabilities of uncertain timing or amount, including provisions for employee benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 54 -Subparagraph l -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_54_l&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The amount reversed for unused other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2024-01-01 -Paragraph 84 -Subparagraph d -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2024-en-r&anchor=para_84_d&doctype=Standard -URIDate 2024-03-27 + Details
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