XML 125 R109.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

Financial Risk and Fair Value Disclosures - Reconciliation for Fair Value Measurement in Level 3 Fair Value Hierarchy (Detail) $ in Thousands, $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 TWD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 TWD ($)
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | $ 524,645,583 |  |
Ending balance | 546,576,832 | $ 17,850,321 | $ 524,645,583
Level 3 [member] | Financial assets at fair value through profit or loss [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 10,726,873 |  | 9,864,160
Recognized in profit (loss) | (1,216,735) |  | (13,041)
Recognized in other comprehensive income (loss) | 0 |  | 0
Acquisition | 1,353,205 |  | 1,303,056
Disposal | (117,737) |  | (546,783)
Return of capital | (37,730) |  | (26,672)
Transfer out of Level 3 | (461,403) |  | (326,577)
Exchange effect | 4,612 |  | 472,730
Ending balance | 10,251,085 |  | 10,726,873
Level 3 [member] | Financial assets at fair value through profit or loss [member] | Common stock [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 3,198,808 |  | 3,584,326
Recognized in profit (loss) | (312,149) |  | (150,786)
Recognized in other comprehensive income (loss) | 0 |  | 0
Acquisition | 610,153 |  | 192,258
Disposal | 0 |  | (186,579)
Return of capital | (1,384) |  | 0
Transfer out of Level 3 | (461,403) |  | (326,577)
Exchange effect | 2,230 |  | 86,166
Ending balance | 3,036,255 |  | 3,198,808
Level 3 [member] | Financial assets at fair value through profit or loss [member] | Preferred stocks [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 2,865,258 |  | 2,580,246
Recognized in profit (loss) | (277,994) |  | (328,602)
Recognized in other comprehensive income (loss) | 0 |  | 0
Acquisition | 294,046 |  | 485,256
Disposal | (89,997) |  | (15,782)
Return of capital | 0 |  | 0
Transfer out of Level 3 | 0 |  | 0
Exchange effect | (4,679) |  | 144,140
Ending balance | 2,786,634 |  | 2,865,258
Level 3 [member] | Financial assets at fair value through profit or loss [member] | Funds [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 4,626,333 |  | 3,464,652
Recognized in profit (loss) | (617,764) |  | 519,572
Recognized in other comprehensive income (loss) | 0 |  | 0
Acquisition | 294,245 |  | 625,542
Disposal | 0 |  | (194,572)
Return of capital | (36,346) |  | (26,672)
Transfer out of Level 3 | 0 |  | 0
Exchange effect | 8,428 |  | 237,811
Ending balance | 4,274,896 |  | 4,626,333
Level 3 [member] | Financial assets at fair value through profit or loss [member] | Convertible bonds [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 36,474 |  | 234,936
Recognized in profit (loss) | (8,828) |  | (53,225)
Recognized in other comprehensive income (loss) | 0 |  | 0
Acquisition | 0 |  | 0
Disposal | (27,740) |  | (149,850)
Return of capital | 0 |  | 0
Transfer out of Level 3 | 0 |  | 0
Exchange effect | 94 |  | 4,613
Ending balance | 0 |  | 36,474
Level 3 [member] | Financial assets at fair value through profit or loss [member] | Others [Member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Recognized in profit (loss) | 0 |  |
Recognized in other comprehensive income (loss) | 0 |  |
Acquisition | 154,761 |  |
Disposal | 0 |  |
Return of capital | 0 |  |
Transfer out of Level 3 | 0 |  |
Exchange effect | (1,461) |  |
Ending balance | 153,300 |  |
Level 3 [member] | Financial assets at fair value through other comprehensive income [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 3,610,267 |  | 2,503,462
Recognized in profit (loss) | 0 |  | 0
Recognized in other comprehensive income (loss) | (372,879) |  | 1,106,805
Acquisition | 0 |  | 0
Disposal | 0 |  | 0
Return of capital | 0 |  | 0
Transfer out of Level 3 | 0 |  | 0
Exchange effect | 0 |  | 0
Ending balance | 3,237,388 |  | 3,610,267
Level 3 [member] | Financial assets at fair value through other comprehensive income [member] | Common stock [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 3,427,720 |  | 2,351,603
Recognized in profit (loss) | 0 |  | 0
Recognized in other comprehensive income (loss) | (365,395) |  | 1,076,117
Acquisition | 0 |  | 0
Disposal | 0 |  | 0
Return of capital | 0 |  | 0
Transfer out of Level 3 | 0 |  | 0
Exchange effect | 0 |  | 0
Ending balance | 3,062,325 |  | 3,427,720
Level 3 [member] | Financial assets at fair value through other comprehensive income [member] | Preferred stocks [member] |  |  |
Disclosure of fair value measurement of assets [line items] |  |  |
Beginning balance | 182,547 |  | 151,859
Recognized in profit (loss) | 0 |  | 0
Recognized in other comprehensive income (loss) | (7,484) |  | 30,688
Acquisition | 0 |  | 0
Disposal | 0 |  | 0
Return of capital | 0 |  | 0
Transfer out of Level 3 | 0 |  | 0
Exchange effect | 0 |  | 0
Ending balance | $ 175,063 |  | $ 182,547

X
- Definition The amount of a present economic resource controlled by the entity as a result of past events. Economic resource is a right that has the potential to produce economic benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_a&doctype=Standard -URIDate 2023-03-23 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2023-01-01 -Paragraph 28 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2023-en-r&anchor=para_28_c&doctype=Standard -URIDate 2023-03-23 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph b -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_b&doctype=Standard -URIDate 2023-03-23 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e&doctype=Standard -URIDate 2023-03-23 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2023-01-01 -Paragraph 23 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2023-en-r&anchor=para_23&doctype=Standard -URIDate 2023-03-23 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2023-01-01 -Paragraph 55 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_55&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_Assets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfFairValueMeasurementOfAssetsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of assets. [Refer: At fair value [member]; Other comprehensive income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -Clause ii -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e_ii&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_GainsLossesRecognisedInOtherComprehensiveIncomeFairValueMeasurementAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of assets. [Refer: At fair value [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e_i&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_GainsLossesRecognisedInProfitOrLossFairValueMeasurementAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase in the fair value measurement of assets resulting from purchases of those assets. [Refer: At fair value [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -Clause iii -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e_iii&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_PurchasesFairValueMeasurementAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease in the fair value measurement of assets resulting from sales. [Refer: At fair value [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -Clause iii -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e_iii&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_SalesFairValueMeasurementAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of transfers of assets out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2023-01-01 -Paragraph 93 -Subparagraph e -Clause iv -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_e_iv&doctype=Standard -URIDate 2023-03-23 + Details
Name: | ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Increase (decrease) through net exchange differences of fair value measurement assets. + References No definition available. + Details
Name: | umc_IncreaseDecreaseThroughNetExchangeDifferencesFairValueMeasurementAssets
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease in the fair value measurement of assets resulting from return of capital. + References No definition available. + Details
Name: | umc_ReturnOfCapitalFairValueMeasurementAssets
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level3OfFairValueHierarchyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CategoriesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_OrdinarySharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_PreferenceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=umc_FundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=umc_ConvertibleBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=umc_OthersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CategoriesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeCategoryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |