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Post-Employment Benefits - Summary of Affected Defined Benefit Obligation Due to Reasonable Possible Changes to Principal Actuarial Assumptions (Detail) - Canada plan [member] $ in Millions | Oct. 31, 2025 CAD ($)
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Pension plan [member] | Actuarial assumption of discount rates [member] |
Disclosure of defined benefit plans [line items] |
Decrease in assumption | $ 1,054
Increase in assumption | (889)
Pension plan [member] | Actuarial assumption of rate of compensation increase [member] |
Disclosure of defined benefit plans [line items] |
Decrease in assumption | (205)
Increase in assumption | 217
Pension plan [member] | Actuarial assumption of future mortality [member] |
Disclosure of defined benefit plans [line items] |
1 year shorter life expectancy | (167)
1 year longer life expectancy | 161
Other post employment benefit plans [member] | Actuarial assumption of discount rates [member] |
Disclosure of defined benefit plans [line items] |
Decrease in assumption | 44
Increase in assumption | (37)
Other post employment benefit plans [member] | Actuarial assumption of health care cost trend rates [member] |
Disclosure of defined benefit plans [line items] |
Decrease in assumption | (13)
Increase in assumption | 15
Other post employment benefit plans [member] | Actuarial assumption of future mortality [member] |
Disclosure of defined benefit plans [line items] |
1 year shorter life expectancy | (8)
1 year longer life expectancy | $ 8

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- Definition One year shorter life expectancy. + References No definition available. + Details
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- Definition The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2024-01-01 -Paragraph 145 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_145_a&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2024-01-01 -Paragraph 145 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_145_a&doctype=Standard -URIDate 2024-03-27 + Details
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