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Financial Risk and Fair Value Disclosures - Summary of Significant Unobservable Inputs of Fair Value Measurement in Level 3 Fair Value Hierarchy (Parenthetical) (Detail) - TWD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022
Embedded Derivatives In Exchangeable Bonds [Member] | Binomial Tree Valuation Model [Member] | Derivative Price Risk [Member] | Historical volatility for shares, measurement input [member] |  |
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items] |  |
Percentage of decrease in volatility | 5.00% | 5.00%
Percentage of increase in volatility | 5.00% | 5.00%
Increase (decrease) in profit or loss due to percentage decrease in volatility | $ 131 | $ 67
Increase (decrease) in profit or loss due to percentage increase in volatility | $ (119) | $ (77)
Unlisted equity securities [member] | Discount for lack of marketability [member] | Market approach [member] | Equity price risk [member] |  |
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items] |  |
Percentage increase in the discount for lack of marketability | 5.00% | 5.00%
Percentage decrease in the discount for lack of marketability | 5.00% | 5.00%
Increase (decrease) in other comprehensive income due to percentage increase in the discount for lack of marketability | $ (214) | $ (248)
Increase (decrease) in other comprehensive income due to percentage decrease in the discount for lack of marketability | 214 | 248
Increase (decrease) in profit or loss due to percentage increase in the discount for lack of marketability | (261) | (273)
Increase (decrease) in profit or loss due to percentage decrease in the discount for lack of marketability | $ 199 | $ 198

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