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Contents of Significant Accounts - Income Tax - Additional Information (Detail) - TWD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022
Disclosure of temporary difference, unused tax losses and unused tax credits [line items] |  |
Taxable temporary differences of unrecognized deferred tax liabilities associated with investments in subsidiaries | $ 20,389 | $ 21,658
Deductible temporary differences for which no deferred income tax assets have been recognized | $ 3,410 | $ 3,001
USJC [Member] |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [line items] |  |
Effective tax rate | 27.70% |
Accounting profit | $ 3,408 |
UMC KOREA [Member] |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [line items] |  |
Effective tax rate | 3.55% |
Accounting profit | $ 2 |
UME BV [Member] |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [line items] |  |
Effective tax rate | 20.12% |
Accounting profit | $ 10 |

X
- Definition The amount of profit (loss) for a period before deducting tax expense. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2023-01-01 -Paragraph 81 -Subparagraph c -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_c_i&doctype=Standard -URIDate 2023-03-23 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2023-01-01 -Paragraph 81 -Subparagraph c -Clause ii -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_c_ii&doctype=Standard -URIDate 2023-03-23 + Details
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- Definition The tax expense (income) divided by the accounting profit. [Refer: Accounting profit] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2023-01-01 -Paragraph 81 -Subparagraph c -Clause ii -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_c_ii&doctype=Standard -URIDate 2023-03-23 + Details
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- Definition The amount of deductible temporary differences for which no deferred tax asset is recognised in the statement of financial position. [Refer: Temporary differences [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2023-01-01 -Paragraph 81 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_e&doctype=Standard -URIDate 2023-03-23 + Details
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- Definition The aggregate amount of temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements, for which deferred tax liabilities have not been recognised as a result of satisfying both of the following conditions: (a) the parent, investor, joint venturer or joint operator is able to control the timing of the reversal of the temporary difference; and (b) it is probable that the temporary difference will not reverse in the foreseeable future. [Refer: Associates [member]; Subsidiaries [member]; Temporary differences [member]; Investments in subsidiaries reported in separate financial statements] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2023-01-01 -Paragraph 81 -Subparagraph f -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_f&doctype=Standard -URIDate 2023-03-23 + Details
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