{ "instance": { "wbk-20210930x20f.htm": { "axisCustom": 12, "axisStandard": 60, "contextCount": 3626, "dts": { "calculationLink": { "local": [ "wbk-20210930_cal.xml" ] }, "definitionLink": { "local": [ "wbk-20210930_def.xml" ], "remote": [ "http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-eedm-def-2020-01-31.xml", "http://xbrl.fasb.org/srt/2020/elts/srt-eedm1-def-2020-01-31.xml" ] }, "inline": { "local": [ "wbk-20210930x20f.htm" ] }, "labelLink": { "local": [ "wbk-20210930_lab.xml" ] }, "presentationLink": { "local": [ "wbk-20210930_pre.xml" ] }, "schema": { "local": [ "wbk-20210930.xsd" ], "remote": [ "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd", "http://www.xbrl.org/2003/xl-2003-12-31.xsd", "http://www.xbrl.org/2003/xlink-2003-12-31.xsd", "http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd", "http://www.xbrl.org/lrr/role/net-2009-12-16.xsd", "https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd", "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd", "http://www.xbrl.org/2005/xbrldt-2005.xsd", "http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd", "http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd", "http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd", "http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd", "http://www.xbrl.org/2006/ref-2006-02-27.xsd", "http://xbrl.fasb.org/srt/2020/elts/srt-types-2020-01-31.xsd", "https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd", "https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd", "http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd", "http://xbrl.fasb.org/us-gaap/2020/elts/us-roles-2020-01-31.xsd", "http://xbrl.fasb.org/srt/2020/elts/srt-roles-2020-01-31.xsd", "http://xbrl.fasb.org/us-gaap/2020/elts/us-types-2020-01-31.xsd", "http://www.xbrl.org/lrr/role/reference-2009-12-16.xsd", "http://www.xbrl.org/lrr/role/deprecated-2009-12-16.xsd" ] } }, "elementCount": 1822, "entityCount": 1, "hidden": { "http://www.westpac.com.au/20210930": 154, "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full": 277, "http://xbrl.sec.gov/dei/2020-01-31": 7, "total": 438 }, "keyCustom": 549, "keyStandard": 485, "memberCustom": 346, "memberStandard": 98, "nsprefix": "wbk", "nsuri": "http://www.westpac.com.au/20210930", "report": { "R1": { "firstAnchor": { "ancestors": [ "p", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "dei:DocumentType", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "document", "isDefault": "true", "longName": "00090 - Document - Document and Entity Information", "role": "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation", "shortName": "Document and Entity Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "p", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "dei:DocumentType", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R10": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10301 - Disclosure - Net interest income", "role": "http://www.westpac.com.au/role/DisclosureNetInterestIncome", "shortName": "Net interest income", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R100": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ProfitLossAttributableToOwnersOfParent", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40801 - Disclosure - Earnings per share (Details)", "role": "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails", "shortName": "Earnings per share (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:EarningsPerShareExplanatory", "ifrs-full:DisclosureOfEarningsPerShareExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:AdjustmentToProfitLossForRestrictedSharePlanDividends", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R101": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:AverageBalanceSheetAndInterestRatesTableTextBlock", "wbk:AverageBalancesAndInterestRatesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalanceOfInterestEarningAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40901 - Disclosure - Average balance sheet and interest rates - Assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "shortName": "Average balance sheet and interest rates - Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:AverageBalanceSheetAndInterestRatesTableTextBlock", "wbk:AverageBalancesAndInterestRatesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalanceOfInterestEarningAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R102": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalanceOfInterestBearingLiabilities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40902 - Disclosure - Average balance sheet and interest rates - Liabilities and Equity (Details)", "role": "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "shortName": "Average balance sheet and interest rates - Liabilities and Equity (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalanceOfInterestBearingLiabilities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R103": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:SummaryOfChangeInNetInterestIncomeTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ChangeInInterestIncomeDueToVolume", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40903 - Disclosure - Average balance sheet and interest rates - Variances (Details)", "role": "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "shortName": "Average balance sheet and interest rates - Variances (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:SummaryOfChangeInNetInterestIncomeTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ChangeInInterestIncomeDueToVolume", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R104": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory", "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:TradingSecuritiesDebtAndEquitySecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41001 - Disclosure - Trading securities and financial assets measured at FVIS (Details)", "role": "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails", "shortName": "Trading securities and financial assets measured at FVIS (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory", "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:TradingSecuritiesDebtAndEquitySecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R105": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41101 - Disclosure - Investment securities - Balances recognised (Details)", "role": "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "shortName": "Investment securities - Balances recognised (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfInvestmentSecuritiesTableTextBlock", "ifrs-full:DisclosureOfFinancialInstrumentsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CategoriesOfFinancialAssetsAxis_ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember_VpuxgNRMvUaN2W1vt4omqQ", "decimals": "-6", "lang": null, "name": "ifrs-full:InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R106": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41102 - Disclosure - Investment securities - Maturities (Details)", "role": "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "shortName": "Investment securities - Maturities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:ScheduleOfMaturitiesAndWeightedAverageYieldOfAvailableForSaleSecuritiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_MaturityAxis_ifrs-full_NotLaterThanOneYearMember__cC6esm6c0eHUHsR5_s3FQ", "decimals": "-6", "lang": null, "name": "ifrs-full:InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R107": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:LoansAndReceivables", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41201 - Disclosure - Loans - Loan portfolio (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "shortName": "Loans - Loan portfolio (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfLoansReceivableTableTextBlock", "ifrs-full:DisclosureOfLoansAndAdvancesToCustomersExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "wbk:SecuritisedLoans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R108": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:LoansAndReceivables", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41202 - Disclosure - Loans - Contractual maturities and interest rate segmentation (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "shortName": "Loans - Contractual maturities and interest rate segmentation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfContractualMaturityDistributionOfLoansByIndustryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis_ifrs-full_GrossCarryingAmountMember_ifrs-full_MaturityAxis_ifrs-full_NotLaterThanOneYearMember_rDNcDqyN-kyTIaXvcBpgrw", "decimals": "-6", "lang": null, "name": "ifrs-full:LoansAndReceivables", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R109": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_LoanAndCreditCommitmentsMember_ysa7ISYMBEK9s23DCzNgOw", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossLoansAndCreditCommitments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41301 - Disclosure - Provisions for expected credit losses/impairment charges - Loans and Credit Commitments (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "shortName": "Provisions for expected credit losses/impairment charges - Loans and Credit Commitments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_LoanAndCreditCommitmentsMember_ysa7ISYMBEK9s23DCzNgOw", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossLoansAndCreditCommitments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R11": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOtherOperatingIncomeExpenseExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10401 - Disclosure - Non-interest income", "role": "http://www.westpac.com.au/role/DisclosureNonInterestIncome", "shortName": "Non-interest income", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOtherOperatingIncomeExpenseExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R110": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_LoanAndCreditCommitmentsMember_ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis_wbk_ProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsMember_qvxTGje2-U-TFPGzyJwmFg", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssets", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41302 - Disclosure - Provisions for expected credit losses/impairment charges - Movement in provision for ECL on loans and credit commitments (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "shortName": "Provisions for expected credit losses/impairment charges - Movement in provision for ECL on loans and credit commitments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_LoanAndCreditCommitmentsMember_ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis_wbk_ProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsMember_JUIL-kEkHUmtc9EWmefSVw", "decimals": "-6", "lang": null, "name": "ifrs-full:DecreaseThroughWriteoffFinancialAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R111": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41303 - Disclosure - Provisions for expected credit losses/impairment charges - Reconciliation of impairment charges (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "shortName": "Provisions for expected credit losses/impairment charges - Reconciliation of impairment charges (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ReconciliationOfImpairmentChargesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis_wbk_ImpairmentChargesForDebtSecuritiesAtAmortisedCostMember_L4Krt0Pvhk2NVQfWXGyHKg", "decimals": "-6", "lang": null, "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLossLoansAndAdvances", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R112": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfWriteOffsNetOfRecoveriesToAverageLoansTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "4", "first": true, "lang": null, "name": "wbk:WriteOffsToAverageLoansNetOfRecoveries", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41304 - Disclosure - Provisions for expected credit losses/impairment charges - Total write-offs net of recoveries to average loans (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails", "shortName": "Provisions for expected credit losses/impairment charges - Total write-offs net of recoveries to average loans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfWriteOffsNetOfRecoveriesToAverageLoansTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "4", "first": true, "lang": null, "name": "wbk:WriteOffsToAverageLoansNetOfRecoveries", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R113": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfAdjustmentsToProvisionForExpectedCreditLossesForCovid19TableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ExpectedCreditLossCovid19ModelledProvisionUsingEconomicInputs", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41305 - Disclosure - Provisions for expected credit losses/impairment charges - Impact of Portfolio Overlays on the provision for ECL (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "shortName": "Provisions for expected credit losses/impairment charges - Impact of Portfolio Overlays on the provision for ECL (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfAdjustmentsToProvisionForExpectedCreditLossesForCovid19TableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ExpectedCreditLossCovid19ModelledProvisionUsingEconomicInputs", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R114": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:SummaryOfKeyMacroeconomicAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_MaturityAxis_wbk_TimeBandCalendarYear2021Member_srt_StatementScenarioAxis_wbk_BaseCaseScenarioMember_97ZjySswI0OBm7IPB3kxZg", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfIncreaseDecreaseInRateOfGrowthInCommercialPropertyPrices", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41306 - Disclosure - Provisions for expected credit losses/impairment charges - Modelled provision for ECL (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "shortName": "Provisions for expected credit losses/impairment charges - Modelled provision for ECL (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:SummaryOfKeyMacroeconomicAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_MaturityAxis_wbk_TimeBandCalendarYear2021Member_srt_StatementScenarioAxis_wbk_BaseCaseScenarioMember_97ZjySswI0OBm7IPB3kxZg", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfIncreaseDecreaseInRateOfGrowthInCommercialPropertyPrices", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R115": { "firstAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:ExpectedCreditLossStagingSensitivityPercentageOfStageOneReflectedInStageTwo", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41307 - Disclosure - Provisions for expected credit losses/impairment charges - Sensitivity analysis (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "shortName": "Provisions for expected credit losses/impairment charges - Sensitivity analysis (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:ExpectedCreditLossStagingSensitivityPercentageOfStageOneReflectedInStageTwo", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R116": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfMacroeconomicScenarioWeightingsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_UpsideScenarioMember_m3mbf8TKE0OnQSed1L38lQ", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfWeightingAssignedToScenario", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41308 - Disclosure - Provisions for expected credit losses/impairment charges - Macroeconomic scenario weightings (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "shortName": "Provisions for expected credit losses/impairment charges - Macroeconomic scenario weightings (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfMacroeconomicScenarioWeightingsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_UpsideScenarioMember_m3mbf8TKE0OnQSed1L38lQ", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfWeightingAssignedToScenario", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R117": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfAdjustmentsToProvisionForExpectedCreditLossesForCovid19TableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ExpectedCreditLossEconomicOverlay", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41309 - Disclosure - Provisions for expected credit losses/impairment charges - Portfolio Overlays (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "shortName": "Provisions for expected credit losses/impairment charges - Portfolio Overlays (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_wbk_IfrsUnusualOrInfrequentItemOrBothAxis_wbk_Covid19Member_2w1Q62jGYUCiX00QCsCDSA", "decimals": "-6", "lang": null, "name": "wbk:ExpectedCreditLossEconomicOverlay", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R118": { "firstAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_wbk_IfrsFinancialInstrumentPerformanceStatusAxis_wbk_StageOneMember_Tg0e3JvXqEG8YWMUdE919Q", "decimals": "-8", "first": true, "lang": null, "name": "wbk:NetIncreaseDecreaseInExposureToCreditRiskFromLoansDueToTransfersBetweenStages", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41310 - Disclosure - Provisions for expected credit losses/impairment charges - Impact of changes in credit exposures on the provision for ECL (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "shortName": "Provisions for expected credit losses/impairment charges - Impact of changes in credit exposures on the provision for ECL (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_wbk_IfrsFinancialInstrumentPerformanceStatusAxis_wbk_StageOneMember_Tg0e3JvXqEG8YWMUdE919Q", "decimals": "-8", "first": true, "lang": null, "name": "wbk:NetIncreaseDecreaseInExposureToCreditRiskFromLoansDueToTransfersBetweenStages", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R119": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfOtherFinancialAssetsTableTextBlock", "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestReceivable", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41401 - Disclosure - Other financial assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails", "shortName": "Other financial assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfOtherFinancialAssetsTableTextBlock", "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestReceivable", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R12": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfExpensesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10501 - Disclosure - Operating expenses", "role": "http://www.westpac.com.au/role/DisclosureOperatingExpenses", "shortName": "Operating expenses", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfExpensesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R120": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LifeInsuranceAssets", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41501 - Disclosure - Life insurance assets and life insurance liabilities - Assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "shortName": "Life insurance assets and life insurance liabilities - Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfAmountsArisingFromInsuranceContractsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfAssetsAxis_wbk_InvestmentsHeldDirectlyAndInUnitTrustsMember_Jh53tBpNJUaiOZmmFzchUQ", "decimals": "-6", "lang": null, "name": "wbk:LifeInsuranceAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R121": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LifeInsuranceLiabilitiesNet", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41502 - Disclosure - Life insurance assets and life insurance liabilities - Liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails", "shortName": "Life insurance assets and life insurance liabilities - Liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2019_g_tUeXRTyU2TEj_5QTkuGg", "decimals": "-6", "lang": null, "name": "wbk:LifeInsuranceLiabilitiesNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R122": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:DepositsAndOtherBorrowings", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41601 - Disclosure - Deposits and other borrowings - Summary (Details)", "role": "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "shortName": "Deposits and other borrowings - Summary (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfDetailedInformationAboutDepositsAndOtherBorrowingsTableTextBlock", "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "-6", "lang": null, "name": "wbk:DepositsAndOtherBorrowings", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R123": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsTableTextBlock", "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalancesOfDeposits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41602 - Disclosure - Deposits and other borrowings - Average balances and average rates for major categories of deposits (Details)", "role": "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "shortName": "Deposits and other borrowings - Average balances and average rates for major categories of deposits (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsTableTextBlock", "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:AverageBalancesOfDeposits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R124": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfMaturityProfileOfCertificatesOfDepositsAndTermDepositsMoreThanUs100000TableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CertificatesOfDepositsMoreThanUs100000", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41603 - Disclosure - Deposits and other borrowings - Certificates of deposit and term deposits (Details)", "role": "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "shortName": "Deposits and other borrowings - Certificates of deposit and term deposits (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfMaturityProfileOfCertificatesOfDepositsAndTermDepositsMoreThanUs100000TableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CertificatesOfDepositsMoreThanUs100000", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R125": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfOtherFinancialLiabilitiesTableTextBlock", "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:SecuritiesSoldUnderAgreementsToRepurchaseRepurchaseLiabilityInTradingPortfolio", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41701 - Disclosure - Other financial liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails", "shortName": "Other financial liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfOtherFinancialLiabilitiesTableTextBlock", "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:SecuritiesSoldUnderAgreementsToRepurchaseRepurchaseLiabilityInTradingPortfolio", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R126": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfBorrowingsExplanatory", "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CurrentDebtInstrumentsIssued", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41801 - Disclosure - Debt issues - Summary of balances (Details)", "role": "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "shortName": "Debt issues - Summary of balances (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfBorrowingsExplanatory", "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_BorrowingsByNameAxis_wbk_CoveredBondsMember_aX8Mn_rJRESdxp9u-yQeMA", "decimals": "-6", "lang": null, "name": "ifrs-full:NoncurrentDebtInstrumentsIssued", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R127": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:DebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41802 - Disclosure - Debt issues - Movement Reconciliation (Details)", "role": "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "shortName": "Debt issues - Movement Reconciliation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfBorrowingsExplanatory", "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:IssuancesOfDebtSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R128": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfBorrowingsExplanatory", "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CurrentDebtInstrumentsIssued", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41803 - Disclosure - Debt issues - By currency (Details)", "role": "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "shortName": "Debt issues - By currency (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfDebtIssuesByTypeAndCurrencyTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_srt_CurrencyAxis_currency_AUD_DXLXdzYlEUq_ZnxDDoL6Xw", "decimals": "-6", "lang": null, "name": "ifrs-full:NoncurrentDebtInstrumentsIssued", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R129": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoanCapital", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41901 - Disclosure - Loan Capital - Summary (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "shortName": "Loan Capital - Summary (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock", "wbk:DisclosureOfLoanCapitalTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_BorrowingsByNameAxis_wbk_TierTwoLoanCapitalMember_d8SkVyHgd0iRwSo8I7nkfw", "decimals": "-6", "lang": null, "name": "wbk:LoanCapital", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R13": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10601 - Disclosure - Impairment charges", "role": "http://www.westpac.com.au/role/DisclosureImpairmentCharges", "shortName": "Impairment charges", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R130": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoanCapital", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41902 - Disclosure - Loan Capital - Movement Reconciliation (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "shortName": "Loan Capital - Movement Reconciliation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock", "wbk:DisclosureOfLoanCapitalTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:LoanCapitalIssuances", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R131": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoanCapital", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41903 - Disclosure - Loan Capital - Additional Tier 1 loan capital (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "shortName": "Loan Capital - Additional Tier 1 loan capital (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_BorrowingsByNameAxis_wbk_AdditionalTierOneLoanCapitalMember_nesboMDyIkKkot4riP46dw", "decimals": null, "lang": "en-US", "name": "wbk:NumberOfBusinessDaysForPaymentOfDividendDistributionOrInterest", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R132": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoanCapital", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41904 - Disclosure - Loan Capital - Tier 2 loan capital (Details)", "role": "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "shortName": "Loan Capital - Tier 2 loan capital (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_BorrowingsByNameAxis_wbk_SubordinatedNotesMember_-ylYSIaB_0WgGHX6H_pEmw", "decimals": "2", "lang": null, "name": "wbk:PercentageOfSharePriceToDetermineMaximumConversionNumber", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R133": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:DerivativeFinancialAssetsHeldForTradingBeforeNettingArrangements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42001 - Disclosure - Derivative financial instruments - Carrying value of derivative instruments (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "shortName": "Derivative financial instruments - Carrying value of derivative instruments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:DerivativeFinancialAssetsHeldForTradingBeforeNettingArrangements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R134": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:NominalAmountOfHedgingInstrument", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42002 - Disclosure - Derivative financial instruments - Hedging instruments (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "shortName": "Derivative financial instruments - Hedging instruments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "wbk:HedgingInstrumentAssetsBeforeNettingArrangements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R135": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfWeightedAverageInterestRatesOfSignificantHedgingInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_HedgedItemsAxis_wbk_CurrencyToCurrencyPairEuroToAustralianDollarsMember_ifrs-full_HedgingInstrumentsAxis_ifrs-full_CurrencySwapContractMember_ifrs-full_TypesOfHedgesAxis_ifrs-full_CashFlowHedgesMember_ifrs-full_TypesOfRisksAxis_ifrs-full_CurrencyRiskMember_wbk_IfrsDerivativeInstrumentAxis_wbk_OneToOneHedgeRelationshipsMember_6jkhnCekl0mno3y00Y2EYA", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:AverageForeignExchangeRate", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_Hs7FagcdWEW-NVdTQQFpuQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42003 - Disclosure - Derivative financial instruments - Weighted average FX rate related to significant hedging instruments in one-to-one hedge relationships (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "shortName": "Derivative financial instruments - Weighted average FX rate related to significant hedging instruments in one-to-one hedge relationships (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfWeightedAverageInterestRatesOfSignificantHedgingInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_HedgedItemsAxis_wbk_CurrencyToCurrencyPairEuroToAustralianDollarsMember_ifrs-full_HedgingInstrumentsAxis_ifrs-full_CurrencySwapContractMember_ifrs-full_TypesOfHedgesAxis_ifrs-full_CashFlowHedgesMember_ifrs-full_TypesOfRisksAxis_ifrs-full_CurrencyRiskMember_wbk_IfrsDerivativeInstrumentAxis_wbk_OneToOneHedgeRelationshipsMember_6jkhnCekl0mno3y00Y2EYA", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:AverageForeignExchangeRate", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_Hs7FagcdWEW-NVdTQQFpuQ", "xsiNil": "false" } }, "R136": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42004 - Disclosure - Derivative financial instruments - Impact of hedge accounting on balance sheet and reserves (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "shortName": "Derivative financial instruments - Impact of hedge accounting on balance sheet and reserves (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R137": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42005 - Disclosure - Derivative financial instruments - Pre-tax impact of cash flow and net investment hedges on reserves (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "shortName": "Derivative financial instruments - Pre-tax impact of cash flow and net investment hedges on reserves (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R138": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42006 - Disclosure - Derivative financial instruments - Hedge effectiveness (Details)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "shortName": "Derivative financial instruments - Hedge effectiveness (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R139": { "firstAnchor": { "ancestors": [ "span", "div", "div", "div", "td", "tr", "table", "ifrs-full:DisclosureOfCreditRiskExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_TradingSecuritiesAndFinancialAssetsDesignatedAtFairValueMember_VOk8sQDePEO7u2_gGVXa6g", "decimals": "2", "first": true, "lang": null, "name": "wbk:PercentageOfCreditConcentrationsFinancialAssetsIssuedByFinancialInstitutions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42101 - Disclosure - Financial risk - Credit concentrations for each significant class of financial asset (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "shortName": "Financial risk - Credit concentrations for each significant class of financial asset (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "div", "div", "div", "td", "tr", "table", "ifrs-full:DisclosureOfCreditRiskExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialAssetsAxis_wbk_TradingSecuritiesAndFinancialAssetsDesignatedAtFairValueMember_VOk8sQDePEO7u2_gGVXa6g", "decimals": "2", "first": true, "lang": null, "name": "wbk:PercentageOfCreditConcentrationsFinancialAssetsIssuedByFinancialInstitutions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R14": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfIncomeTaxExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10701 - Disclosure - Income tax", "role": "http://www.westpac.com.au/role/DisclosureIncomeTax", "shortName": "Income tax", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfIncomeTaxExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R140": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfCommitmentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:UndrawnCreditCommitments", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42102 - Disclosure - Financial risk - Credit risk by industry (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "shortName": "Financial risk - Credit risk by industry (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfGrossCreditRiskByGeographicLocationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_CreditRiskMember_pdQkIQ-ow0-d94g3OWtbUg", "decimals": "-6", "lang": null, "name": "wbk:MaximumExposureToCreditRiskLoans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R141": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfCreditQualityOfGrossCreditRiskExposuresTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_CreditRiskMember_pdQkIQ-ow0-d94g3OWtbUg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:MaximumExposureToCreditRiskOfFinancialAssetsMeasuredAtAmortisedCostOrAtFairValueThroughOtherComprehensiveIncome", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42103 - Disclosure - Financial risk - Credit quality of financial assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "shortName": "Financial risk - Credit quality of financial assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfCreditQualityOfGrossCreditRiskExposuresTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_CreditRiskMember_pdQkIQ-ow0-d94g3OWtbUg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:MaximumExposureToCreditRiskOfFinancialAssetsMeasuredAtAmortisedCostOrAtFairValueThroughOtherComprehensiveIncome", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R142": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:IfrsFinancingReceivableCreditQualityIndicatorsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis_ifrs-full_AccumulatedImpairmentMember_us-gaap_FinancialInstrumentAxis_wbk_RestructuredLoansAndCreditCommitmentsMember_jZOxdDfM7Ua64Eqnc1zw0Q", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoansAndCreditCommitments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42104 - Disclosure - Financial risk - Non-performing loans and credit commitments (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "shortName": "Financial risk - Non-performing loans and credit commitments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:IfrsFinancingReceivableCreditQualityIndicatorsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis_ifrs-full_AccumulatedImpairmentMember_us-gaap_FinancialInstrumentAxis_wbk_RestructuredLoansAndCreditCommitmentsMember_jZOxdDfM7Ua64Eqnc1zw0Q", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LoansAndCreditCommitments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R143": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis_wbk_PerformingLoansMember_HShaMi9_zUKzZoH2rZdZTQ", "decimals": "3", "first": true, "lang": null, "name": "wbk:TotalPercentageOfLoanPortfolio", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42105 - Disclosure - Financial risk - Collateral held (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "shortName": "Financial risk - Collateral held (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis_wbk_PerformingLoansMember_HShaMi9_zUKzZoH2rZdZTQ", "decimals": "3", "first": true, "lang": null, "name": "wbk:TotalPercentageOfLoanPortfolio", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R144": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CashPrimarilyForDerivativesOtherCollateral", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42106 - Disclosure - Financial risk - Collateral held against financial assets other than loans (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "shortName": "Financial risk - Collateral held against financial assets other than loans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CashPrimarilyForDerivativesOtherCollateral", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R145": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DescriptionOfManagingLiquidityRisk", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_LiquidityRiskMember_N2I4Ocor8UiEQmh8HnVO9A", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssetsHeldForManagingLiquidityRisk", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42107 - Disclosure - Financial risk - Liquid assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "shortName": "Financial risk - Liquid assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DescriptionOfManagingLiquidityRisk", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_LiquidityRiskMember_N2I4Ocor8UiEQmh8HnVO9A", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssetsHeldForManagingLiquidityRisk", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R146": { "firstAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfFundingThroughCustomerDeposits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42108 - Disclosure - Financial risk - Funding composition and Term Funding Facility (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails", "shortName": "Financial risk - Funding composition and Term Funding Facility (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "3", "first": true, "lang": null, "name": "wbk:PercentageOfFundingThroughCustomerDeposits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R147": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAssetsPledgedAsCollateralExplanatoryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42109 - Disclosure - Financial risk - Assets pledged as collateral (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "shortName": "Financial risk - Assets pledged as collateral (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAssetsPledgedAsCollateralExplanatoryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R148": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:MaturityAnalysisForNonderivativeFinancialLiabilities", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:FinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42110 - Disclosure - Financial risk - Contractual maturity of financial liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "shortName": "Financial risk - Contractual maturity of financial liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:MaturityAnalysisForNonderivativeFinancialLiabilities", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:FinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R149": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:AnalysisOfExpectedMaturitiesForFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CashAndBankBalancesAtCentralBanksBasedOnExpectedMaturities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42111 - Disclosure - Financial risk - Expected maturity of financial assets and financial liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "shortName": "Financial risk - Expected maturity of financial assets and financial liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:AnalysisOfExpectedMaturitiesForFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:CashAndBankBalancesAtCentralBanksBasedOnExpectedMaturities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R15": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEarningsPerShareExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10801 - Disclosure - Earnings per share", "role": "http://www.westpac.com.au/role/DisclosureEarningsPerShare", "shortName": "Earnings per share", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEarningsPerShareExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R150": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "wbk:DisclosureOfValuationAssumptionsUsedToCalculateValueAtRiskTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_MarketRiskMember_vsxYkjSO8k-TW2LKw2nh-w", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:HoldingPeriodForVar", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42112 - Disclosure - Financial risk - Value-at-Risk (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails", "shortName": "Financial risk - Value-at-Risk (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "wbk:DisclosureOfValuationAssumptionsUsedToCalculateValueAtRiskTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfRisksAxis_ifrs-full_MarketRiskMember_vsxYkjSO8k-TW2LKw2nh-w", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:HoldingPeriodForVar", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R151": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfTradedMarketRiskExplanatoryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_RangeAxis_ifrs-full_TopOfRangeMember_ifrs-full_TypesOfRisksAxis_ifrs-full_MarketRiskMember_XD7enaeSHU-licScS0BZKQ", "decimals": "-5", "first": true, "lang": null, "name": "ifrs-full:ValueAtRisk", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42113 - Disclosure - Financial risk - Traded market risk (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "shortName": "Financial risk - Traded market risk (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfTradedMarketRiskExplanatoryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_RangeAxis_ifrs-full_TopOfRangeMember_ifrs-full_TypesOfRisksAxis_ifrs-full_MarketRiskMember_XD7enaeSHU-licScS0BZKQ", "decimals": "-5", "first": true, "lang": null, "name": "ifrs-full:ValueAtRisk", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R152": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:PeriodOfProjectionForNar", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42114 - Disclosure - Financial risk - Non-traded market risk (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "shortName": "Financial risk - Non-traded market risk (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:PeriodOfProjectionForNar", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R153": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:DerivativeFinancialAssetsHeldForTrading", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42115 - Disclosure - Financial risk - Interest rate benchmark reform - Derivatives (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "shortName": "Financial risk - Interest rate benchmark reform - Derivatives (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfQuantitativeInformationAboutFinancialInstrumentsThatHaveYetToTransitionToAlternativeBenchmarkRateTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialInstrumentsAxis_ifrs-full_DerivativesMember_srt_StatementScenarioAxis_wbk_FinancialInstrumentsImpactedByInterbankOfferingRateReformAndYetToTransitionToAlternativeReferenceRateMember_ERRqCtKz3kKAD7dquUKK0w", "decimals": "-6", "lang": null, "name": "ifrs-full:DerivativeFinancialAssetsHeldForTrading", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R154": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfQuantitativeInformationAboutFinancialInstrumentsThatHaveYetToTransitionToAlternativeBenchmarkRateTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialInstrumentsAxis_wbk_FinancialInstrumentsExcludingDerivativesMember_srt_StatementScenarioAxis_wbk_FinancialInstrumentsImpactedByInterbankOfferingRateReformAndYetToTransitionToAlternativeReferenceRateMember_9zlaSGu1F0C2xbEOEtjwuQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:NonDerivativeExposureToInterestRateReformFinancialAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42116 - Disclosure - Financial risk - Interest rate benchmark reform - Non-derivatives (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "shortName": "Financial risk - Interest rate benchmark reform - Non-derivatives (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfQuantitativeInformationAboutFinancialInstrumentsThatHaveYetToTransitionToAlternativeBenchmarkRateTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialInstrumentsAxis_wbk_FinancialInstrumentsExcludingDerivativesMember_srt_StatementScenarioAxis_wbk_FinancialInstrumentsImpactedByInterbankOfferingRateReformAndYetToTransitionToAlternativeReferenceRateMember_9zlaSGu1F0C2xbEOEtjwuQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:NonDerivativeExposureToInterestRateReformFinancialAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R155": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialLiabilitiesAxis_wbk_DepositsAndOtherBorrowingsMember_5F3G5vhB-kugpanEGjWltg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ContractualOutstandingAmountsPayableAtMaturity", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42201 - Disclosure - Fair values of financial assets and financial liabilities - Hierarchy (Details)", "role": "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "shortName": "Fair values of financial assets and financial liabilities - Hierarchy (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfFinancialLiabilitiesAxis_wbk_DepositsAndOtherBorrowingsMember_5F3G5vhB-kugpanEGjWltg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ContractualOutstandingAmountsPayableAtMaturity", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R156": { "firstAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ClosingBalanceOfUnrecognisedDayOneProfit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42202 - Disclosure - Fair values of financial assets and financial liabilities - Reconciliation of non-market observables (Details)", "role": "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "shortName": "Fair values of financial assets and financial liabilities - Reconciliation of non-market observables (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ClosingBalanceOfUnrecognisedDayOneProfit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R157": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfFinancialInstrumentsNotMeasuredAtFairValueTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_MeasurementAxis_ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember_E7VXrywV00-UPOjyekJpWQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42203 - Disclosure - Fair values of financial assets and financial liabilities - Not measured at fair value (Details)", "role": "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "shortName": "Fair values of financial assets and financial liabilities - Not measured at fair value (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfFinancialInstrumentsNotMeasuredAtFairValueTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_MeasurementAxis_ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember_E7VXrywV00-UPOjyekJpWQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:FinancialAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R158": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42301 - Disclosure - Offsetting financial assets and financial liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "shortName": "Offsetting financial assets and financial liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R159": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AssetsThatEntityContinuesToRecognise", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42401 - Disclosure - Securitisation, covered bonds and other transferred assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails", "shortName": "Securitisation, covered bonds and other transferred assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AssetsThatEntityContinuesToRecognise", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R16": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:AverageBalancesAndInterestRatesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10901 - Disclosure - Average balance sheet and interest rates", "role": "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRates", "shortName": "Average balance sheet and interest rates", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:AverageBalancesAndInterestRatesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R160": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "ifrs-full:DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory", "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis_ifrs-full_ComputerSoftwareMember_ifrs-full_RangeAxis_ifrs-full_BottomOfRangeMember_ZvBadU_TqkS4fi9HINBKRQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42501 - Disclosure - Intangible assets - Useful life (Details)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "shortName": "Intangible assets - Useful life (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "ifrs-full:DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory", "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis_ifrs-full_ComputerSoftwareMember_ifrs-full_RangeAxis_ifrs-full_BottomOfRangeMember_ZvBadU_TqkS4fi9HINBKRQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R161": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Goodwill", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42502 - Disclosure - Intangible assets - Changes (Details)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "shortName": "Intangible assets - Changes (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "ifrs-full:DecreaseThroughClassifiedAsHeldForSaleGoodwill", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R162": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Goodwill", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42503 - Disclosure - Intangible assets - Balances (Details)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "shortName": "Intangible assets - Balances (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis_ifrs-full_ComputerSoftwareMember_ifrs-full_VoluntaryChangesInAccountingPolicyAxis_wbk_SoftwareServiceArrangementsMember_wsyORc1GQ0exCguvapF9Iw", "decimals": "-6", "lang": null, "name": "wbk:AdjustmentDueToChangeInAccountingPolicy", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R163": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Goodwill", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42504 - Disclosure - Intangible assets - Goodwill allocation to CGUs (Details)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "shortName": "Intangible assets - Goodwill allocation to CGUs (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis_wbk_ConsumerBankMember_lOIKJ4Iz5UeAepRgnLlZnQ", "decimals": "-6", "lang": null, "name": "ifrs-full:Goodwill", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R164": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLossGoodwill", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42505 - Disclosure - Intangible assets - Impairment testing (Details)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "shortName": "Intangible assets - Impairment testing (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis_wbk_WestpacLendersMortgageInsuranceLimitedMember_srt_StatementScenarioAxis_wbk_AnnualImpairmentTestingMember_G-vTEpWOG0eYTmVCKHhTBA", "decimals": "-6", "lang": null, "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLossGoodwill", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R165": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfProvisionsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:OtherProvisions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42601 - Disclosure - Provisions, contingent liabilities, contingent assets and credit commitments - Movements in provisions (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "shortName": "Provisions, contingent liabilities, contingent assets and credit commitments - Movements in provisions (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfProvisionsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:OtherProvisions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R166": { "firstAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_wbk_NewSouthWalesMember_5ffSZIyzO0qhOZ1I6thmEA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ActuarialAssessmentLiability", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42602 - Disclosure - Provisions, contingent liabilities, contingent assets and credit commitments - Provisions and contingent liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails", "shortName": "Provisions, contingent liabilities, contingent assets and credit commitments - Provisions and contingent liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_wbk_NewSouthWalesMember_5ffSZIyzO0qhOZ1I6thmEA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ActuarialAssessmentLiability", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R167": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfCommitmentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LettersOfCreditAndGuarantees", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42603 - Disclosure - Provisions, contingent liabilities, contingent assets and credit commitments - Undrawn credit commitments (Details)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails", "shortName": "Provisions, contingent liabilities, contingent assets and credit commitments - Undrawn credit commitments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfCommitmentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:LettersOfCreditAndGuarantees", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R168": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:IssuedCapital", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42701 - Disclosure - Shareholders' equity - Share capital (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "shortName": "Shareholders' equity - Share capital (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "wbk:RestrictedSharePlanTreasuryShares", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R169": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReservesAndOtherEquityInterestExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ReserveOfGainsAndLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42702 - Disclosure - Shareholders' equity - Reconciliation of movement in reserves (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "shortName": "Shareholders' equity - Reconciliation of movement in reserves (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfReservesAndOtherEquityInterestExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxExcludingExchangeDifferences", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R17": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11000 - Disclosure - FINANCIAL ASSETS AND FINANCIAL LIABILITIES", "role": "http://www.westpac.com.au/role/DisclosureFinancialAssetsAndFinancialLiabilities", "shortName": "FINANCIAL ASSETS AND FINANCIAL LIABILITIES", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R170": { "firstAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-9", "first": true, "lang": null, "name": "wbk:CommittedLiquidityFacilityUsage", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42801 - Disclosure - Capital adequacy (Details)", "role": "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "shortName": "Capital adequacy (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-9", "first": true, "lang": null, "name": "wbk:CommittedLiquidityFacilityUsage", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R171": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfDividendsNotRecognisedAtYearEndTableTextBlock", "ifrs-full:DisclosureOfDividendsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42901 - Disclosure - Dividends (Details)", "role": "http://www.westpac.com.au/role/DisclosureDividendsDetails", "shortName": "Dividends (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ifrs-full:DisclosureOfDividendsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_11_1_2021_To_11_1_2021_srt_StatementScenarioAxis_wbk_SharesIssuedToSatisfyDividendReinvestmentPlanMember_wr8g4lIz2k6kwrPANPFs3A", "decimals": null, "lang": "en-US", "name": "wbk:DividendsProposedOrDeclaredTradingPeriodToDetermineNumberOfSharesForDividendReinvestmentPlan", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R172": { "firstAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "INF", "first": true, "lang": null, "name": "wbk:NumberOfAssociates", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_Hs7FagcdWEW-NVdTQQFpuQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43001 - Disclosure - Investments in subsidiaries and associates (Details)", "role": "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails", "shortName": "Investments in subsidiaries and associates (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "INF", "first": true, "lang": null, "name": "wbk:NumberOfAssociates", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_Hs7FagcdWEW-NVdTQQFpuQ", "xsiNil": "false" } }, "R173": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:BalanceSheetExposureToLossFromInterestsInStructuredEntities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43101 - Disclosure - Structured entities (Details)", "role": "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails", "shortName": "Structured entities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:BalanceSheetExposureToLossFromInterestsInStructuredEntities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R174": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory", "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_WestpacLongTermIncentivePlanMember_eKKoqm6CBk6elr9AuQMXqQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:SharebasedPaymentArrangementCostOfSharesAllocated", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43201 - Disclosure - Share-based payments - Summary of plans (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "shortName": "Share-based payments - Summary of plans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory", "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_WestpacLongTermIncentivePlanMember_eKKoqm6CBk6elr9AuQMXqQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:SharebasedPaymentArrangementCostOfSharesAllocated", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R175": { "firstAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:NumberOfOutstandingShareOptions", "reportCount": 1, "unitRef": "Unit_Standard_Options__84N-88fuUW9OZofZKIdrA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43202 - Disclosure - Share-based payments - Westpac Long Term Incentive Plan, Westpac Performance Plan (WPP) & Restricted Share Plan (RSP) (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "shortName": "Share-based payments - Westpac Long Term Incentive Plan, Westpac Performance Plan (WPP) & Restricted Share Plan (RSP) (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfSharebasedPaymentArrangementActivityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2019_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_WestpacLongTermIncentivePlanMember_wbk_IfrsAwardTypeAxis_wbk_ShareRightsMember_GkNgP3GU1EaOptla5_Q7ag", "decimals": "INF", "lang": null, "name": "ifrs-full:NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_EquityInstruments_gcmn1gvJQkeq2_ij2VbnTQ", "xsiNil": "false" } }, "R176": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_EmployeeSharePlanMember_i8I5Xx8Ep0uoEjVCNyBYhA", "decimals": "INF", "first": true, "lang": null, "name": "wbk:SharebasedPaymentArrangementNumberOfParticipants", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_employee_EOdiTETAyE6WlP_rH_TQkg", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43203 - Disclosure - Share-based payments - Employee Share Plan (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "shortName": "Share-based payments - Employee Share Plan (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_EmployeeSharePlanMember_i8I5Xx8Ep0uoEjVCNyBYhA", "decimals": "INF", "first": true, "lang": null, "name": "wbk:SharebasedPaymentArrangementNumberOfParticipants", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_employee_EOdiTETAyE6WlP_rH_TQkg", "xsiNil": "false" } }, "R177": { "firstAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_ShareOptionsAndShareRightsMember_K46q0PRZwk2MK6fihdKsPg", "decimals": "3", "first": true, "lang": null, "name": "ifrs-full:DescriptionOfRiskFreeInterestRateShareOptionsGranted", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43204 - Disclosure - Share-based payments - Fair value assumptions (Details)", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails", "shortName": "Share-based payments - Fair value assumptions (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_TypesOfSharebasedPaymentArrangementsAxis_wbk_ShareOptionsAndShareRightsMember_K46q0PRZwk2MK6fihdKsPg", "decimals": "3", "first": true, "lang": null, "name": "ifrs-full:DescriptionOfRiskFreeInterestRateShareOptionsGranted", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R178": { "firstAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:DefinedBenefitPlanFundingSurplus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43301 - Disclosure - Superannuation commitments (Details)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails", "shortName": "Superannuation commitments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:DefinedBenefitPlanFundingSurplus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R179": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfDefinedBenefitPlanContributionTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:EmployerContributions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43302 - Disclosure - Superannuation commitments - Contributions and Expense recognised (Details)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "shortName": "Superannuation commitments - Contributions and Expense recognised (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfDefinedBenefitPlanContributionTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:EmployerContributions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R18": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11001 - Disclosure - Trading securities and financial assets measured at FVIS", "role": "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvis", "shortName": "Trading securities and financial assets measured at FVIS", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R180": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfDefinedBenefitPlanSignificantAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "3", "first": true, "lang": null, "name": "ifrs-full:ActuarialAssumptionOfDiscountRates", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43303 - Disclosure - Superannuation commitments - Significant assumptions (Details)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails", "shortName": "Superannuation commitments - Significant assumptions (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfDefinedBenefitPlanSignificantAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "3", "first": true, "lang": null, "name": "ifrs-full:ActuarialAssumptionOfDiscountRates", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R181": { "firstAnchor": { "ancestors": [ "ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption", "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ActuarialAssumptionsAxis_ifrs-full_ActuarialAssumptionOfDiscountRatesMember_YwaKPcOF5kimxyjFoG2esw", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43304 - Disclosure - Superannuation commitments - Sensitivity to changes in significant assumptions (Details)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails", "shortName": "Superannuation commitments - Sensitivity to changes in significant assumptions (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption", "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_ActuarialAssumptionsAxis_ifrs-full_ActuarialAssumptionOfDiscountRatesMember_YwaKPcOF5kimxyjFoG2esw", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R182": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFairValueOfPlanAssetsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:DefinedBenefitPlanPercentageOfPlanAssetAllocation", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43305 - Disclosure - Superannuation commitments - Asset allocation (Details)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "shortName": "Superannuation commitments - Asset allocation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfFairValueOfPlanAssetsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_GeographicalAreasAxis_ifrs-full_CountryOfDomicileMember_DwLVX2Yr1Eu34fzohYFgeQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:DefinedBenefitPlanPercentageOfPlanAssetAllocation", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" } }, "R183": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAuditorsRemunerationTableTextBlock", "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-3", "first": true, "lang": null, "name": "ifrs-full:AuditorsRemunerationForAuditServices", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43401 - Disclosure - Auditor's remuneration (Details)", "role": "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails", "shortName": "Auditor's remuneration (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:DisclosureOfAuditorsRemunerationTableTextBlock", "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-3", "first": true, "lang": null, "name": "ifrs-full:AuditorsRemunerationForAuditServices", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R184": { "firstAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ContributionsToPlanByEmployerDefinedContributionPlans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43501 - Disclosure - Related party disclosures - Superannuation plans (Details)", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresSuperannuationPlansDetails", "shortName": "Related party disclosures - Superannuation plans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ContributionsToPlanByEmployerDefinedContributionPlans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R185": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfInformationAboutKeyManagementPersonnelExplanatory", "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "0", "first": true, "lang": null, "name": "ifrs-full:KeyManagementPersonnelCompensationShorttermEmployeeBenefits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43502 - Disclosure - Related party disclosures - Remuneration of KMP (Details)", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails", "shortName": "Related party disclosures - Remuneration of KMP (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfInformationAboutKeyManagementPersonnelExplanatory", "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "0", "first": true, "lang": null, "name": "ifrs-full:KeyManagementPersonnelCompensationShorttermEmployeeBenefits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R186": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_CategoriesOfRelatedPartiesAxis_ifrs-full_KeyManagementPersonnelOfEntityOrParentMember_wwOXLAmda0iskndTqF5Zqg", "decimals": "0", "first": true, "lang": null, "name": "wbk:RevenueFromInterestRelatedPartyTransactions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43503 - Disclosure - Related party disclosures - Other transactions with KMP (Details)", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails", "shortName": "Related party disclosures - Other transactions with KMP (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_CategoriesOfRelatedPartiesAxis_ifrs-full_KeyManagementPersonnelOfEntityOrParentMember_wwOXLAmda0iskndTqF5Zqg", "decimals": "0", "first": true, "lang": null, "name": "wbk:RevenueFromInterestRelatedPartyTransactions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R187": { "firstAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "INF", "first": true, "lang": null, "name": "ifrs-full:NumberOfOutstandingShareOptions", "reportCount": 1, "unitRef": "Unit_Standard_Options__84N-88fuUW9OZofZKIdrA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43504 - Disclosure - Related party disclosures - Options and share rights holdings (Details)", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "shortName": "Related party disclosures - Options and share rights holdings (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfRelatedPartyPerformanceOptionsAndShareRightsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_CategoriesOfRelatedPartiesAxis_wbk_PeterKingMember_srt_TitleOfIndividualAxis_wbk_ManagingDirectorAndChiefExecutiveOfficerMember_oWEPwAiONUuA-oLUrBlCzQ", "decimals": "INF", "lang": null, "name": "ifrs-full:NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_EquityInstruments_gcmn1gvJQkeq2_ij2VbnTQ", "xsiNil": "false" } }, "R188": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43601 - Disclosure - Notes to the cash flow statements - Reconciliation of net cash provided by/(used in) operating activities to net profit (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "shortName": "Notes to the cash flow statements - Reconciliation of net cash provided by/(used in) operating activities to net profit (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfReconciliationOfNetCashInOperatingActivitiesToNetProfitTableTextBlock", "ifrs-full:DisclosureOfCashFlowStatementExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "ifrs-full:AdjustmentsForDepreciationAndAmortisationExpenseAndImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R189": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CashAndBankBalancesAtCentralBanks", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43602 - Disclosure - Notes to the cash flow statements - Assets and liabilities over which control ceased (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "shortName": "Notes to the cash flow statements - Assets and liabilities over which control ceased (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_srt_StatementScenarioAxis_wbk_EntitiesOverWhichControlHasCeasedMember_h8gFFgsDuk2_E3RZkEIW5w", "decimals": "-6", "lang": null, "name": "ifrs-full:CashAndBankBalancesAtCentralBanks", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R19": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11101 - Disclosure - Investment securities", "role": "http://www.westpac.com.au/role/DisclosureInvestmentSecurities", "shortName": "Investment securities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R190": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_EntitiesOverWhichControlHasCeasedMember_DOeIRX98g0Cg4WwCY9TbbQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ProceedsFromDisposalOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43603 - Disclosure - Notes to the cash flow statements - Other disclosures for entities over which control ceased (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "shortName": "Notes to the cash flow statements - Other disclosures for entities over which control ceased (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_EntitiesOverWhichControlHasCeasedMember_DOeIRX98g0Cg4WwCY9TbbQ", "decimals": "-6", "lang": null, "name": "wbk:ExpectedReceivableCompletionSettlement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R191": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_EntitiesOverWhichControlHasCeasedMember_DOeIRX98g0Cg4WwCY9TbbQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ProceedsFromDisposalOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43604 - Disclosure - Notes to the cash flow statements - Reconciliation of cash proceeds from disposal (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails", "shortName": "Notes to the cash flow statements - Reconciliation of cash proceeds from disposal (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_srt_StatementScenarioAxis_wbk_EntitiesOverWhichControlHasCeasedMember_DOeIRX98g0Cg4WwCY9TbbQ", "decimals": "-6", "lang": null, "name": "wbk:CashDeconsolidatedOnDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R192": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:IfrsStockIssuedDuringPeriodValueDividendReinvestmentPlan", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43605 - Disclosure - Notes to the cash flow statements - Non-cash financing activities and restricted cash (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails", "shortName": "Notes to the cash flow statements - Non-cash financing activities and restricted cash (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:ScheduleOfNonCashFinancingActivitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:AdjustmentsForIncreaseDecreaseInLeaseLiability", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R193": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfCashAndBankBalancesAtCentralBanksExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Cash", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43606 - Disclosure - Notes to the cash flow statements - Cash and balances with central banks and restricted cash (Details)", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "shortName": "Notes to the cash flow statements - Cash and balances with central banks and restricted cash (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfCashAndBankBalancesAtCentralBanksExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Cash", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R194": { "firstAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_wbk_IfrsDisposalGroupNameAxis_wbk_MotorVehicleDealerFinanceAndNovatedLeasingBusinessesMember_9jLx3NcRf0uZ5ng94EUdhw", "decimals": "-9", "first": true, "lang": null, "name": "wbk:AmountOfExistingRetailAutoLoans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43701 - Disclosure - Assets and liabilities held for sale - Businesses held for sale (Details)", "role": "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "shortName": "Assets and liabilities held for sale - Businesses held for sale (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_wbk_IfrsDisposalGroupNameAxis_wbk_MotorVehicleDealerFinanceAndNovatedLeasingBusinessesMember_9jLx3NcRf0uZ5ng94EUdhw", "decimals": "-9", "first": true, "lang": null, "name": "wbk:AmountOfExistingRetailAutoLoans", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R195": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfInterestsInMateriallyControlledEntitiesWhichAreNotWhollyOwnedTableTextBlock", "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_SignificantInvestmentsInSubsidiariesAxis_wbk_WestpacBankPNGLimitedMember_ftm5tJYR8kmpStSCEMAVRw", "decimals": "3", "first": true, "lang": null, "name": "ifrs-full:ProportionOfOwnershipInterestInSubsidiary", "reportCount": 1, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43702 - Disclosure - Assets and liabilities held for sale - Businesses no longer held for sale (Details)", "role": "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "shortName": "Assets and liabilities held for sale - Businesses no longer held for sale (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_7_1_2021_To_7_1_2021_wbk_IfrsDisposalGroupNameAxis_wbk_WestpacGeneralInsuranceLimitedAndWestpacGeneralInsuranceServicesLimitedMember_RD21Dnh6g0C55OeFbs4zWQ", "decimals": "-6", "lang": null, "name": "wbk:GrossProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R196": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43703 - Disclosure - Assets and liabilities held for sale - Balance sheet presentation (Details)", "role": "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "shortName": "Assets and liabilities held for sale - Balance sheet presentation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_wbk_IfrsDisposalGroupClassificationAxis_wbk_IfrsDiscontinuedOperationsHeldForSaleMember_0X_GQ5_2gUmxkGteXbx70g", "decimals": "-6", "lang": null, "name": "ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R197": { "firstAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfDividendsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_12_21_2021_To_12_21_2021_IOj6ouaA2UWkGC9pEyykfw", "decimals": "2", "first": true, "lang": null, "name": "ifrs-full:DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwnersPerShare", "reportCount": 1, "unitRef": "Unit_Divide_AUD_shares_RccRn-UL206BeMtqJEf-GA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "43801 - Disclosure - Subsequent events (Details)", "role": "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails", "shortName": "Subsequent events (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "ifrs-full:DisclosureOfEventsAfterReportingPeriodExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_NonadjustingEventsAfterReportingPeriodAxis_wbk_ProposedDividendMember_KmFmMSfHWkiIlDwnZwyCJw", "decimals": "2", "lang": null, "name": "ifrs-full:DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwnersPerShare", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_AUD_shares_RccRn-UL206BeMtqJEf-GA", "xsiNil": "false" } }, "R2": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestRevenueCalculatedUsingEffectiveInterestMethod", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00100 - Statement - Income statements", "role": "http://www.westpac.com.au/role/StatementIncomeStatements", "shortName": "Income statements", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "ifrs-full:OtherOperatingIncomeExpense", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R20": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfLoansAndAdvancesToCustomersExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11201 - Disclosure - Loans", "role": "http://www.westpac.com.au/role/DisclosureLoans", "shortName": "Loans", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfLoansAndAdvancesToCustomersExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R21": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAllowanceForCreditLossesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11301 - Disclosure - Provisions for expected credit losses", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLosses", "shortName": "Provisions for expected credit losses", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAllowanceForCreditLossesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R22": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11401 - Disclosure - Other financial assets", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialAssets", "shortName": "Other financial assets", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R23": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInsuranceContractsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11501 - Disclosure - Life insurance assets and life insurance liabilities", "role": "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilities", "shortName": "Life insurance assets and life insurance liabilities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInsuranceContractsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R24": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11601 - Disclosure - Deposits and other borrowings", "role": "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowings", "shortName": "Deposits and other borrowings", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R25": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11701 - Disclosure - Other financial liabilities", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilities", "shortName": "Other financial liabilities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R26": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11801 - Disclosure - Debt issues", "role": "http://www.westpac.com.au/role/DisclosureDebtIssues", "shortName": "Debt issues", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R27": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfLoanCapitalTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11901 - Disclosure - Loan capital", "role": "http://www.westpac.com.au/role/DisclosureLoanCapital", "shortName": "Loan capital", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfLoanCapitalTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R28": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDerivativeFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12001 - Disclosure - Derivative financial instruments", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstruments", "shortName": "Derivative financial instruments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDerivativeFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R29": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialRiskManagementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12101 - Disclosure - Financial risk", "role": "http://www.westpac.com.au/role/DisclosureFinancialRisk", "shortName": "Financial risk", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialRiskManagementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R3": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00200 - Statement - Statements of comprehensive income", "role": "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome", "shortName": "Statements of comprehensive income", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "ifrs-full:GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R30": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFairValueMeasurementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12201 - Disclosure - Fair values of financial assets and financial liabilities", "role": "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilities", "shortName": "Fair values of financial assets and financial liabilities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFairValueMeasurementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R31": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12301 - Disclosure - Offsetting financial assets and financial liabilities", "role": "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilities", "shortName": "Offsetting financial assets and financial liabilities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R32": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfTransfersOfFinancialAssetsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12401 - Disclosure - Securitisation, covered bonds and other transferred assets", "role": "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssets", "shortName": "Securitisation, covered bonds and other transferred assets", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfTransfersOfFinancialAssetsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R33": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12501 - Disclosure - Intangible assets", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssets", "shortName": "Intangible assets", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R34": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12601 - Disclosure - Provisions, contingent liabilities, contingent assets and credit commitments", "role": "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitments", "shortName": "Provisions, contingent liabilities, contingent assets and credit commitments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R35": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12701 - Disclosure - Shareholders' equity", "role": "http://www.westpac.com.au/role/DisclosureShareholdersEquity", "shortName": "Shareholders' equity", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R36": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12801 - Disclosure - Capital adequacy", "role": "http://www.westpac.com.au/role/DisclosureCapitalAdequacy", "shortName": "Capital adequacy", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R37": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDividendsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12901 - Disclosure - Dividends", "role": "http://www.westpac.com.au/role/DisclosureDividends", "shortName": "Dividends", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfDividendsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R38": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13001 - Disclosure - Investments in subsidiaries and associates", "role": "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociates", "shortName": "Investments in subsidiaries and associates", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R39": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13101 - Disclosure - Structured entities", "role": "http://www.westpac.com.au/role/DisclosureStructuredEntities", "shortName": "Structured entities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R4": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CashAndBankBalancesAtCentralBanks", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00300 - Statement - Balance sheets", "role": "http://www.westpac.com.au/role/StatementBalanceSheets", "shortName": "Balance sheets", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "wbk:CollateralPaid", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R40": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13201 - Disclosure - Share-based payments", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPayments", "shortName": "Share-based payments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R41": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13301 - Disclosure - Superannuation commitments", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitments", "shortName": "Superannuation commitments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R42": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13401 - Disclosure - Auditor's remuneration", "role": "http://www.westpac.com.au/role/DisclosureAuditorSRemuneration", "shortName": "Auditor's remuneration", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R43": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfRelatedPartyExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13501 - Disclosure - Related party disclosures", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosures", "shortName": "Related party disclosures", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfRelatedPartyExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R44": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfCashFlowStatementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13601 - Disclosure - Notes to the cash flow statements", "role": "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatements", "shortName": "Notes to the cash flow statements", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfCashFlowStatementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R45": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13701 - Disclosure - Assets and liabilities held for sale", "role": "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSale", "shortName": "Assets and liabilities held for sale", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R46": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEventsAfterReportingPeriodExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "13801 - Disclosure - Subsequent events", "role": "http://www.westpac.com.au/role/DisclosureSubsequentEvents", "shortName": "Subsequent events", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEventsAfterReportingPeriodExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R47": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DescriptionOfAccountingPolicyForBasisOfAccountingPolicyTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "20102 - Disclosure - Financial statements preparation (Policies)", "role": "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies", "shortName": "Financial statements preparation (Policies)", "subGroupType": "policies", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DescriptionOfAccountingPolicyForBasisOfAccountingPolicyTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R48": { "firstAnchor": { "ancestors": [ "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DescriptionOfVoluntaryChangeInAccountingPolicy", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30103 - Disclosure - Financial statements preparation (Tables)", "role": "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationTables", "shortName": "Financial statements preparation (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DescriptionOfVoluntaryChangeInAccountingPolicy", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R49": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOperatingSegmentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30203 - Disclosure - Segment reporting (Tables)", "role": "http://www.westpac.com.au/role/DisclosureSegmentReportingTables", "shortName": "Segment reporting (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfOperatingSegmentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R5": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2018_ifrs-full_ComponentsOfEquityAxis_ifrs-full_EquityAttributableToOwnersOfParentMember_yIX19VBh30yHYymoDcLZcQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:IfrsCumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00400 - Statement - Statements of changes in