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Insurance - Summary of Insurance Investment Results (Detail) - CAD ($) $ in Millions | 12 Months Ended
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Oct. 31, 2025 | Oct. 31, 2024
Insurance Investment Results [Abstract] |  |
Investment return | $ 1,122 | $ 2,320
Insurance finance (expense) from insurance and reinsurance contracts held | (955) | (2,098)
Movement in investment contract liabilities | (43) | (117)
Insurance investment results | $ 124 | $ 105

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