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Financial Risk and Fair Value Disclosures - Additional Information (Detail) - TWD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Accounts receivables from the top ten customers | 66.00% | 67.00% |
Profit or loss attributable to change in unrealized gains or losses for financial assets without quoted market prices held at end of period | $ 128 | $ (1,329) | $ (74)
Profit or loss attributable to change in unrealized gains or losses for financial liabilities without quoted market prices held at end of period | 119 | (581) | 829
Interest rate risk [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Increase (decrease) in profit due to percentage increase in market risk | 45 | 36 | 19
Increase (decrease) in profit due to percentage decrease in market risk | $ (45) | $ (36) | $ (19)
Equity price risk [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Percentage increase in market risk | 5.00% | 5.00% | 5.00%
Increase (decrease) in profit due to percentage increase in market risk | $ 261 | $ 270 | $ 285
Percentage decrease in market risk | 5.00% | 5.00% | 5.00%
Increase (decrease) in profit due to percentage decrease in market risk | $ (261) | $ (270) | $ (285)
Increase (decrease) in other comprehensive income due to percentage increase in market risk | 689 | 722 | 579
Increase (decrease) in other comprehensive income due to percentage decrease in market risk | $ (689) | $ (722) | $ (579)
Taiwan, New Dollars [member] | Currency risk [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Percentage increase in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage increase in market risk | $ 1,095 | $ 620 | $ 1,305
Percentage decrease in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage decrease in market risk | $ (1,095) | $ (620) | $ (1,305)
China, Yuan Renminbi [member] | Currency risk [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Percentage increase in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage increase in market risk | $ 615 | $ 582 | $ 572
Percentage decrease in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage decrease in market risk | $ (615) | $ (582) | $ (572)
Japan, Yen [member] | Currency risk [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Percentage increase in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage increase in market risk | $ 237 | $ 290 | $ 538
Percentage decrease in market risk | 10.00% | 10.00% | 10.00%
Increase (decrease) in profit due to percentage decrease in market risk | $ (237) | $ (290) | $ (538)
Financial assets at fair value through profit or loss, category [member] |  |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |  |
Financial assets transfer from level two to level one |  | $ 655 |

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