equity", "role": "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "shortName": "Statements of changes in equity", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2018_ifrs-full_ComponentsOfEquityAxis_ifrs-full_EquityAttributableToOwnersOfParentMember_yIX19VBh30yHYymoDcLZcQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:IfrsCumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R50": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfInterestIncomeAndExpenseTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30303 - Disclosure - Net interest income (Tables)", "role": "http://www.westpac.com.au/role/DisclosureNetInterestIncomeTables", "shortName": "Net interest income (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfInterestIncomeAndExpenseTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R51": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfNonInterestIncomeTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30403 - Disclosure - Non-interest income (Tables)", "role": "http://www.westpac.com.au/role/DisclosureNonInterestIncomeTables", "shortName": "Non-interest income (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfNonInterestIncomeTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R52": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfExpensesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfExpensesByNatureExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30503 - Disclosure - Operating expenses (Tables)", "role": "http://www.westpac.com.au/role/DisclosureOperatingExpensesTables", "shortName": "Operating expenses (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfExpensesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfExpensesByNatureExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R53": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30603 - Disclosure - Impairment charges (Tables)", "role": "http://www.westpac.com.au/role/DisclosureImpairmentChargesTables", "shortName": "Impairment charges (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R54": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30703 - Disclosure - Income tax (Tables)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxTables", "shortName": "Income tax (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R55": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfEarningsPerShareExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:EarningsPerShareExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30803 - Disclosure - Earnings per share (Tables)", "role": "http://www.westpac.com.au/role/DisclosureEarningsPerShareTables", "shortName": "Earnings per share (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfEarningsPerShareExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:EarningsPerShareExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R56": { "firstAnchor": { "ancestors": [ "wbk:AverageBalancesAndInterestRatesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:AverageBalanceSheetAndInterestRatesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30903 - Disclosure - Average balance sheet and interest rates (Tables)", "role": "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesTables", "shortName": "Average balance sheet and interest rates (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:AverageBalancesAndInterestRatesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:AverageBalanceSheetAndInterestRatesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R57": { "firstAnchor": { "ancestors": [ "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31003 - Disclosure - Trading securities and financial assets measured at FVIS (Tables)", "role": "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisTables", "shortName": "Trading securities and financial assets measured at FVIS (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R58": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfFinancialInstrumentsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfInvestmentSecuritiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31103 - Disclosure - Investment securities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesTables", "shortName": "Investment securities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfFinancialInstrumentsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfInvestmentSecuritiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R59": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfLoansAndAdvancesToCustomersExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfLoansReceivableTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31203 - Disclosure - Loans (Tables)", "role": "http://www.westpac.com.au/role/DisclosureLoansTables", "shortName": "Loans (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfLoansAndAdvancesToCustomersExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfLoansReceivableTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R6": { "firstAnchor": { "ancestors": [ "link:footnote", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:DividendsPaidOrdinarySharesPerShareRelatingToCurrentYear", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_AUD_shares_RccRn-UL206BeMtqJEf-GA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00405 - Statement - Statement of changes in equity (Parenthetical)", "role": "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "shortName": "Statement of changes in equity (Parenthetical)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "link:footnote", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "2", "first": true, "lang": null, "name": "wbk:DividendsPaidOrdinarySharesPerShareRelatingToCurrentYear", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_AUD_shares_RccRn-UL206BeMtqJEf-GA", "xsiNil": "false" } }, "R60": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ReconciliationOfImpairmentChargesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31303 - Disclosure - Provisions for expected credit losses (Tables)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables", "shortName": "Provisions for expected credit losses (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ReconciliationOfImpairmentChargesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R61": { "firstAnchor": { "ancestors": [ "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialAssetsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31403 - Disclosure - Other financial assets (Tables)", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsTables", "shortName": "Other financial assets (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:DisclosureOfOtherFinancialAssetsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialAssetsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R62": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAmountsArisingFromInsuranceContractsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31503 - Disclosure - Life insurance assets and life insurance liabilities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesTables", "shortName": "Life insurance assets and life insurance liabilities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfAmountsArisingFromInsuranceContractsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R63": { "firstAnchor": { "ancestors": [ "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDetailedInformationAboutDepositsAndOtherBorrowingsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31603 - Disclosure - Deposits and other borrowings (Tables)", "role": "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsTables", "shortName": "Deposits and other borrowings (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:DisclosureOfDepositsAndOtherBorrowingsTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDetailedInformationAboutDepositsAndOtherBorrowingsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R64": { "firstAnchor": { "ancestors": [ "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31703 - Disclosure - Other financial liabilities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesTables", "shortName": "Other financial liabilities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:DisclosureOfOtherFinancialLiabilitiesTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfOtherFinancialLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R65": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfBorrowingsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31803 - Disclosure - Debt issues (Tables)", "role": "http://www.westpac.com.au/role/DisclosureDebtIssuesTables", "shortName": "Debt issues (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfBorrowingsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R66": { "firstAnchor": { "ancestors": [ "wbk:DisclosureOfLoanCapitalTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31903 - Disclosure - Loan capital (Tables)", "role": "http://www.westpac.com.au/role/DisclosureLoanCapitalTables", "shortName": "Loan capital (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "wbk:DisclosureOfLoanCapitalTextBlock", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R67": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32003 - Disclosure - Derivative financial instruments (Tables)", "role": "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables", "shortName": "Derivative financial instruments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R68": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfCreditRiskRatingsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32103 - Disclosure - Financial risk (Tables)", "role": "http://www.westpac.com.au/role/DisclosureFinancialRiskTables", "shortName": "Financial risk (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfCreditRiskRatingsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R69": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32203 - Disclosure - Fair values of financial assets and financial liabilities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesTables", "shortName": "Fair values of financial assets and financial liabilities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R7": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestReceivedClassifiedAsOperatingActivities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00500 - Statement - Cash flow statements", "role": "http://www.westpac.com.au/role/StatementCashFlowStatements", "shortName": "Cash flow statements", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestReceivedClassifiedAsOperatingActivities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R70": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32303 - Disclosure - Offsetting financial assets and financial liabilities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesTables", "shortName": "Offsetting financial assets and financial liabilities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R71": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32403 - Disclosure - Securitisation, covered bonds and other transferred assets (Tables)", "role": "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsTables", "shortName": "Securitisation, covered bonds and other transferred assets (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R72": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32503 - Disclosure - Intangible assets (Tables)", "role": "http://www.westpac.com.au/role/DisclosureIntangibleAssetsTables", "shortName": "Intangible assets (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R73": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfProvisionsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32603 - Disclosure - Provisions, contingent liabilities, contingent assets and credit commitments (Tables)", "role": "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTables", "shortName": "Provisions, contingent liabilities, contingent assets and credit commitments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfProvisionsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R74": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32703 - Disclosure - Shareholders' equity (Tables)", "role": "http://www.westpac.com.au/role/DisclosureShareholdersEquityTables", "shortName": "Shareholders' equity (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R75": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfDividendsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfDividendsNotRecognisedAtYearEndTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32903 - Disclosure - Dividends (Tables)", "role": "http://www.westpac.com.au/role/DisclosureDividendsTables", "shortName": "Dividends (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfDividendsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:ScheduleOfDividendsNotRecognisedAtYearEndTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R76": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestsInSubsidiariesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33003 - Disclosure - Investments in subsidiaries and associates (Tables)", "role": "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesTables", "shortName": "Investments in subsidiaries and associates (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInterestsInSubsidiariesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R77": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33103 - Disclosure - Structured entities (Tables)", "role": "http://www.westpac.com.au/role/DisclosureStructuredEntitiesTables", "shortName": "Structured entities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R78": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33203 - Disclosure - Share-based payments (Tables)", "role": "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsTables", "shortName": "Share-based payments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R79": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDefinedBenefitPlanContributionTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33303 - Disclosure - Superannuation commitments (Tables)", "role": "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables", "shortName": "Superannuation commitments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfDefinedBenefitPlanContributionTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R8": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10101 - Disclosure - Financial statements preparation", "role": "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparation", "shortName": "Financial statements preparation", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R80": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfAuditorsRemunerationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33403 - Disclosure - Auditor's remuneration (Tables)", "role": "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationTables", "shortName": "Auditor's remuneration (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfAuditorsRemunerationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R81": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInformationAboutKeyManagementPersonnelExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33503 - Disclosure - Related party disclosures (Tables)", "role": "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresTables", "shortName": "Related party disclosures (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfRelatedPartyExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfInformationAboutKeyManagementPersonnelExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R82": { "firstAnchor": { "ancestors": [ "ifrs-full:DisclosureOfCashFlowStatementExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfReconciliationOfNetCashInOperatingActivitiesToNetProfitTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33603 - Disclosure - Notes to the consolidated cash flow statement (Tables)", "role": "http://www.westpac.com.au/role/DisclosureNotesToConsolidatedCashFlowStatementTables", "shortName": "Notes to the consolidated cash flow statement (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ifrs-full:DisclosureOfCashFlowStatementExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "wbk:DisclosureOfReconciliationOfNetCashInOperatingActivitiesToNetProfitTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R83": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "33703 - Disclosure - Assets and liabilities held for sale (Tables)", "role": "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleTables", "shortName": "Assets and liabilities held for sale (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R84": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DescriptionOfVoluntaryChangeInAccountingPolicy", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_VoluntaryChangesInAccountingPolicyAxis_wbk_SoftwareServiceArrangementsMember_srt_RestatementAxis_srt_RevisionOfPriorPeriodChangeInAccountingPrincipleAdjustmentMember_AfKZkM-QGEGUGxZAyx80sQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:IncreaseDecreaseInIntangibleAssetsComputerSoftware", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40101 - Disclosure - Financial statements preparation - Changes in accounting policy (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "shortName": "Financial statements preparation - Changes in accounting policy (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DescriptionOfVoluntaryChangeInAccountingPolicy", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_ifrs-full_VoluntaryChangesInAccountingPolicyAxis_wbk_SoftwareServiceArrangementsMember_srt_RestatementAxis_srt_RevisionOfPriorPeriodChangeInAccountingPrincipleAdjustmentMember_AfKZkM-QGEGUGxZAyx80sQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:IncreaseDecreaseInIntangibleAssetsComputerSoftware", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R85": { "firstAnchor": { "ancestors": [ "p", "ifrs-full:DisclosureOfAccountingJudgementsAndEstimatesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_10_1_2020_ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis_ifrs-full_ComputerSoftwareMember_aRtA4MB2bUayj2zBXucElg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ThresholdForCapitalisationForSoftwareDevelopmentCosts", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40102 - Disclosure - Financial statements preparation - Critical accounting assumptions and estimates (Details)", "role": "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails", "shortName": "Financial statements preparation - Critical accounting assumptions and estimates (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ifrs-full:DisclosureOfAccountingJudgementsAndEstimatesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_10_1_2020_ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis_ifrs-full_ComputerSoftwareMember_aRtA4MB2bUayj2zBXucElg", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ThresholdForCapitalisationForSoftwareDevelopmentCosts", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R86": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestRevenueExpense", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40201 - Disclosure - Segment reporting - Segment results (Details)", "role": "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "shortName": "Segment reporting - Segment results (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfOperatingSegmentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:OtherIncomeNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R87": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfOperatingSegmentsExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "wbk:ProfitLossFromOperationsBeforeCashEarningsAdjustment", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40202 - Disclosure - Segment reporting - Reconciliation of cash earnings to net profit attributable to owners of WBC (Details)", "role": "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "shortName": "Segment reporting - Reconciliation of cash earnings to net profit attributable to owners of WBC (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfReconciliationOfCashEarningsToNetProfitExplanatoryTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_SegmentConsolidationItemsAxis_wbk_MaterialReconcilingItemsFairValueGainOrLossOnEconomicHedgesMember_Fh7GXCMOdUSZ3oGju2SetQ", "decimals": "-6", "lang": null, "name": "wbk:NetCashEarningsAdjustments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R88": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfGeographicalAreasExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Revenue", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40203 - Disclosure - Segment reporting - Geographic segments (Details)", "role": "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails", "shortName": "Segment reporting - Geographic segments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfGeographicalAreasExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:Revenue", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R89": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:InterestRevenueCalculatedUsingEffectiveInterestMethod", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40301 - Disclosure - Net interest income (Details)", "role": "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "shortName": "Net interest income (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfInterestIncomeAndExpenseTableTextBlock", "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "lang": null, "name": "wbk:IncreaseInInterestIncomeRelatedToComplianceRegulationAndRemediationCosts", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R9": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEntitysReportableSegmentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10201 - Disclosure - Segment reporting", "role": "http://www.westpac.com.au/role/DisclosureSegmentReporting", "shortName": "Segment reporting", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": null, "first": true, "lang": "en-US", "name": "ifrs-full:DisclosureOfEntitysReportableSegmentsExplanatory", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R90": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfNonInterestIncomeTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CreditrelatedFeeAndCommissionIncome", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40401 - Disclosure - Non-interest income (Details)", "role": "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "shortName": "Non-interest