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Consolidated Statements of Changes in Equity $ in Thousands, $ in Thousands | TWD ($) | USD ($) | Capital [member] Common stock [member] TWD ($) | Additional paid-in capital [member] TWD ($) | Legal Reserve [member] TWD ($) | Special Reserve [member] TWD ($) | Unappropriated Earnings [member] TWD ($) | Exchange Differences on Translation of Foreign Operations [member] TWD ($) | Unrealized Gains or Losses on Financial Assets Measured at Fair Value through Other Comprehensive Income [Member] TWD ($) | Unearned Employee Compensation [Member] TWD ($) | Treasury Stock [member] TWD ($) | Equity attributable to the parent company [member] TWD ($) | Non-controlling Interests [member] TWD ($)
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Balance at Dec. 31, 2020 | $ 223,139,562 |  | $ 124,224,015 | $ 44,452,987 | $ 12,536,526 | $ 11,022,314 | $ 53,429,442 | $ (11,877,253) | $ 1,327,344 | $ (3,667,395) | $ (8,421,774) | $ 223,026,206 | $ 113,356
Appropriation and distribution of retained earnings |  |  |  |  |  |  |  |  |  |  |  |  |
Legal reserve |  |  |  |  | 3,197,890 |  | (3,197,890) |  |  |  |  |  |
Special reserve reversed |  |  |  |  |  | (2,857,666) | 2,857,666 |  |  |  |  |  |
Cash dividends | (19,875,842) |  |  |  |  |  | (19,875,842) |  |  |  |  | (19,875,842) |
Net income (loss) | 50,578,180 |  |  |  |  |  | 51,246,425 |  |  |  |  | 51,246,425 | (668,245)
Other comprehensive income (loss) | 3,420,429 |  |  |  |  |  | (148,768) | (4,735,471) | 8,304,687 |  |  | 3,420,448 | (19)
Total comprehensive income (loss) | 53,998,609 |  |  |  |  |  | 51,097,657 | (4,735,471) | 8,304,687 |  |  | 54,666,873 | (668,264)
Share-based payment transaction | 1,745,711 |  | (2,617) | 293,374 |  |  |  |  |  | 1,454,954 |  | 1,745,711 |
Share of changes in net assets of associates and joint ventures accounted for using equity method | (540) |  |  | (540) |  |  | 430,850 |  | (430,850) |  |  | (540) |
Changes in subsidiaries' ownership | (1,020,566) |  |  |  |  |  | (1,009,440) |  |  |  |  | (1,009,440) | (11,126)
Adjustments due to reciprocal stockholdings held by subsidiaries and associates | 1,070,932 |  |  | 961,003 |  |  |  |  |  |  | 109,929 | 1,070,932 |
Disposal of equity instruments investments measured at fair value through other comprehensive income | 0 |  |  |  |  |  |  |  |  |  |  |  |
Non-Controlling Interests | 23,430 |  |  |  |  |  |  |  |  |  |  |  | 23,430
Share exchange | 4,661,865 |  | 611,078 | 3,930,986 |  |  |  |  |  |  | 119,801 | 4,661,865 |
Others | 631,886 |  |  | 442,786 |  |  | (576,685) |  |  |  |  | (133,899) | 765,785
Balance at Dec. 31, 2021 | 264,375,047 |  | 124,832,476 | 50,080,596 | 15,734,416 | 8,164,648 | 83,155,758 | (16,612,724) | 9,201,181 | (2,212,441) | (8,192,044) | 264,151,866 | 223,181
Impact of retroactive applications at Dec. 31, 2021 | (219,932) |  |  |  |  |  | (153,843) |  |  |  |  | (153,843) | (66,089)
Adjusted balance at Dec. 31, 2021 | 264,155,115 |  | 124,832,476 | 50,080,596 | 15,734,416 | 8,164,648 | 83,001,915 | (16,612,724) | 9,201,181 | (2,212,441) | (8,192,044) | 263,998,023 | 157,092
Appropriation and distribution of retained earnings |  |  |  |  |  |  |  |  |  |  |  |  |
Legal reserve |  |  |  |  | 5,832,570 |  | (5,832,570) |  |  |  |  |  |
Special reserve reversed |  |  |  |  |  | (3,250,434) | 3,250,434 |  |  |  |  |  |
Cash distributed from additional paid-in capital | (37,446,370) |  |  | (37,446,370) |  |  |  |  |  |  |  | (37,446,370) |
Net income (loss) | 90,298,765 |  |  |  |  |  | 89,478,805 |  |  |  |  | 89,478,805 | 819,960
Other comprehensive income (loss) | 4,192,092 |  |  |  |  |  | 258,171 | 10,243,308 | (6,309,395) |  |  | 4,192,084 | 8
Total comprehensive income (loss) | 94,490,857 |  |  |  |  |  | 89,736,976 | 10,243,308 | (6,309,395) |  |  | 93,670,889 | 819,968
Share-based payment transaction | 1,351,738 |  | 215,014 | 755,313 |  |  | (1,490) |  |  | 381,411 |  | 1,350,248 | 1,490
