1001 - Document - Cover link:presentationLink link:definitionLink link:calculationLink 1002 - Statement - Consolidated Balance Sheets link:presentationLink link:definitionLink link:calculationLink 1003 - Statement - Consolidated Balance Sheets (Parenthetical) link:presentationLink link:definitionLink link:calculationLink 1004 - Statement - Consolidated Statements of Comprehensive Income link:presentationLink link:definitionLink link:calculationLink 1005 - Statement - Consolidated Statements of Changes in Equity link:presentationLink link:definitionLink link:calculationLink 1006 - Statement - Consolidated Statements of Cash Flows link:presentationLink link:definitionLink link:calculationLink 999001 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure link:presentationLink link:definitionLink link:calculationLink 999002 - Disclosure - History and Organization link:presentationLink link:definitionLink link:calculationLink 999003 - Disclosure - Date and Procedures of Authorization of Financial Statements for Issue link:presentationLink link:definitionLink link:calculationLink 999004 - Disclosure - New Accounting Pronouncement under IFRS Accounting Standards link:presentationLink link:definitionLink link:calculationLink 999005 - Disclosure - Summary of Material Accounting Policies link:presentationLink link:definitionLink link:calculationLink 999006 - Disclosure - Significant Accounting Judgments, Estimates and Assumptions link:presentationLink link:definitionLink link:calculationLink 999007 - Disclosure - Contents of Significant Accounts link:presentationLink link:definitionLink link:calculationLink 999008 - Disclosure - Significant Related Party Transactions link:presentationLink link:definitionLink link:calculationLink 999009 - Disclosure - Assets Pledged as Collateral link:presentationLink link:definitionLink link:calculationLink 999010 - Disclosure - Significant Contingencies and Unrecognized Contract Commitments link:presentationLink link:definitionLink link:calculationLink 999011 - Disclosure - Significant Subsequent Events link:presentationLink link:definitionLink link:calculationLink 999012 - Disclosure - Financial Risk and Fair Value Disclosures link:presentationLink link:definitionLink link:calculationLink 999013 - Disclosure - Operating Segment Information link:presentationLink link:definitionLink link:calculationLink 999014 - Disclosure - Capital Management link:presentationLink link:definitionLink link:calculationLink 999015 - Disclosure - Summary of Material Accounting Policies (Policies) link:presentationLink link:definitionLink link:calculationLink 999016 - Disclosure - Summary of Material Accounting Policies (Tables) link:presentationLink link:definitionLink link:calculationLink 999017 - Disclosure - Contents of Significant Accounts (Tables) link:presentationLink link:definitionLink link:calculationLink 999018 - Disclosure - Significant Related Party Transactions (Tables) link:presentationLink link:definitionLink link:calculationLink 999019 - Disclosure - Assets Pledged as Collateral (Tables) link:presentationLink link:definitionLink link:calculationLink 999020 - Disclosure - Financial Risk and Fair Value Disclosures (Tables) link:presentationLink link:definitionLink link:calculationLink 999021 - Disclosure - Operating Segment Information (Tables) link:presentationLink link:definitionLink link:calculationLink 999022 - Disclosure - Capital Management (Tables) link:presentationLink link:definitionLink link:calculationLink 999023 - Disclosure - Summary of Material Accounting Policies - Consolidated Entities (Detail) link:presentationLink link:definitionLink link:calculationLink 999024 - Disclosure - Summary of Material Accounting Policies - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999025 - Disclosure - Summary of Material Accounting Policies - Estimated Useful Lives of Property, Plant and Equipment (Detail) link:presentationLink link:definitionLink link:calculationLink 999026 - Disclosure - Summary of Material Accounting Policies - Intangible Assets - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999027 - Disclosure - Contents of Significant Accounts - Cash and Cash Equivalents (Detail) link:presentationLink link:definitionLink link:calculationLink 999028 - Disclosure - Contents of Significant Accounts - Financial Assets at Fair Value through Profit or Loss (Detail) link:presentationLink link:definitionLink link:calculationLink 999029 - Disclosure - Contents of Significant Accounts - Financial Assets at Fair Value through Other Comprehensive Income (Detail) link:presentationLink link:definitionLink link:calculationLink 999030 - Disclosure - Contents of Significant Accounts - Summary of Fair Value of Each Investment in Equity Instrument (Detail) link:presentationLink link:definitionLink link:calculationLink 999031 - Disclosure - Contents of Significant Accounts - Summary of Income Recognized in Profit or Loss from Equity Instruments Designated as Fair Value Through Other Comprehensive Income (Detail) link:presentationLink link:definitionLink link:calculationLink 999032 - Disclosure - Contents of Significant Accounts - Summary of Details on Derecognition of Such Investments (Detail) link:presentationLink link:definitionLink link:calculationLink 999033 - Disclosure - Contents of Significant Accounts - Financial Assets Measured at Amortized Cost (Detail) link:presentationLink link:definitionLink link:calculationLink 999034 - Disclosure - Contents of Significant Accounts - Accounts Receivable, Net (Detail) link:presentationLink link:definitionLink link:calculationLink 999035 - Disclosure - Contents of Significant Accounts - Aging Analysis of Accounts Receivable (Detail) link:presentationLink link:definitionLink link:calculationLink 999036 - Disclosure - Contents of Significant Accounts - Movement of Loss Allowance (Detail) link:presentationLink link:definitionLink link:calculationLink 999037 - Disclosure - Contents of Significant Accounts - Accounts Receivable, Net - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999038 - Disclosure - Contents of Significant Accounts - Inventories, Net (Detail) link:presentationLink link:definitionLink link:calculationLink 999039 - Disclosure - Contents of Significant Accounts - Inventories, Net - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999040 - Disclosure - Contents of Significant Accounts - Details of Investments Accounted for Under the Equity Method (Detail) link:presentationLink link:definitionLink link:calculationLink 999041 - Disclosure - Contents of Significant Accounts - Investments Accounted For Under the Equity Method - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999042 - Disclosure - Contents of Significant Accounts - Aggregate Amount of the Company's Share of its Individually Immaterial Associates (Detail) link:presentationLink link:definitionLink link:calculationLink 999043 - Disclosure - Contents of Significant Accounts - Property, Plant and Equipment (Detail) link:presentationLink link:definitionLink link:calculationLink 999044 - Disclosure - Contents of Significant Accounts - Summary of Interest Expense Capitalized (Detail) link:presentationLink link:definitionLink link:calculationLink 999045 - Disclosure - Contents of Significant Accounts - Leases (Detail) link:presentationLink link:definitionLink link:calculationLink 999046 - Disclosure - Contents of Significant Accounts - Leases - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999047 - Disclosure - Contents of Significant Accounts - Intangible Assets (Detail) link:presentationLink link:definitionLink link:calculationLink 999048 - Disclosure - Contents of Significant Accounts - Amortization Amounts of Intangible Assets (Detail) link:presentationLink link:definitionLink link:calculationLink 999049 - Disclosure - Contents of Significant Accounts - Short-Term Loans (Detail) link:presentationLink link:definitionLink link:calculationLink 999050 - Disclosure - Contents of Significant Accounts - Financial Liabilities at Fair Value through Profit or Loss, Current (Detail) link:presentationLink link:definitionLink link:calculationLink 999051 - Disclosure - Contents of Significant Accounts - Bonds Payable (Detail) link:presentationLink link:definitionLink link:calculationLink 999052 - Disclosure - Contents of Significant Accounts - Summary of Terms and Conditions of Bonds (Detail) link:presentationLink link:definitionLink link:calculationLink 999053 - Disclosure - Contents of Significant Accounts - Bonds Payable - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999054 - Disclosure - Contents of Significant Accounts - Details of Long-term Loans (Detail) link:presentationLink link:definitionLink link:calculationLink 999055 - Disclosure - Contents of Significant Accounts - Long-Term Loans - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999056 - Disclosure - Contents of Significant Accounts - Post-Employment Benefits - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999057 - Disclosure - Contents of Significant Accounts - Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets (Detail) link:presentationLink link:definitionLink link:calculationLink 999058 - Disclosure - Contents of Significant Accounts - Defined Benefit Plan Recognized on the Consolidated Balance Sheets (Detail) link:presentationLink link:definitionLink link:calculationLink 999059 - Disclosure - Contents of Significant Accounts - Major Categories of Plan Assets as a Percentage of Fair Value of the Total Plan Assets (Detail) link:presentationLink link:definitionLink link:calculationLink 999060 - Disclosure - Contents of Significant Accounts - Principal Underlying Actuarial Assumptions (Detail) link:presentationLink link:definitionLink link:calculationLink 999061 - Disclosure - Contents of Significant Accounts - Expected Future Benefit Payments (Detail) link:presentationLink link:definitionLink link:calculationLink 999062 - Disclosure - Contents of Significant Accounts - Sensitivity Analysis (Detail) link:presentationLink link:definitionLink link:calculationLink 999063 - Disclosure - Contents of Significant Accounts - Deferred Government Grants (Detail) link:presentationLink link:definitionLink link:calculationLink 999064 - Disclosure - Contents of Significant Accounts - Refund Liabilities - Summary of Refund Liabilities (classified under other current liabilities) (Detail) link:presentationLink link:definitionLink link:calculationLink 999065 - Disclosure - Contents of Significant Accounts - Summary of Provisions (Detail) link:presentationLink link:definitionLink link:calculationLink 999066 - Disclosure - Contents of Significant Accounts - Summary of Information about Provisions of Liabilities (Detail) link:presentationLink link:definitionLink link:calculationLink 999067 - Disclosure - Contents of Significant Accounts - Equity - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999068 - Disclosure - Contents of Significant Accounts - Summary of Stock Held by Associates (Detail) link:presentationLink link:definitionLink link:calculationLink 999069 - Disclosure - Contents of Significant Accounts - Details of Distribution (Detail) link:presentationLink link:definitionLink link:calculationLink 999070 - Disclosure - Contents of Significant Accounts - Non-controlling Interests (Detail) link:presentationLink link:definitionLink link:calculationLink 999071 - Disclosure - Contents Of Significant Accounts - Equity Settled Share Based Payment Of Restricted Stock Plans For Employees (Detail) link:presentationLink link:definitionLink link:calculationLink 999072 - Disclosure - Contents of Significant Accounts - Share-Based Payment - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999073 - Disclosure - Contents Of Significant Accounts - Summary of Assumptions Used for Compensation Cost for These Market Conditions Was Measured at Fair Value Initially by Using Monte Carlo Simulation on The Grant Date (Detail) link:presentationLink link:definitionLink link:calculationLink 999074 - Disclosure - Contents of Significant Accounts - Summary of Disaggregation of Revenue by Geography (Detail) link:presentationLink link:definitionLink link:calculationLink 999075 - Disclosure - Contents of Significant Accounts - Summary of Disaggregation of Revenue by Product (Detail) link:presentationLink link:definitionLink link:calculationLink 999076 - Disclosure - Contents of Significant Accounts - Summary of Disaggregation of Revenue by The Timing of Revenue Recognition (Detail) link:presentationLink link:definitionLink link:calculationLink 999077 - Disclosure - Contents of Significant Accounts - Summary of Balances of Contract Assets and Contract Liabilities (Detail) link:presentationLink link:definitionLink link:calculationLink 999078 - Disclosure - Contents of Significant Accounts - Operating Revenues - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999079 - Disclosure - Contents of Significant Accounts - Operating Costs and Expenses (Detail) link:presentationLink link:definitionLink link:calculationLink 999080 - Disclosure - Contents of Significant Accounts - Operating Costs and Expenses - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999081 - Disclosure - Contents of Significant Accounts - Details of Distribution of Employees' Compensation and Directors' Compensation (Detail) link:presentationLink link:definitionLink link:calculationLink 999082 - Disclosure - Contents of Significant Accounts - Net Other Operating Income and Expenses (Detail) link:presentationLink link:definitionLink link:calculationLink 999083 - Disclosure - Contents of Significant Accounts - Non-Operating Income and Expenses (Detail) link:presentationLink link:definitionLink link:calculationLink 999084 - Disclosure - Contents of Significant Accounts - Components of Other Comprehensive Income (Loss) (Detail) link:presentationLink link:definitionLink link:calculationLink 999085 - Disclosure - Contents of Significant Accounts - Major Components of Income Tax Expense (Detail) link:presentationLink link:definitionLink link:calculationLink 999086 - Disclosure - Contents of Significant Accounts - Reconciliation Between Income Tax Expense and Income Before Tax At UMC's Applicable Tax Rate (Detail) link:presentationLink link:definitionLink link:calculationLink 999087 - Disclosure - Contents of Significant Accounts - Significant Components of Deferred Income Tax Assets and Liabilities (Detail) link:presentationLink link:definitionLink link:calculationLink 999088 - Disclosure - Contents of Significant Accounts - Movement of Deferred Tax (Detail) link:presentationLink link:definitionLink link:calculationLink 999089 - Disclosure - Contents of Significant Accounts - Unused Tax Loss Carry-forward for Which No Deferred Income Tax Assets have been Recognized (Detail) link:presentationLink link:definitionLink link:calculationLink 999090 - Disclosure - Contents of Significant Accounts - Income Tax - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999091 - Disclosure - Contents of Significant Accounts - Earnings Per Share (Detail) link:presentationLink link:definitionLink link:calculationLink 999092 - Disclosure - Contents of Significant Accounts - Reconciliation of Liabilities Arising from Financing Activities (Detail) link:presentationLink link:definitionLink link:calculationLink 999093 - Disclosure - Significant Related Party Transactions - Significant Intercompany Transactions Between Consolidated Entities (Detail) link:presentationLink link:definitionLink link:calculationLink 999094 - Disclosure - Significant Related Party Transactions - Significant Transactions between Company and Other Related Parties (Detail) link:presentationLink link:definitionLink link:calculationLink 999095 - Disclosure - Significant Related Party Transactions - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999096 - Disclosure - Significant Related Party Transactions - Key Management Personnel Compensation (Detail) link:presentationLink link:definitionLink link:calculationLink 999097 - Disclosure - Assets Pledged as Collateral - Summary of Assets Pledged as Collateral (Detail) link:presentationLink link:definitionLink link:calculationLink 999098 - Disclosure - Significant Contingencies and Unrecognized Contract Commitments - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999099 - Disclosure - Significant Subsequent Events - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999100 - Disclosure - Financial Risk and Fair Value Disclosures - Categories of Financial Instruments (Detail) link:presentationLink link:definitionLink link:calculationLink 999101 - Disclosure - Financial Risk and Fair Value Disclosures - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999102 - Disclosure - Financial Risk and Fair Value Disclosures - Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments and Contractual Maturity (Detail) link:presentationLink link:definitionLink link:calculationLink 999103 - Disclosure - Financial Risk and Fair Value Disclosures - Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments and Contractual Maturity (Parenthetical) (Detail) link:presentationLink link:definitionLink link:calculationLink 999104 - Disclosure - Financial Risk and Fair Value Disclosures - Details of Forward Exchange Contracts (Detail) link:presentationLink link:definitionLink link:calculationLink 999105 - Disclosure - Financial Risk and Fair Value Disclosures - Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Detail) link:presentationLink link:definitionLink link:calculationLink 999106 - Disclosure - Financial Risk and Fair Value Disclosures - Reconciliation for Fair Value Measurement in Level 3 Fair Value Hierarchy (Detail) link:presentationLink link:definitionLink link:calculationLink 999107 - Disclosure - Financial Risk and Fair Value Disclosures - Reconciliation for Fair Value Measurement in Level 3 Derivatives Financial Liabilities (Detail) link:presentationLink link:definitionLink link:calculationLink 999108 - Disclosure - Financial Risk and Fair Value Disclosures - Summary of Significant Unobservable Inputs of Fair Value Measurement in Level 3 Fair Value Hierarchy (Detail) link:presentationLink link:definitionLink link:calculationLink 999109 - Disclosure - Financial Risk and Fair Value Disclosures - Summary of Significant Unobservable Inputs of Fair Value Measurement in Level 3 Fair Value Hierarchy (Parenthetical) (Detail) link:presentationLink link:definitionLink link:calculationLink 999110 - Disclosure - Financial Risk and Fair Value Disclosures - Assets and Liabilities Not Recorded at Fair Value on a Recurring Basis But for Which Fair Value is Disclosed (Detail) link:presentationLink link:definitionLink link:calculationLink 999111 - Disclosure - Operating Segment Information - Geographic Non-current Assets Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999112 - Disclosure - Operating Segment Information - Individual Customers Accounting for at least 10% of Operating Revenues (Detail) link:presentationLink link:definitionLink link:calculationLink 999113 - Disclosure - Capital Management - Debt to Capital Ratios (Detail) link:presentationLink link:definitionLink link:calculationLink 1007 - Statement - Contents of Significant Accounts - Earnings Per Share (Detail) Alternate 1 link:presentationLink link:definitionLink link:calculationLink 1008 - Statement - Consolidated Statements of Comprehensive Income Alternate 1 link:presentationLink link:definitionLink link:calculationLink Cover [Abstract] Document Information [Table] Entity Addresses, Address Type [Axis] Address Type [Domain] Business Contact [Member] Document Information [Line Items] Document Type Document Period End Date Amendment Flag Document Fiscal Year Focus Document Fiscal Period Focus Entity Current Reporting Status Entity Filer Category Entity Registrant Name Entity Voluntary Filers Entity Interactive Data Current Entity Well-known Seasoned Issuer Current Fiscal Year End Date Entity Central Index Key Entity Common Stock, Shares Outstanding Security Exchange Name Title of 12(b) Security Trading Symbol Entity File Number Entity Address, Address Line One Document Annual Report Document Transition Report Document Shell Company Report Document Registration Statement Document Accounting Standard Entity Shell Company Entity Emerging Growth Company Entity Address, Country ICFR Auditor Attestation Flag Entity Incorporation, State or Country Code Contact Personnel Name Entity Address, Address Line Two Entity Address, Address Line Three Entity Address, City or Town City Area Code Local Phone Number Contact Personnel Email Address Entity Address, Postal Zip Code Auditor Name Auditor Firm ID Auditor Location Document Financial Statement Error Correction [Flag] Statement Of Financial Position [Abstract] Assets [abstract] Assets Current assets [abstract] Current assets Cash and cash equivalents Cash and cash equivalents Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year Total Less: Cash and cash equivalents Current financial assets at fair value through profit or loss Financial assets at fair value through profit or loss, current Current Current contract assets Contract assets, current Current trade receivables Accounts receivable, net Accounts receivable Current receivables due from related parties Accounts receivable-related parties, net Other current receivables Other receivables Current tax assets, current Current tax assets Current inventories Inventories, net Total Other current assets Other current assets Current assets Total current assets Current financial assets at fair value through other comprehensive income Financial assets at fair value through other comprehensive income, current Financial assets at fair value through other comprehensive income, current Current financial assets at amortised cost Financial assets measured at amortized cost, current Current Non-current assets [abstract] Non-current assets Non-current financial assets at fair value through profit or loss Financial assets at fair value through profit or loss, noncurrent Noncurrent Non-current financial assets at fair value through other comprehensive income Financial assets at fair value through other comprehensive income, noncurrent Financial assets at fair value through other comprehensive income, non-current Investments accounted for using equity method Investments accounted for under the equity method Amount Investments accounted for using equity method for which there are published price quotations Acquisition of investments accounted for under the equity method, Purchase price Property, plant and equipment Property, plant and equipment Beginning balance Ending balance Intangible assets and goodwill Intangible assets Beginning balance Ending balance Non-current prepayments Prepayment for equipment Long-term deposits Refundable deposits Other non-current assets Other noncurrent assets Non-current assets Total non-current assets Right-of-use assets Right-of-use assets Right-of-use assets Deferred tax assets Deferred tax assets Deferred income tax assets Assets Total assets Beginning balance Ending balance Equity and liabilities [abstract] Liabilities and Equity Current liabilities [abstract] Current liabilities Current borrowings Short-term loans Current contract liabilities Contract liabilities, current Current notes and accounts payable Accounts payable The amount of current notes and accounts payable. Other current payables Other payables Current payables for purchase of non-current assets Payables on equipment Current tax liabilities, current Current tax liabilities Current portion of non-current borrowings Current portion of long-term liabilities Other current liabilities Other current liabilities Current liabilities Total current liabilities Current lease liabilities Lease liabilities, current Current Current financial liabilities at fair value through profit or loss Financial liabilities at fair value through profit or loss, current Financial liabilities at fair value through profit or loss, current Financial liabilities at fair value through profit or loss, current Equity [abstract] Equity attributable to the parent company Additional Paid In Capital 1 [Abstract] Additional paid-in capital Additional paid in capital 1 Abstract. Share premium Premiums Capital redemption reserve Treasury stock transactions Transactions with noncontrolling interests Transactions with noncontrolling interests Transactions with noncontrolling interests. Reserve From Sharebased Payment Transactions Share-based payment Reserve from share-based payment transactions. Other equity interest Other Capital 1 [abstract] Capital Capital. Issued capital Common stock Other Reserve [Abstract] Other components of equity Reserve of exchange differences on translation Exchange differences on translation of foreign operations Reserve of gains and losses on financial assets measured at fair value through other comprehensive income Unrealized gains or losses on financial assets measured at fair value through other comprehensive income Unearned Employee Compensation Unearned employee compensation Unearned employee compensation. Retained earnings [abstract] Retained earnings Statutory reserve Legal reserve Unappropriated earnings Unappropriated earnings Unappropriated earnings. Treasury shares Treasury stock Equity attributable to owners of parent Total equity attributable to the parent company Non-controlling interests Non-controlling interests Beginning balance Ending balance Equity Total equity Balance Balance Total equity Non-current liabilities [abstract] Non-current liabilities Non-current portion of non-current bonds issued Bonds payable Net Non-current portion of non-current loans received Long-term loans Total Deferred tax liabilities Deferred tax liabilities Deferred income tax liabilities Non-current net defined benefit liability Net defined benefit liabilities, noncurrent Net defined benefit liabilities, noncurrent recognized on the consolidated balance sheets Noncurrent guarantee deposits Guarantee deposits The amount of non-current guarantee deposits. Other non-current liabilities Other noncurrent liabilities Non-current liabilities Total non-current liabilities Non-current contract liabilities Contract liabilities, noncurrent Contract liabilities, non-current Non-current lease liabilities Lease liabilities, noncurrent Noncurrent Liabilities Total liabilities Beginning balance Ending balance Total liabilities Commitments and Contingencies1 Commitments and contingencies Commitments and contingencies. Equity and liabilities Total liabilities and equity Par value per share Common stock, par value Shares par value Number of shares authorised Common stock, shares authorized Shares authorized Number of shares issued Common stock, shares issued Shares issued Statement of comprehensive income [abstract] Comprehensive income attributable to [abstract] Comprehensive income (loss) attributable to: Comprehensive income, attributable to owners of parent Shareholders of the parent Comprehensive income, attributable to non-controlling interests Non-controlling interests Comprehensive income Total comprehensive income (loss) Earnings per share [abstract] Earnings per share (NTD) Basic earnings (loss) per share Earnings per share-basic Earnings per share-basic (NTD) Diluted earnings (loss) per share Earnings per share-diluted Earnings per share-diluted (NTD) Non Operating Income And Expenses [abstract] Non-operating income and expenses Non-operating income and expenses. Other income Other income Other gains (losses) Other gains and losses Total other gains and losses Finance costs Finance costs Total finance costs Share of profit (loss) of associates and joint ventures accounted for using equity method Share of profit or loss of associates and joint ventures Share of profit of associates and joint ventures Income (loss) from continuing operations Net foreign exchange gain Exchange gain, net Net foreign exchange loss Exchange loss, net Non-operating income and expenses Subtotal Non-operating income and expenses. Profit (loss) before tax Income from continuing operations before income tax Net income before tax Income before tax Tax expense (income) Income tax expense Income tax expense recorded in profit or loss Income tax expense recorded in profit or loss Profit (loss) Net income Net income (loss) Interest income Interest income Bargain Purchase Gain in Acquisition of Equity Investee Bargain purchase gain in acquisition of equity investee Bargain purchase gain in acquisition of equity investee The amount of bargain purchase​ gain in acquisition of equity investee. Operating Expenses 1 [Abstract] Operating expenses Operating expenses. Sales and marketing expense Sales and marketing expenses General and Administrative Expense General and administrative expenses Research and Development Expense Research and development expenses Expected Credit Impairment Gain Loss Expected credit impairment gains Expected credit impairment gain loss. Operating expense excluding cost of sales Subtotal Other comprehensive income [abstract] Other comprehensive income (loss) Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] Items that may be reclassified subsequently to profit or loss Other comprehensive income, before tax, exchange differences on translation Exchange differences on translation of foreign operations Exchange differences on translation of foreign operations, Before tax Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, before tax Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss, Before tax Income tax relating to components of other comprehensive income that will be reclassified to profit or loss Income tax related to items that may be reclassified subsequently Income tax related to items that may be reclassified subsequently to profit or loss Other comprehensive income that will be reclassified to profit or loss, net of tax Subtotal Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract] Items that will not be reclassified subsequently to profit or loss Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans Remeasurements of defined benefit pension plans Remeasurements of defined benefit pension plans, Arising during the period Remeasurements of defined benefit pension plans, Before tax Share of other comprehensive income of associates and joint ventures accounted for using equity method that will not be reclassified to profit or loss, before tax Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss, Arising during the period Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss, Before tax Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss Income tax related to items that will not be reclassified subsequently Income tax related to items that will not be reclassified subsequently to profit or loss Other comprehensive income that will not be reclassified to profit or loss, net of tax Subtotal Other comprehensive income, before tax, gains (losses) from investments in equity instruments Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income, Arising during the period Other comprehensive income Total other comprehensive income (loss) Other comprehensive income (loss) Profit (loss), attributable to [abstract] Net income (loss) attributable to: Profit (loss), attributable to owners of parent Shareholders of the parent Net income attributable to the parent company Profit (loss), attributable to non-controlling interests Non-controlling interests Net income (loss) Revenue Operating revenues Cost of sales Operating costs Gross profit Gross profit Other operating income (expense) Net other operating income and expenses Total Profit (loss) from operating activities Operating income Statement of changes in equity [abstract] Statement of changes in equity [table] Statement of changes in equity [table] Classes of share capital [axis] Classes of share capital [axis] Classes of share capital [domain] Classes of share capital [domain] Ordinary shares [member] Common stock [member] Common stocks [member] Components of equity [axis] Components of equity [axis] Components of equity [domain] Components of equity [domain] Issued capital [member] Capital [member] Additional paid-in capital [member] Additional paid-in capital [member] Statutory reserve [member] Legal Reserve [member] Unappropriated earnings [member] Unappropriated Earnings [member] Unappropriated earnings. Reserve of exchange differences on translation [member] Exchange Differences on Translation of Foreign Operations [member] Reserve of gains and losses on financial assets measured at fair value through other comprehensive income [member] Unrealized Gains or Losses on Financial Assets Measured at Fair Value through Other Comprehensive Income [Member] Treasury shares [member] Treasury Stock [member] Equity attributable to owners of parent [member] Equity attributable to the parent company [member] Non-controlling interests [member] Non-controlling Interests [member] Special Reserve [member] Special Reserve [member] Special Reserve [member] Unearned Employee Compensation [Member] Unearned Employee Compensation [Member] Unearned employee compensation. Statement of changes in equity [line items] Statement of changes in equity [line items] Appropriation And Distribution Of Retained Earnings [Abstract] Appropriation and distribution of retained earnings Appropriation and distribution of retained earnings. Increase (decrease) through transfer to statutory reserve, equity Legal reserve Appropriation of earnings Dividends recognised as distributions to owners of parent Cash dividends Appropriation of earnings, Cash dividends Special Reserve Reversed Special reserve reversed Special reserve reversed. Increase (decrease) through share-based payment transactions, equity Share-based payment transaction Share of changes in net assets of associates and joint ventures accounted for using equity method Share of changes in net assets of associates and joint ventures accounted for using equity method Share of changes in net assets of associates and joint ventures accounted for using equity method. Increase (decrease) through changes in ownership interests in subsidiaries that do not result in loss of control, equity Changes in subsidiaries' ownership Increase Decrease Through Adjustments Due To Reciprocal Stockholdings Held By Subsidiaries And Associates Adjustments due to reciprocal stockholdings held by subsidiaries and associates The increase (decrease) in the entity's equity resulting from the adjustments due to reciprocal stockholdings held by subsidiaries and associates. Increase (decrease) through other changes, equity Others Increase (decrease) in noncontrolling interests Non-Controlling Interests Others Increase (decrease) in noncontrolling interests. Increase Decrease Through Acquisition Or Disposal Of Subsidiary The differences between the fair value of the consideration paid or received from acquiring or disposing subsidiaries and the carrying amounts of the subsidiaries Increase decrease through acquisition or disposal of subsidiary. Cumulative gain (loss) on disposal of investments in equity instruments designated at fair value through other comprehensive income Disposal of equity instruments investments measured at fair value through other comprehensive income Cumulative gains (losses) reclassified to retained earnings due to derecognition Disposal Of Investments Measured Under the Equity Method Effect on Equity Disposal of investments accounted for under the equity method Disposal of investments measured under the equity method effect on equity. Statement of Cash Flows [Abstract] Cash flows from (used in) financing activities [abstract] Cash flows from financing activities: Proceeds from current borrowings Increase in short-term loans Repayments of current borrowings Decrease in short-term loans Proceeds from issue of bonds, notes and debentures Proceeds from bonds issued Payments for debt issue costs Bonds issuance costs Repayments of bonds, notes and debentures Redemption of bonds Proceeds from non-current borrowings Proceeds from long-term loans Repayments of non-current borrowings Repayments of long-term loans Increase in guarantee deposits Increase in guarantee deposits The cash inflow from increase in guarantee deposits. Decrease in guarantee deposits Decrease in guarantee deposits The cash outflow for decrease in guarantee deposits. Change in Noncontrolling Interest Classified as Financing Activities Change in non-controlling interests Change in noncontrolling interest classified as financing activities. Cash flows from (used in) financing activities Net cash used in financing activities Payments of lease liabilities, classified as financing activities Cash payments for the principal portion of the lease liability Cash Dividends And Cash Distributed From Additional Paid In Capital Cash dividends Cash dividends and cash distributed from additional paid in capital. Decrease in Other Financial Liabilities Classified as Financing Activities Decrease in other financial liabilities Decrease in other financial liabilities classified as financing activities. Cash flows from (used in) investing