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Contents of Significant Accounts - Long-Term Loans - Additional Information (Detail) $ in Millions, $ in Millions | Oct. 10, 2024 TWD ($) | Sep. 26, 2024 USD ($) | Jul. 09, 2024 TWD ($) | Mar. 29, 2024 TWD ($) | Jul. 20, 2023 TWD ($) | Apr. 25, 2023 TWD ($) | Nov. 28, 2022 TWD ($) | Dec. 24, 2021 TWD ($) | Mar. 03, 2021 TWD ($) | Dec. 31, 2024 TWD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 TWD ($)
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First Commercial Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  | 1-year |  |  | 1-year |  |  |  |  |  |
Debt maximum borrowing capacity |  |  | $ 2,000 |  |  | $ 2,000 |  |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | $ 1,200 |  | $ 1,200
Yuanta Commercial Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  |  |  |  |  |  |  | 5-year |  |  |
Debt maximum borrowing capacity |  |  |  |  |  |  |  |  | $ 4,000 |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 0 |  | 0
CTBC Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  |  |  |  |  |  | 5-year |  |  |  |
Debt maximum borrowing capacity |  |  |  |  |  |  |  | $ 4,000 |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 4,000 |  | 0
Secured syndicated loans from China development bank [member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Endorsement |  |  |  |  |  |  |  |  |  | 8,477 |  | 9,946
Secured syndicated loans from China development bank [member] | HEJIAN TECHNOLOGY (SUZHOU) CO., LTD. (HEJIAN) [member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Endorsement |  |  |  |  |  |  |  |  |  | 1,437 |  | 1,686
Secured syndicated loans from China development bank [member] | Top of range [member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Endorsement |  |  |  |  |  |  |  |  |  | 10,620 |  | 10,351
Secured syndicated loans from China development bank [member] | Top of range [member] | HEJIAN TECHNOLOGY (SUZHOU) CO., LTD. (HEJIAN) [member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Endorsement |  |  |  |  |  |  |  |  |  | 1,800 |  | 2,934
Mega International Commercial Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  |  |  |  |  | 5-year |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  |  |  | $ 5,000 |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 2,000 |  | 5,000
Australia and New Zealand Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  | 5-year |  |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  | $ 300 |  |  |  |  |  |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 8,500 | $ 260 |
DBS Bank Taiwan [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period | 5-year |  |  |  |  |  |  |  |  |  |  |
Debt maximum borrowing capacity | $ 4,000 |  |  |  |  |  |  |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 0 |  |
DBS Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  |  | 5-year |  |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  | $ 6,000 |  |  |  |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | 1,300 |  |
Taipei Fubon Bank [Member] | Unsecured Revolving Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity period |  |  |  |  | 5-year |  |  |  |  |  |  |
Debt maximum borrowing capacity |  |  |  |  | $ 3,000 |  |  |  |  |  |  |
Unused line of credit |  |  |  |  |  |  |  |  |  | $ 0 |  | $ 3,000

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