XML 61 R44.htm IDEA: XBRL DOCUMENT
v3.25.1

Contents of Significant Accounts - Movement of Loss Allowance (Detail) - Accounts receivable [member] - TWD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Disclosure of financial assets [line items] |  |
Beginning balance | $ 79,062 | $ 209,101
Net recognition (reversal) for the period | (68,066) | (130,039)
Ending balance | $ 10,996 | $ 79,062

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

X
- Definition Allowance for credit losses of financial assets. + References No definition available. + Details
Name: | umc_AllowanceForCreditLossesOfFinancialAssets
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Increase decrease in allowance for credit losses of financial assets. + References No definition available. + Details
Name: | umc_IncreaseDecreaseInAllowanceForCreditLossesOfFinancialAssets
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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