Share of changes in net assets of associates and joint ventures accounted for using equity method | 55,392 |  |  | 55,392 |  |  | (797) |  | 797 |  |  | 55,392 |
Changes in subsidiaries' ownership | (430,436) |  |  |  |  |  | (429,097) |  |  |  |  | (429,097) | (1,339)
Adjustments due to reciprocal stockholdings held by subsidiaries and associates | 205,857 |  |  | 635,761 |  |  |  |  |  |  | (429,904) | 205,857 |
Disposal of equity instruments investments measured at fair value through other comprehensive income | 0 |  |  |  |  |  |  |  |  |  |  |  |
Non-Controlling Interests | 5,456 |  |  |  |  |  |  |  |  |  |  |  | 5,456
Others | 423,339 |  |  | 1,062,327 |  |  |  |  |  |  |  | 1,062,327 | (638,988)
Balance at Dec. 31, 2022 | 322,810,948 |  | 125,047,490 | 15,143,019 | 21,566,986 | 4,914,214 | 169,725,371 | (6,369,416) | 2,892,583 | (1,831,030) | (8,621,948) | 322,467,269 | 343,679
Appropriation and distribution of retained earnings |  |  |  |  |  |  |  |  |  |  |  |  |
Legal reserve |  |  |  |  | 8,905,139 |  | (8,905,139) |  |  |  |  |  |
Special reserve reversed |  |  |  |  |  | (2,180,156) | 2,180,156 |  |  |  |  |  |
Cash dividends | (45,017,096) |  |  |  |  |  | (45,017,096) |  |  |  |  | (45,017,096) |
Net income (loss) | 60,139,134 | $ 1,964,047 |  |  |  |  | 59,688,950 |  |  |  |  | 59,688,950 | 450,184
Other comprehensive income (loss) | 5,058,046 | 165,188 |  |  |  |  | 327,156 | (2,070,254) | 6,801,158 |  |  | 5,058,060 | (14)
Total comprehensive income (loss) | 65,197,180 | 2,129,235 |  |  |  |  | 60,016,106 | (2,070,254) | 6,801,158 |  |  | 64,747,010 | 450,170
Share-based payment transaction | 1,026,023 |  | 250,732 | 934,945 |  |  | (5,170) |  | 0 | (160,301) |  | 1,020,206 | 5,817
Share of changes in net assets of associates and joint ventures accounted for using equity method | 17,396 |  |  | 46,265 |  |  | 403,488 |  | (432,357) |  |  | 17,396 |
Disposal of investments accounted for under the equity method | 5 |  |  | 5 |  |  | (56) |  | 56 |  |  | 5 |
The differences between the fair value of the consideration paid or received from acquiring or disposing subsidiaries and the carrying amounts of the subsidiaries | 2,572,818 |  |  | 2,572,818 |  |  |  |  |  |  |  | 2,572,818 |
Changes in subsidiaries' ownership | (288,284) |  |  | 3,485 |  |  | (292,225) |  |  |  |  | (288,740) | 456
Adjustments due to reciprocal stockholdings held by subsidiaries and associates | (415,962) |  |  | 851,695 |  |  | (85,827) |  |  |  | (1,181,830) | (415,962) |
Disposal of equity instruments investments measured at fair value through other comprehensive income | (1,628,388) |  |  |  |  |  | (1,628,388) |  | 1,628,388 |  |  |  |
Non-Controlling Interests | 4,187 |  |  |  |  |  |  |  |  |  |  |  | 4,187
Others | (2,190,247) |  |  | (1,726,797) |  |  |  |  |  |  |  | (1,726,797) | (463,450)
Balance at Dec. 31, 2023 | $ 343,716,968 | $ 11,225,244 | $ 125,298,222 | $ 17,825,435 | $ 30,472,125 | $ 2,734,058 | $ 176,391,220 | $ (8,439,670) | $ 10,889,828 | $ (1,991,331) | $ (9,803,778) | $ 343,376,109 | $ 340,859

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- Definition Share exchange during the period. + References No definition available. + Details
Name: | umc_ShareExchangeDuringThePeriod
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Share of changes in net assets of associates and joint ventures accounted for using equity method. + References No definition available. + Details
Name: | umc_ShareOfChangesInNetAssetsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Special reserve reversed. + References No definition available. + Details
Name: | umc_SpecialReserveReversed
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Stockholders Equity Adjusted Balance + References No definition available. + Details
Name: | umc_StockholdersEquityAdjustedBalance
Namespace Prefix: | umc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant