XML 84 R67.htm IDEA: XBRL DOCUMENT
v3.25.1

Contents of Significant Accounts - Major Categories of Plan Assets as a Percentage of Fair Value of the Total Plan Assets (Detail) | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Disclosure Of Fair Value Of Plan Assets [Abstract] |  |
Cash | 21.00% | 21.00%
Equity instruments | 47.00% | 46.00%
Debt instruments | 21.00% | 23.00%
Others | 11.00% | 10.00%

X
- References No definition available. + Details
Name: | ifrs-full_DisclosureOfFairValueOfPlanAssetsAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of cash in the plan assets. + References No definition available. + Details
Name: | umc_PercentageOfCashInThePlanAssets
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of debt instruments in the plan assets. + References No definition available. + Details
Name: | umc_PercentageOfDebtInstrumentsInThePlanAssets
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of equity instruments in the plan assets. + References No definition available. + Details
Name: | umc_PercentageOfEquityInstrumentsInThePlanAssets
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage ​of othe​r assets ​in the​ plan​ assets. + References No definition available. + Details
Name: | umc_PercentageOfOtherAssetsInThePlanAssets
Namespace Prefix: | umc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant