3.26.1 html 1678 891 1 false 483 0 false 20 false false R1.htm 1001 - Document - Cover Page Sheet http://www.aseglobal.com/role/CoverPage Cover Page Cover 1 false false R2.htm 1002 - Statement - Consolidated Balance Sheets Sheet http://www.aseglobal.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 2 false false R3.htm 1003 - Statement - Consolidated Statements of Comprehensive Income Sheet http://www.aseglobal.com/role/ConsolidatedStatementsOfComprehensiveIncome Consolidated Statements of Comprehensive Income Statements 3 false false R4.htm 1004 - Statement - Consolidated Statements of Changes in Equity Sheet http://www.aseglobal.com/role/ConsolidatedStatementsOfChangesInEquity Consolidated Statements of Changes in Equity Statements 4 false false R5.htm 1005 - Statement - Consolidated Statements of Cash Flows Sheet http://www.aseglobal.com/role/ConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows Statements 5 false false R6.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 6 false false R7.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 7 false false R8.htm 999002 - Disclosure - General Information Sheet http://www.aseglobal.com/role/GeneralInformation General Information Notes 8 false false R9.htm 999003 - Disclosure - Approval of Financial Statements Sheet http://www.aseglobal.com/role/ApprovalOfFinancialStatements Approval of Financial Statements Notes 9 false false R10.htm 999004 - Disclosure - APPLICATION OF NEW, AMENDED AND REVISED INTERNATIONAL FINANCIAL REPORTING STANDARDS AS ISSUED BY THE INTERNATIONAL ACCOUNTING STANDARDS BOARD ("IASB") (collectively, "IFRS Accounting Standards") Sheet http://www.aseglobal.com/role/ApplicationOfNewAmendedAndRevisedInternationalFinancialReportingStandardsAsIssuedByTheInternationalAccountingStandardsBoardIasbCollectivelyIfrsAccountingStandards APPLICATION OF NEW, AMENDED AND REVISED INTERNATIONAL FINANCIAL REPORTING STANDARDS AS ISSUED BY THE INTERNATIONAL ACCOUNTING STANDARDS BOARD ("IASB") (collectively, "IFRS Accounting Standards") Notes 10 false false R11.htm 999005 - Disclosure - Summary of Material Accounting Policy Information Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformation Summary of Material Accounting Policy Information Notes 11 false false R12.htm 999006 - Disclosure - Material Accounting Judgments and Key Sources of Estimation Uncertainty Sheet http://www.aseglobal.com/role/MaterialAccountingJudgmentsAndKeySourcesOfEstimationUncertainty Material Accounting Judgments and Key Sources of Estimation Uncertainty Notes 12 false false R13.htm 999007 - Disclosure - Cash and Cash Equivalents Sheet http://www.aseglobal.com/role/CashAndCashEquivalents Cash and Cash Equivalents Notes 13 false false R14.htm 999008 - Disclosure - Financial Instruments at Fair Value Through Profit or Loss (FVTPL) Sheet http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtpl Financial Instruments at Fair Value Through Profit or Loss (FVTPL) Notes 14 false false R15.htm 999009 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income (FVTOCI) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeFvtoci Financial Assets at Fair Value Through Other Comprehensive Income (FVTOCI) Notes 15 false false R16.htm 999010 - Disclosure - Credit Risk Management for Investments in Debt Instruments Sheet http://www.aseglobal.com/role/CreditRiskManagementForInvestmentsInDebtInstruments Credit Risk Management for Investments in Debt Instruments Notes 16 false false R17.htm 999011 - Disclosure - Trade Receivables, Net Sheet http://www.aseglobal.com/role/TradeReceivablesNet Trade Receivables, Net Notes 17 false false R18.htm 999012 - Disclosure - Inventories Sheet http://www.aseglobal.com/role/Inventories Inventories Notes 18 false false R19.htm 999013 - Disclosure - Inventories Related to Real Estate Business Sheet http://www.aseglobal.com/role/InventoriesRelatedToRealEstateBusiness Inventories Related to Real Estate Business Notes 19 false false R20.htm 999014 - Disclosure - Other Financial Assets Sheet http://www.aseglobal.com/role/OtherFinancialAssets Other Financial Assets Notes 20 false false R21.htm 999015 - Disclosure - Investments Accounted for Using the Equity Method Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethod Investments Accounted for Using the Equity Method Notes 21 false false R22.htm 999016 - Disclosure - Property, Plant and Equipment Sheet http://www.aseglobal.com/role/PropertyPlantAndEquipment Property, Plant and Equipment Notes 22 false false R23.htm 999017 - Disclosure - Lease Arrangements Sheet http://www.aseglobal.com/role/LeaseArrangements Lease Arrangements Notes 23 false false R24.htm 999018 - Disclosure - Investment Properties Sheet http://www.aseglobal.com/role/InvestmentProperties Investment Properties Notes 24 false false R25.htm 999019 - Disclosure - Goodwill Sheet http://www.aseglobal.com/role/Goodwill Goodwill Notes 25 false false R26.htm 999020 - Disclosure - Other Intangible Assets Sheet http://www.aseglobal.com/role/OtherIntangibleAssets Other Intangible Assets Notes 26 false false R27.htm 999021 - Disclosure - Borrowings Sheet http://www.aseglobal.com/role/Borrowings Borrowings Notes 27 false false R28.htm 999022 - Disclosure - Bonds Payable Sheet http://www.aseglobal.com/role/BondsPayable Bonds Payable Notes 28 false false R29.htm 999023 - Disclosure - Other Payables Sheet http://www.aseglobal.com/role/OtherPayables Other Payables Notes 29 false false R30.htm 999024 - Disclosure - Retirement Benefit Plans Sheet http://www.aseglobal.com/role/RetirementBenefitPlans Retirement Benefit Plans Notes 30 false false R31.htm 999025 - Disclosure - Equity Sheet http://www.aseglobal.com/role/Equity Equity Notes 31 false false R32.htm 999026 - Disclosure - Profit Before Income Tax Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTax Profit Before Income Tax Notes 32 false false R33.htm 999027 - Disclosure - Income Tax Sheet http://www.aseglobal.com/role/IncomeTax Income Tax Notes 33 false false R34.htm 999028 - Disclosure - Earnings Per Share Sheet http://www.aseglobal.com/role/EarningsPerShare Earnings Per Share Notes 34 false false R35.htm 999029 - Disclosure - Share-based Payment Arrangements Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangements Share-based Payment Arrangements Notes 35 false false R36.htm 999030 - Disclosure - Business Combinations Sheet http://www.aseglobal.com/role/BusinessCombinations Business Combinations Notes 36 false false R37.htm 999031 - Disclosure - Disposal of Subsidiary Sheet http://www.aseglobal.com/role/DisposalOfSubsidiary Disposal of Subsidiary Notes 37 false false R38.htm 999032 - Disclosure - Equity Transaction with Non-controlling Interests Sheet http://www.aseglobal.com/role/EquityTransactionWithNonControllingInterests Equity Transaction with Non-controlling Interests Notes 38 false false R39.htm 999033 - Disclosure - Cash Flow Information Sheet http://www.aseglobal.com/role/CashFlowInformation Cash Flow Information Notes 39 false false R40.htm 999034 - Disclosure - Capital Management Sheet http://www.aseglobal.com/role/CapitalManagement Capital Management Notes 40 false false R41.htm 999035 - Disclosure - Financial Instruments Sheet http://www.aseglobal.com/role/FinancialInstruments Financial Instruments Notes 41 false false R42.htm 999036 - Disclosure - Related Party Transactions Sheet http://www.aseglobal.com/role/RelatedPartyTransactions Related Party Transactions Notes 42 false false R43.htm 999037 - Disclosure - Assets Pledged as Collateral or for Security Sheet http://www.aseglobal.com/role/AssetsPledgedAsCollateralOrForSecurity Assets Pledged as Collateral or for Security Notes 43 false false R44.htm 999038 - Disclosure - Significant Contingent Liabilities and Unrecognized Commitments Sheet http://www.aseglobal.com/role/SignificantContingentLiabilitiesAndUnrecognizedCommitments Significant Contingent Liabilities and Unrecognized Commitments Notes 44 false false R45.htm 999039 - Disclosure - Significant Events After Reporting Period Sheet http://www.aseglobal.com/role/SignificantEventsAfterReportingPeriod Significant Events After Reporting Period Notes 45 false false R46.htm 999040 - Disclosure - Others Sheet http://www.aseglobal.com/role/Others Others Notes 46 false false R47.htm 999041 - Disclosure - Significant Assets and Liabilities Denominated in Foreign Currencies Sheet http://www.aseglobal.com/role/SignificantAssetsAndLiabilitiesDenominatedInForeignCurrencies Significant Assets and Liabilities Denominated in Foreign Currencies Notes 47 false false R48.htm 999042 - Disclosure - Operating Segments Information Sheet http://www.aseglobal.com/role/OperatingSegmentsInformation Operating Segments Information Notes 48 false false R49.htm 999043 - Disclosure - Summary of Material Accounting Policy Information (Policies) Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformationPolicies Summary of Material Accounting Policy Information (Policies) Policies http://www.aseglobal.com/role/ApplicationOfNewAmendedAndRevisedInternationalFinancialReportingStandardsAsIssuedByTheInternationalAccountingStandardsBoardIasbCollectivelyIfrsAccountingStandards 49 false false R50.htm 999044 - Disclosure - Summary Of Material Accounting Policy Information (Tables) Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformationTables Summary Of Material Accounting Policy Information (Tables) Tables 50 false false R51.htm 999045 - Disclosure - Cash and Cash Equivalents (Tables) Sheet http://www.aseglobal.com/role/CashAndCashEquivalentsTables Cash and Cash Equivalents (Tables) Tables http://www.aseglobal.com/role/CashAndCashEquivalents 51 false false R52.htm 999046 - Disclosure - Financial Instruments at Fair Value Through Profit or Loss (FVTPL) (Tables) Sheet http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtplTables Financial Instruments at Fair Value Through Profit or Loss (FVTPL) (Tables) Tables http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtpl 52 false false R53.htm 999047 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income - (FVTOCI) (Tables) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeFvtociTables Financial Assets at Fair Value Through Other Comprehensive Income - (FVTOCI) (Tables) Tables http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeFvtoci 53 false false R54.htm 999048 - Disclosure - Trade Receivables, Net (Tables) Sheet http://www.aseglobal.com/role/TradeReceivablesNetTables Trade Receivables, Net (Tables) Tables http://www.aseglobal.com/role/TradeReceivablesNet 54 false false R55.htm 999049 - Disclosure - Inventories (Tables) Sheet http://www.aseglobal.com/role/InventoriesTables Inventories (Tables) Tables http://www.aseglobal.com/role/Inventories 55 false false R56.htm 999050 - Disclosure - Inventories Related to Real Estate Business (Tables) Sheet http://www.aseglobal.com/role/InventoriesRelatedToRealEstateBusinessTables Inventories Related to Real Estate Business (Tables) Tables http://www.aseglobal.com/role/InventoriesRelatedToRealEstateBusiness 56 false false R57.htm 999051 - Disclosure - Other Financial Assets (Tables) Sheet http://www.aseglobal.com/role/OtherFinancialAssetsTables Other Financial Assets (Tables) Tables http://www.aseglobal.com/role/OtherFinancialAssets 57 false false R58.htm 999052 - Disclosure - Investments Accounted for Using the Equity Method (Tables) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodTables Investments Accounted for Using the Equity Method (Tables) Tables http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethod 58 false false R59.htm 999053 - Disclosure - Property, Plant and Equipment (Tables) Sheet http://www.aseglobal.com/role/PropertyPlantAndEquipmentTables Property, Plant and Equipment (Tables) Tables http://www.aseglobal.com/role/PropertyPlantAndEquipment 59 false false R60.htm 999054 - Disclosure - Lease Arrangements (Tables) Sheet http://www.aseglobal.com/role/LeaseArrangementsTables Lease Arrangements (Tables) Tables http://www.aseglobal.com/role/LeaseArrangements 60 false false R61.htm 999055 - Disclosure - Investment Properties (Tables) Sheet http://www.aseglobal.com/role/InvestmentPropertiesTables Investment Properties (Tables) Tables http://www.aseglobal.com/role/InvestmentProperties 61 false false R62.htm 999056 - Disclosure - Goodwill (Tables) Sheet http://www.aseglobal.com/role/GoodwillTables Goodwill (Tables) Tables http://www.aseglobal.com/role/Goodwill 62 false false R63.htm 999057 - Disclosure - Other Intangible Assets (Tables) Sheet http://www.aseglobal.com/role/OtherIntangibleAssetsTables Other Intangible Assets (Tables) Tables http://www.aseglobal.com/role/OtherIntangibleAssets 63 false false R64.htm 999058 - Disclosure - Borrowings (Tables) Sheet http://www.aseglobal.com/role/BorrowingsTables Borrowings (Tables) Tables http://www.aseglobal.com/role/Borrowings 64 false false R65.htm 999059 - Disclosure - Bonds Payable (Tables) Sheet http://www.aseglobal.com/role/BondsPayableTables Bonds Payable (Tables) Tables http://www.aseglobal.com/role/BondsPayable 65 false false R66.htm 999060 - Disclosure - Other Payables (Tables) Sheet http://www.aseglobal.com/role/OtherPayablesTables Other Payables (Tables) Tables http://www.aseglobal.com/role/OtherPayables 66 false false R67.htm 999061 - Disclosure - Retirement Benefit Plans (Tables) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansTables Retirement Benefit Plans (Tables) Tables http://www.aseglobal.com/role/RetirementBenefitPlans 67 false false R68.htm 999062 - Disclosure - Equity (Tables) Sheet http://www.aseglobal.com/role/EquityTables Equity (Tables) Tables http://www.aseglobal.com/role/Equity 68 false false R69.htm 999063 - Disclosure - Profit Before Income Tax (Tables) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxTables Profit Before Income Tax (Tables) Tables http://www.aseglobal.com/role/ProfitBeforeIncomeTax 69 false false R70.htm 999064 - Disclosure - Income Tax (Tables) Sheet http://www.aseglobal.com/role/IncomeTaxTables Income Tax (Tables) Tables http://www.aseglobal.com/role/IncomeTax 70 false false R71.htm 999065 - Disclosure - Earnings Per Share (Tables) Sheet http://www.aseglobal.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://www.aseglobal.com/role/EarningsPerShare 71 false false R72.htm 999066 - Disclosure - Share-based Payment Arrangements (Tables) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsTables Share-based Payment Arrangements (Tables) Tables http://www.aseglobal.com/role/ShareBasedPaymentArrangements 72 false false R73.htm 999067 - Disclosure - Business Combinations (Tables) Sheet http://www.aseglobal.com/role/BusinessCombinationsTables Business Combinations (Tables) Tables http://www.aseglobal.com/role/BusinessCombinations 73 false false R74.htm 999068 - Disclosure - Disposal of Subsidiary (Tables) Sheet http://www.aseglobal.com/role/DisposalOfSubsidiaryTables Disposal of Subsidiary (Tables) Tables http://www.aseglobal.com/role/DisposalOfSubsidiary 74 false false R75.htm 999069 - Disclosure - Cash Flow Information (Tables) Sheet http://www.aseglobal.com/role/CashFlowInformationTables Cash Flow Information (Tables) Tables http://www.aseglobal.com/role/CashFlowInformation 75 false false R76.htm 999070 - Disclosure - Financial Instruments (Tables) Sheet http://www.aseglobal.com/role/FinancialInstrumentsTables Financial Instruments (Tables) Tables http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtpl 76 false false R77.htm 999071 - Disclosure - Related Party Transactions (Tables) Sheet http://www.aseglobal.com/role/RelatedPartyTransactionsTables Related Party Transactions (Tables) Tables http://www.aseglobal.com/role/RelatedPartyTransactions 77 false false R78.htm 999072 - Disclosure - Assets Pledged as Collateral or for Security (Tables) Sheet http://www.aseglobal.com/role/AssetsPledgedAsCollateralOrForSecurityTables Assets Pledged as Collateral or for Security (Tables) Tables http://www.aseglobal.com/role/AssetsPledgedAsCollateralOrForSecurity 78 false false R79.htm 999073 - Disclosure - Significant Assets and Liabilities Denominated in Foreign Currencies (Tables) Sheet http://www.aseglobal.com/role/SignificantAssetsAndLiabilitiesDenominatedInForeignCurrenciesTables Significant Assets and Liabilities Denominated in Foreign Currencies (Tables) Tables http://www.aseglobal.com/role/SignificantAssetsAndLiabilitiesDenominatedInForeignCurrencies 79 false false R80.htm 999074 - Disclosure - Operating Segments Information (Tables) Sheet http://www.aseglobal.com/role/OperatingSegmentsInformationTables Operating Segments Information (Tables) Tables http://www.aseglobal.com/role/OperatingSegmentsInformation 80 false false R81.htm 999075 - Disclosure - Summary of Material Accounting Policy Information - Summary of Subsidiaries (Detail) Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformationSummaryOfSubsidiariesDetail Summary of Material Accounting Policy Information - Summary of Subsidiaries (Detail) Details 81 false false R82.htm 999076 - Disclosure - Summary of Material Accounting Policy Information - Summary of Subsidiaries (Parenthetical) (Detail) Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformationSummaryOfSubsidiariesParentheticalDetail Summary of Material Accounting Policy Information - Summary of Subsidiaries (Parenthetical) (Detail) Details 82 false false R83.htm 999077 - Disclosure - Summary of Material Accounting Policy Information - Additional Information (Detail) Sheet http://www.aseglobal.com/role/SummaryOfMaterialAccountingPolicyInformationAdditionalInformationDetail Summary of Material Accounting Policy Information - Additional Information (Detail) Details 83 false false R84.htm 999078 - Disclosure - Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) Sheet http://www.aseglobal.com/role/CashAndCashEquivalentsSummaryOfCashAndCashEquivalentsDetail Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) Details 84 false false R85.htm 999079 - Disclosure - Financial Instruments at Fair Value Through Profit or Loss (FVTPL) - Summary of Financial Instruments at Fair Value Through Profit or Loss (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtplSummaryOfFinancialInstrumentsAtFairValueThroughProfitOrLossDetail Financial Instruments at Fair Value Through Profit or Loss (FVTPL) - Summary of Financial Instruments at Fair Value Through Profit or Loss (Detail) Details http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtplTables 85 false false R86.htm 999080 - Disclosure - Financial Instruments at Fair Value Through Profit or Loss (FVTPL) - Summary of Outstanding Contracts Not Accounted for Hedge Accounting (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtplSummaryOfOutstandingContractsNotAccountedForHedgeAccountingDetail Financial Instruments at Fair Value Through Profit or Loss (FVTPL) - Summary of Outstanding Contracts Not Accounted for Hedge Accounting (Detail) Details http://www.aseglobal.com/role/FinancialInstrumentsAtFairValueThroughProfitOrLossFvtplTables 86 false false R87.htm 999081 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Financial Assets at Fair Value Through Other Comprehensive Income (Detail) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeSummaryOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeDetail Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Financial Assets at Fair Value Through Other Comprehensive Income (Detail) Details 87 false false R88.htm 999082 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Investments in Equity Instruments at Fair Value Through Other Comprehensive Income (Detail) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeSummaryOfInvestmentsInEquityInstrumentsAtFairValueThroughOtherComprehensiveIncomeDetail Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Investments in Equity Instruments at Fair Value Through Other Comprehensive Income (Detail) Details 88 false false R89.htm 999083 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Investments in Debt Instruments at Fair Value Through Other Comprehensive Income (Detail) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeSummaryOfInvestmentsInDebtInstrumentsAtFairValueThroughOtherComprehensiveIncomeDetail Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Investments in Debt Instruments at Fair Value Through Other Comprehensive Income (Detail) Details 89 false false R90.htm 999084 - Disclosure - Financial Assets at Fair Value Through Other Comprehensive Income - Additional Information (Detail) Sheet http://www.aseglobal.com/role/FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeAdditionalInformationDetail Financial Assets at Fair Value Through Other Comprehensive Income - Additional Information (Detail) Details 90 false false R91.htm 999085 - Disclosure - Trade Receivables, Net - Summary of Trade Receivables, Net (Detail) Sheet http://www.aseglobal.com/role/TradeReceivablesNetSummaryOfTradeReceivablesNetDetail Trade Receivables, Net - Summary of Trade Receivables, Net (Detail) Details 91 false false R92.htm 999086 - Disclosure - Trade Receivables, Net - Additional Information (Detail) Sheet http://www.aseglobal.com/role/TradeReceivablesNetAdditionalInformationDetail Trade Receivables, Net - Additional Information (Detail) Details 92 false false R93.htm 999087 - Disclosure - Trade Receivables, Net - Summary of Loss Allowance of Trade Receivables Based on Group's Provision Matrix (Detail) Sheet http://www.aseglobal.com/role/TradeReceivablesNetSummaryOfLossAllowanceOfTradeReceivablesBasedOnGroupsProvisionMatrixDetail Trade Receivables, Net - Summary of Loss Allowance of Trade Receivables Based on Group's Provision Matrix (Detail) Details 93 false false R94.htm 999088 - Disclosure - Trade Receivables, Net - Summary of Movements of Loss Allowance of Trade Receivables (Detail) Sheet http://www.aseglobal.com/role/TradeReceivablesNetSummaryOfMovementsOfLossAllowanceOfTradeReceivablesDetail Trade Receivables, Net - Summary of Movements of Loss Allowance of Trade Receivables (Detail) Details 94 false false R95.htm 999089 - Disclosure - Trade Receivables, Net - Summary of Loss Allowance For Current Financial Assets At FVTOCI (Detail) Sheet http://www.aseglobal.com/role/TradeReceivablesNetSummaryOfLossAllowanceForCurrentFinancialAssetsAtFvtociDetail Trade Receivables, Net - Summary of Loss Allowance For Current Financial Assets At FVTOCI (Detail) Details 95 false false R96.htm 999090 - Disclosure - Inventories - Summary of Inventories (Detail) Sheet http://www.aseglobal.com/role/InventoriesSummaryOfInventoriesDetail Inventories - Summary of Inventories (Detail) Details 96 false false R97.htm 999091 - Disclosure - Inventories - Additional Information (Detail) Sheet http://www.aseglobal.com/role/InventoriesAdditionalInformationDetail Inventories - Additional Information (Detail) Details 97 false false R98.htm 999092 - Disclosure - Inventories Related to Real Estate Business - Summary of Inventories Related to Real Estate Business (Detail) Sheet http://www.aseglobal.com/role/InventoriesRelatedToRealEstateBusinessSummaryOfInventoriesRelatedToRealEstateBusinessDetail Inventories Related to Real Estate Business - Summary of Inventories Related to Real Estate Business (Detail) Details 98 false false R99.htm 999093 - Disclosure - Inventories Related to Real Estate Business - Additional Information (Detail) Sheet http://www.aseglobal.com/role/InventoriesRelatedToRealEstateBusinessAdditionalInformationDetail Inventories Related to Real Estate Business - Additional Information (Detail) Details 99 false false R100.htm 999094 - Disclosure - Other Financial Assets - Summary of Other Financial Assets (Detail) Sheet http://www.aseglobal.com/role/OtherFinancialAssetsSummaryOfOtherFinancialAssetsDetail Other Financial Assets - Summary of Other Financial Assets (Detail) Details 100 false false R101.htm 999095 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Investments Accounted for Using the Equity Method (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfInvestmentsAccountedForUsingTheEquityMethodDetail Investments Accounted for Using the Equity Method - Summary of Investments Accounted for Using the Equity Method (Detail) Details 101 false false R102.htm 999096 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Investments in Associates Accounted for Using the Equity Method (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfInvestmentsInAssociatesAccountedForUsingTheEquityMethodDetail Investments Accounted for Using the Equity Method - Summary of Investments in Associates Accounted for Using the Equity Method (Detail) Details 102 false false R103.htm 999097 - Disclosure - Investments Accounted for Using the Equity Method - Additional Information (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodAdditionalInformationDetail Investments Accounted for Using the Equity Method - Additional Information (Detail) Details 103 false false R104.htm 999098 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Fair Values of Investments in Associates with Available Published Price Quotation (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfFairValuesOfInvestmentsInAssociatesWithAvailablePublishedPriceQuotationDetail Investments Accounted for Using the Equity Method - Summary of Fair Values of Investments in Associates with Available Published Price Quotation (Detail) Details 104 false false R105.htm 999099 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Aggregate Information of Associates that are Not Individually Material (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfAggregateInformationOfAssociatesThatAreNotIndividuallyMaterialDetail Investments Accounted for Using the Equity Method - Summary of Aggregate Information of Associates that are Not Individually Material (Detail) Details 105 false false R106.htm 999100 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Investments in joint ventures Accounted for using the Equity Method (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfInvestmentsInJointVenturesAccountedForUsingTheEquityMethodDetail Investments Accounted for Using the Equity Method - Summary of Investments in joint ventures Accounted for using the Equity Method (Detail) Details 106 false false R107.htm 999101 - Disclosure - Investments Accounted for Using the Equity Method - Summary of Aggregate Information of the Joint Venture that is Not Individually Material (Detail) Sheet http://www.aseglobal.com/role/InvestmentsAccountedForUsingTheEquityMethodSummaryOfAggregateInformationOfTheJointVentureThatIsNotIndividuallyMaterialDetail Investments Accounted for Using the Equity Method - Summary of Aggregate Information of the Joint Venture that is Not Individually Material (Detail) Details 107 false false R108.htm 999102 - Disclosure - Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) Sheet http://www.aseglobal.com/role/PropertyPlantAndEquipmentSummaryOfPropertyPlantAndEquipmentDetail Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) Details 108 false false R109.htm 999103 - Disclosure - Property, Plant and Equipment - Additional Information (Detail) Sheet http://www.aseglobal.com/role/PropertyPlantAndEquipmentAdditionalInformationDetail Property, Plant and Equipment - Additional Information (Detail) Details 109 false false R110.htm 999104 - Disclosure - Property, Plant and Equipment - Summary of Property, Plant and Equipment Depreciated Useful Lives (Detail) Sheet http://www.aseglobal.com/role/PropertyPlantAndEquipmentSummaryOfPropertyPlantAndEquipmentDepreciatedUsefulLivesDetail Property, Plant and Equipment - Summary of Property, Plant and Equipment Depreciated Useful Lives (Detail) Details 110 false false R111.htm 999105 - Disclosure - Lease Arrangements - Summary of Right-of-Use Assets (Detail) Sheet http://www.aseglobal.com/role/LeaseArrangementsSummaryOfRightOfUseAssetsDetail Lease Arrangements - Summary of Right-of-Use Assets (Detail) Details 111 false false R112.htm 999106 - Disclosure - Lease Arrangements - Summary of Lease Liabilities (Detail) Sheet http://www.aseglobal.com/role/LeaseArrangementsSummaryOfLeaseLiabilitiesDetail Lease Arrangements - Summary of Lease Liabilities (Detail) Details 112 false false R113.htm 999107 - Disclosure - Lease Arrangements - Summary of the Group's Lease Liabilities are Mainly From Land and Buildings and Improvements. Range of Discount Rate for Lease Liabilities (Detail) Sheet http://www.aseglobal.com/role/LeaseArrangementsSummaryOfTheGroupsLeaseLiabilitiesAreMainlyFromLandAndBuildingsAndImprovementsRangeOfDiscountRateForLeaseLiabilitiesDetail Lease Arrangements - Summary of the Group's Lease Liabilities are Mainly From Land and Buildings and Improvements. Range of Discount Rate for Lease Liabilities (Detail) Details 113 false false R114.htm 999108 - Disclosure - Lease Arrangements - Additional Information (Detail) Sheet http://www.aseglobal.com/role/LeaseArrangementsAdditionalInformationDetail Lease Arrangements - Additional Information (Detail) Details 114 false false R115.htm 999109 - Disclosure - Lease Arrangements - Summary of Other Related Lease Information (Detail) Sheet http://www.aseglobal.com/role/LeaseArrangementsSummaryOfOtherRelatedLeaseInformationDetail Lease Arrangements - Summary of Other Related Lease Information (Detail) Details 115 false false R116.htm 999110 - Disclosure - Investment Properties - Summary of Investment Properties (Detail) Sheet http://www.aseglobal.com/role/InvestmentPropertiesSummaryOfInvestmentPropertiesDetail Investment Properties - Summary of Investment Properties (Detail) Details 116 false false R117.htm 999111 - Disclosure - Investment Properties - Summary of Maturity Analysis Of Operating Lease Payments (Detail) Sheet http://www.aseglobal.com/role/InvestmentPropertiesSummaryOfMaturityAnalysisOfOperatingLeasePaymentsDetail Investment Properties - Summary of Maturity Analysis Of Operating Lease Payments (Detail) Details 117 false false R118.htm 999112 - Disclosure - Investment Properties - Investment Properties Depreciated on a Straight-Line Basis Over Useful Lives (Detail) Sheet http://www.aseglobal.com/role/InvestmentPropertiesInvestmentPropertiesDepreciatedOnAStraightLineBasisOverUsefulLivesDetail Investment Properties - Investment Properties Depreciated on a Straight-Line Basis Over Useful Lives (Detail) Details 118 false false R119.htm 999113 - Disclosure - Investment Properties - Summary of Investment Properties, Fair Value (Detail) Sheet http://www.aseglobal.com/role/InvestmentPropertiesSummaryOfInvestmentPropertiesFairValueDetail Investment Properties - Summary of Investment Properties, Fair Value (Detail) Details 119 false false R120.htm 999114 - Disclosure - Goodwill - Summary of Goodwill (Detail) Sheet http://www.aseglobal.com/role/GoodwillSummaryOfGoodwillDetail Goodwill - Summary of Goodwill (Detail) Details 120 false false R121.htm 999115 - Disclosure - Goodwill - Summary of Carrying Amounts of Goodwill Allocated to Cash-generating Units (Detail) Sheet http://www.aseglobal.com/role/GoodwillSummaryOfCarryingAmountsOfGoodwillAllocatedToCashGeneratingUnitsDetail Goodwill - Summary of Carrying Amounts of Goodwill Allocated to Cash-generating Units (Detail) Details 121 false false R122.htm 999116 - Disclosure - Goodwill - Additional Information (Detail) Sheet http://www.aseglobal.com/role/GoodwillAdditionalInformationDetail Goodwill - Additional Information (Detail) Details 122 false false R123.htm 999117 - Disclosure - Other Intangible Assets - Summary of Carrying Amounts of Each Class of Other Intangible Assets (Detail) Sheet http://www.aseglobal.com/role/OtherIntangibleAssetsSummaryOfCarryingAmountsOfEachClassOfOtherIntangibleAssetsDetail Other Intangible Assets - Summary of Carrying Amounts of Each Class of Other Intangible Assets (Detail) Details 123 false false R124.htm 999118 - Disclosure - Other Intangible Assets - Summary of Other Intangible Assets Useful Lives (Detail) Sheet http://www.aseglobal.com/role/OtherIntangibleAssetsSummaryOfOtherIntangibleAssetsUsefulLivesDetail Other Intangible Assets - Summary of Other Intangible Assets Useful Lives (Detail) Details 124 false false R125.htm 999119 - Disclosure - Borrowings - Additional Information (Detail) Sheet http://www.aseglobal.com/role/BorrowingsAdditionalInformationDetail Borrowings - Additional Information (Detail) Details 125 false false R126.htm 999120 - Disclosure - Borrowings - Summary of Short Term Borrowings (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfShortTermBorrowingsDetail Borrowings - Summary of Short Term Borrowings (Detail) Details 126 false false R127.htm 999121 - Disclosure - Borrowings - Summary of Short Term Borrowings (Parenthetical) (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfShortTermBorrowingsParentheticalDetail Borrowings - Summary of Short Term Borrowings (Parenthetical) (Detail) Details 127 false false R128.htm 999122 - Disclosure - Borrowings - Summary of Bills Payable (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfBillsPayableDetail Borrowings - Summary of Bills Payable (Detail) Details 128 false false R129.htm 999123 - Disclosure - Borrowings - Summary of Bills Payable (Parenthetical) (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfBillsPayableParentheticalDetail Borrowings - Summary of Bills Payable (Parenthetical) (Detail) Details 129 false false R130.htm 999124 - Disclosure - Borrowings - Summary of Bank Loans (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfBankLoansDetail Borrowings - Summary of Bank Loans (Detail) Details 130 false false R131.htm 999125 - Disclosure - Borrowings - Summary of Bank Loans (Parenthetical) (Detail) Sheet http://www.aseglobal.com/role/BorrowingsSummaryOfBankLoansParentheticalDetail Borrowings - Summary of Bank Loans (Parenthetical) (Detail) Details 131 false false R132.htm 999126 - Disclosure - Bonds Payable - Summary of Bonds Payable (Detail) Sheet http://www.aseglobal.com/role/BondsPayableSummaryOfBondsPayableDetail Bonds Payable - Summary of Bonds Payable (Detail) Details 132 false false R133.htm 999127 - Disclosure - Bonds Payable - Summary of Bonds Payable (Parenthetical) (Detail) Sheet http://www.aseglobal.com/role/BondsPayableSummaryOfBondsPayableParentheticalDetail Bonds Payable - Summary of Bonds Payable (Parenthetical) (Detail) Details 133 false false R134.htm 999128 - Disclosure - Bonds Payable - Additional Information (Detail) Sheet http://www.aseglobal.com/role/BondsPayableAdditionalInformationDetail Bonds Payable - Additional Information (Detail) Details 134 false false R135.htm 999129 - Disclosure - Other Payables - Summary of Other Payables (Detail) Sheet http://www.aseglobal.com/role/OtherPayablesSummaryOfOtherPayablesDetail Other Payables - Summary of Other Payables (Detail) Details 135 false false R136.htm 999130 - Disclosure - Retirement Benefit Plans - Additional Information (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansAdditionalInformationDetail Retirement Benefit Plans - Additional Information (Detail) Details 136 false false R137.htm 999131 - Disclosure - Retirement Benefit Plans - Summary of Defined Benefit Plans Amounts Included in Consolidated Balance Sheets (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfDefinedBenefitPlansAmountsIncludedInConsolidatedBalanceSheetsDetail Retirement Benefit Plans - Summary of Defined Benefit Plans Amounts Included in Consolidated Balance Sheets (Detail) Details 137 false false R138.htm 999132 - Disclosure - Retirement Benefit Plans - Summary of Movements in Net Defined Benefit Liability (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfMovementsInNetDefinedBenefitLiabilityDetail Retirement Benefit Plans - Summary of Movements in Net Defined Benefit Liability (Detail) Details 138 false false R139.htm 999133 - Disclosure - Retirement Benefit Plans - Summary of Fair Value of the Plan Assets by Major Categories (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfFairValueOfThePlanAssetsByMajorCategoriesDetail Retirement Benefit Plans - Summary of Fair Value of the Plan Assets by Major Categories (Detail) Details 139 false false R140.htm 999134 - Disclosure - Retirement Benefit Plans - Summary of Key Assumptions Used for the Actuarial Valuations (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfKeyAssumptionsUsedForTheActuarialValuationsDetail Retirement Benefit Plans - Summary of Key Assumptions Used for the Actuarial Valuations (Detail) Details 140 false false R141.htm 999135 - Disclosure - Retirement Benefit Plans - Summary of Sensitivity Analysis on Defined Obligations (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfSensitivityAnalysisOnDefinedObligationsDetail Retirement Benefit Plans - Summary of Sensitivity Analysis on Defined Obligations (Detail) Details 141 false false R142.htm 999136 - Disclosure - Retirement Benefit Plans - Summary of Maturity Analysis of Undiscounted Pension Benefit (Detail) Sheet http://www.aseglobal.com/role/RetirementBenefitPlansSummaryOfMaturityAnalysisOfUndiscountedPensionBenefitDetail Retirement Benefit Plans - Summary of Maturity Analysis of Undiscounted Pension Benefit (Detail) Details 142 false false R143.htm 999137 - Disclosure - Equity - Summary of Share Capital (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfShareCapitalDetail Equity - Summary of Share Capital (Detail) Details 143 false false R144.htm 999138 - Disclosure - Equity - Additional Information (Detail) Sheet http://www.aseglobal.com/role/EquityAdditionalInformationDetail Equity - Additional Information (Detail) Details 144 false false R145.htm 999139 - Disclosure - Equity - Summary of Capital Surplus (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfCapitalSurplusDetail Equity - Summary of Capital Surplus (Detail) Details 145 false false R146.htm 999140 - Disclosure - Equity - Schedule of appropriation of retained earnings (Detail) Sheet http://www.aseglobal.com/role/EquityScheduleOfAppropriationOfRetainedEarningsDetail Equity - Schedule of appropriation of retained earnings (Detail) Details 146 false false R147.htm 999141 - Disclosure - Equity - Summary of Exchange Differences on Translating Foreign Operations (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfExchangeDifferencesOnTranslatingForeignOperationsDetail Equity - Summary of Exchange Differences on Translating Foreign Operations (Detail) Details 147 false false R148.htm 999142 - Disclosure - Equity - Summary of Unrealized Gain (Loss) on Financial Assets at FVTOCI (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfUnrealizedGainLossOnFinancialAssetsAtFvtociDetail Equity - Summary of Unrealized Gain (Loss) on Financial Assets at FVTOCI (Detail) Details 148 false false R149.htm 999143 - Disclosure - Equity - Schedule Of Detailed Information About Hedges Of Net Investments Of Foreign Operations (Detail) Sheet http://www.aseglobal.com/role/EquityScheduleOfDetailedInformationAboutHedgesOfNetInvestmentsOfForeignOperationsDetail Equity - Schedule Of Detailed Information About Hedges Of Net Investments Of Foreign Operations (Detail) Details 149 false false R150.htm 999144 - Disclosure - Equity - Summary of Unearned Employee Compensation (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfUnearnedEmployeeCompensationDetail Equity - Summary of Unearned Employee Compensation (Detail) Details 150 false false R151.htm 999145 - Disclosure - Equity - Summary of Shares Held By Subsidiaries (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfSharesHeldBySubsidiariesDetail Equity - Summary of Shares Held By Subsidiaries (Detail) Details 151 false false R152.htm 999146 - Disclosure - Equity - Summary of Non-controlling Interests (Detail) Sheet http://www.aseglobal.com/role/EquitySummaryOfNonControllingInterestsDetail Equity - Summary of Non-controlling Interests (Detail) Details 152 false false R153.htm 999147 - Disclosure - Profit Before Income Tax - Summary of Other Operating Income and Expenses, Net (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfOtherOperatingIncomeAndExpensesNetDetail Profit Before Income Tax - Summary of Other Operating Income and Expenses, Net (Detail) Details 153 false false R154.htm 999148 - Disclosure - Profit Before Income Tax - Summary of Other Income (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfOtherIncomeDetail Profit Before Income Tax - Summary of Other Income (Detail) Details 154 false false R155.htm 999149 - Disclosure - Profit Before Income Tax - Summary of Other Gains and Losses (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfOtherGainsAndLossesDetail Profit Before Income Tax - Summary of Other Gains and Losses (Detail) Details 155 false false R156.htm 999150 - Disclosure - Profit Before Income Tax - Summary of Finance Costs (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfFinanceCostsDetail Profit Before Income Tax - Summary of Finance Costs (Detail) Details 156 false false R157.htm 999151 - Disclosure - Profit Before Income Tax - Summary of Annual interest rates of capitalized borrowing Costs (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfAnnualInterestRatesOfCapitalizedBorrowingCostsDetail Profit Before Income Tax - Summary of Annual interest rates of capitalized borrowing Costs (Detail) Details 157 false false R158.htm 999152 - Disclosure - Profit Before Income Tax - Summary of Depreciation and Amortization (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfDepreciationAndAmortizationDetail Profit Before Income Tax - Summary of Depreciation and Amortization (Detail) Details 158 false false R159.htm 999153 - Disclosure - Profit Before Income Tax - Summary of Operating Expenses Directly Related to Investment Properties (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfOperatingExpensesDirectlyRelatedToInvestmentPropertiesDetail Profit Before Income Tax - Summary of Operating Expenses Directly Related to Investment Properties (Detail) Details 159 false false R160.htm 999154 - Disclosure - Profit Before Income Tax - Summary of Employee Benefits Expense (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfEmployeeBenefitsExpenseDetail Profit Before Income Tax - Summary of Employee Benefits Expense (Detail) Details 160 false false R161.htm 999155 - Disclosure - Profit Before Income Tax - Additional Information (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxAdditionalInformationDetail Profit Before Income Tax - Additional Information (Detail) Details 161 false false R162.htm 999156 - Disclosure - Profit Before Income Tax - Summary of Employees' Compensation and Remuneration to Directors (Detail) Sheet http://www.aseglobal.com/role/ProfitBeforeIncomeTaxSummaryOfEmployeesCompensationAndRemunerationToDirectorsDetail Profit Before Income Tax - Summary of Employees' Compensation and Remuneration to Directors (Detail) Details 162 false false R163.htm 999157 - Disclosure - Income Tax - Summary of Major Components of Income Tax Expense (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfMajorComponentsOfIncomeTaxExpenseDetail Income Tax - Summary of Major Components of Income Tax Expense (Detail) Details 163 false false R164.htm 999158 - Disclosure - Income Tax - Summary of Reconciliation of Income Tax Expense (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfReconciliationOfIncomeTaxExpenseDetail Income Tax - Summary of Reconciliation of Income Tax Expense (Detail) Details 164 false false R165.htm 999159 - Disclosure - Income Tax - Additional Information (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxAdditionalInformationDetail Income Tax - Additional Information (Detail) Details 165 false false R166.htm 999160 - Disclosure - Income Tax - Summary of Income Tax Recognized Directly in Equity (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfIncomeTaxRecognizedDirectlyInEquityDetail Income Tax - Summary of Income Tax Recognized Directly in Equity (Detail) Details 166 false false R167.htm 999161 - Disclosure - Income Tax - Summary of Income Tax Recognized in Other Comprehensive Income (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfIncomeTaxRecognizedInOtherComprehensiveIncomeDetail Income Tax - Summary of Income Tax Recognized in Other Comprehensive Income (Detail) Details 167 false false R168.htm 999162 - Disclosure - Income Tax - Summary of Current Tax Assets and Liabilities (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfCurrentTaxAssetsAndLiabilitiesDetail Income Tax - Summary of Current Tax Assets and Liabilities (Detail) Details 168 false false R169.htm 999163 - Disclosure - Income Tax - Summary of Movements of Deferred Tax Assets and Deferred Tax Liabilities (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfMovementsOfDeferredTaxAssetsAndDeferredTaxLiabilitiesDetail Income Tax - Summary of Movements of Deferred Tax Assets and Deferred Tax Liabilities (Detail) Details 169 false false R170.htm 999164 - Disclosure - Income Tax - Summary of Unrecognized Deferred Tax Assets Related to Loss Carry-forward, Investment Credits and Deductible Temporary Differences (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfUnrecognizedDeferredTaxAssetsRelatedToLossCarryForwardInvestmentCreditsAndDeductibleTemporaryDifferencesDetail Income Tax - Summary of Unrecognized Deferred Tax Assets Related to Loss Carry-forward, Investment Credits and Deductible Temporary Differences (Detail) Details 170 false false R171.htm 999165 - Disclosure - Income Tax - Summary of Unused Loss Carry-forward (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfUnusedLossCarryForwardDetail Income Tax - Summary of Unused Loss Carry-forward (Detail) Details 171 false false R172.htm 999166 - Disclosure - Income Tax - Summary of Unused Investment Credits (Detail) Sheet http://www.aseglobal.com/role/IncomeTaxSummaryOfUnusedInvestmentCreditsDetail Income Tax - Summary of Unused Investment Credits (Detail) Details 172 false false R173.htm 999167 - Disclosure - Earnings Per Share - Summary of Earnings and Weighted Average Number of Ordinary Shares Outstanding in Computation of Earnings Per Share (Detail) Sheet http://www.aseglobal.com/role/EarningsPerShareSummaryOfEarningsAndWeightedAverageNumberOfOrdinarySharesOutstandingInComputationOfEarningsPerShareDetail Earnings Per Share - Summary of Earnings and Weighted Average Number of Ordinary Shares Outstanding in Computation of Earnings Per Share (Detail) Details 173 false false R174.htm 999168 - Disclosure - Earnings Per Share - Additional Information (Detail) Sheet http://www.aseglobal.com/role/EarningsPerShareAdditionalInformationDetail Earnings Per Share - Additional Information (Detail) Details 174 false false R175.htm 999169 - Disclosure - Share-based Payment Arrangements - Additional Information (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsAdditionalInformationDetail Share-based Payment Arrangements - Additional Information (Detail) Details 175 false false R176.htm 999170 - Disclosure - Share-based Payment Arrangements - Summary of Information About ASE Inc. Option Plans (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfInformationAboutAseIncOptionPlansDetail Share-based Payment Arrangements - Summary of Information About ASE Inc. Option Plans (Detail) Details 176 false false R177.htm 999171 - Disclosure - Share-based Payment Arrangements - Summary Of Information About Employee Restricted Stock Awards (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfInformationAboutEmployeeRestrictedStockAwardsDetail Share-based Payment Arrangements - Summary Of Information About Employee Restricted Stock Awards (Detail) Details 177 false false R178.htm 999172 - Disclosure - Share-based Payment Arrangements - Summary of ASE Inc. Option Plans Outstanding Share Options (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfAseIncOptionPlansOutstandingShareOptionsDetail Share-based Payment Arrangements - Summary of ASE Inc. Option Plans Outstanding Share Options (Detail) Details 178 false false R179.htm 999173 - Disclosure - Share-based Payment Arrangements - Summary of Information About USISH Option Plans (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfInformationAboutUsishOptionPlansDetail Share-based Payment Arrangements - Summary of Information About USISH Option Plans (Detail) Details 179 false false R180.htm 999174 - Disclosure - Share-based Payment Arrangements - Summary of USISH's outstanding share options balance sheet (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfUsishSOutstandingShareOptionsBalanceSheetDetail Share-based Payment Arrangements - Summary of USISH's outstanding share options balance sheet (Detail) Details 180 false false R181.htm 999175 - Disclosure - Share-based Payment Arrangements - Summary of Information About Restricted Shares (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfInformationAboutRestrictedSharesDetail Share-based Payment Arrangements - Summary of Information About Restricted Shares (Detail) Details 181 false false R182.htm 999176 - Disclosure - Share-based Payment Arrangements - Summary of Outstanding Restricted Shares At Balance Sheet (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfOutstandingRestrictedSharesAtBalanceSheetDetail Share-based Payment Arrangements - Summary of Outstanding Restricted Shares At Balance Sheet (Detail) Details 182 false false R183.htm 999177 - Disclosure - Share-based Payment Arrangements - Summary of Fair Value using Trinomial Tree Model and Inputs (Detail) Sheet http://www.aseglobal.com/role/ShareBasedPaymentArrangementsSummaryOfFairValueUsingTrinomialTreeModelAndInputsDetail Share-based Payment Arrangements - Summary of Fair Value using Trinomial Tree Model and Inputs (Detail) Details 183 false false R184.htm 999178 - Disclosure - Business Combinations - Summary of Subsidiary Acquired (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfSubsidiaryAcquiredDetail Business Combinations - Summary of Subsidiary Acquired (Detail) Details 184 false false R185.htm 999179 - Disclosure - Business Combinations - Additional Information (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsAdditionalInformationDetail Business Combinations - Additional Information (Detail) Details 185 false false R186.htm 999180 - Disclosure - Business Combinations - Summary of Consideration Transferred in business combination (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfConsiderationTransferredInBusinessCombinationDetail Business Combinations - Summary of Consideration Transferred in business combination (Detail) Details 186 false false R187.htm 999181 - Disclosure - Business Combinations - Summary of Assets Acquired and Liabilities Assumed at the Date of Acquisition (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfAssetsAcquiredAndLiabilitiesAssumedAtTheDateOfAcquisitionDetail Business Combinations - Summary of Assets Acquired and Liabilities Assumed at the Date of Acquisition (Detail) Details 187 false false R188.htm 999182 - Disclosure - Business Combinations - Summary of Goodwill Recognized on Acquisitions (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfGoodwillRecognizedOnAcquisitionsDetail Business Combinations - Summary of Goodwill Recognized on Acquisitions (Detail) Details 188 false false R189.htm 999183 - Disclosure - Business Combinations - Summary of Net Cash Outflow on Acquisition of Subsidiary (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfNetCashOutflowOnAcquisitionOfSubsidiaryDetail Business Combinations - Summary of Net Cash Outflow on Acquisition of Subsidiary (Detail) Details 189 false false R190.htm 999184 - Disclosure - Business Combinations - Summary of Impact of Acquisitions by Comprehensive Income (Detail) Sheet http://www.aseglobal.com/role/BusinessCombinationsSummaryOfImpactOfAcquisitionsByComprehensiveIncomeDetail Business Combinations - Summary of Impact of Acquisitions by Comprehensive Income (Detail) Details 190 false false R191.htm 999185 - Disclosure - Disposal of Subsidiary - Summary of Analysis of Assets and Liabilities on Date Control was Lost (Detail) Sheet http://www.aseglobal.com/role/DisposalOfSubsidiarySummaryOfAnalysisOfAssetsAndLiabilitiesOnDateControlWasLostDetail Disposal of Subsidiary - Summary of Analysis of Assets and Liabilities on Date Control was Lost (Detail) Details 191 false false R192.htm 999186 - Disclosure - Disposal of Subsidiary - Summary of Gain on Disposal of Subsidiary (Detail) Sheet http://www.aseglobal.com/role/DisposalOfSubsidiarySummaryOfGainOnDisposalOfSubsidiaryDetail Disposal of Subsidiary - Summary of Gain on Disposal of Subsidiary (Detail) Details 192 false false R193.htm 999187 - Disclosure - Disposal of Subsidiary - Summary of Net Cash Inflow on Disposal of Subsidiaries (Detail) Sheet http://www.aseglobal.com/role/DisposalOfSubsidiarySummaryOfNetCashInflowOnDisposalOfSubsidiariesDetail Disposal of Subsidiary - Summary of Net Cash Inflow on Disposal of Subsidiaries (Detail) Details 193 false false R194.htm 999188 - Disclosure - Disposal of Subsidiary - Additional Information (Detail) Sheet http://www.aseglobal.com/role/DisposalOfSubsidiaryAdditionalInformationDetail Disposal of Subsidiary - Additional Information (Detail) Details 194 false false R195.htm 999189 - Disclosure - Equity Transaction with Non-controlling Interests - Additional Information (Detail) Sheet http://www.aseglobal.com/role/EquityTransactionWithNonControllingInterestsAdditionalInformationDetail Equity Transaction with Non-controlling Interests - Additional Information (Detail) Details 195 false false R196.htm 999190 - Disclosure - Cash Flow Information - Additional Information (Detail) Sheet http://www.aseglobal.com/role/CashFlowInformationAdditionalInformationDetail Cash Flow Information - Additional Information (Detail) Details 196 false false R197.htm 999191 - Disclosure - Cash Flow Information - Summary of Non-cash Activities (Detail) Sheet http://www.aseglobal.com/role/CashFlowInformationSummaryOfNonCashActivitiesDetail Cash Flow Information - Summary of Non-cash Activities (Detail) Details 197 false false R198.htm 999192 - Disclosure - Cash Flow Information - Change in Liabilities Arising From Financing Activities (Detail) Sheet http://www.aseglobal.com/role/CashFlowInformationChangeInLiabilitiesArisingFromFinancingActivitiesDetail Cash Flow Information - Change in Liabilities Arising From Financing Activities (Detail) Details 198 false false R199.htm 999193 - Disclosure - Cash Flow Information - Summary of Supplier Financing Arrangements - Received Payment (Detail) Sheet http://www.aseglobal.com/role/CashFlowInformationSummaryOfSupplierFinancingArrangementsReceivedPaymentDetail Cash Flow Information - Summary of Supplier Financing Arrangements - Received Payment (Detail) Details 199 false false R200.htm 999194 - Disclosure - Cash Flow Information - Summary of Supplier Financing Arrangements - Trade Payables (Detail) Sheet http://www.aseglobal.com/role/CashFlowInformationSummaryOfSupplierFinancingArrangementsTradePayablesDetail Cash Flow Information - Summary of Supplier Financing Arrangements - Trade Payables (Detail) Details 200 false false R201.htm 999195 - Disclosure - Financial Instruments - Summary of Fair Value of Financial Instruments Not Measured at Fair Value but for Which Fair Value is Disclosed (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfFairValueOfFinancialInstrumentsNotMeasuredAtFairValueButForWhichFairValueIsDisclosedDetail Financial Instruments - Summary of Fair Value of Financial Instruments Not Measured at Fair Value but for Which Fair Value is Disclosed (Detail) Details 201 false false R202.htm 999196 - Disclosure - Financial Instruments - Summary of Fair Value of Financial Instruments that are Measured at Fair Value on a Recurring Basis (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfFairValueOfFinancialInstrumentsThatAreMeasuredAtFairValueOnARecurringBasisDetail Financial Instruments - Summary of Fair Value of Financial Instruments that are Measured at Fair Value on a Recurring Basis (Detail) Details 202 false false R203.htm 999197 - Disclosure - Financial Instruments - Additional Information (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsAdditionalInformationDetail Financial Instruments - Additional Information (Detail) Details 203 false false R204.htm 999198 - Disclosure - Financial Instruments - Summary of Financial Assets Measured at Level 3 Fair Value (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfFinancialAssetsMeasuredAtLevel3FairValueDetail Financial Instruments - Summary of Financial Assets Measured at Level 3 Fair Value (Detail) Details 204 false false R205.htm 999199 - Disclosure - Financial Instruments - Summary of Categories of Financial Instruments (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfCategoriesOfFinancialInstrumentsDetail Financial Instruments - Summary of Categories of Financial Instruments (Detail) Details 205 false false R206.htm 999200 - Disclosure - Financial Instruments - Summary of Detailed Information About Hedges (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfDetailedInformationAboutHedgesDetail Financial Instruments - Summary of Detailed Information About Hedges (Detail) Details 206 false false R207.htm 999201 - Disclosure - Financial Instruments - Summary of Detailed Information About Hedges Items (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfDetailedInformationAboutHedgesItemsDetail Financial Instruments - Summary of Detailed Information About Hedges Items (Detail) Details 207 false false R208.htm 999202 - Disclosure - Financial Instruments - Summary of Interest Rate Risk (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfInterestRateRiskDetail Financial Instruments - Summary of Interest Rate Risk (Detail) Details 208 false false R209.htm 999203 - Disclosure - Financial Instruments - Summary of Maturity Analysis for Non-derivative Financial Liabilities (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfMaturityAnalysisForNonDerivativeFinancialLiabilitiesDetail Financial Instruments - Summary of Maturity Analysis for Non-derivative Financial Liabilities (Detail) Details 209 false false R210.htm 999204 - Disclosure - Financial Instruments - Summary of Detailed Information about Maturity Analysis of Obligation under Leases (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfDetailedInformationAboutMaturityAnalysisOfObligationUnderLeasesDetail Financial Instruments - Summary of Detailed Information about Maturity Analysis of Obligation under Leases (Detail) Details 210 false false R211.htm 999205 - Disclosure - Financial Instruments - Summary of Maturity Analysis for Derivative Financial Instruments (Detail) Sheet http://www.aseglobal.com/role/FinancialInstrumentsSummaryOfMaturityAnalysisForDerivativeFinancialInstrumentsDetail Financial Instruments - Summary of Maturity Analysis for Derivative Financial Instruments (Detail) Details 211 false false R212.htm 999206 - Disclosure - Related Party Transactions - Additional Information (Detail) Sheet http://www.aseglobal.com/role/RelatedPartyTransactionsAdditionalInformationDetail Related Party Transactions - Additional Information (Detail) Details 212 false false R213.htm 999207 - Disclosure - Related Party Transactions - Schedule of Loan to Related Parties (Detail) Sheet http://www.aseglobal.com/role/RelatedPartyTransactionsScheduleOfLoanToRelatedPartiesDetail Related Party Transactions - Schedule of Loan to Related Parties (Detail) Details 213 false false R214.htm 999208 - Disclosure - Related Party Transactions - Summary of Transactions Between Related Parties (Detail) Sheet http://www.aseglobal.com/role/RelatedPartyTransactionsSummaryOfTransactionsBetweenRelatedPartiesDetail Related Party Transactions - Summary of Transactions Between Related Parties (Detail) Details 214 false false R215.htm 999209 - Disclosure - Related Party Transactions - Summary of Compensation to Key Management Personnel (Detail) Sheet http://www.aseglobal.com/role/RelatedPartyTransactionsSummaryOfCompensationToKeyManagementPersonnelDetail Related Party Transactions - Summary of Compensation to Key Management Personnel (Detail) Details 215 false false R216.htm 999210 - Disclosure - Assets Pledged as Collateral or for Security - Summary of Assets Pledged as Collateral or for Security (Detail) Sheet http://www.aseglobal.com/role/AssetsPledgedAsCollateralOrForSecuritySummaryOfAssetsPledgedAsCollateralOrForSecurityDetail Assets Pledged as Collateral or for Security - Summary of Assets Pledged as Collateral or for Security (Detail) Details 216 false false R217.htm 999211 - Disclosure - Significant Contingent Liabilities and Unrecognized Commitments - Additional Information (Detail) Sheet http://www.aseglobal.com/role/SignificantContingentLiabilitiesAndUnrecognizedCommitmentsAdditionalInformationDetail Significant Contingent Liabilities and Unrecognized Commitments - Additional Information (Detail) Details 217 false false R218.htm 999212 - Disclosure - Significant Events After Reporting Period - Additional Information (Detail) Sheet http://www.aseglobal.com/role/SignificantEventsAfterReportingPeriodAdditionalInformationDetail Significant Events After Reporting Period - Additional Information (Detail) Details 218 false false R219.htm 999213 - Disclosure - Others - Additional Information (Detail) Sheet http://www.aseglobal.com/role/OthersAdditionalInformationDetail Others - Additional Information (Detail) Details 219 false false R220.htm 999214 - Disclosure - Significant Assets and Liabilities Denominated in Foreign Currencies - Summary of Significant Assets and Liabilities Denominated in Foreign Currencies (Detail) Sheet http://www.aseglobal.com/role/SignificantAssetsAndLiabilitiesDenominatedInForeignCurrenciesSummaryOfSignificantAssetsAndLiabilitiesDenominatedInForeignCurrenciesDetail Significant Assets and Liabilities Denominated in Foreign Currencies - Summary of Significant Assets and Liabilities Denominated in Foreign Currencies (Detail) Details 220 false false R221.htm 999215 - Disclosure - Significant Assets and Liabilities Denominated in Foreign Currencies - Summary of Realized and Unrealized Foreign Exchange Gain (Loss) (Detail) Sheet http://www.aseglobal.com/role/SignificantAssetsAndLiabilitiesDenominatedInForeignCurrenciesSummaryOfRealizedAndUnrealizedForeignExchangeGainLossDetail Significant Assets and Liabilities Denominated in Foreign Currencies - Summary of Realized and Unrealized Foreign Exchange Gain (Loss) (Detail) Details 221 false false R222.htm 999216 - Disclosure - Operating Segments Information - Summary of Segment Information (Detail) Sheet http://www.aseglobal.com/role/OperatingSegmentsInformationSummaryOfSegmentInformationDetail Operating Segments Information - Summary of Segment Information (Detail) Details 222 false false R223.htm 999217 - Disclosure - Operating Segments Information - Summary of Revenue from Major Products and Services (Detail) Sheet http://www.aseglobal.com/role/OperatingSegmentsInformationSummaryOfRevenueFromMajorProductsAndServicesDetail Operating Segments Information - Summary of Revenue from Major Products and Services (Detail) Details 223 false false R224.htm 999218 - Disclosure - Operating Segments Information - Summary of Geographical Information (Detail) Sheet http://www.aseglobal.com/role/OperatingSegmentsInformationSummaryOfGeographicalInformationDetail Operating Segments Information - Summary of Geographical Information (Detail) Details 224 false false R225.htm 999219 - Disclosure - Operating Segments Information - Additional Information (Detail) Sheet http://www.aseglobal.com/role/OperatingSegmentsInformationAdditionalInformationDetail Operating Segments Information - Additional Information (Detail) Details 225 false false All Reports Book All Reports asx-20251231.xsd d50802d20f.htm g50802g35v35.jpg g50802g56v56.jpg http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full false false