activities [abstract] Cash flows from investing activities: Purchase of Financial Assets at Fair Value Through Profit or Loss Acquisition of financial assets at fair value through profit or loss The cash outflow for the purchase of financial assets at fair value through profit or loss. Proceeds from Disposal of Financial Assets at Fair Value Through Profit or Loss Proceeds from disposal of financial assets at fair value through profit or loss The cash inflow from the disposal of financial assets at fair value through profit or loss. Acquisition Of Financial Assets Measured At Amortized Cost Acquisition of financial assets measured at amortized cost The cash outflow for the purchase of financial assets measured at amortized cost. Purchase of interests in investments accounted for using equity method Acquisition of investments accounted for under the equity method Purchase of financial instruments, classified as investing activities Increase in prepayment for investments Net Cash Flows From Losing Control Of Subsidiaries Or Businesses Classified As Investing Activities Disposal of subsidiary Net cash flows from losing control of subsidiaries or businesses classified as investing activities. Purchase of property, plant and equipment, classified as investing activities Acquisition of property, plant and equipment Proceeds from sales of property, plant and equipment, classified as investing activities Proceeds from disposal of property, plant and equipment Increase in refundable deposits Increase in refundable deposits The cash outflow for increase in refundable deposits. Decrease in refundable deposits Decrease in refundable deposits The cash inflow from decrease in refundable deposits. Purchase of intangible assets, classified as investing activities Acquisition of intangible assets Acquisition of intangible assets Proceeds from government grants, classified as investing activities Government grants related to assets acquisition Purchase of other long-term assets, classified as investing activities Increase in other noncurrent assets Proceeds from sales of other long-term assets, classified as investing activities Decrease in other noncurrent assets Cash flows from (used in) investing activities Net cash used in investing activities Proceeds from sales of investments accounted for using equity method Proceeds from disposal of investments accounted for under the equity method Cash Flows From Acquisition Of Subsidiaries Net Of Cash Acquired Acquisition of subsidiary (net of cash acquired) Cash flows from acquisition of subsidiaries net of cash acquired. Proceeds From Redemption Of Financial Assets Measured At Amortized Cost Classified As Investing Activities Proceeds from redemption of financial assets measured at amortized cost Proceeds from redemption of financial assets measured at amortized cost classified as investing activities. PurchaseOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeOrLoss Acquisition of financial assets at fair value through other comprehensive income PurchaseOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeOrLoss Proceeds From Capital Reduction Financial Assets at Fair Value through Other Comprehensive Income Proceeds from capital reduction of financial assets at fair value through other comprehensive income Proceeds from capital reduction financial assets at fair value through other comprehensive income. Proceeds from Capital Reduction of Investments Accounted for Under the Equity Method Proceeds from capital reduction of investments accounted for under the equity method Proceeds from capital reduction of investments accounted for under the equity method. Cash flows from (used in) operating activities [abstract] Cash flows from operating activities: Adjustments to reconcile profit (loss) [abstract] Adjustments to reconcile net income before tax to net cash provided by operating activities: Changes in Operating Assets and Liabilities [abstract] Changes in operating assets and liabilities: Changes in operating assets and liabilities. Adjustments For Decrease Increase In Financial Assets And Liabilities At Fair Value Through Profit Or Loss Financial assets and liabilities at fair value through profit or loss Adjustments for decrease (increase) in financial assets and liabilities at fair value through profit or loss. Increase (decrease) through cumulative catch-up adjustments to revenue, contract assets Contract assets Adjustments for decrease (increase) in trade accounts receivable Accounts receivable Adjustments for decrease (increase) in other operating receivables Other receivables Adjustments for decrease (increase) in inventories Inventories Adjustments for decrease (increase) in other current assets Other current assets Adjustments for increase (decrease) in contract fulfillment costs Contract fulfillment costs Adjustments for increase (decrease) in contract fulfillment costs. Increase (decrease) through cumulative catch-up adjustments to revenue, contract liabilities Contract liabilities Adjustments for increase (decrease) in trade accounts payable Accounts payable Adjustments for increase (decrease) in other operating payables Other payables Adjustments for increase (decrease) in other current liabilities Other current liabilities Adjustments for increase (decrease) in employee benefit liabilities Net defined benefit liabilities Adjustments For Increase Decrease In Other Noncurrent Liabilities Other noncurrent liabilities Adjustments for increase (decrease) in other non-current liabilities. Cash flows from (used in) operations Cash generated from operations Interest received, classified as operating activities Interest received Dividends received, classified as operating activities Dividend received Interest paid, classified as operating activities Interest paid Income taxes paid (refund), classified as operating activities Income tax paid Depreciation, property, plant and equipment Depreciation Amortisation expense Amortization Expected Credit Impairment Loss Gains Expected credit impairment gains Expected credit impairment loss (gains). Adjustments for fair value losses (gains) Net loss (gain) of financial assets and liabilities at fair value through profit or loss Adjustments for interest expense Interest expense Adjustments for interest income Interest income Dividend income Dividend income Adjustments for share-based payments Share-based payment Gains on disposals of property, plant and equipment Gain on disposal of property, plant and equipment Gain on disposal of property, plant and equipment Adjustments For Exchange loss (gain) on financial assets and liabilities Exchange loss (gain) on financial assets and liabilities Adjustments for exchange loss (gain) on financial assets and liabilities. Amortization of Deferred Government Grants Amortization of deferred government grants Other operating income Amortization of deferred government grants. Adjustments to reconcile profit (loss) other than changes in working capital Income and expense adjustments Loss Gain On Lease Modification Gain on lease modification The loss (gain) on lease modification. Gains on Disposals of Subsidiary Gain on disposal of subsidiary Gains on disposals of subsidiary. Loss Gain on Disposal of Investments Accounted for under the Equity Method Loss (gain) on disposal of investments accounted for under the equity method Loss (gain) on disposal of investments accounted for under the equity method. Cash flows from (used in) operating activities Net cash provided by operating activities Effect of exchange rate changes on cash and cash equivalents Effect of exchange rate changes on cash and cash equivalents Increase (decrease) in cash and cash equivalents Net increase (decrease) in cash and cash equivalents History And Organization [Abstract] History and organization abstract. Disclosure In Entirety Of Notes And Other Information Explanatory History and Organization Disclosure in entirety of notes and other information explanatory. Disclosure Of Date And Procedures Of Authorization Of Financial Statements For Issue [Abstract] The entire disclosure of date and procedures of authorization of financial statements for issue. Disclosure of authorisation of financial statements [text block] Date and Procedures of Authorization of Financial Statements for Issue Disclosure Of New Accounting Pronouncements Under International Financial Reporting Standards [Abstract] Disclosure of new accounting pronouncements under International Financial Reporting Standards. Disclosure Of New Accounting Pronouncements Under IFRS Accounting Standards Explanatory New Accounting Pronouncement under IFRS Accounting Standards Disclosure of new accounting pronouncements under IFRS Accounting Standards. Disclosure Of Summary Of Material Accounting Policies [Abstract] Disclosure of summary of material​ accounting policies. Disclosure of material accounting policy information [text block] Summary of Material Accounting Policies Text block1 [abstract] Text block1 [abstract] Text block. Disclosure of accounting judgements and estimates [text block] Significant Accounting Judgments, Estimates and Assumptions Contents Of Significant Accounts [Abstract] Contents of significant accounts. Contents of Significant Accounts Explanatory Contents of Significant Accounts Contents of significant accounts. Disclosure of transactions between related parties [abstract] Disclosure of related party [text block] Significant Related Party Transactions Disclosure Of Assets Pledged As Collateral [Abstract] The entire disclosure of assets pledged as collateral. Disclosure of collateral [text block] Assets Pledged as Collateral Significant Contingencies And Unrecognized Contract Commitments [Abstract] Significant contingencies and unrecognized contract commitments. Disclosure of commitments and contingent liabilities [text block] Significant Contingencies and Unrecognized Contract Commitments Disclosure of non-adjusting events after reporting period [abstract] Disclosure of events after reporting period [text block] Significant Subsequent Events Disclosure of detailed information about financial instruments [abstract] Disclosure Of Financial Instruments [Abstract] Disclosure of financial instruments [text block] Financial Risk and Fair Value Disclosures Disclosure of operating segments [abstract] Disclosure Of Operating Segments [Abstract] Disclosure of entity's operating segments [text block] Operating Segment Information Capital Management [Abstract] Capital management. Disclosure of objectives, policies and processes for managing capital [text block] Capital Management Statement of IFRS compliance [text block] Statement of Compliance Disclosure of basis of preparation of financial statements [text block] Basis of Preparation Disclosure of basis of consolidation [text block] General Description of Reporting Entity Description of accounting policy for business combinations and goodwill [text block] Business Combinations and Goodwill Description of accounting policy for functional currency [text block] Foreign Currency Transactions Description of accounting policy for foreign currency translation [text block] Translation of Foreign Currency Financial Statements Description Of Accounting Policy For Convenience Translation [Text Block] Convenience Translation into U.S. Dollars Description of accounting policy for convenience translation. Description Of Accounting Policy For Current And Noncurrent Classification Explanatory Current and Non-Current Distinction Description of accounting policy for current and noncurrent classification. Description of accounting policy for determining components of cash and cash equivalents [text block] Cash Equivalents Description of accounting policy for financial instruments [text block] Financial Instruments Description of accounting policy for measuring inventories [text block] Inventories Description of accounting policy for investment in associates and joint ventures [text block] Investments Accounted for Under the Equity Method Description of accounting policy for property, plant and equipment [text block] Property, Plant and Equipment Description of accounting policy for intangible assets and goodwill [text block] Intangible Assets Description of accounting policy for impairment of non-financial assets [text block] Impairment of Non-Financial Assets Description Of Accounting Policy For Bonds Explanatory Bonds The description of the entity's accounting policy for bonds. Description of accounting policy for employee benefits [text block] Post-Employment Benefits Description of accounting policy for government grants [text block] Government Grants Description of accounting policy for treasury shares [text block] Treasury Stock Description of accounting policy for share-based payment transactions [text block] Share-Based Payment Transactions Description of accounting policy for recognition of revenue [text block] Revenue Recognition Description of accounting policy for income tax [text block] Income Tax Description of accounting policy for earnings per share [text block] Earnings per Share Description of accounting policy for leases [text block] Lease Description of accounting policy for provisions [text block] Provision Disclosure of subsidiaries [text block] Consolidated Entities Contents Of Significant Accounts [Table] Categories of financial assets [axis] Categories of financial assets [axis] Categories of financial assets [domain] Categories of financial assets [domain] Financial assets at fair value through profit or loss, category [member] Financial assets at fair value through profit or loss [member] Financial assets at fair value through other comprehensive income, category [member] Financial assets at fair value through other comprehensive income [member] Financial assets at amortised cost, category [member] Financial assets measured at amortized cost [member] Classes of financial assets [axis] Classes of financial assets [axis] Classes of financial assets [domain] Classes of financial assets [domain] Trade receivables [member] Trade receivables [member] Accounts receivable [member] Joint ventures [axis] Joint ventures [axis] Joint ventures [domain] Joint ventures [domain] Maturity [axis] Maturity [axis] Maturity [domain] Maturity [domain] Later than one year [member] More than 1 year [member] Net defined benefit liability (asset) [axis] Net defined benefit liability (asset) [axis] Net defined benefit liability (asset) [domain] Net defined benefit liability (asset) [domain] Plan assets [member] Plan assets [member] Present value of defined benefit obligation [member] Present value of defined benefit obligation [member] Associates [axis] Associates [axis] Associates [domain] Associates [domain] Aggregated individually immaterial associates [member] Aggregated individually immaterial associates [member] Contents Of Significant Accounts [Line Items] Contents of significant accounts. Disclosure of cash and cash equivalents [text block] Cash and Cash Equivalents Disclosure of financial assets [text block] Financial Assets Disclosure Of Aging Analysis Of Accounts Receivable [Text Block] Aging Analysis of Accounts Receivable Disclosure of aging analysis of accounts receivable. Disclosure of allowance for credit losses [text block] Movement of Loss Allowance Disclosure of inventories [text block] Inventories, Net Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [text block] Summary of Fair Value of Each Investment in Equity Instrument Disclosure of investments accounted for using equity method [text block] Details of Investments Accounted for Under the Equity Method Disclosure of interests in associates [text block] Aggregate Amount of the Company's Share of its Individually Immaterial Associates Disclosure of detailed information about property, plant and equipment [text block] Property, Plant and Equipment Disclosure of intangible assets [text block] Intangible Assets Disclosure of depreciation and amortisation expense [text block] Amortization Amounts of Intangible Assets Disclosure of detailed information about borrowings [text block] Details of Loans Disclosure of debt instruments [text block] Bonds Payable Disclosure of detailed information about terms and conditions of bonds explanatory Summary of Terms and Conditions of Bonds The disclosure of detailed information about terms and conditions of bonds. Disclosure of net defined benefit liability (asset) [text block] Defined Benefit Plan Recognized on the Consolidated Balance Sheets Disclosure of fair value of plan assets [text block] Major Categories of Plan Assets as a Percentage of Fair Value of the Total Plan Assets Disclosure of additional information about defined benefit plans [text block] Principal Underlying Actuarial Assumptions Disclosure of information about maturity profile of defined benefit obligation [text block] Expected Future Benefit Payments Disclosure of sensitivity analysis for actuarial assumptions [text block] Sensitivity Analysis Disclosure of government grants [text block] Deferred Government Grants Disclosure of refund liability [text block] Summary of Refund Liabilities (classified under other current liabilities) Disclosure of refund liability [text block] Disclosure Of Dividends And Statutory Reserve Explanatory Details of Distribution The disclosure of dividends and statutory reserve. Disclosure of non-controlling interests [text block] Non-controlling Interests Disaggregation of revenue by geography [Table Text Block] Summary of Disaggregation of Revenue by Geography Disaggregation of revenue by geography. Disclosure of detailed information about revenue from products [text block] Summary of Disaggregation of Revenue by Product Disclosure of detailed information about revenue from products. Disclosure of disaggregation of revenue from contracts with customers [text block] Summary of Disaggregation of Revenue by the Timing of Revenue Recognition Disclosure Of Balances Of Contract Assets And Contract Liabilities Explanatory Summary of Balances of Contract Assets and Contract Liabilities Disclosure of balances of contract assets and contract liabilities explanatory. Disclosure of expenses by nature [text block] Employee Benefit, Depreciation and Amortization Expenses Disclosure of information about employees and directors [text block] Details of Distribution of Employees' Compensation and Directors' Compensation The entire disclosure of information about distributions of employees' compensation and directors' compensation. Disclosure of other operating income (expense) [text block] Net Other Operating Income and Expenses Disclosure Of Detailed Information About Non Operating Income And Expenses Explanatory [Text Block] Non-Operating Income and Expenses Disclosure of detailed information about non-operating income and expenses. Disclosure of analysis of other comprehensive income by item [text block] Components of Other Comprehensive Income (Loss) Disclosure of income tax [text block] Major Components of Income Tax Expense Disclosure of Reconciliation of Income Tax Expense Benefit Explanatory [Table Text block] Reconciliation Between Income Tax Expense and Income Before Tax at UMC's Applicable Tax Rate Disclosure of reconciliation of income tax expense and benefit. Disclosure of deferred taxes [text block] Significant Components of Deferred Income Tax Assets and Liabilities Disclosure Of Detailed Information About Deferred Taxes Explanatory [Text Block] Movement of Deferred Tax Disclosure of detailed movement information about deferred taxes. Disclosure of temporary difference, unused tax losses and unused tax credits [text block] Unused Tax Credits and Losses Disclosure of earnings per share [text block] Earnings Per Share Disclosure of reconciliation of liabilities arising from financing activities [text block] Reconciliation of Liabilities Arising from Financing Activities Disclosure Of Detailed Information About Lease Right Of Use Assets Explanatory [Text Block] Disclosure Of Detailed Information About Lease Right Of Use Assets Explanatory Disclosure Of Detailed Information About Lease Right Of Use Assets Explanatory. Disclosure Of Income Recognized In Profit Or Loss From Equity Instruments Designated As Fair Value Through Other Comprehensive Income [Table Text Block] Summary of Income Recognized in Profit or Loss from Equity Instruments Designated as Fair Value Through Other Comprehensive Income Disclosure​ of income​ recognized​ in profit or loss from equity instruments designated as fair value through​ other comprehensive​ income​. Disclosure of financial instruments at fair value through profit or loss [text block] Financial Liabilities at Fair Value Through Profit or Loss, Current Assumptions Used For Share Based Payment Explanatory [Table Text Block] Assumptions Used for Share-Based Payment Assumptions used for share-based payment explanatory. Disclosure Of Detailed Information About Interest Expense Capitalized Explanatory Summary of Interest Expense Capitalized Disclosure of detailed information about interest expense capitalized. Disclosure of terms and conditions of share-based payment arrangement [text block] Disclosure of Equity-Settled Share-Based Payment of Restricted Stock Plans for Employees Disclosure Of Stock Held By Associates Explanatory Summary of Stock Held by Associates Disclosure of stock held by associates explanatory. Disclosure of other provisions [text block] Summary of Information about Provisions of Liabilities Disclosure of provisions [text block] Summary of Provisions Disclosure Of Disposed And Derecognized Equity Instrument Investments Measured At Fair Value Through Other Comprehensive Income Explantory Summary of Details on Derecognition of Such Investments Disclosure of disposed and derecognized equity instrument investments measured at fair value through other comprehensive income explanatory. Temporary difference, unused tax losses and unused tax credits [axis] Temporary difference, unused tax losses and unused tax credits [axis] Temporary difference, unused tax losses and unused tax credits [domain] Temporary difference, unused tax losses and unused tax credits [domain] Unused tax losses [member] Unused tax losses [member] Loss carry-forward [member] Subsidiaries [axis] Subsidiaries [axis] Subsidiaries [domain] Subsidiaries [domain] Types of share-based payment arrangements [axis] Types of share-based payment arrangements [domain] Restricted Stock Plan For Employees [Member] Restricted stock plan for employees. Disclosure of transactions between related parties [table] Disclosure of transactions between related parties [table] Categories of related parties [axis] Categories of related parties [axis] Categories of related parties [domain] Categories of related parties [domain] Total for all subsidiaries [member] Subsidiaries [member] Subsidiary [member] Other related parties [member] Other related parties [member] Other related party [member] Disclosure of transactions between related parties [line items] Disclosure of transactions between related parties [line items] Disclosure of transactions between related parties [text block] Significant Transactions Between the Company and Related Parties Disclosure of information about key management personnel [text block] Key Management Personnel Compensation Disclosure Of Detailed Information About Assets Pledged As Collateral Explanatory [Text Block] Summary of Assets Pledged as Collateral Disclosure of detailed information about assets pledged as collateral. Disclosure of detailed information about financial instruments [table] Disclosure of detailed information about financial instruments [table] Measurement [axis] Measurement [axis] Measurement [domain] Measurement [domain] Recurring fair value measurement [member] Recurring fair value measurement [member] Not measured at fair value in statement of financial position but for which fair value is disclosed [member] Not measured at fair value in statement of financial position but for which fair value is disclosed [member] Disclosure of detailed information about financial instruments [line items] Disclosure of detailed information about financial instruments [line items] Disclosure of detailed information about financial instruments [text block] Categories of Financial Instruments Disclosure of Maturity Analysis for Financial Liabilities [Text Block] Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments and Contractual Maturity Disclosure of maturity analysis for financial liabilities. Disclosure of Fair Value Measurement of Assets and Liabilities [Text Block] Assets and Liabilities Measured and Recorded at Fair Value The disclosure of the level of the fair value hierarchy within which the fair value measurements are categorized for each class of assets and liabilities measured at fair value. Disclosure of fair value measurement of assets [text block] Reconciliation for Fair Value Measurement in Level 3 Fair Value Hierarchy Disclosure of significant unobservable inputs used in fair value measurement of equity [text block] Summary of Significant Unobservable Inputs of Fair Value Measurement in Level 3 Fair Value Hierarchy Disclosure of fair value measurement of liabilities [text block] Reconciliation for Fair Value Measurement in Level 3 Derivatives Financial Liabilities Disclosure Of Forward Exchange Contracts Explanatory Details of Forward Exchange Contracts Disclosure of forward exchange contracts explanatory. Disclosure of geographical areas [text block] Geographic Non-current Assets Information Disclosure of major customers [text block] Individual Customers Accounting for at least 10% of Operating Revenues Disclosure of debt to capital ratios [Text Block] Debt to Capital Ratios The disclosure of debt to capital ratios. Disclosure of subsidiaries [abstract] Disclosure of subsidiaries [table] Disclosure of subsidiaries [table] Disclosure of subsidiaries [line items] Disclosure of subsidiaries [line items] Name of investor Investor Name of investor. Description of nature of entity's operations and principal activities Business nature Proportion of ownership interest in subsidiary Percentage of ownership UMC Group (USA) [Member] UMC GROUP (USA) [member] UMC Group (USA). United Microelectronics Europe BV [Member] UNITED MICROELECTRONICS (EUROPE) B.V. [member] United microelectronics (europe) BV. UMC Capital Corp. [Member] UMC CAPITAL CORP. [member] UMC Capital Corp. Green Earth Limited G E [Member] GREEN EARTH LIMITED (GE) [member] Green Earth Limited (GE). TLC Capital Co Ltd TLC [Member] TLC CAPITAL CO., LTD. (TLC) [member] TLC Capital Co., Ltd. (TLC). UMC Investment (Samoa) Limited [Member] UMC INVESTMENT (SAMOA) LIMITED [member] UMC Investment (Samoa) Limited. Fortune Venture Capital Corp F O R T U N E [Member] FORTUNE VENTURE CAPITAL CORP. (FORTUNE) [member] Fortune Venture Capital Corp. (FORTUNE). UMC Korea Co Ltd [Member] UMC KOREA CO., LTD. [member] UMC Korea Co., Ltd. Omni Global Limited O M N I [Member] OMNI GLOBAL LIMITED (OMNI) [member] Omni Global Limited (OMNI). Sino Paragon Limited [Member] SINO PARAGON LIMITED [member] Sino Paragon Limited. Best Elite International Limited B E [Member] BEST ELITE INTERNATIONAL LIMITED (BE) [member] Best Elite International Limited (BE). Wavetek Microelectronics Corporation W A V E T E K [Member] WAVETEK MICROELECTRONICS CORPORATION (WAVETEK) [member] WAVETEK MICROELECTRONICS CORPORATION (WAVETEK) (WTK) [member] Wavetek Microelectronics Corporation (WAVETEK). Soaring Capital Corp [Member] SOARING CAPITAL CORP. [member] Soaring Capital Corp. Unitruth Advisor Shanghai Co Ltd [Member] UNITRUTH ADVISOR (SHANGHAI) CO., LTD. [member] Unitruth Advisor (Shanghai) Co., Ltd. United Microchip Corporation [Member] UNITED MICROCHIP CORPORATION [member] United Microchip Corporation. Tera Energy Development Co Ltd T E R A E N E R G Y [Member] TERA ENERGY DEVELOPMENT CO., LTD. (TERA ENERGY) [member] Tera Energy Development Co., Ltd. (TERA ENERGY). Everrich Energy Investment (H K) Limited E V E R R I C H H K [Member] EVERRICH ENERGY INVESTMENT (HK) LIMITED (EVERRICH-HK) [member] Everrich Energy Investment (HK) Limited (EVERRICH-HK). Everrich Jining New Energy Technology Co Ltd [Member] EVERRICH (JINING) NEW ENERGY TECHNOLOGY CO., LTD. (formerly EVERRICH (SHANDONG) ENERGY CO., LTD.) [member] United Microtechnology Corporation California [Member] UNITED MICROTECHNOLOGY CORPORATION (CALIFORNIA) [member] United Microtechnology Corporation (California). ECP Vita Pte. Ltd. [Member] ECP VITA PTE. LTD. [member] ECP Vita Pte. Ltd. Infoshine Technology Limited I N F O S H I N E [Member] INFOSHINE TECHNOLOGY LIMITED (INFOSHINE) [member] Infoshine Technology Limited (INFOSHINE). Oakwood Associates Limited O A K W O O D [Member] OAKWOOD ASSOCIATES LIMITED (OAKWOOD) [member] Oakwood Associates Limited (OAKWOOD). Hejian Technology Suzhou Co Ltd HEJIAN [Member] HEJIAN TECHNOLOGY (SUZHOU) CO., LTD. (HEJIAN) [member] Hejian Technology (Suzhou) Co., Ltd. (HEJIAN). United Semiconductor Xiamen Co Ltd U S C X M [Member] UNITED SEMICONDUCTOR (XIAMEN) CO., LTD. (USCXM) [member] United Semiconductor (Xiamen) Co., Ltd. (USCXM). United Semiconductor Japan Co Ltd U S J C [Member] UNITED SEMICONDUCTOR JAPAN CO., LTD. (USJC) [member] UNITED SEMICONDUCTOR JAPAN CO., LTD. (USJC) [member] United Semiconductor Japan Co., Ltd. (USJC). Wavetek Microelectronics Corporation USA [Member] WAVETEK MICROELECTRONICS CORPORATION (USA) [member] Wavetek Microelectronics Corporation (USA). Disclosure Of Initial Application Of Standards Or Interpretations [Abstract] Closing foreign exchange rate Convenience translation into U.S. Dollars, rate of USD1.00 Disclosure of detailed information about property, plant and equipment [abstract] Disclosure of detailed information about property, plant and equipment [table] Disclosure of detailed information about property, plant and equipment [table] Classes of property, plant and equipment [axis] Classes of property, plant and equipment [axis] Classes of property, plant and equipment [domain] Classes of property, plant and equipment [domain] Buildings [member] Buildings [member] Machinery And Equipment1 [Member] Machinery and equipment [member] Machinery and equipment. Vehicles [member] Transportation equipment [member] Fixtures and fittings [member] Furniture and fixtures [member] Leasehold improvements [member] Leasehold improvement [member] Disclosure of detailed information about property, plant and equipment [line items] Disclosure of detailed information about property, plant and equipment [line items] Description of useful life, property, plant and equipment Estimated useful lives of the assets Useful life measured as period of time, property, plant and equipment Estimated useful lives of the assets Range [axis] Range [axis] Range [domain] Range [domain] Bottom of range [member] Bottom of range [member] Top of range [member] Top of range [member] Disclosure of initial application of standards or interpretations [table] Disclosure of initial application of standards or interpretations [table] Classes of intangible assets and goodwill [axis] Classes of intangible assets and goodwill [axis] Classes of intangible assets and goodwill [domain] Classes of intangible assets and goodwill [domain] Computer software [member] Software [member] Technology-based intangible assets [member] Patent and technology license fee [member] Other intangible assets [member] Others [member] Disclosure of initial application of standards or interpretations [line items] Disclosure of initial application of standards or interpretations [line items] Useful Lives Of Amortisation Rates Intangible Assets Other Than Goodwill Estimated useful life of intangible assets Useful lives of amortisation rates intangible assets other than goodwill. Cash And Cash Equivalents [Abstract] Cash on hand Cash on hand and petty cash Balances with banks Checking and savings accounts Short-term deposits, classified as cash equivalents Time deposits Reverse repurchase agreements and cash collateral on securities borrowed Repurchase agreements collateralized by government bonds and corporate notes Additional disclosures for amounts recognised as of acquisition date for each major class of assets acquired and liabilities assumed [abstract] Disclosure of financial assets [table] Disclosure of financial assets [table] Common Stocks 1 [Member] Common stocks [member] Common stocks. Preferred Stocks 1 [Member] Preferred stocks [member] Preferred stocks. Funds [Member] Funds [member] Funds. Convertible bonds [member] Convertible bonds [member] Convertible bonds. Forward exchange contracts [member] Forward exchange contracts Others [Member] Others [member] Others. Disclosure of financial assets [line items] Disclosure of financial assets [line items] Financial assets at fair value through profit or loss, mandatorily measured at fair value Financial assets mandatorily measured at fair value through profit or loss Financial assets at fair value through profit or loss Total Financial assets at fair value through profit or loss Categories of non-current financial assets [abstract] Preference shares [member] Preferred stocks [member] Financial assets at fair value through other comprehensive income Total Financial assets at fair value through other comprehensive income Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [abstract] Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [table] Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [table] UNIMICRON Holding Limited [Member] UNIMICRON HOLDING LIMITED [member] Unimicron Holding Limited [member] I T E Tech Inc [Member] ITE TECH. INC. [member] ITE Tech. Inc. [member] Shin Etsu Handotai Taiwan Co.Ltd [member] [Member] SHIN-ETSU HANDOTAI TAIWAN CO., LTD. [member] Shin Etsu Handotai Taiwan Co., Ltd. [member]. M T I C Holdings Pte Ltd [Member] MTIC HOLDINGS PTE. LTD. [member] MTIC Holdings Pte. Ltd. [member] Chipbond Technology Corporation [Member] CHIPBOND TECHNOLOGY CORPORATION [member] Chipbond Technology Corporation [member] TAIWAN SMART ELECTRICITY And ENERGY CO., LTD. [Member] TAIWAN SMART ELECTRICITY & ENERGY CO., LTD. KAIHONG ENERGY CO., LTD. [Member] KAI-HONG ENERGY CO., LTD. [Member] KAI-HONG ENERGY CO., LTD. Novatek Microelectronics Corp NOVATEK [Member] NOVATEK MICROELECTRONICS CORP. (NOVATEK) [member] Novatek​ Micro​electronics ​Corp. (NOVATEK) [member] Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] Investments in equity instruments designated at fair value through other comprehensive income Fair value of investments in equity instruments Dividend Income [Abstract] Dividend income recognized in profit or loss [abstract] Dividend income. Dividends recognised for investments in equity instruments designated at fair value through other comprehensive income, held at end of reporting period Held at end of period Dividends recognised for investments in equity instruments designated at fair value through other comprehensive income, derecognised during period Derecognized during the period Dividends Recognised For Investments In Equity Instruments Designated As Measured At Fair Value Through Other Comprehensive Income Held At End Of Reporting Period And Derecognised During Period Total The amount of dividends related to investments in equity instruments that the entity has designated at fair value through other comprehensive income, held at the end of the reporting period and derecognised during the reporting period. Disposed and Derecognized Investments Designated as Fair Value Through Other Comprehensive Income [Abstract] Disposed and derecognized investments designated as fair value through other comprehensive income. Fair Value Of Investments Measured At Fair Value Through Other Comprehensive Income At Date Of Disposal Fair value on the date of disposal Fair value of investments measured at fair value through other comprehensive income at date of disposal. Financial Assets Measured At Amortized Cost [Abstract] Financial assets measured at amortized cost [abstract] Financial assets measured at amortized cost Financial assets measured at amortized cost. Financial assets at amortised cost Total Non-current financial assets at amortised cost Non-current Deposits Measured At Amortized Cost Time deposits with original maturities over three months Deposits measured at amortized cost. Trade and other current receivables [abstract] Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Carrying amount, accumulated depreciation, amortization and impairment and gross carrying amount [Axis] Carrying amount [member] Carrying amount [member] Gross carrying amount [member] Cost [member] Allowances [member] Loss Allowance [member] Allowances. Loss Allowance Less: loss allowance The amount of loss allowance. Impairment of financial assets [axis] Impairment of financial assets [axis] Impairment of financial assets [domain] Impairment of financial assets [domain] Financial assets neither past due nor impaired [member] Neither past due [member] Financial assets past due but not impaired [member] Past due [member] Past due status [axis] Past due status [axis] Past due status [domain] Past due status [domain] Not later than one month [member] Less than or equal to 30 days [member] Later than one month and not later than two months [member] 31 to 60 days [member] Later than two months and not later than three months [member] 61 to 90 days [member] Later than three months and not later than four months [member] 91 to 120 days [member] Later than four months [member] Greater than or equal to 121 days [member] Allowance For Credit Losses Of Financial Assets Beginning balance Ending balance Allowance for credit losses of financial assets. Increase Decrease In Allowance For Credit Losses Of Financial Assets Net recognition (reversal) for the period Increase decrease in allowance for credit losses of financial assets. Expected credit loss rate Expected credit loss rate Classes Of Inventories [Abstract] Current raw materials Raw materials Supplies and spare parts Supplies and spare parts Supplies and spare parts. Current work in progress Work in process Current finished goods Finished goods Cost of inventories recognised as expense during period Inventories recognized in operating costs Inventory write-down Write-down of inventories Inventories pledged as security for liabilities Inventories pledged Equity Method Investments [Abstract] Equity method investments. Investments In Associates And Joint Ventures [Table] Investments In Associates And Joint Ventures [Table] Investments in associates and joint ventures. Investments In Associates And Joint Ventures [Line Items] Investments in associates and joint ventures [line items] Investments in associates and joint ventures. Proportion of ownership interest in associate Percentage of ownership or voting rights, Associates Faraday Technology Corp [Member] FARADAY TECHNOLOGY CORP. (FARADAY) [member] FARADAY TECHNOLOGY CORP. [member] Faraday Technology Corp. Unitech Capital Inc [Member] UNITECH CAPITAL INC. [member] Unitech Capital Inc. Tri Knight Capital Corporation [Member] TRIKNIGHT CAPITAL CORPORATION (TRIKNIGHT) [member] TriKnight Capital Corporation HSUN CHIEH INVESTMENT CO., LTD [Member] HSUN CHIEH INVESTMENT CO., LTD. (HSUN CHIEH) [member] HSUN CHIEH [member] Hsun Chieh Investment Co., Ltd. YANN YUAN INVESTMENT CO., LTD [Member] YANN YUAN INVESTMENT CO., LTD. (YANN YUAN) [member] YANN YUAN [member] Yann Yuan Investment Co., Ltd. VSENSE CO., LTD. (VSENSE) [Member] VSENSE CO., LTD. (VSENSE) [member] VSense CO., Ltd. (VSENSE) United LED Corporation Hong Kong Limited [Member] UNITED LED CORPORATION HONG KONG LIMITED [member] United LED Corporation Hong Kong Limited Translink Capital Partners I L P [Member] TRANSLINK CAPITAL PARTNERS I, L.P. [member] Translink Capital Partners I, L.P. PURIUMFIL INC [Member] PURIUMFIL INC. [member] PURIUMFIL INC. Unimicron Technology Corp [Member] UNIMICRON TECHNOLOGY CORP. (UNIMICRON) [member] Unimicron Technology Corp. Silicon Integrated Systems Corp. (Sis) [Member] SILICON INTEGRATED SYSTEMS CORP. (SIS) [member] SIS [member] Silicon Integrated Systems Corp. (Sis) [Member] HSUN CHIEH CAPITAL CORP [Member] HSUN CHIEH CAPITAL CORP. [member] Hsun ​Chieh​ Capital​ Corp​. Classes of assets [axis] Classes of assets [axis] Classes of assets [domain] Classes of assets [domain] Investments with published price quotations [Member] Investments with published price quotations [member] Investments with published price quotations. Investments In Associates [Line Items] Investments in associates [Line Items] Investments in associates. Gains (losses) on exchange differences on translation, net of tax Exchange differences arising from translation of the foreign entity Capital Reduction And Refunded On Investment Accounted For Using Equity Method Capital reduction and refunded on investment accounted for using equity method. Number of Shares Allotted Number of shares allotted Number of shares allotted. Number of Shares Exchanged Number of shares exchanged Number of shares exchanged. Share Exchange Description Share exchange description Share exchange description. At fair value [member] Fair value [member] FULLSignificant Investments In Associates [Axis] FULLSignificant Investments In Associates [Domain] Silicon integrated systems corp [Member] Silicon Integrated Systems Corp. [member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] SUBTRON TECHNOLOGY CO LTD [Member] SUBTRON TECHNOLOGY CO., LTD. (SUBTRON) [member] SUBTRON TECHNOLOGY CO., LTD. (SUBTRON). Disclosure Of Significant Investments In Associates [Abstract] Disclosure of associates [table] Disclosure of associates [table] Disclosure of associates [line items] Disclosure of associates [line items] Share of other comprehensive income of associates and joint ventures accounted for using equity method, net of tax Other comprehensive income (loss) Share of total comprehensive income of associates and joint ventures accounted for using equity method Total comprehensive income (loss) Accumulated depreciation, amortisation and impairment [member] Accumulated depreciation, amortisation and impairment [member] Accumulated amortisation and impairment [member] Land [member] Land [member] Construction in progress [member] Construction in progress and equipment awaiting inspection [member] Additions other than through business combinations, property, plant and equipment Additions Disposals, property, plant and equipment Disposals Decrease through loss of control of subsidiary, property, plant and equipment Disposals Increase (decrease) through transfers and other changes, property, plant and equipment Transfers and reclassifications Increase (decrease) through net exchange differences, property, plant and equipment Exchange effect Disposal Of A Subsidiary Disposal of a subsidiary Disposal of a subsidiary. Property, plant and equipment by operating lease status [axis] Property, plant and equipment by operating lease status [domain] Property, plant and equipment subject to operating leases [member] Operating Leases [member] Property, plant and equipment not subject to operating leases [member] Property, plant and equipment not subject to operating leases [member] Interest Expense Capitalized [Abstract] Interest expense capitalized. Disclosure Of Detailed Information About Interest Expense Capitalized [Table] Disclosure of detailed information about interest expense capitalized. Disclosure Of Detailed Information About Interest Expense Capitalized [Line Items] Disclosure of detailed information about interest expense capitalized. Interest costs capitalised Interest expense capitalized Capitalisation rate of borrowing costs eligible for capitalisation Interest rates applied Disclosures Of Leases [Abstract] Disclosures of leases Disclosure Of Recognised Financial Lease As Assets By Lessee [Table] Disclosure of recognised financial lease as assets by lessee. Other property, plant and equipment [member] Other property, plant and equipment [member] Disclosure Of Lease By Lessee [Line Items] Disclosure Of Lease By Lessee [Line Items] Disclosure of lease by lessee. Depreciation, right-of-use assets Depreciation Lease liabilities Total Lease liabilities Additions to right-of-use assets Addition to right of use assets Disclosure of reconciliation of changes in intangible assets and goodwill [abstract] Disclosure of reconciliation of changes in intangible assets and goodwill [table] Disclosure of reconciliation of changes in intangible assets and goodwill [table] Goodwill [member] Goodwill [member] Disclosure of reconciliation of changes in intangible assets and goodwill [line items] Disclosure of reconciliation of changes in intangible assets and goodwill [line items] Additions other than through business combinations, intangible assets other than goodwill Additions Amortisation, intangible assets other than goodwill Amortization Amortization amounts of intangible assets Write off Intangible Assets And Goodwill Write-off The decrease in intangible assets and goodwill resulting from write off. Disposal Group Goodwill and intangible assets Disposal of a subsidiary Disposal Group Goodwill and intangible assets Increase (decrease) through transfers and other changes, intangible assets and goodwill Reclassifications Increase (decrease) through net exchange differences, intangible assets and goodwill Exchange effect Acquisition Of Group Goodwill And Intangible Assets Acquisition of a subsidiary Acquisition of group goodwill and intangible assets. Net Carrying Amount [Abstract] Net carrying amount: Net carrying amount. Disclosure of detailed information about intangible assets [abstract] Disclosure of detailed information about intangible assets [table] Disclosure of detailed information about intangible assets [table] Disclosure of detailed information about intangible assets [line items] Disclosure Of Intangible Assets [Line Items] Statement of comprehensive income, profit or loss location [axis] Statement of comprehensive income, profit or loss location [axis] Statement of comprehensive income, profit or loss location. Statement Of Comprehensive Income Profit Or Loss Location [Domain] Statement of comprehensive income, profit or loss location [domain] Statement of comprehensive income, profit or loss location. Operating costs [member] Operating costs [member] Operating costs. Operating Expense 1 [Member] Operating expenses [member] Operating Expense 1. Disclosure of detailed information about borrowings [abstract] Disclosure of detailed information about borrowings [table] Disclosure of detailed information about borrowings [table] Borrowings by name [axis] Borrowings by name [axis] Borrowings by name [domain] Borrowings by name [domain] Unsecured bank loans [Member] Unsecured bank loans [member] Unsecured bank loans. Disclosure of detailed information about borrowings [line items] Disclosure of detailed information about borrowings [line items] Shortterm Borrowings Interest Rate Interest rates applied The interest rate on short-term borrowings. Current financial liabilities at fair value through profit or loss [Line Items] Current Financial Liabilities At Fair Value Through Profit Or Loss [Line Items] Current financial liabilities at fair value through profit or loss. Embedded Derivatives In Exchangeable Bonds [member] Embedded derivatives in exchangeable bonds [Member] Embedded derivatives in exchangeable bonds. Disclosure of detailed information about bonds [Table] Disclosure of detailed information about bonds [Table] Disclosure of detailed information about bonds [Table] Unsecured Domestic Bonds Payable [member] Unsecured domestic bonds payable [member] Unsecured domestic bonds payable. Unsecured Exchangeable Bonds Payable [Member] Unsecured exchangeable bonds payable [member] Unsecured exchangeable bonds payable. Discounts on bonds payable [Member] Less: Discounts on bonds payable [member] Discounts on bonds payable. Disclosure of detailed information about bonds [Line Items] Disclosure of detailed information about bonds [Line Items] Disclosure of detailed information about bonds. Bonds Payable Bonds payable Bonds payable. Current bonds issued and current portion of non-current bonds issued Less: Current or exchangeable portion due within one year Domestic unsecured corporate bonds maturing in April 2026 [Member] Domestic unsecured corporate bonds maturing in april 2026. Domestic Unsecured Corporate Bonds Maturing In April 2028 [Member] Domestic unsecured corporate bonds maturing in April 2028 [Member] Domestic unsecured corporate bonds maturing in april 2028. Domestic Unsecured Corporate Bonds Maturing In April 2031 [Member] Domestic unsecured corporate bonds maturing in April 2031 [Member] Domestic unsecured corporate bonds maturing in april 2031. Domestic Unsecured Corporate Bonds Maturing In December 2026 [Member] Domestic unsecured corporate bonds maturing in December 2026 [member] Domestic unsecured corporate bonds maturing in december 2026 Domestic Unsecured Corporate Bonds Maturing In December 2030 [Member] Domestic unsecured corporate bonds maturing in December 2030 [Member] Domestic Unsecured Corporate Bonds Maturing In December 2028 [Member] Domestic unsecured corporate bonds maturing in December 2028 [Member] Domestic Unsecured Corporate Bonds Maturing In October 2028 [Member] Domestic unsecured corporate bonds maturing in October 2028 [Member] Domestic Unsecured Corporate Bonds Maturing In August 2028 [Member] Domestic unsecured corporate bonds maturing in August 2028 [Member] Domestic Unsecured Corporate Bonds Maturing In June 2030 One [Member] Domestic unsecured corporate bonds maturing in June 2030 one [Member] Domestic Unsecured Corporate Bonds Maturing In June 2030 [Member] Domestic unsecured corporate bonds maturing in June 2030 [Member] Domestic Unsecured Corporate Bonds Maturing In September 2028 [Member] Domestic unsecured corporate bonds maturing In September 2028 [Member] Domestic unsecured corporate bonds maturing in september 2028. Borrowings, maturity Term Bond Issuance Date Issuance date Issuance date of bonds. Bonds issued Issued amount Bonds issued amount Bonds payable (current portion included) Bonds payables (current portion included) Bonds Interest Rate Coupon rate The interest rate on bonds. Bonds Payable Repayment And Interest Payable Description Repayment The description of bonds payable repayment and interest payable. Currency linked zero coupon exchangeable bonds maturing on July 7, 2026 [Member] Currency linked zero coupon exchangeable bonds maturing on July 7, 2026 [member] Currency linked zero coupon exchangeable bonds maturing on July 7, 2026. Early Redemption Price Interest Rate Per annum interest rate related to early redemption of bonds The interest rate used to determine early redemption price. Early Redemption Price Fixed Exchange Rate Early Redemption Price, fixed exchange rate The fixed exchange rate used for early redemption price. Percentage of principal amount, bond will be redeemable for early redemption Percentage of principal amount, bond will be redeemable for early redemption Percentage of principal amount, bond will be redeemable for early redemption. Percentage of principal amount to redeem bonds on maturity date Percentage of principal amount to redeem bonds on maturity date Percentage of principal amount to redeem bonds on maturity date. Effective Rate Of The Host Bonds Effective rate of the host bonds Effective rate of the host bonds. Percentage of closing stock price to quotient of early redemption amount multiplied by then exchange price divided by principal amount of bonds Percentage of closing stock price to quotient of early redemption amount multiplied by then exchange price divided by principal amount of bonds Percentage of closing stock price to quotient of early redemption amount multiplied by then exchange price divided by principal amount of bonds. Percentage of the bonds that have been previously redeemed, repurchased and cancelled or exchanged, where issuer may redeem the outstanding bonds Percentage of the bonds that have been previously redeemed, repurchased and cancelled or exchanged, where issuer may redeem the outstanding bonds Percentage of the bonds that have been previously redeemed, repurchased and cancelled or exchanged, where issuer may redeem the outstanding bonds. Exchange Price Per Share Exchange price per share Exchange price per share. Bonds Repurchased And Cancelled Bonds repurchased and cancelled value Bonds repurchased and cancelled. Number Of Bondholder Requied Redeemable Outstanding Exchangeable Bonds Number of bondholder requied redeemable outstanding exchangeable bonds Number of bondholder requied redeemable outstanding exchangeable bonds. Common Shares of Novatek [Member] Common Shares of Novatek [Member] Common shares of novatek. USD Unsecured Revolving Bank Loans (Note) [Member] USD unsecured revolving bank loans (Note) [member] NTD Unsecured Revolving Bank Loans (Note) [Member] NTD unsecured revolving bank loans (Note) [member] RMB Unsecured Bank Loans [Member] RMB unsecured bank loans [member] USD Unsecured Bank Loans [Member] USD unsecured bank loans [member] NTD Unsecured Bank Loans [Member] NTD unsecured bank loans [member] RMB Secured Bank Loans [Member] RMB secured bank loans [member] NTD Secured Bank Loans [Member] NTD secured bank loans [member] Loans received Long-term loans Long-term loans (current portion included) Current loans received and current portion of non-current loans received Less: Current portion Description of details of defaults during period of principal, interest, sinking fund, or redemption terms of loans payable Redemption Borrowings, interest rate Interest rates applied Secured Syndicated Loans from China Development Bank [Member] Secured syndicated loans from China development bank [member] Secured syndicated loans from China development bank. Revolving Credit Facilitys [Member] Revolving Credit Facility [Member] Unused Line Of Credit Unused line of credit Unused line of credit. Available Revolving Line Of Credit Available revolving line of credit Available revolving line of credit. Endorsement Amount For Other Entities Endorsement The amount of endorsement for other entities. Classes of financial liabilities [axis] Classes of financial liabilities [domain] Disclosure Of Defined Benefit Plans [Abstract] Disclosure of defined benefit plans and defined contribution plans [Table] Disclosure of defined benefit plans and defined contribution plans [Table] Disclosure of defined benefit plans and defined contribution plans [Table] Defined benefit plans [axis] Defined benefit plans [axis] Defined benefit plans [domain] Defined benefit plans [domain] Defined benefit plan [member] Defined benefit plan [member] Pension [member] Defined benefit plan Defined contribution plans [Axis] Defined contribution plans [Axis] Defined contribution plans [Axis] Defined contribution plans [Domain] Defined contribution plans [Domain] Defined contribution plans [Domain] Defined contribution plan [Member] Defined contribution plan [member] Defined contribution plan. Disclosure of defined benefit plans and defined contribution plans [Line Items] Disclosure of defined benefit plans and defined contribution plans [Line Items] Disclosure of defined benefit plans and defined contribution plans [Line Items] Post-employment benefit expense, defined contribution plans Pension expenses Percentage of employees monthly wages and salaries as contributions to defined benefit plan Percentages of employees' total monthly salaries and wages to pension fund Percentage of employees' monthly salaries and wages as contributions to defined benefit plan. Post-employment benefit expense, defined benefit plans Pension expenses Actual return on plan assets Actual returns on plan assets Actual return on plan assets. Estimate of contributions expected to be paid to plan for next annual reporting period Expected pension fund contribution in 2026 Weighted average duration of defined benefit obligation Weighted-average durations of defined benefit obligation Percentage Of Monthly Salary Or Wages As Monthly Contributions To Defined Contribution Plan Percentage of employees' monthly salary or wages as monthly contributions to defined contribution plan Percentage of monthly salary or wages as monthly contributions to defined contribution plan. Disclosure of net defined benefit liability (asset) [abstract] Disclosure of net defined benefit liability (asset) [table] Disclosure of net defined benefit liability (asset) [table] Disclosure of net defined benefit liability (asset) [line items] Disclosure of net defined benefit liability (asset) [line items] Net defined benefit liability (asset) Beginning balance Ending balance Current service cost, net defined benefit liability (asset) Service cost Interest expense (income), net defined benefit liability (asset) Interest income (cost) Current service cost, and Interest (expense) income, net defined benefit liability (asset) Subtotal The increase (decrease) in the net defined benefit liability (asset) resulting from service cost and interest income (cost). Contributions to plan by employer, net defined benefit liability (asset) Contribution by employer Actuarial gains (losses) arising from changes in financial assumptions, net defined benefit liability (asset) Arising from changes in financial assumptions Actuarial Gains Losses Arising From Changes In Experience Adjustments On Plan Liabilities Net Defined Benefit Liability Asset Experience adjustments Actuarial gains and losses arising from changes in experience adjustments in the present value of the defined benefit obligation. Gain (loss) on remeasurement, net defined benefit liability (asset) Subtotal Payments from plan, net defined benefit liability (asset) Benefits paid Return on plan assets excluding interest income or expense, net defined benefit liability (asset) Return on plan assets, excluding amounts included in interest income Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions Arising from changes in demographic assumptions Defined benefit obligation, at present value Present value of the defined benefit obligation Plan assets, at fair value Fair value of plan assets Surplus (deficit) in plan Funded status Disclosure Of Fair Value Of Plan Assets [Abstract] Percentage Of Cash In The Plan Assets Cash Percentage of cash in the plan assets. Percentage Of Equity Instruments In The Plan Assets Equity instruments Percentage of equity instruments in the plan assets. Percentage Of Debt Instruments In The Plan Assets Debt instruments Percentage of debt instruments in the plan assets. Percentage Of Other Assets In The Plan Assets Others Percentage ​of othe​r assets ​in the​ plan​ assets. Actuarial assumption of discount rates Discount rate Actuarial assumption of expected rates of salary increases Rate of future salary increase Disclosure of defined benefit plans [table] Disclosure of defined benefit plans [table] Disclosure of defined benefit plans [line items] Disclosure of defined benefit plans [line items] Expected future benefit payments of defined benefit plan Expected future benefit payments The estimate of the expected future payments to be made to employees under a defined benefit plan. Not later than one year [member] Not later than one year [member] Later than one year and not later than two years [member] Later than one year and not later than two years [member] Later than two years and not later than three years [member] Later than two years and not later than three years [member] Later than three years and not later than four years [member] Later than three years and not later than four years [member] Later than four years and not later than five years [member] Later than four years and not later than five years [member] Later than five years [member] Later than five years [member] Disclosure of sensitivity analysis for actuarial assumptions [abstract] Disclosure of sensitivity analysis for actuarial assumptions [table] Disclosure of sensitivity analysis for actuarial assumptions [table] Actuarial assumptions [axis] Actuarial assumptions [axis] Actuarial assumptions [domain] Actuarial assumptions [domain] Actuarial assumption of discount rates [member] Discount rate [member] Actuarial assumption of expected rates of salary increases [member] Rate of future salary increase [member] Disclosure of sensitivity analysis for actuarial assumptions [line items] Disclosure of sensitivity analysis for actuarial assumptions [line items] Percentage of reasonably possible increase in actuarial assumption Percentage increase in actuarial assumptions Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption Decrease (increase) in defined benefit obligation due to 0.5% increase in actuarial assumptions Percentage of reasonably possible decrease in actuarial assumption Percentage decrease in actuarial assumptions Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption Decrease (increase) in defined benefit obligation due to 0.5% decrease in actuarial assumptions Miscellaneous Liabilities [Abstract] Government grants Beginning balance Ending balance Total Government Grants Arising During Period Arising during the period Government grants arising during period. Increase decrease through net exchange differences government grants Exchange effect The increase (decrease) in government grants resulting from net exchange differences. Current government grants Current (classified under other current liabilities) Non-current government grants Non-current (classified under other noncurrent liabilities) Disclosure Of Refund Liability [Abstract] Disclosure of refund liability [abstract] Refund liabilities Refund liabilities Refund liabilities. Non-current provision for decommissioning, restoration and rehabilitation costs Decommissioning Liabilities (classified under other noncurrent liabilities) Current miscellaneous other provisions Others (classified under other current liabilities) Provisions Total Current onerous contracts provision Onerous Contracts (classified under other current liabilities) Disclosure of other provisions [abstract] Disclosure of other provisions [table] Classes of other provisions [axis] Classes of other provisions [domain] Miscellaneous other provisions [member] Others Provision for decommissioning, restoration and rehabilitation costs [member] Decommissioning Liabilities [member] Onerous contracts provision [member] Onerous Contracts [member] Disclosure of other provisions [line items] Other provisions Balance as of January 1, 2025 Balance as of December 31, 2025 Increase (decrease) through net exchange differences, other provisions Exchange effect Increase (decrease) through change in discount rate, other provisions Discount rate adjustment and unwinding of discount from the passage of time Unused provision reversed, other provisions Unused provision reversed Additional provisions, other provisions Arising during the period Disclosure of classes of share capital [table] Disclosure of classes of share capital [table] American depositary shares [member] American depositary shares [member] American depositary shares. Disclosure of classes of share capital [line items] Disclosure of classes of share capital [line items] Number of American Depositary Shares Issued Number of American Depositary Shares traded on NYSE Number of American Depositary Shares issued. Number of Common Shares Represented by Issued American Depositary Shares Number of common shares represented by issued American Depositary Shares Number of common shares represented by issued American Depositary Shares. Number of Common Shares Represented by ADSs Number of common shares represented by 1 ADS Number of common shares represented by ADSs. Percentage of legal reserve Percentage of legal reserve Percentage of legal reserve. Cash Dividend Percentage on Dividend Distribution Percentage of cash dividend on dividend distribution Percentage of cash dividend on dividend distribution. Stock Dividend Percentage on Dividend Distribution Percentage of stock dividend on dividend distribution Percentage of stock dividend on dividend distribution. Number of other equity instruments granted in share-based payment arrangement Number Of Other Equity Instruments Recalled And Cancelled In Sharebased Payment Arrangement Number of other equity instruments recalled and cancelled in share-based payment arrangement The number of other equity instruments (ie other than share options) recalled and cancelled in a share-based payment arrangement. Dividends paid, ordinary shares per share Cash dividends Restricted Stocks [Member] Restricted Stocks [member] Restricted stocks. Non-adjusting events after reporting period [axis] Non-adjusting events after reporting period [axis] Non-adjusting events after reporting period [domain] Non-adjusting events after reporting period [domain] Geographical [Axis] Geographical [Domain] Period [Axis] Period. Period [Domain] Period. Disclosure Of Stock Held By Associates [Abstract] Disclosure of stock held by associates. Disclosure Of Stock Held By Associates [Table] Disclosure of stock held by associates. UNIMICRON And Subsidiaries [Member] UNIMICRON and its Subsidiaries [member] Disclosure Of Stock Held By Associates [Line Items] Disclosure of stock held by associates. Number of shares in entity held by entity or by its subsidiaries or associates Number of shares in entity held by its subsidiaries or associates Disclosure of equity [Table] Disclosure of equity [Table] Disclosure of equity [Table] Legal Reserve [Member] Legal Reserve [Member] Legal reserve1. Cash Dividend [Member] Cash dividends [member] Cash dividend. Disclosure of equity [Line Items] Disclosure of equity [Line Items] Disclosure of equity [Line Items] Cash Dividends Declared Per Share Cash dividends The amount of cash dividends declared per share. Other comprehensive income, attributable to non-controlling interests Other comprehensive income (loss) Non-controlling Interests Changes in subsidiaries ownership Changes in subsidiaries' ownership Non-controlling interests changes in subsidiaries ownership. Non-controlling Interests Derecognition of non-controlling interests Derecognition of the non-controlling interests Derecognition of non-controlling interests. Expense from share-based payment transactions Share-based payment transactions Disclosure of terms and conditions of share-based payment arrangement [abstract] Disclosure of terms and conditions of share-based payment arrangement [table] Disclosure of terms and conditions of share-based payment arrangement [table] Plan [Axis] Plan [Domain] Two Thousand Twenty Two Plan [Member] 2022 Plan [Member] Two Thousand Twenty Plan [Member] 2020 Plan [Member] Two Thousand Twenty Four Plan [Member] 2024 Plan [Member] Tranche [Axis] Tranche [Domain] Second Tranche [Member] 2nd Tranche [Member] First Tranche [Member] 1st Tranche [Member] Disclosure of terms and conditions of share-based payment arrangement [line items] Disclosure of terms and conditions of share-based payment arrangement [line items] Weighted average exercise price of share options granted in share-based payment arrangement Weighted-average fair value on the grant date (NT$/ per share) Date of grant of share-based payment arrangement Issuance date Shares Of Restricted Stock For Employees Issued Issuance of shares (in thousands) Shares of restricted stock for employees issued. Description Of Eligible Employees Eligible employees Description Of Eligible Employees. Maximum Shares To Be Issued Under Compensation Plan Maximum shares to be issued (in thousands) Maximum shares to be issued under compensation plan. Resolution Date Of Shareholders Meeting Resolution date of UMC's shareholders meeting Resolution Date Of Shareholders Meeting. Expense from share-based payment transactions with employees Compensation expenses | $ Description of vesting requirements for share-based payment arrangement Eligibility terms to vested restricted stocks Stock Appreciation Right Plan For Employees Description Stock appreciation right plan for employees description. Life Of Plan Life of plan Life of plan. Liabilities from share-based payment transactions Liabilities for stock appreciation right recognized Unit Of Cash Settled Stock Appreciation Right Unit of cash-settled stock appreciation right Unit of cash-settled stock appreciation right. Intrinsic value of liabilities from share-based payment transactions for which counterparty's right to cash or other assets vested Intrinsic Value for the Liabilities of Vested Rights Stock Appreciation Right Plan For Employees [Member] Stock appreciation right plan for employees. Risk Free Interest Rate Used To Calculate Fair Value Of Share Based Payment Risk-free interest rate The risk-free interest rate used to calculate the fair value of the share-based payment. Expected Life Used To Calculate Fair Value Of Share Based Payment Expected life The expected life used to calculate the fair value of the share-based payment. Expected Volatility Used To Calculate Fair Value Of Share Based Payment Expected volatility The expected volatility used to calculate the fair value of the share-based payment. Share Price of Measurement Date Used To Calculate Fair Value of Share Based Payment Share price of measurement date (NT$/ per share) The share price of measurement date used to calculate the fair value of the share-based payment. Disclosure of geographical areas [abstract] Disclosure of geographical areas [table] Disclosure of Geographical Areas [Table] Disclosure of geographical areas [line items] Disclosure of Geographical Areas [Line Items] Revenue from contracts with customers Revenue from contracts with customers Geographical areas [axis] Geographical areas [axis] Geographical areas [domain] Geographical areas [domain] TAIWAN, PROVINCE OF CHINA Taiwan [member] China (includes Hong Kong) [Member] China (includes Hong Kong) [member] China (includes Hong Kong). JAPAN Japan [member] UNITED STATES USA [member] Europe 1 [Member] Europe [member] Europe 1 [Member] All other countries [member] Others [member] All other countries. KOREA, REPUBLIC OF Korea [member] Disclosure Of Products [Line Items] Disclosure Of Products [Line Items] Disclosure of products. Products and services [axis] Products and services [axis] Products and services [domain] Products and services [domain] Wafer [Member] Wafer [member] Wafer. Other Products [Member] Other products [member] Other products. Disclosure of disaggregation of revenue from contracts with customers [abstract] Disclosure of disaggregation of revenue from contracts with customers [table] Disclosure of disaggregation of revenue from contracts with customers [table] Disclosure of disaggregation of revenue from contracts with customers [line items] Disclosure of disaggregation of revenue from contracts with customers [line items] Segments [axis] Segments [axis] Segments [domain] Segments [domain] Timing of transfer of goods or services [axis] Timing of transfer of goods or services [axis] Timing of transfer of goods or services [domain] Timing of transfer of goods or services [domain] Goods or services transferred at point in time [member] Goods or services transferred at point in time [member] Goods or services transferred over time [member] Goods or services transferred over time [member] Disclosure of balances of contract assets and contract liabilities [line items] Disclosure of balances of contract assets and contract liabilities [line items] Disclosure of balances of contract assets and contract liabilities. Contract liabilities Contract liabilities Contract Assets Current Contract assets, current Contract assets, current. Sales of Goods and Services [Member] Sales of Goods and Services [member] Sales of goods and services. Adjustment in Loss allowance [member] Loss allowance [member] Adjustment in loss allowance. Disclosure of additional information about revenue [Abstract] Disclosure of additional information about revenue. Revenue that was included in contract liability balance at beginning of period Revenue that was included in contract liability balance at beginning of period Transaction price allocated to remaining performance obligations Transaction price allocated to unsatisfied performance obligations Assets recognised from costs to obtain or fulfil contracts with customers Asset recognized from the cost to fulfill a contract with customer Analysis of income and expense [abstract] Disclosure of Operating Costs and Expenses [Table] Disclosure of Operating Costs and Expenses [Table] Disclosure of operating costs and expenses. Disclosure Of Operating Costs And Expenses [Line Items] Disclosure Of Operating Costs And Expenses [Line Items] Disclosure of operating costs and expense. Wages and salaries Salaries Insurance expense Labor and health insurance Postemployment Benefit Expense Defined Benefit Plans and Defined Contribution Plan Pension Post-employment benefit expense of defined benefit plans and defined contribution plans. Other employee expense Other employee benefit expenses Depreciation expense Depreciation manik [Axis] Allocated Profit Percentage For Directors Compensation Allocated profit percentage for directors' compensation Allocated profit percentage for directors' compensation. Allocated Profit Percentage For Employees Compensation Allocated profit percentage for employees' compensation Allocated profit percentage for employees' compensation. Percentage Of Employees Compensation Should Be Allocated To Entry Level Employees Percentage of employees' compensation should be allocated to entry-level employees Percentage of employees' compensation should be allocated to entry-level employees. Short-term employee benefits expense Employees' compensation – Cash Directors' remuneration expense Directors' compensation Income from government grants Government grants Miscellaneous other operating income expense Others Miscellaneous other operating income (expense). Rental income Rental income from property, plant and equipment Gain Loss On Financial Assets Liabilities At Fair Value Through Profit Or Loss Gain (Loss) on valuation of financial assets and liabilities at fair value through profit or loss Gain (loss) on financial assets and liabilities at fair value through profit or loss. Gains (losses) on disposals of investments Gain (Loss) on disposal of investments accounted for under the equity method Other Gains And Losses Categorized As Other Non Operating Income And Expenses Others Other gains and losses categorized as other non-operating income and expenses. Interest expense on bonds Interest expenses, bonds payable Interest expense on bank loans and overdrafts Interest expenses, bank loans Interest expense on other financial liabilities Interest expenses, others Other finance cost Financial expenses Interest expense on lease liabilities Interest expenses, lease liabilities Gains (losses) on exchange differences on translation, before tax Exchange differences on translation of foreign operations, Arising during the period Share of other comprehensive income of associates and joint ventures accounted for using equity method before reclassification to profit or loss, before tax Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss, Arising during the period Share of other comprehensive income of associates and joint ventures accounted for using equity method before reclassification to profit or loss, before tax. Other comprehensive income, before reclassification and tax Total other comprehensive income (loss), Arising during the period Other comprehensive income, before reclassification and tax. Reclassification adjustments on exchange differences on translation, before tax Exchange differences on translation of foreign operations, Reclassification adjustments during the period Share of other comprehensive income of associates and joint ventures accounted for using equity method reclassified to profit or loss, before tax Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss, Reclassification adjustments during the period Share of other comprehensive income of associates and joint ventures accounted for using equity method reclassified to profit or loss, before tax. Reclassification adjustments on other comprehensive income before tax Total other comprehensive income (loss), Reclassification adjustments during the period Reclassification adjustments on other comprehensive income before tax. Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income, Before tax Other comprehensive income, before tax Total other comprehensive income (loss), Before tax Income tax relating to remeasurements of defined benefit plans included in other comprehensive income Remeasurements of defined benefit pension plans, Income tax effect Remeasurements of defined benefit pension plans Income tax relating to investments in equity instruments included in other comprehensive income Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income, Income tax effect Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income Income tax relating to share of other comprehensive income of associates and joint ventures accounted for using equity method that will not be reclassified to profit or loss Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss, Income tax effect Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss Income tax relating to exchange differences on translation included in other comprehensive income Exchange differences on translation of foreign operations, Income tax effect Exchange differences on translation of foreign operations Income tax relating to share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss, Income tax effect Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss Income tax relating to components of other comprehensive income Total other comprehensive income (loss), Income tax effect Amounts recognized in other comprehensive income (loss) Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans Remeasurements of defined benefit pension plans, Net of tax Share of other comprehensive income of associates and joint ventures accounted for using equity method that will not be reclassified to profit or loss, net of tax Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss, Net of tax Other comprehensive income, net of tax, exchange differences on translation Exchange differences on translation of foreign operations, Net of tax Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, net of tax Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss, Net of tax Other comprehensive income, net of tax, gains (losses) from investments in equity instruments Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income, Net of tax Major components of tax expense (income) [abstract] Current and deferred tax relating to items charged or credited directly to equity [abstract] Income tax charged directly to equity Deferred Tax Relating To Adjustments Of Changes In Net Assets Of Associates And Joint Ventures Accounted For Using Equity Method Charged Or Credited Directly To Equity Adjustments of changes in net assets of associates and joint ventures accounted for using equity method Deferred tax relating to adjustments of changes in net assets of associates and joint ventures accounted for using equity method charged or credited directly to equity. Deferred tax relating to items credited (charged) directly to equity Deferred income tax charged directly to equity Amounts recognized in equity Share of the net assets of the subsidiary Deferred tax relating to share of net assets of subsidiary charged or credited directly to equity. Current tax expense (income) and adjustments for current tax of prior periods [abstract] Current income tax expense (benefit): Current tax expense (income) Current income tax charge Adjustments for current tax of prior periods Adjustments in respect of current income tax of prior periods Current tax expense (income), related to Pillar Two income taxes Income tax expense affected by the Pillar Two legislation Deferred tax expense (income) [abstract] Deferred income tax expense (benefit): Deferred tax expense (income) relating to origination and reversal of temporary differences Deferred income tax related to origination and reversal of temporary differences Deferred Tax Expense Income Relating To Recognition And Derecognition Of Tax Losses And Unused Tax Credits Deferred income tax related to recognition and derecognition of tax losses and unused tax credits Deferred tax expense (income) relating to recognition and derecognition of tax losses and unused tax credits. Deferred tax expense (income) relating to tax rate changes or imposition of new taxes Deferred income tax related to changes in tax rates Adjustments for deferred tax of prior periods Adjustment of prior year's deferred income tax Deferred tax expense arising from write-down or reversal of write-down of deferred tax asset Deferred income tax arising from write-down or reversal of write-down of deferred tax assets Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] Income tax related to components of other comprehensive income (loss), Items that may be reclassified subsequently to profit or loss Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] Income tax related to components of other comprehensive income (loss), Items that will not be reclassified subsequently to profit or loss Reconciliation of accounting profit multiplied by applicable tax rates [abstract] Tax Effect Of Non Taxable Income And Non Deductible Expenses [Abstract] Tax effect of non-taxable income and non-deductible expenses: Tax effect of non taxable income and non deductible expenses. Tax Effect Of Non Taxable Income And Non Deductible Expenses Tax Exempt Income Tax exempt income Tax effect of non taxable income and non deductible expenses - tax exempt income. Tax Effect Of Non Taxable Income And Non Deductible Expenses Investment Loss (Gain) Investment loss (gain) Tax effect of non taxable income and non deductible expenses - investment loss (gain). Tax Effect Of Non Taxable Income And Non Deductible Expenses Dividend Income Dividend income Tax effect of non taxable income and non deductible expenses - dividend income. Tax Effect Of Non Taxable Income And Non Deductible Expenses Others Others Tax effect of non taxable income and non deductible expenses - others. Income Tax Expense Basic Tax Basic tax Income tax expense - basic tax. Estimated income tax on unappropriated earnings Estimated income tax on unappropriated earnings Current tax expense (income) on unappropriated retained earnings. Tax effect of different tax rates applicable to subsidiaries Effect of different tax rates applicable to UMC and its subsidiaries Tax effect of different tax rates applicable to subsidiaries. Tax effect of foreign tax rates Taxes withheld in other jurisdictions Other tax effects for reconciliation between accounting profit and tax expense (income) Others Tax expense (income) at applicable tax rate At UMC's statutory income tax rate Net Change In Loss Carry Forward And Investment Tax Credits Net changes in loss carry-forward and investment tax credits Net change in loss carry forward and investment tax credits. Adjustments for deferred tax assets and liabilities for write-downs (reversal) and different jurisdictional tax rates Adjustment of deferred tax assets/liabilities for write-downs/reversals and different jurisdictional tax rates Adjustments for deferred tax assets and liabilities for writedowns reversal and different jurisdictional tax rates. Deferred tax assets and liabilities [abstract] Disclosure Of Deferred Taxes [Table] Disclosure Of Deferred Taxes [Table] Disclosure of deferred taxes. Assets and liabilities [axis] Assets and liabilities [axis] Assets and liabilities [domain] Assets and liabilities [domain] Accumulated depreciation and amortisation [member] Depreciation [member] Refund liabilities [Member] Refund liabilities [member] Refund liabilities. Allowance for inventory valuation losses [Member] Allowance for inventory valuation losses [member] Allowance for inventory valuation losses. Investment loss [Member] Investment loss [member] Investment loss. Unrealized profit on intercompany sales [Member] Unrealized profit on intercompany sales [member] Unrealized profit on intercompany sales. Other temporary differences [member] Others [member] Investment gain [Member] Investment gain [member] Investment gain. Amortizable assets [Member] Amortizable assets [member] Amortizable assets. Disclosure Of Deferred Taxes [Line Items] Disclosure Of Deferred Taxes [Line Items] Disclosure of deferred taxes. Deferred tax liability (asset) Net deferred income tax assets (liabilities) Beginning Balance Ending Balance Reconciliation of changes in deferred tax liability (asset) [abstract] Changes in deferred tax assets and liabilities [Table] Changes in deferred tax assets and liabilities [Table] Changes in deferred tax assets and liabilities [Table] Changes in deferred tax assets and liabilities [Line Items] Changes in deferred tax assets and liabilities [Line Items] Changes in deferred tax assets and liabilities [Line Items] Deferred tax expense (income) recognised in profit or loss Amounts recognized in profit or loss during the period Increase (decrease) through net exchange differences, deferred tax liability (asset) Exchange adjustments Retrospective application and retrospective restatement [axis] Retrospective application and retrospective restatement [axis] Currently stated [member] Currently stated [member] Disclosure of temporary difference, unused tax losses and unused tax credits [abstract] Disclosure of temporary difference, unused tax losses and unused tax credits [table] Disclosure of temporary difference, unused tax losses and unused tax credits [table] Disclosure of temporary difference, unused tax losses and unused tax credits [line items] Disclosure of temporary difference, unused tax losses and unused tax credits [line items] Unused tax losses for which no deferred tax asset recognised Unused tax loss carry-forward for which no deferred income tax assets have been recognized Later than one year and not later than five years [member] 1-5 years [member] Later than five years and not later than ten years [member] 6-10 years [member] Counterparties [axis] Counterparties [axis] Counterparties [domain] Counterparties [domain] UMC [Member] UMC [Member] UMC [Member] UMC. Deductible temporary differences for which no deferred tax asset is recognised Deductible temporary differences for which no deferred income tax assets have been recognized Temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements for which deferred tax liabilities have not been recognised Taxable temporary differences of unrecognized deferred tax liabilities associated with investments in subsidiaries Basic earnings per share [abstract] Earnings per share-basic Weighted average number of ordinary shares outstanding Weighted-average number of ordinary shares for basic earnings per share (thousand shares) Diluted earnings per share [abstract] Earnings per share-diluted Dilutive Effect On Shares [Abstract] Effect of dilution Dilutive effect on shares. Dilutive effect of employee compensation on number of ordinary shares Employees' compensation Dilutive effect of employee compensation on number of ordinary shares. Dilutive Effect Of Restricted Stocks For Employees Restricted stocks for employees Dilutive effect of restricted stocks for employees. Adjusted weighted average number of ordinary shares outstanding Weighted-average number of ordinary shares after dilution (thousand shares) Disclosure of financial liabilities [abstract] Disclosure of reconciliation of liabilities arising from financing activities [table] Disclosure of reconciliation of liabilities arising from financing activities [table] Disclosure of reconciliation of liabilities arising from financing activities [line items] Disclosure of reconciliation of liabilities arising from financing activities [line items] Liabilities arising from financing activities Beginning balance Ending Balance Increase (decrease) through financing cash flows, liabilities arising from financing activities Cash Flows Increase (decrease) through effect of changes in foreign exchange rates, liabilities arising from financing activities Non-cash changes,Foreign exchange Increase (decrease) through other changes, liabilities arising from financing activities Non-cash changes,Others Liabilities arising from financing activities [axis] Liabilities arising from financing activities [axis] Liabilities arising from financing activities [domain] Liabilities arising from financing activities [domain] Short-term borrowings [member] Short-term loans [member] Long Term Loans Current Portion Included [Member] Long-term loans (current portion included) [member] Long-term loans (current portion included). Bonds Payable Current Portion Included [Member] Bonds payable (current portion included) [member] Bonds payable (current portion included). Guarantee Deposits Current Portion Included [Member] Guarantee deposits (current portion included) [member] Guarantee deposits (current portion included). Other Financial Liabilities [Member] Other financial liabilities [member] Other financial liabilities. Lease liabilities [member] Lease liabilities [member] UDS [Member] UDS United D S Semiconductor Shandong Co Ltd [Member] UNITEDDS SEMICONDUCTOR (SHANDONG) CO., LTD. (UDS) [member] UnitedDS Semiconductor Shandong Co., Ltd. Revenue from sale of goods, related party transactions Sales Operating revenues Amounts receivable, related party transactions Accounts receivable Explanation of terms and conditions of outstanding balances for related party transaction Explanation of terms and conditions of outstanding balances for related party transaction Collection periods for accounts receivables Transfers under licence agreements from entity, related party transactions Amount of downstream transaction Disposal Of Proportion Of Ownership Interest In Subsidiary Disposal of proportion of ownership interest in subsidiary Disposal of proportion of ownership interest in subsidiary. Hejian Technology Suzhou Co Ltd H J [Member] HEJIAN TECHNOLOGY (SUZHOU) CO., LTD. (HJ) [member] Hejian Technology (Suzhou) Co., Ltd. (HJ). United Semiconductor Xiamen Co Ltd [Member] UNITED SEMICONDUCTOR (XIAMEN) CO., LTD. (USCXM) [member] United Semiconductor (Xiamen) Co., Ltd. Associates [member] Associates [member] All other related parties [Member] All other related parties [member] All other related parties. Fujian Electronics Information Industry Enrepreneurship Investent Limited Partnership [Member] FUJIAN ELECTRONICS & INFORMATION INDUSTRY ENTREPRENEURSHIP INVESTMENT LIMITED PARTNERSHIP [member] Fujian electronics & information industry enrepreneurship investent limited partnership member. Xiamen Jinyuan Industrial Development [Member] XIAMEN JINYUAN INDUSTRIAL DEVELOPMENT CO., LTD. [member] Xiamen jinyuan industrial development member. Other Associates [Member] Other Associates [member] Other associates member. Mask expenditure, related party transactions Mask expenditure The amount of mask expenditure in related party transactions. Other payables of Mask expenditure, related party transactions Other payables of mask expenditure The amount of other payables of mask expenditure in related party transactions. Acquisition Of Shares Investments Accounted For Under The Equity Method Acquisition of investments accounted for under the equity method, Trading Volume Acquisition of shares, investments accounted for under the equity method. Cash Dividends from Investees Cash dividends from investees Cash dividends from investees. Gain Loss On Disposal Of Subsidiary Ownership Gain on disposal Gain loss on disposal of subsidiary ownership. Disposal Price Of Subsidiary Ownership Disposal price Disposal price of subsidiary ownership. Trading Capital Trading capital Trading capital. Gains on disposals of investment properties Disposal of subsidiary ownership Volume Of Capital Traded Trading Capital Amount Volume of capital traded. Purchase Price For Acquisition Of A Subsidiary Ownership Purchase price Purchase price for acquisition of a subsidiary's ownership. Transaction With Related Party [Axis] Transaction With Related Party [Domain] Stock Of Faraday [Member] Stock of FARADAY [Member] Increase Of Ownership Stake In The Subsidiary Company USCXM [Member] Increase of ownership stake in the subsidiary company USCXM [member] Increase of ownership stake in the subsidiary company USCXM. Artery Technology Corporation LTD [Member] ARTERY TECHNOLOGY CORPORATION, LTD. [member] Artery technology corporation, ltd. member. Stock Of UNIMICRON [Member] Stock Of