XML 99 R82.htm IDEA: XBRL DOCUMENT
v3.25.1

Contents of Significant Accounts - Summary of Assumptions Used for Compensation Cost for Cash-settled Share-based Payment Measured at Fair Value on Grant Date by using Black-Scholes Option Pricing Model (Detail) - Granted in June 2021 [Member] - Stock Appreciation Right Plan For Employees [Member] | 12 Months Ended
--- | ---
Dec. 31, 2024 yr $ / shares
Contents Of Significant Accounts [Line Items] |
Share price of measurement date (NT$/ per share) | $ / shares | $ 43.05
Expected volatility | 25.80%
Expected life | yr | 0.44
Expected dividend yield | 6.46%
Risk-free interest rate | 1.38%

X
- Definition Contents of significant accounts. + References No definition available. + Details
Name: | umc_ContentsOfSignificantAccountsLineItems
Namespace Prefix: | umc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of an expected dividend used to calculate the fair value of the cash-settled share-based payment. + References No definition available. + Details
Name: | umc_ExpectedDividendUsedToCalculateFairValueOfCashSettledShareBasedPayment
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The expected life used to calculate the fair value of the cash-settled share-based payment. + References No definition available. + Details
Name: | umc_ExpectedLifeUsedToCalculateFairValueOfCashSettledShareBasedPayment
Namespace Prefix: | umc_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The expected volatility used to calculate the fair value of the cash-settled share-based payment. + References No definition available. + Details
Name: | umc_ExpectedVolatilityUsedToCalculateFairValueOfCashSettledShareBasedPayment
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The risk-free interest rate used to calculate the fair value of the cash-settled share-based payment. + References No definition available. + Details
Name: | umc_RiskFreeInterestRateUsedToCalculateFairValueOfCashSettledShareBasedPayment
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The share price of measurement date used to calculate the fair value of the cash-settled share-based payment. + References No definition available. + Details
Name: | umc_SharePriceOfMeasurementDateUsedToCalculateFairValueOfCashSettledShareBasedPayment
Namespace Prefix: | umc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | umc_GrantedAxis=umc_GrantedInJune2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=umc_StockAppreciationRightPlanForEmployeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |