XML 120 R103.htm IDEA: XBRL DOCUMENT v3.25.1

Significant Related Party Transactions - Significant Transactions between Company and Other Related Parties (Detail) ¥ in Thousands, shares in Thousands, $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024 TWD ($) shares	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 TWD ($) shares	Dec. 31, 2022 TWD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2024 CNY (¥)	Dec. 31, 2023 CNY (¥)
Disclosure of transactions between related parties [line items]
Accounts receivable-related parties, net	$ 620,013		$ 347,964		$ 18,909
Acquisition of investments accounted for under the equity method, Purchase price	33,274,869		32,785,800		$ 1,014,787
Acquisition of intangible assets	2,799,420	$ 85,374	2,546,516	$ 2,756,155
Disposal of subsidiary ownership			0	0
Trading Capital Amount | ¥							¥ 4,416,624
Purchase price			21,209,443
SIS - SIS SEMICONDUCTOR (SHANDONG) CO., LTD [member]
Disclosure of transactions between related parties [line items]
Gain on disposal	352
Disposal price	341,387
Trading capital | ¥						¥ 30,000
FARADAY TECHNOLOGY CORP. [member]
Disclosure of transactions between related parties [line items]
Acquisition of investments accounted for under the equity method, Purchase price	2,484,001		1,990,073
Acquisition of intangible assets	310,460		323,551	266,053
FARADAY TECHNOLOGY CORP. [member]
Disclosure of transactions between related parties [line items]
Accounts receivable-related parties, net	456,332		302,828
ARTERY TECHNOLOGY CORPORATION, LTD. [member]
Disclosure of transactions between related parties [line items]
Accounts receivable-related parties, net	148,508		40,886
Associates [member]
Disclosure of transactions between related parties [line items]
Operating revenues	3,611,015		3,018,171	5,744,098
Associates [member] | Stock of FARADAY [Member]
Disclosure of transactions between related parties [line items]
Acquisition of investments accounted for under the equity method, Purchase price	$ 533,973
Acquisition of investments accounted for under the equity method, Trading Volume | shares	1,723	1,723
Associates [member] | Stock Of UNIMICRON [member]
Disclosure of transactions between related parties [line items]
Acquisition of investments accounted for under the equity method, Purchase price			$ 608,224
Acquisition of investments accounted for under the equity method, Trading Volume | shares			4,945
Other related party [member]
Disclosure of transactions between related parties [line items]
Operating revenues	$ 0		$ 4,463	40,474
Mask expenditure	2,285,797		2,375,225	2,581,409
Other payables of mask expenditure	621,737		751,763	812,185
All other related parties [member]
Disclosure of transactions between related parties [line items]
Operating revenues	3,611,015		3,022,634	$ 5,784,572
Others [member]
Disclosure of transactions between related parties [line items]
Accounts receivable-related parties, net	493		3,602
Other Associates [member]
Disclosure of transactions between related parties [line items]
Accounts receivable-related parties, net	$ 14,680		648
XIAMEN JINYUAN INDUSTRIAL DEVELOPMENT CO., LTD. [member] | Increase of ownership stake in the subsidiary company USCXM [member]
Disclosure of transactions between related parties [line items]
Trading Capital Amount | ¥							3,741,862
Purchase price			17,945,970
FUJIAN ELECTRONICS & INFORMATION INDUSTRY ENTREPRENEURSHIP INVESTMENT LIMITED PARTNERSHIP [member] | Increase of ownership stake in the subsidiary company USCXM [member]
Disclosure of transactions between related parties [line items]
Trading Capital Amount | ¥							¥ 674,762
Purchase price			$ 3,263,473

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_DisclosureOfTransactionsBetweenRelatedPartiesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The gain on disposals of investment properties. [Refer: Investment property]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_GainsOnDisposalsOfInvestmentProperties
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 24
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_24_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B16
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B16&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 54
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_54_e&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_InvestmentAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The cash outflow for the purchases of intangible assets, classified as investing activities. [Refer: Intangible assets other than goodwill]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 16
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_16_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of revenue arising from the sale of goods in related party transactions. [Refer: Revenue; Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 21
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_21_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_RevenueFromSaleOfGoodsRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of current receivables due from related parties. [Refer: Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_TradeAndOtherCurrentReceivablesDueFromRelatedParties
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Acquisition of shares, investments accounted for under the equity method.

+ References

No definition available.

+ Details

Name:	umc_AcquisitionOfSharesInvestmentsAccountedForUnderTheEquityMethod
Namespace Prefix:	umc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Disposal price of subsidiary ownership.

+ References

No definition available.

+ Details

Name:	umc_DisposalPriceOfSubsidiaryOwnership
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Gain loss on disposal of subsidiary ownership.

+ References

No definition available.

+ Details

Name:	umc_GainLossOnDisposalOfSubsidiaryOwnership
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The amount of mask expenditure in related party transactions.

+ References

No definition available.

+ Details

Name:	umc_MaskExpenditureRelatedPartyTransactions
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The amount of other payables of mask expenditure in related party transactions.

+ References

No definition available.

+ Details

Name:	umc_OtherPayablesOfMaskExpenditureRelatedPartyTransactions
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Purchase price for acquisition of a subsidiary's ownership.

+ References

No definition available.

+ Details

Name:	umc_PurchasePriceForAcquisitionOfASubsidiaryOwnership
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Trading capital.

+ References

No definition available.

+ Details

Name:	umc_TradingCapital
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Volume of capital traded.

+ References

No definition available.

+ Details

Name:	umc_VolumeOfCapitalTraded
Namespace Prefix:	umc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=umc_SISSemiconductorShandongCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=umc_FaradayTechnologyCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	umc_TransactionWithRelatedPartyAxis=umc_FaradayTechnologyCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	umc_TransactionWithRelatedPartyAxis=umc_ArteryTechnologyCorporationLTDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_AssociatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	umc_TransactionWithRelatedPartyAxis=umc_StockOfFaradayMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	umc_TransactionWithRelatedPartyAxis=umc_StockOfUNIMICRONMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_OtherRelatedPartiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=umc_AllOtherRelatedPartiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=umc_OthersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=umc_OtherAssociatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=umc_XiamenJinyuanIndustrialDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	umc_TransactionWithRelatedPartyAxis=umc_IncreaseOfOwnershipStakeInTheSubsidiaryCompanyUSCXMMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=umc_FujianElectronicsInformationIndustryEnrepreneurshipInvestentLimitedPartnershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: