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Financial Risk and Fair Value Disclosures - Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments and Contractual Maturity (Parenthetical) (Detail) - TWD ($) $ in Millions | 4 Months Ended |  |
--- | --- | --- | ---
Apr. 24, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] |  |  |
Investments in equity instruments designated at fair value through other comprehensive income |  | $ 5,893 | $ 5,753
Non Adjusting Events After Reporting Period [member] |  |  |
Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] |  |  |
Total amount of repayments of the long-term loans which were classified as non-current liabilities | $ 11,102 |  |
2 to 3 years [member] | Non Adjusting Events After Reporting Period [member] |  |  |
Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] |  |  |
Total amount of repayments of the long-term loans which were classified as non-current liabilities | 1,971 |  |
4 to 5 years [member] | Non Adjusting Events After Reporting Period [member] |  |  |
Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] |  |  |
Total amount of repayments of the long-term loans which were classified as non-current liabilities | $ 9,131 |  |

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