UNIMICRON [member] Stock of UNIMICRON member. S I S SEMICONDUCTOR (SHANDONG) CO., LTD [Member] SIS - SIS SEMICONDUCTOR (SHANDONG) CO., LTD [member] Cash Dividends Receivable Cash dividends receivable Cash dividends receivable. Country of domicile [member] Domestic [member] Foreign countries [member] Overseas [member] Key management personnel compensation, short-term employee benefits Short-term employee benefits Key management personnel compensation, post-employment benefits Post-employment benefits Key management personnel compensation, share-based payment Share-based payment Key management personnel compensation, other long-term employee benefits Others Key management personnel compensation Total Disclosure of financial assets [abstract] Disclosure Assets Pledged As Collateral [Table] Disclosure Assets Pledged As Collateral [Table] Disclosure assets pledged as collateral. Assets Pledged As Collateral [Line Items] Assets Pledged As Collateral [Line Items] Assets pledged as collateral. Collateral held permitted to be sold or repledged in absence of default by owner of collateral, at fair value Assets pledged as collateral Purpose of Pledge Purpose of pledge Purpose of pledge. Classes of acquired receivables [axis] Classes of acquired receivables [axis] Classes of acquired receivables [domain] Classes of acquired receivables [domain] Dormitory Lease [Member] Dormitory Lease [member] Dormitory Lease. Refundable Deposits Time Deposit [Member] Refundable deposits time deposit [member] Refundable deposits time deposit. Right-of-use assets [member] Right-of-use assets [member] Customs [Member] Customs [member] Customs. Science Park Bureau [Member] Science Park Bureau [member] Science Park Bureau. Liquefied Natural Gas Business Division, CPC Corporation, Taiwan [Member] Liquefied Natural Gas Business Division, CPC Corporation, Taiwan [member] Liquefied Natural Gas Business Division, CPC Corporation, Taiwan. Taiwan Cooperative Bank And Secured Syndicated Loans From China Development Bank And 6 Others [member] [Member] Taiwan Cooperative Bank and Secured Syndicated Loans from China Development Bank and 6 others [member] Taiwan Cooperative Bank and Secured Syndicated Loans from China Development Bank and 6 others. Secured Syndicated Loans from China Development Bank and 6 others [Member] Secured Syndicated Loans from China Development Bank and 6 others [member] Secured Syndicated Loans from China Development Bank and 6 others. C T B C Bank Singapore Branch [Member] CTBC Bank Singapore Branch [member] CTBC Bank Singapore Branch. National Property Administration Ministry Of Finance [Member] National Property Administration, Ministry of Finance [member] National Property Administration, Ministry of Finance. Taiwan Cooperative Bank meg International Commercial Bank KGI Bank First Commercial bank Shanghai Commercial Bank CTBC Bank And secured Syndicated loans From China Development Bank And 6 Others [Member] Taiwan Cooperative Bank, Mega International Commercial Bank, KGI Bank, First Commercial Bank, Shanghai Commercial Bank, CTBC Bank and Secured Syndicated Loans from China Development Bank and 6 others [member] Taiwan cooperative bank meg international commercial bank KGI bank first commercial bank shanghai commercial bank CTBC bank and secured syndicated loans from china development bank and 6 others. Bureau of Land Administration, Tainan City Government [Member] Bureau of Land Administration, Tainan City Government [Member] Bureau of Land Administration, Tainan City Government. Disclosure of contingent liabilities [abstract] Disclosure of contingent liabilities [table] Disclosure of contingent liabilities [table] Classes of intangible assets other than goodwill [axis] Classes of intangible assets other than goodwill [axis] Classes of intangible assets other than goodwill [domain] Classes of intangible assets other than goodwill [domain] Disclosure of contingent liabilities [line items] Disclosure of contingent liabilities [line items] Undrawn borrowing facilities Amounts available under unused letters of credit Contractual commitments for acquisition of intangible assets Patent license agreements and development contracts of intellectual property, contract amount Royalties And Development Fees Not Yet Recognized Royalties and development fees not yet recognized The amount of the portion of royalties and development fees not yet recognized. Contractual commitments for acquisition of property, plant and equipment Construction contracts, amount Construction Contracts Not Yet Recognized Construction contracts not yet recognized The amount of the portion of the construction contracts not yet recognized. Customs Tax And Electricity Supply Guarantee Amount Customs tax and electricity supply guarantee Customs tax and electricity supply guarantee amount. Litigation Cases [Axis] Litigation Case . Litigation Cases [Domain] Litigation Case . Authority [Axis] Authority Authority [Domain] Authority. Changes in tax rates or tax laws enacted or announced [member] Non Adjusting Events After Reporting Period [Member] Non Adjusting Events After Reporting Period [member] Purchase Of Interests In Associates [Member] Purchase Of Interests In Associates [member] Purchase of interests in associates member. Increase (decrease) in deferred tax liability (asset) Increase in deferred tax assets Total Amount Of Repayments Of The Long Term Loans Which Were Classified As Non Current Liabilities Total amount of repayments of the long-term loans which were classified as non-current liabilities Total amount of repayments of the long-term loans which were classified as non-current liabilities. Purchase of interests in associates Purchase of interests in associates Cash and cash equivalents excluding cash on hand Cash and cash equivalents (cash on hand excluded) Cash and cash equivalents excluding cash on hand. Trade and other receivables Receivables Other financial assets Other financial assets Financial assets Total Financial liabilities at fair value through profit or loss Financial liabilities at fair value through profit or loss Financial Liabilities Measured At Amortized Cost [Abstract] Financial liabilities measured at amortized cost Financial liabilities measured at amortized cost. Trade and other payables Payables Guarantee deposits Guarantee deposits (current portion included) The amount of guarantee deposits. Financial liabilities Total Disclosure of nature and extent of risks arising from financial instruments [table] Disclosure of nature and extent of risks arising from financial instruments [table] Currency [Axis] Currency [Axis] All Currencies [Domain] All Currencies [Domain] Taiwan Dollars [Member] Taiwan, New Dollars [member] Taiwan, New Dollars. China Yuan Renminbi [Member] China, Yuan Renminbi [member] China Yuan Renminbi Japan, Yen Japan, Yen [member] Disclosure of nature and extent of risks arising from financial instruments [line items] Disclosure of nature and extent of risks arising from financial instruments [line items] Percentage increase in market risk Percentage increase in market risk Percentage increase in market risk. Increase (Decrease) in Profit Due to Percentage Increase in Market Risk Increase (decrease) in profit due to percentage increase in market risk Increase (decrease) in profit due to percentage increase in market risk. Percentage decrease in market risk Percentage decrease in market risk Percentage decrease in market risk. Increase (Decrease) in Profit Due to Percentage Decrease in Market Risk Increase (decrease) in profit due to percentage decrease in market risk Increase (decrease) in profit due to percentage decrease in market risk. Increase (Decrease) in Other Comprehensive Income Due to Percentage Increase in Market Risk Increase (decrease) in other comprehensive income due to percentage increase in market risk Increase (decrease) in other comprehensive income due to percentage increase in market risk. Increase (Decrease) in Other Comprehensive Income Due to Percentage Decrease in Market Risk Increase (decrease) in other comprehensive income due to percentage decrease in market risk Increase (decrease) in other comprehensive income due to percentage decrease in market risk. Percentage Of Accounts Receivable From Top Ten Customers Accounts receivables from the top ten customers Percentage of accounts receivable from the top ten customers. Gains (losses) recognised in profit or loss attributable to change in unrealised gains or losses for assets held at end of period, fair value measurement Profit or loss attributable to change in unrealized gains or losses for financial assets without quoted market prices held at end of period Gains (losses) recognised in profit or loss attributable to change in unrealised gains or losses for liabilities held at end of period, fair value measurement Profit or loss attributable to change in unrealized gains or losses for financial liabilities without quoted market prices held at end of period Types of risks [axis] Types of risks [axis] Types of risks [domain] Risks [member] Currency risk [member] Currency risk [member] Interest rate risk [member] Interest rate risk [member] Equity price risk [member] Equity price risk [member] Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Table] Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Table] Disclosure of maturity analysis for non-derivative and derivative financial liabilities. Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] Disclosure Of Maturity Analysis For Non-derivative And Derivative Financial Liabilities [Line Items] Disclosure of maturity analysis for non-derivative and derivative financial liabilities. Short-term loans, undiscounted cash flows Short-term loans The amount of contractual undiscounted cash flows in relation to short-term loans. Trade and other payables, undiscounted cash flows Payables Guarantee deposits , undiscounted cash flows Guarantee deposits The amount of contractual undiscounted cash flows in relation to guarantee deposits. Bonds issued, undiscounted cash flows Bonds payable Long-term loans, undiscounted cash flows Long-term loans The amount of contractual undiscounted cash flows in relation to long-term loans. Non-derivative financial liabilities, undiscounted cash flows Total Lease Liabilities Undiscounted Cash Flows Lease liabilities Lease Liabilities Undiscounted Cash Flows. Derivative financial liabilities, undiscounted cash flows Net settlement-outflow Four to Five Years [Member] 4 to 5 years [member] Four to five years. Two to Three Years [Member] 2 to 3 years [member] Two to three years. Forward contract [member] Forward exchange contracts [member] Notional amount Notional Amount on sale of foreign currency Beginning Date of Forward Exchange Contract Period Contract Period, beginning date Beginning date of forward exchange contract period. End Date of Forward Exchange Contract Period Contract Period, end date End date of forward exchange contract period. Levels of fair value hierarchy [axis] Levels of fair value hierarchy [axis] Levels of fair value hierarchy [domain] Levels of fair value hierarchy [domain] Level 1 of fair value hierarchy [member] Level 1 [member] Level 2 of fair value hierarchy [member] Level 2 [member] Level 3 of fair value hierarchy [member] Level 3 [member] Disclosure of fair value measurement of assets [abstract] Disclosure of fair value measurement of assets [table] Disclosure of fair value measurement of assets [table] Financial assets measured at fair value through other comprehensive income, category [member] Financial assets at fair value through other comprehensive income [member] Disclosure of fair value measurement of assets [line items] Disclosure of fair value measurement of assets [line items] Gains (losses) recognised in profit or loss, fair value measurement, assets Recognized in profit (loss) Gains (losses) recognised in other comprehensive income, fair value measurement, assets Recognized in other comprehensive income (loss) Purchases, fair value measurement, assets Acquisition Sales, fair value measurement, assets Disposal Return of Capital Fair Value Measurement Assets Return of capital The decrease in the fair value measurement of assets resulting from return of capital. Transfers out of Level 3 of fair value hierarchy, assets Transfer out of Level 3 Increase Decrease Through Net Exchange Differences Fair Value Measurement Assets Exchange effect Increase (decrease) through net exchange differences of fair value measurement assets. Disclosure of fair value measurement of liabilities [abstract] Disclosure of fair value measurement of liabilities [table] Disclosure of fair value measurement of liabilities [table] Disclosure of fair value measurement of liabilities [line items] Disclosure of fair value measurement of liabilities [line items] Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, liabilities Recognized in loss (profit) Classes of liabilities [axis] Classes of liabilities [domain] Derivatives [member] Categories of financial liabilities [axis] Categories of financial liabilities [domain] Financial liabilities at fair value through profit or loss, category [member] Disclosure of significant unobservable inputs used in fair value measurement of equity [abstract] Disclosure of significant unobservable inputs used in fair value measurement of equity [table] Disclosure of significant unobservable inputs used in fair value measurement of equity [table] Classes of entity's own equity instruments [axis] Classes of entity's own equity instruments [axis] Classes of entity's own equity instruments [domain] Classes of entity's own equity instruments [domain] Discount for lack of marketability [member] Discount for lack of marketability [member] Discount for lack of marketability. Unlisted Equity Securities [Member] Unlisted equity securities [member] Unlisted equity securities. Disclosure of significant unobservable inputs used in fair value measurement of equity [line items] Disclosure of significant unobservable inputs used in fair value measurement of equity [line items] Discount for lack of marketability significant unobservable inputs entity own equity instruments Discount for lack of marketability significant unobservable inputs entity own equity instruments Discount for lack of marketability used as a significant Level 3 unobservable input for the entity's own equity instruments. Significant Unobservable Input Entity Own Equity Instruments Volatility Significant unobservable input entity own equity instruments volatility Significant unobservable input entity own equity instruments volatility. Valuation techniques used in fair value measurement [axis] Valuation techniques used in fair value measurement [axis] Valuation techniques used in fair value measurement [domain] Valuation techniques used in fair value measurement [domain] Market approach [member] Market approach [member] Binomial Tree Valuation Model [Member] Unobservable inputs [axis] Unobservable inputs [domain] Historical volatility for shares, measurement input [member] Percentage increase in the discount for lack of marketability Percentage increase in the discount for lack of marketability Percentage increase in the discount for lack of marketability. Percentage decrease in the discount for lack of marketability Percentage decrease in the discount for lack of marketability Percentage decrease in the discount for lack of marketability. Increase (decrease) in other comprehensive income due to percentage increase in the discount for lack of marketability Increase (decrease) in other comprehensive income due to percentage increase in the discount for lack of marketability Increase (decrease) in other comprehensive income due to percentage increase in the discount for lack of marketability. Increase decrease in other comprehensive income due to percentage decrease in the discount for lack of marketability Increase (decrease) in other comprehensive income due to percentage decrease in the discount for lack of marketability Increase decrease in other comprehensive income due to percentage decrease in the discount for lack of marketability. Increase (decrease) in profit or loss due to percentage increase in the discount for lack of marketability Increase (decrease) in profit or loss due to percentage increase in the discount for lack of marketability Increase (decrease) in profit or loss due to percentage increase in the discount for lack of marketability. Increase (decrease) in profit or loss due to percentage decrease in the discount for lack of marketability Increase (decrease) in profit or loss due to percentage decrease in the discount for lack of marketability Increase (decrease) in profit or loss due to percentage decrease in the discount for lack of marketability. Percentage Of Decrease In Volatility Percentage of decrease in volatility Percentage of decrease in volatility. Percentage Of Increase In Volatility Percentage of increase in volatility Percentage of increase in volatility. Increase Decrease in Profit or Loss Due to Percentage Decrease in Volatility Increase (decrease) in profit or loss due to percentage decrease in volatility Increase decrease in profit or loss due to percentage decrease in volatility. Increase Decrease in Profit or Loss Due to Percentage Increase in Volatility Increase (decrease) in profit or loss due to percentage increase in volatility Increase decrease in profit or loss due to percentage increase in volatility. Derivative Price Risk [Member] Convertible Price Risk [Member] Convertible price risk [member] Non-current assets other than financial instruments, deferred tax assets, post-employment benefit assets, and rights arising under insurance contracts Non-current assets SINGAPORE Singapore [member] Disclosure of major customers [abstract] Disclosure of major customers [table] Disclosure of Major Customers [Table] Disclosure of major customers [line items] Disclosure of Major Customers [Line Items] Major customers [axis] Major customers [axis] Major customers [domain] Major customers [domain] Customer A [member] Customer A [member] Customer A. Customer B [member] Customer B [member] Customer B [member] Wafer Fabrication Segment [Member] Wafer fabrication [member] Wafer fabrication segment. Customer Concentration Risk 1 [Member] Customer concentration risk [member] Customer concentration risk. Disclosure Of Capital Management [Abstract] Disclosure of capital management. Net debt Net debt Capital1 Total capital Capital. Debt To Capital Ratios Debt to capital ratios Debt to capital ratios.