income (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfNonInterestIncomeTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CreditrelatedFeeAndCommissionIncome", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R91": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfExpensesByNatureExplanatory", "ifrs-full:DisclosureOfExpensesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ShorttermEmployeeBenefitsExpense", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40501 - Disclosure - Operating expenses (Details)", "role": "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "shortName": "Operating expenses (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfExpensesByNatureExplanatory", "ifrs-full:DisclosureOfExpensesExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:ShorttermEmployeeBenefitsExpense", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R92": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40601 - Disclosure - Impairment charges (Details)", "role": "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "shortName": "Impairment charges (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_ifrs-full_RiskExposuresAxis_wbk_PerformingMember_BwKWKEyNxUGkFbXEw6Zpeg", "decimals": "-6", "lang": null, "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLoss", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R93": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AccountingProfit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40701 - Disclosure - Income tax - Expense (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "shortName": "Income tax - Expense (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:AccountingProfit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R94": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40702 - Disclosure - Income tax - Analysis (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "shortName": "Income tax - Analysis (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R95": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDeferredTaxesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossDeferredTaxAssetsRecognisedInIncomeStatementsAndOpeningRetainedProfitsDueToAdoptionOfNewAccountingStandards", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40703 - Disclosure - Income tax - Deferred tax assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "shortName": "Income tax - Deferred tax assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDeferredTaxesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossDeferredTaxAssetsRecognisedInIncomeStatementsAndOpeningRetainedProfitsDueToAdoptionOfNewAccountingStandards", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R96": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDeferredTaxesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2019_g_tUeXRTyU2TEj_5QTkuGg", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:NetDeferredTaxAssets", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40704 - Disclosure - Income tax - Movements in deferred tax assets (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "shortName": "Income tax - Movements in deferred tax assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ifrs-full:DisclosureOfDeferredTaxesExplanatory", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "wbk:ImpactOnNetDeferredTaxAssetsDueToAdoptionOfNewAccountingPolicies", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R97": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossDeferredTaxLiabilitiesRecognisedInIncomeStatement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40705 - Disclosure - Income tax - Deferred tax liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "shortName": "Income tax - Deferred tax liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "first": true, "lang": null, "name": "wbk:GrossDeferredTaxLiabilitiesRecognisedInIncomeStatement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R98": { "firstAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2019_g_tUeXRTyU2TEj_5QTkuGg", "decimals": "-6", "first": true, "lang": null, "name": "ifrs-full:NetDeferredTaxLiabilities", "reportCount": 1, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40706 - Disclosure - Income tax - Movements in deferred tax liabilities (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails", "shortName": "Income tax - Movements in deferred tax liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2020_xRymae2xgkS2fGlHFVWDcA", "decimals": "-6", "lang": null, "name": "wbk:ImpactOnNetDeferredTaxLiabilitiesDueToAdoptionOfNewAccountingPolicies", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } }, "R99": { "firstAnchor": { "ancestors": [ "ifrs-full:ApplicableTaxRate", "ifrs-full:ApplicableTaxRate", "b", "p", "td", "tr", "table", "wbk:IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "Duration_10_1_2020_To_9_30_2021_uIkOEcfAnU6Z8vmn6TlYiQ", "decimals": "2", "first": true, "lang": null, "name": "ifrs-full:ApplicableTaxRate", "reportCount": 1, "unitRef": "Unit_Standard_pure_I6Z2-pgg-E-n20Oqbv3XGA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40707 - Disclosure - Income tax - Unrecognised deferred tax balances (Details)", "role": "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "shortName": "Income tax - Unrecognised deferred tax balances (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "wbk:DisclosureOfUnrecognisedDeferredTaxBalancesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "wbk-20210930x20f.htm", "contextRef": "As_Of_9_30_2021_eCvdGANriU-B174e-MXViA", "decimals": "-6", "lang": null, "name": "ifrs-full:UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_AUD_fsVjFpkk-EiRoVY1V_LOTQ", "xsiNil": "false" } } }, "segmentCount": 485, "tag": { "country_AU": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "A [U]", "terseLabel": "Australia" } } }, "localname": "AU", "nsuri": "http://xbrl.sec.gov/country/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "country_NZ": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "N [Z]", "terseLabel": "New Zealand" } } }, "localname": "NZ", "nsuri": "http://xbrl.sec.gov/country/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "domainItemType" }, "currency_AUD": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "A U [D]", "terseLabel": "AUD" } } }, "localname": "AUD", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_AllCurrenciesDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "All Currencies [Domain]", "terseLabel": "All Currencies [Domain]" } } }, "localname": "AllCurrenciesDomain", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_CHF": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "C H [F]", "terseLabel": "CHF" } } }, "localname": "CHF", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_EUR": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "E U [R]", "terseLabel": "EUR" } } }, "localname": "EUR", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_GBP": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "G B [P]", "terseLabel": "GBP" } } }, "localname": "GBP", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_JPY": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "J P [Y]", "terseLabel": "JPY" } } }, "localname": "JPY", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_NZD": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "N Z [D]", "terseLabel": "NZD" } } }, "localname": "NZD", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "currency_USD": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "U S [D]", "terseLabel": "USD" } } }, "localname": "USD", "nsuri": "http://xbrl.sec.gov/currency/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "dei_AddressTypeDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "An entity may have several addresses for different purposes and this domain represents all such types.", "label": "Address Type [Domain]", "terseLabel": "Address Type [Domain]" } } }, "localname": "AddressTypeDomain", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "domainItemType" }, "dei_AdrMember": { "auth_ref": [ "r422" ], "lang": { "en-us": { "role": { "documentation": "American Depository Receipt (or American Depository Share, ADS).", "label": "Adr [Member]", "terseLabel": "American Depositary Shares" } } }, "localname": "AdrMember", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "domainItemType" }, "dei_AmendmentFlag": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.", "label": "Amendment Flag" } } }, "localname": "AmendmentFlag", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_BusinessContactMember": { "auth_ref": [ "r424", "r425" ], "lang": { "en-us": { "role": { "documentation": "Business contact for the entity", "label": "Business Contact [Member]", "terseLabel": "Business Contact" } } }, "localname": "BusinessContactMember", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "domainItemType" }, "dei_CityAreaCode": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Area code of city", "label": "City Area Code" } } }, "localname": "CityAreaCode", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_ContactPersonnelName": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Name of contact personnel", "label": "Contact Personnel Name" } } }, "localname": "ContactPersonnelName", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_CoverAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Cover page.", "label": "Document and Entity Information" } } }, "localname": "CoverAbstract", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "xbrltype": "stringItemType" }, "dei_CurrentFiscalYearEndDate": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "End date of current fiscal year in the format --MM-DD.", "label": "Current Fiscal Year End Date" } } }, "localname": "CurrentFiscalYearEndDate", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "gMonthDayItemType" }, "dei_DocumentAccountingStandard": { "auth_ref": [ "r424" ], "lang": { "en-us": { "role": { "documentation": "The basis of accounting the registrant has used to prepare the financial statements included in this filing This can either be 'U.S. GAAP', 'International Financial Reporting Standards', or 'Other'.", "label": "Document Accounting Standard" } } }, "localname": "DocumentAccountingStandard", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "accountingStandardItemType" }, "dei_DocumentAnnualReport": { "auth_ref": [ "r423", "r424", "r425" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true only for a form used as an annual report.", "label": "Document Annual Report" } } }, "localname": "DocumentAnnualReport", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentFiscalPeriodFocus": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Fiscal period values are FY, Q1, Q2, and Q3. 1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY.", "label": "Document Fiscal Period Focus" } } }, "localname": "DocumentFiscalPeriodFocus", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "fiscalPeriodItemType" }, "dei_DocumentFiscalYearFocus": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This is focus fiscal year of the document report in YYYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.", "label": "Document Fiscal Year Focus" } } }, "localname": "DocumentFiscalYearFocus", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "gYearItemType" }, "dei_DocumentInformationLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Document Information [Line Items]", "terseLabel": "Document and Entity Information" } } }, "localname": "DocumentInformationLineItems", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stringItemType" }, "dei_DocumentInformationTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Container to support the formal attachment of each official or unofficial, public or private document as part of a submission package.", "label": "Document Information [Table]" } } }, "localname": "DocumentInformationTable", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stringItemType" }, "dei_DocumentPeriodEndDate": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is YYYY-MM-DD.", "label": "Document Period End Date" } } }, "localname": "DocumentPeriodEndDate", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "dateItemType" }, "dei_DocumentRegistrationStatement": { "auth_ref": [ "r429" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true only for a form used as a registration statement.", "label": "Document Registration Statement" } } }, "localname": "DocumentRegistrationStatement", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentShellCompanyReport": { "auth_ref": [ "r424" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true for a Shell Company Report pursuant to section 13 or 15(d) of the Exchange Act.", "label": "Document Shell Company Report" } } }, "localname": "DocumentShellCompanyReport", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentTransitionReport": { "auth_ref": [ "r426" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true only for a form used as a transition report.", "label": "Document Transition Report" } } }, "localname": "DocumentTransitionReport", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentType": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.", "label": "Document Type" } } }, "localname": "DocumentType", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "submissionTypeItemType" }, "dei_EntityAddressAddressLine1": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Address Line 1 such as Attn, Building Name, Street Name", "label": "Entity Address, Address Line One" } } }, "localname": "EntityAddressAddressLine1", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressCityOrTown": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Name of the City or Town", "label": "Entity Address, City or Town" } } }, "localname": "EntityAddressCityOrTown", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressCountry": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "ISO 3166-1 alpha-2 country code.", "label": "Entity Address, Country" } } }, "localname": "EntityAddressCountry", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "countryCodeItemType" }, "dei_EntityAddressPostalZipCode": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Code for the postal or zip code", "label": "Entity Address, Postal Zip Code" } } }, "localname": "EntityAddressPostalZipCode", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressStateOrProvince": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Name of the state or province.", "label": "Entity Address, State or Province" } } }, "localname": "EntityAddressStateOrProvince", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stateOrProvinceItemType" }, "dei_EntityAddressesAddressTypeAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table.", "label": "Entity Addresses, Address Type [Axis]" } } }, "localname": "EntityAddressesAddressTypeAxis", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stringItemType" }, "dei_EntityCentralIndexKey": { "auth_ref": [ "r427" ], "lang": { "en-us": { "role": { "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.", "label": "Entity Central Index Key" } } }, "localname": "EntityCentralIndexKey", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "centralIndexKeyItemType" }, "dei_EntityCommonStockSharesOutstanding": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.", "label": "Entity Common Stock, Shares Outstanding" } } }, "localname": "EntityCommonStockSharesOutstanding", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "sharesItemType" }, "dei_EntityCurrentReportingStatus": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure.", "label": "Entity Current Reporting Status" } } }, "localname": "EntityCurrentReportingStatus", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityEmergingGrowthCompany": { "auth_ref": [ "r427" ], "lang": { "en-us": { "role": { "documentation": "Indicate if registrant meets the emerging growth company criteria.", "label": "Entity Emerging Growth Company" } } }, "localname": "EntityEmergingGrowthCompany", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_EntityFileNumber": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.", "label": "Entity File Number" } } }, "localname": "EntityFileNumber", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "fileNumberItemType" }, "dei_EntityFilerCategory": { "auth_ref": [ "r427" ], "lang": { "en-us": { "role": { "documentation": "Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure.", "label": "Entity Filer Category" } } }, "localname": "EntityFilerCategory", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "filerCategoryItemType" }, "dei_EntityIncorporationStateCountryCode": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Two-character EDGAR code representing the state or country of incorporation.", "label": "Entity Incorporation, State or Country Code" } } }, "localname": "EntityIncorporationStateCountryCode", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "edgarStateCountryItemType" }, "dei_EntityInteractiveDataCurrent": { "auth_ref": [ "r428" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).", "label": "Entity Interactive Data Current" } } }, "localname": "EntityInteractiveDataCurrent", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityRegistrantName": { "auth_ref": [ "r427" ], "lang": { "en-us": { "role": { "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.", "label": "Entity Registrant Name" } } }, "localname": "EntityRegistrantName", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityShellCompany": { "auth_ref": [ "r427" ], "lang": { "en-us": { "role": { "documentation": "Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act.", "label": "Entity Shell Company" } } }, "localname": "EntityShellCompany", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_EntityVoluntaryFilers": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Indicate 'Yes' or 'No' if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.", "label": "Entity Voluntary Filers" } } }, "localname": "EntityVoluntaryFilers", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityWellKnownSeasonedIssuer": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Indicate 'Yes' or 'No' if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A.", "label": "Entity Well-known Seasoned Issuer" } } }, "localname": "EntityWellKnownSeasonedIssuer", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_IcfrAuditorAttestationFlag": { "auth_ref": [ "r423", "r424", "r425" ], "lang": { "en-us": { "role": { "label": "ICFR Auditor Attestation Flag" } } }, "localname": "IcfrAuditorAttestationFlag", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_LocalPhoneNumber": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Local phone number for entity.", "label": "Local Phone Number" } } }, "localname": "LocalPhoneNumber", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_Security12bTitle": { "auth_ref": [ "r420" ], "lang": { "en-us": { "role": { "documentation": "Title of a 12(b) registered security.", "label": "Title of 12(b) Security" } } }, "localname": "Security12bTitle", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "securityTitleItemType" }, "dei_SecurityExchangeName": { "auth_ref": [ "r421" ], "lang": { "en-us": { "role": { "documentation": "Name of the Exchange on which a security is registered.", "label": "Security Exchange Name" } } }, "localname": "SecurityExchangeName", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "edgarExchangeCodeItemType" }, "dei_TradingSymbol": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Trading symbol of an instrument as listed on an exchange.", "label": "Trading Symbol" } } }, "localname": "TradingSymbol", "nsuri": "http://xbrl.sec.gov/dei/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "tradingSymbolItemType" }, "ifrs-full_AccountingProfit": { "auth_ref": [ "r70", "r71" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of profit (loss) for a period before deducting tax expense. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Accounting profit", "terseLabel": "Profit before income tax expense" } } }, "localname": "AccountingProfit", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember": { "auth_ref": [ "r79", "r82", "r150", "r164", "r167" ], "lang": { "en": { "role": { "documentation": "This member stands for accumulated depreciation, amortisation and impairment. [Refer: Impairment loss; Depreciation and amortisation expense]" } }, "en-us": { "role": { "label": "Accumulated Depreciation Amortisation And Impairment [Member]", "terseLabel": "Accumulated amortisation and impairment" } } }, "localname": "AccumulatedDepreciationAmortisationAndImpairmentMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssets": { "auth_ref": [ "r284" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as an asset. [Refer: Hedged items [member]]" } }, "en-us": { "role": { "label": "Accumulated fair value hedge adjustment on hedged item included in carrying amount, assets", "terseLabel": "FVHA included in carrying amount, hedged assets" } } }, "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountLiabilities": { "auth_ref": [ "r284" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as a liability. [Refer: Hedged items [member]]" } }, "en-us": { "role": { "label": "Accumulated fair value hedge adjustment on hedged item included in carrying amount, liabilities", "negatedLabel": "FVHA included in carrying amount, hedged liabilities" } } }, "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets": { "auth_ref": [ "r286" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial asset measured at amortised cost and has ceased to be adjusted for hedging gains and losses. [Refer: Financial assets at amortised cost; Hedged items [member]]" } }, "en-us": { "role": { "label": "Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, assets", "terseLabel": "FVHA included in carrying amounts relating to hedged items that have ceased to be adjusted for hedging gains and losses, assets" } } }, "localname": "AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesLiabilities": { "auth_ref": [ "r286" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial liability measured at amortised cost and has ceased to be adjusted for hedging gains and losses. [Refer: Financial liabilities at amortised cost; Hedged items [member]]" } }, "en-us": { "role": { "label": "Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, liabilities", "terseLabel": "FVHA included in carrying amounts relating to hedged items that have ceased to be adjusted for hedging gains and losses, liabilities" } } }, "localname": "AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AccumulatedImpairmentMember": { "auth_ref": [ "r79", "r150", "r164", "r167", "r263", "r300", "r306", "r409", "r418" ], "lang": { "en": { "role": { "documentation": "This member stands for accumulated impairment. [Refer: Impairment loss]" } }, "en-us": { "role": { "label": "Accumulated Impairment [Member]", "terseLabel": "Provision" } } }, "localname": "AccumulatedImpairmentMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ActuarialAssumptionOfDiscountRates": { "auth_ref": [ "r89" ], "lang": { "en": { "role": { "documentation": "The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial assumption of discount rates", "terseLabel": "Discount rate" } } }, "localname": "ActuarialAssumptionOfDiscountRates", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_ActuarialAssumptionOfDiscountRatesMember": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "This member stands for the discount rates used as actuarial assumptions. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial Assumption Of Discount Rates [Member]", "terseLabel": "Discount rate" } } }, "localname": "ActuarialAssumptionOfDiscountRatesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflation": { "auth_ref": [ "r89" ], "lang": { "en": { "role": { "documentation": "The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial assumption of expected rates of inflation", "terseLabel": "Inflation rate (pensioners received inflationary increase)" } } }, "localname": "ActuarialAssumptionOfExpectedRatesOfInflation", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflationMember": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "This member stands for the expected rates of inflation used as actuarial assumptions. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial Assumption Of Expected Rates Of Inflation [Member]", "terseLabel": "Inflation rate" } } }, "localname": "ActuarialAssumptionOfExpectedRatesOfInflationMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ActuarialAssumptionOfExpectedRatesOfSalaryIncreases": { "auth_ref": [ "r89" ], "lang": { "en": { "role": { "documentation": "The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial assumption of expected rates of salary increases", "terseLabel": "Salary increases" } } }, "localname": "ActuarialAssumptionOfExpectedRatesOfSalaryIncreases", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_ActuarialAssumptionOfExpectedRatesOfSalaryIncreasesMember": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "This member stands for the expected rates of salary increases used as actuarial assumptions. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial Assumption Of Expected Rates Of Salary Increases [Member]", "terseLabel": "Annual salary increases" } } }, "localname": "ActuarialAssumptionOfExpectedRatesOfSalaryIncreasesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ActuarialAssumptionOfLifeExpectancyAfterRetirementMember": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "This member stands for the life expectancy after retirement used as actuarial assumptions. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Actuarial Assumption Of Life Expectancy After Retirement [Member]", "terseLabel": "Expected lifetime" } } }, "localname": "ActuarialAssumptionOfLifeExpectancyAfterRetirementMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ActuarialAssumptionsAxis": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Actuarial assumptions [axis]" } } }, "localname": "ActuarialAssumptionsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ActuarialAssumptionsMember": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "This member stands for all actuarial assumptions. Actuarial assumptions are the entity\u2019s unbiased and mutually compatible best estimates of the demographic and financial variables that will determine the ultimate cost of providing post-employment benefits. It also represents the standard value for the 'Actuarial assumptions' axis if no other member is used." } }, "en-us": { "role": { "label": "Actuarial Assumptions [Member]", "terseLabel": "Actuarial assumptions [member]" } } }, "localname": "ActuarialAssumptionsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AdditionalProvisionsOtherProvisions": { "auth_ref": [ "r140" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of additional other provisions made. [Refer: Other provisions]" } }, "en-us": { "role": { "label": "Additional provisions, other provisions", "terseLabel": "Additions" } } }, "localname": "AdditionalProvisionsOtherProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdditionsLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued": { "auth_ref": [ "r395", "r399" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase in liabilities under insurance contracts and reinsurance contracts issued, resulting from additions other than through business combinations. [Refer: Liabilities under insurance contracts and reinsurance contracts issued; Business combinations [member]]" } }, "en-us": { "role": { "label": "Additions other than through business combinations, liabilities under insurance contracts and reinsurance contracts issued", "terseLabel": "Contract contributions recognised in policy liabilities" } } }, "localname": "AdditionsLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r151" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of additions to intangible assets other than goodwill, other than those acquired through business combinations. [Refer: Business combinations [member]; Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Additions other than through business combinations, intangible assets other than goodwill", "terseLabel": "Additions" } } }, "localname": "AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustedWeightedAverageShares": { "auth_ref": [ "r124" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en": { "role": { "documentation": "The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]" } }, "en-us": { "role": { "label": "Adjusted weighted average number of ordinary shares outstanding", "totalLabel": "Adjusted weighted average number of ordinary shares - Diluted" } } }, "localname": "AdjustedWeightedAverageShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "ifrs-full_AdjustmentsForDecreaseIncreaseInOtherAssets": { "auth_ref": [ "r181" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 8.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for decrease (increase) in other assets to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other assets; Profit (loss)]" } }, "en-us": { "role": { "label": "Adjustments for decrease (increase) in other assets", "terseLabel": "Other assets" } } }, "localname": "AdjustmentsForDecreaseIncreaseInOtherAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForDepreciationAndAmortisationExpenseAndImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss": { "auth_ref": [ "r181" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 2.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for depreciation and amortisation expense and impairment loss (reversal of impairment loss) to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Impairment loss; Depreciation and amortisation expense; Impairment loss (reversal of impairment loss) recognised in profit or loss; Profit (loss)]" } }, "en-us": { "role": { "label": "Adjustments for depreciation and amortisation expense and impairment loss (reversal of impairment loss) recognised in profit or loss", "terseLabel": "Depreciation, amortisation and impairment" } } }, "localname": "AdjustmentsForDepreciationAndAmortisationExpenseAndImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvances": { "auth_ref": [ "r181" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 3.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for impairment loss (reversal of impairment loss) on loans and advances recognised in profit or loss to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss]" } }, "en-us": { "role": { "label": "Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss, loans and advances", "terseLabel": "Impairment charges" } } }, "localname": "AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvances", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForIncomeTaxExpense": { "auth_ref": [ "r185" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 4.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for income tax expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Adjustments for income tax expense", "terseLabel": "Net decrease/(increase) in current and deferred tax" } } }, "localname": "AdjustmentsForIncomeTaxExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForIncreaseDecreaseInOtherLiabilities": { "auth_ref": [ "r181" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 12.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for increase (decrease) in other liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other liabilities; Profit (loss)]" } }, "en-us": { "role": { "label": "Adjustments for increase (decrease) in other liabilities", "terseLabel": "Other liabilities" } } }, "localname": "AdjustmentsForIncreaseDecreaseInOtherLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForProvisions": { "auth_ref": [ "r180" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 7.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for provisions to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Provisions; Profit (loss)]" } }, "en-us": { "role": { "label": "Adjustments for provisions", "terseLabel": "(Decrease)/increase in provisions" } } }, "localname": "AdjustmentsForProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AdjustmentsForReconcileProfitLossAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Adjustments to reconcile profit (loss) [abstract]", "verboseLabel": "Adjustments:" } } }, "localname": "AdjustmentsForReconcileProfitLossAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_AdvertisingExpense": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 4.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense arising from advertising." } }, "en-us": { "role": { "label": "Advertising expense", "terseLabel": "Advertising" } } }, "localname": "AdvertisingExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AggregatedMeasurementMember": { "auth_ref": [ "r162", "r166", "r224" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of measurement. It also represents the standard value for the 'Measurement' axis if no other member is used." } }, "en-us": { "role": { "label": "Aggregated Measurement [Member]", "terseLabel": "Aggregated measurement [member]" } } }, "localname": "AggregatedMeasurementMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AggregatedTimeBandsMember": { "auth_ref": [ "r34", "r242", "r249", "r250", "r278", "r329", "r336", "r372", "r374", "r380" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated time bands. It also represents the standard value for the 'Maturity' axis if no other member is used." } }, "en-us": { "role": { "label": "Aggregated Time Bands [Member]", "terseLabel": "Aggregated time bands [member]" } } }, "localname": "AggregatedTimeBandsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AllLevelsOfFairValueHierarchyMember": { "auth_ref": [ "r88", "r225" ], "lang": { "en": { "role": { "documentation": "This member stands for all levels of the fair value hierarchy. It also represents the standard value for the 'Levels of fair value hierarchy' axis if no other member is used." } }, "en-us": { "role": { "label": "All Levels Of Fair Value Hierarchy [Member]", "terseLabel": "All levels of fair value hierarchy [member]" } } }, "localname": "AllLevelsOfFairValueHierarchyMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AllOtherSegmentsMember": { "auth_ref": [ "r241", "r350" ], "lang": { "en": { "role": { "documentation": "This member stands for business activities and operating segments that are not reportable." } }, "en-us": { "role": { "label": "All Other Segments [Member]", "terseLabel": "Other segments" } } }, "localname": "AllOtherSegmentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AllowanceForCreditLossesMember": { "auth_ref": [ "r76" ], "lang": { "en": { "role": { "documentation": "This member stands for an allowance account used to record impairments to financial assets due to credit losses." } }, "en-us": { "role": { "label": "Allowance For Credit Losses [Member]", "terseLabel": "Provision for ECL" } } }, "localname": "AllowanceForCreditLossesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AmortisationIntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r153" ], "lang": { "en": { "role": { "documentation": "The amount of amortisation of intangible assets other than goodwill. [Refer: Depreciation and amortisation expense; Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Amortisation, intangible assets other than goodwill", "negatedLabel": "Amortisation" } } }, "localname": "AmortisationIntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AmountOfReclassificationsOrChangesInPresentation": { "auth_ref": [ "r16" ], "lang": { "en": { "role": { "documentation": "The amount that is reclassified when the entity changes classification or presentation in its financial statements." } }, "en-us": { "role": { "label": "Amount of reclassifications or changes in presentation", "terseLabel": "Amount of reclassification" } } }, "localname": "AmountOfReclassificationsOrChangesInPresentation", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AmountsReceivableRelatedPartyTransactions": { "auth_ref": [ "r106", "r110" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amounts receivable resulting from related party transactions. [Refer: Related parties [member]]" } }, "en-us": { "role": { "label": "Amounts receivable, related party transactions", "terseLabel": "Closing loan balance" } } }, "localname": "AmountsReceivableRelatedPartyTransactions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial assets [abstract]", "terseLabel": "Amounts subject to enforceable netting arrangements but not offset" } } }, "localname": "AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssetsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities [abstract]", "terseLabel": "Amounts subject to enforceable netting arrangements but not offset" } } }, "localname": "AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ApplicableTaxRate": { "auth_ref": [ "r71" ], "lang": { "en": { "role": { "documentation": "The applicable income tax rate." } }, "en-us": { "role": { "label": "Applicable tax rate", "verboseLabel": "Australian company tax rate (as a percent)" } } }, "localname": "ApplicableTaxRate", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_AssetbackedFinancingsMember": { "auth_ref": [ "r219" ], "lang": { "en": { "role": { "documentation": "This member stands for asset-backed financings." } }, "en-us": { "role": { "label": "Assetbacked Financings [Member]", "terseLabel": "Investment in Third Party Mortgage and Other Asset-Backed Securities" } } }, "localname": "AssetbackedFinancingsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Assets": { "auth_ref": [ "r30", "r224", "r225", "r229", "r355", "r358" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "ifrs-full_NetAssetsLiabilities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of a present economic resource controlled by the entity as a result of past events. Economic resource is a right that has the potential to produce economic benefits." } }, "en-us": { "role": { "label": "Assets", "totalLabel": "Total assets" } } }, "localname": "Assets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Assets [abstract]", "terseLabel": "Assets", "verboseLabel": "Assets:" } } }, "localname": "AssetsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "stringItemType" }, "ifrs-full_AssetsThatEntityContinuesToRecognise": { "auth_ref": [ "r315" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of transferred financial assets that the entity continues to recognise in full. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Assets that entity continues to recognise", "terseLabel": "Carrying amount of transferred assets" } } }, "localname": "AssetsThatEntityContinuesToRecognise", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AssociatedLiabilitiesThatEntityContinuesToRecognise": { "auth_ref": [ "r315" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities associated with transferred financial assets that the entity continues to recognise in full. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Associated liabilities that entity continues to recognise", "terseLabel": "Carrying amount of associated liabilities" } } }, "localname": "AssociatedLiabilitiesThatEntityContinuesToRecognise", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AtFairValueMember": { "auth_ref": [ "r162", "r166", "r224" ], "lang": { "en": { "role": { "documentation": "This member stands for measurement based on fair value. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date." } }, "en-us": { "role": { "label": "At Fair Value [Member]", "terseLabel": "At fair value" } } }, "localname": "AtFairValueMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_AuditorsRemuneration": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors." } }, "en-us": { "role": { "label": "Auditor's remuneration.", "totalLabel": "Total audit and non-audit fees" } } }, "localname": "AuditorsRemuneration", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AuditorsRemunerationAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Auditor's remuneration" } } }, "localname": "AuditorsRemunerationAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_AuditorsRemunerationForAuditServices": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails": { "order": 2.0, "parentTag": "wbk_AuditorsRemunerationForAuditAndAuditRelatedServices", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors for auditing services." } }, "en-us": { "role": { "label": "Auditor's remuneration for audit services", "terseLabel": "Audit fees" } } }, "localname": "AuditorsRemunerationForAuditServices", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AuditorsRemunerationForTaxServices": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails": { "order": 2.0, "parentTag": "ifrs-full_AuditorsRemuneration", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors for tax services." } }, "en-us": { "role": { "label": "Auditor's remuneration for tax services", "terseLabel": "Tax fees" } } }, "localname": "AuditorsRemunerationForTaxServices", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_AverageEffectiveTaxRate": { "auth_ref": [ "r71" ], "lang": { "en": { "role": { "documentation": "The tax expense (income) divided by the accounting profit. [Refer: Accounting profit]" } }, "en-us": { "role": { "label": "Average effective tax rate", "verboseLabel": "Effective income tax rate (as a percent)" } } }, "localname": "AverageEffectiveTaxRate", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_AverageForeignExchangeRate": { "auth_ref": [ "r12" ], "lang": { "en": { "role": { "documentation": "The average exchange rate used by the entity. Exchange rate is the ratio of exchange for two currencies." } }, "en-us": { "role": { "label": "Average foreign exchange rate", "terseLabel": "Weighted average FX rate" } } }, "localname": "AverageForeignExchangeRate", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_BasicEarningsLossPerShare": { "auth_ref": [ "r122" ], "lang": { "en": { "role": { "documentation": "The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator) divided by the weighted average number of ordinary shares outstanding during the period (the denominator)." } }, "en-us": { "role": { "label": "Basic earnings (loss) per share", "terseLabel": "Basic", "verboseLabel": "Earnings per ordinary share (cents) - Basic" } } }, "localname": "BasicEarningsLossPerShare", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "perShareItemType" }, "ifrs-full_BorrowingsAdjustmentToInterestRateBasis": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "The adjustment to the basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Borrowings, adjustment to interest rate basis", "terseLabel": "Interest rate adjustments (as a percent)" } } }, "localname": "BorrowingsAdjustmentToInterestRateBasis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_BorrowingsByNameAxis": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Borrowings by name [axis]" } } }, "localname": "BorrowingsByNameAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_BorrowingsByNameMember": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "This member stands for all borrowings when disaggregated by name. It also represents the standard value for the 'Borrowings by name' axis if no other member is used. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Borrowings By Name [Member]", "terseLabel": "Borrowings by name [member]" } } }, "localname": "BorrowingsByNameMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_BorrowingsInterestRate": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "The interest rate on borrowings. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Borrowings, interest rate", "terseLabel": "Interest rate (as a percent)" } } }, "localname": "BorrowingsInterestRate", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_BottomOfRangeMember": { "auth_ref": [ "r236", "r238", "r240", "r255", "r320", "r374" ], "lang": { "en": { "role": { "documentation": "This member stands for the bottom of a range." } }, "en-us": { "role": { "label": "Bottom Of Range [Member]", "terseLabel": "Minimum" } } }, "localname": "BottomOfRangeMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_BrandNamesMember": { "auth_ref": [ "r156" ], "lang": { "en": { "role": { "documentation": "This member stands for a class of intangible assets representing rights to a group of complementary assets such as a trademark (or service mark) and its related trade name, formulas, recipes and technological expertise. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Brand Names [Member]", "terseLabel": "Brand Names" } } }, "localname": "BrandNamesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_BrokerageFeeIncome": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "ifrs-full_FeeAndCommissionIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income recognised for brokerage fees charged by the entity." } }, "en-us": { "role": { "label": "Brokerage fee income", "terseLabel": "Transactions fees" } } }, "localname": "BrokerageFeeIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis": { "auth_ref": [ "r79", "r80", "r150", "r154", "r163", "r164", "r165", "r166", "r167", "r263", "r300", "r302", "r409", "r419" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis]" } } }, "localname": "CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_CarryingAmountMember": { "auth_ref": [ "r80", "r154", "r163", "r165", "r166", "r263", "r300", "r302", "r409", "r417" ], "lang": { "en": { "role": { "documentation": "This member stands for the amount at which an asset is recognised in the statement of financial position (after deducting any accumulated depreciation or amortisation and accumulated impairment losses). It also represents the standard value for the 'Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount' axis if no other member is used. [Refer: Depreciation and amortisation expense; Impairment loss]" } }, "en-us": { "role": { "label": "Carrying Amount [Member]", "terseLabel": "Carrying amount [member]" } } }, "localname": "CarryingAmountMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Cash": { "auth_ref": [ "r186" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails": { "order": 1.0, "parentTag": "ifrs-full_CashAndBankBalancesAtCentralBanks", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of cash on hand and demand deposits. [Refer: Cash on hand]" } }, "en-us": { "role": { "label": "Cash", "terseLabel": "Cash and cash at bank" } } }, "localname": "Cash", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashAndBankBalancesAtCentralBanks": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of cash and bank balances held at central banks." } }, "en-us": { "role": { "label": "Cash and bank balances at central banks", "terseLabel": "Cash and balances with central banks", "totalLabel": "Total cash and balances with central banks" } } }, "localname": "CashAndBankBalancesAtCentralBanks", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashAndCashEquivalents": { "auth_ref": [ "r20", "r186", "r213" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]" } }, "en-us": { "role": { "label": "Cash and cash equivalents", "periodEndLabel": "Cash and balances with central banks as at end of year", "periodStartLabel": "Cash and balances with central banks as at beginning of year" } } }, "localname": "CashAndCashEquivalents", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": { "auth_ref": [ "r272", "r344" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 3.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of cash collateral pledged that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial liabilities. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Cash collateral pledged subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities", "negatedTerseLabel": "Cash collateral" } } }, "localname": "CashCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": { "auth_ref": [ "r272", "r344" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 3.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of cash collateral received that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial assets. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets", "negatedTerseLabel": "Cash collateral" } } }, "localname": "CashCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashFlowHedgesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Cash flow hedges [abstract]", "verboseLabel": "Cash flow hedge reserve" } } }, "localname": "CashFlowHedgesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_CashFlowHedgesMember": { "auth_ref": [ "r160", "r282", "r289", "r293" ], "lang": { "en": { "role": { "documentation": "This member stands for hedges of the exposure to variability in cash flows that (a) are attributable to a particular risk associated with a recognised asset or liability (such as all or some future interest payments on variable rate debt) or a highly probable forecast transaction; and (b) could affect profit or loss. [Refer: Hedges [member]]" } }, "en-us": { "role": { "label": "Cash Flow Hedges [Member]", "terseLabel": "Cash flow hedges" } } }, "localname": "CashFlowHedgesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CashFlowsFromUsedInFinancingActivities": { "auth_ref": [ "r168", "r187" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 3.0, "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash flows from (used in) financing activities, which are activities that result in changes in the size and composition of the contributed equity and borrowings of the entity." } }, "en-us": { "role": { "label": "Cash flows from (used in) financing activities", "totalLabel": "Net cash provided by/(used in) financing activities" } } }, "localname": "CashFlowsFromUsedInFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Cash flows from (used in) financing activities [abstract]", "terseLabel": "Cash flows from financing activities" } } }, "localname": "CashFlowsFromUsedInFinancingActivitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "ifrs-full_CashFlowsFromUsedInInvestingActivities": { "auth_ref": [ "r168", "r187" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 2.0, "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash flows from (used in) investing activities, which are the acquisition and disposal of long-term assets and other investments not included in cash equivalents." } }, "en-us": { "role": { "label": "Cash flows from (used in) investing activities", "totalLabel": "Net cash provided by/(used in) investing activities" } } }, "localname": "CashFlowsFromUsedInInvestingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Cash flows from (used in) investing activities [abstract]", "terseLabel": "Cash flows from investing activities" } } }, "localname": "CashFlowsFromUsedInInvestingActivitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "ifrs-full_CashFlowsFromUsedInOperatingActivities": { "auth_ref": [ "r168", "r187" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 1.0, "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges", "weight": 1.0 } }, "lang": { "en": { "role": { "documentation": "The cash flows from (used in) operating activities, which are the principal revenue-producing activities of the entity and other activities that are not investing or financing activities. [Refer: Revenue]" } }, "en-us": { "role": { "label": "Cash flows from (used in) operating activities", "totalLabel": "Net cash provided by/(used in) operating activities" } } }, "localname": "CashFlowsFromUsedInOperatingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Cash flows from (used in) operating activities [abstract]", "terseLabel": "Cash flows from operating activities", "verboseLabel": "Reconciliation of net cash provided by/(used in) operating activities to net profit for the year" } } }, "localname": "CashFlowsFromUsedInOperatingActivitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital": { "auth_ref": [ "r181", "r188" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 1.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "lang": { "en": { "role": { "documentation": "The cash inflow (outflow) from the entity's operations before changes in working capital." } }, "en-us": { "role": { "label": "Cash flows from (used in) operations before changes in working capital", "totalLabel": "Cash flows from operating activities before changes in operating assets and liabilities" } } }, "localname": "CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CashPaidLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued": { "auth_ref": [ "r395", "r400" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The decrease in liabilities under insurance contracts and reinsurance contracts issued resulting from cash paid. [Refer: Liabilities under insurance contracts and reinsurance contracts issued]" } }, "en-us": { "role": { "label": "Cash paid, liabilities under insurance contracts and reinsurance contracts issued", "negatedTerseLabel": "Contract withdrawals recognised in policy liabilities" } } }, "localname": "CashPaidLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CategoriesOfFinancialAssetsAxis": { "auth_ref": [ "r324" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Categories of financial assets [axis]" } } }, "localname": "CategoriesOfFinancialAssetsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_CategoriesOfRelatedPartiesAxis": { "auth_ref": [ "r109" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Categories of related parties [axis]" } } }, "localname": "CategoriesOfRelatedPartiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ChangesInEquity": { "auth_ref": [ "r8" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in equity. [Refer: Equity]" } }, "en-us": { "role": { "label": "Increase (decrease) in equity", "totalLabel": "Total contributions and distributions" } } }, "localname": "ChangesInEquity", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ClassesOfAssetsAxis": { "auth_ref": [ "r127", "r131", "r232", "r247" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of assets [axis]" } } }, "localname": "ClassesOfAssetsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfAssetsMember": { "auth_ref": [ "r127", "r232", "r247" ], "lang": { "en": { "role": { "documentation": "This member stands for a present economic resource controlled by the entity as a result of past events. Economic resource is a right that has the potential to produce economic benefits. It also represents the standard value for the 'Classes of assets' axis if no other member is used." } }, "en-us": { "role": { "label": "Classes Of Assets [Member]", "terseLabel": "Assets [member]" } } }, "localname": "ClassesOfAssetsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ClassesOfContingentLiabilitiesAxis": { "auth_ref": [ "r144", "r259" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of contingent liabilities [axis]" } } }, "localname": "ClassesOfContingentLiabilitiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfEmployeeBenefitsExpenseAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Classes of employee benefits expense [abstract]", "terseLabel": "Staff expenses" } } }, "localname": "ClassesOfEmployeeBenefitsExpenseAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfFinancialAssetsAxis": { "auth_ref": [ "r318", "r319", "r370", "r384", "r386" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of financial assets [axis]" } } }, "localname": "ClassesOfFinancialAssetsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfFinancialInstrumentsAxis": { "auth_ref": [ "r300", "r304", "r305", "r307" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of financial instruments [axis]" } } }, "localname": "ClassesOfFinancialInstrumentsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfFinancialInstrumentsMember": { "auth_ref": [ "r300", "r304", "r305", "r307" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated classes of financial instruments. Financial instruments are contracts that give rise to a financial asset of one entity and a financial liability or equity instrument of another entity. It also represents the standard value for the 'Classes of financial instruments' axis if no other member is used. [Refer: Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Classes Of Financial Instruments [Member]", "terseLabel": "Financial instruments, class [member]" } } }, "localname": "ClassesOfFinancialInstrumentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ClassesOfFinancialLiabilitiesAxis": { "auth_ref": [ "r318", "r319", "r370" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of financial liabilities [axis]" } } }, "localname": "ClassesOfFinancialLiabilitiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of intangible assets and goodwill [axis]" } } }, "localname": "ClassesOfIntangibleAssetsAndGoodwillAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of intangible assets other than goodwill [axis]" } } }, "localname": "ClassesOfIntangibleAssetsOtherThanGoodwillAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfLiabilitiesAxis": { "auth_ref": [ "r232" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of liabilities [axis]" } } }, "localname": "ClassesOfLiabilitiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis": { "auth_ref": [ "r81" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of property, plant and equipment [axis]" } } }, "localname": "ClassesOfPropertyPlantAndEquipmentAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfProvisionsAxis": { "auth_ref": [ "r143" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of other provisions [axis]" } } }, "localname": "ClassesOfProvisionsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfShareCapitalAxis": { "auth_ref": [ "r42" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Classes of share capital [axis]" } } }, "localname": "ClassesOfShareCapitalAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stringItemType" }, "ifrs-full_ClassesOfShareCapitalMember": { "auth_ref": [ "r42" ], "lang": { "en": { "role": { "documentation": "This member stands for share capital of the entity. It also represents the standard value for the 'Classes of share capital' axis if no other member is used." } }, "en-us": { "role": { "label": "Classes Of Share Capital [Member]", "terseLabel": "Share capital [member]" } } }, "localname": "ClassesOfShareCapitalMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "domainItemType" }, "ifrs-full_CommodityPriceRiskMember": { "auth_ref": [ "r312", "r342" ], "lang": { "en": { "role": { "documentation": "This member stands for a component of other price risk that represents the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in commodity prices. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Commodity Price Risk [Member]", "terseLabel": "Commodity risk" } } }, "localname": "CommodityPriceRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CommunicationExpense": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 5.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense arising from communication." } }, "en-us": { "role": { "label": "Communication expense", "terseLabel": "Telecommunications" } } }, "localname": "CommunicationExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ComponentsOfEquityAxis": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Components of equity [axis]" } } }, "localname": "ComponentsOfEquityAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "stringItemType" }, "ifrs-full_ComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTaxAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract]", "verboseLabel": "Items that may be reclassified subsequently to profit or loss" } } }, "localname": "ComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTaxAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_ComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTaxAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract]", "verboseLabel": "Items that will not be reclassified subsequently to profit or loss" } } }, "localname": "ComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTaxAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_ComprehensiveIncome": { "auth_ref": [ "r4", "r47", "r195", "r197", "r209", "r210" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncomeCalc2": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of change in equity resulting from transactions and other events, other than those changes resulting from transactions with owners in their capacity as owners." } }, "en-us": { "role": { "label": "Comprehensive income", "totalLabel": "Total comprehensive income/(expense) for the year" } } }, "localname": "ComprehensiveIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ComprehensiveIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Comprehensive income [abstract]", "terseLabel": "Statements of comprehensive income" } } }, "localname": "ComprehensiveIncomeAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_ComprehensiveIncomeAttributableToAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Comprehensive income attributable to [abstract]", "terseLabel": "Attributable to:" } } }, "localname": "ComprehensiveIncomeAttributableToAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_ComprehensiveIncomeAttributableToNoncontrollingInterests": { "auth_ref": [ "r4", "r50" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncomeCalc2": { "order": 2.0, "parentTag": "ifrs-full_ComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of comprehensive income attributable to non-controlling interests. [Refer: Comprehensive income; Non-controlling interests]" } }, "en-us": { "role": { "label": "Comprehensive income, attributable to non-controlling interests", "terseLabel": "NCI" } } }, "localname": "ComprehensiveIncomeAttributableToNoncontrollingInterests", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent": { "auth_ref": [ "r4", "r51" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncomeCalc2": { "order": 1.0, "parentTag": "ifrs-full_ComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of comprehensive income attributable to owners of the parent. [Refer: Comprehensive income]" } }, "en-us": { "role": { "label": "Comprehensive income, attributable to owners of parent", "terseLabel": "Owners of WBC" } } }, "localname": "ComprehensiveIncomeAttributableToOwnersOfParent", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ComputerSoftwareMember": { "auth_ref": [ "r157" ], "lang": { "en": { "role": { "documentation": "This member stands for a class of intangible assets representing computer software. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Computer Software [Member]", "terseLabel": "Computer software" } } }, "localname": "ComputerSoftwareMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ConsolidatedStructuredEntitiesAxis": { "auth_ref": [ "r223" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Consolidated structured entities [axis]" } } }, "localname": "ConsolidatedStructuredEntitiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ContingentLiabilitiesMember": { "auth_ref": [ "r146", "r259" ], "lang": { "en": { "role": { "documentation": "This member stands for possible obligations that arise from past events and whose existence will be confirmed only by the occurrence or non-occurrence of one or more uncertain future events not wholly within the control of the entity; or, present obligations that arise from past events but are not recognised because (a) it is probable that an outflow of resources embodying economic benefits will be required to settle the obligations; or (b) the amount of the obligations cannot be measured with sufficient reliability. It also represents the standard value for the 'Classes of contingent liabilities' axis if no other member is used." } }, "en-us": { "role": { "label": "Contingent Liabilities [Member]", "terseLabel": "Contingent liabilities [member]" } } }, "localname": "ContingentLiabilitiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ContingentLiabilityForGuaranteesMember": { "auth_ref": [ "r146" ], "lang": { "en": { "role": { "documentation": "This member stands for a contingent liability for guarantees. [Refer: Contingent liabilities [member]; Guarantees [member]]" } }, "en-us": { "role": { "label": "Contingent Liability For Guarantees [Member]", "terseLabel": "Guarantees" } } }, "localname": "ContingentLiabilityForGuaranteesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset": { "auth_ref": [ "r87" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Contributions to plan by employer, net defined benefit liability (asset)", "terseLabel": "Group contributions to defined benefit plans" } } }, "localname": "ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresSuperannuationPlansDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CounterpartiesAxis": { "auth_ref": [ "r338" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Counterparties [axis]" } } }, "localname": "CounterpartiesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_CounterpartiesMember": { "auth_ref": [ "r338" ], "lang": { "en": { "role": { "documentation": "This member stands for the parties to the transaction other than the entity. It also represents the standard value for the 'Counterparties' axis if no other member is used." } }, "en-us": { "role": { "label": "Counterparties [Member]", "terseLabel": "Counterparties [member]" } } }, "localname": "CounterpartiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CountryOfDomicileMember": { "auth_ref": [ "r363", "r364" ], "lang": { "en": { "role": { "documentation": "This member stands for the country in which the entity is registered and where it has its legal address or registered office." } }, "en-us": { "role": { "label": "Country Of Domicile [Member]", "terseLabel": "Australia" } } }, "localname": "CountryOfDomicileMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis": { "auth_ref": [ "r300", "r305" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Credit impairment of financial instruments [axis]" } } }, "localname": "CreditImpairmentOfFinancialInstrumentsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_CreditImpairmentOfFinancialInstrumentsMember": { "auth_ref": [ "r300", "r305" ], "lang": { "en": { "role": { "documentation": "This member stands for all statuses of credit impairment of financial instruments. A financial instrument is credit-impaired when one or more events that have a detrimental impact on the estimated future cash flows of that financial instrument have occurred. This member also represents the standard value for the 'Credit impairment of financial instruments' axis if no other member is used." } }, "en-us": { "role": { "label": "Credit Impairment Of Financial Instruments [Member]", "terseLabel": "Credit impairment of financial instruments [member]" } } }, "localname": "CreditImpairmentOfFinancialInstrumentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CreditRiskMember": { "auth_ref": [ "r297", "r375", "r376", "r377" ], "lang": { "en": { "role": { "documentation": "This member stands for the risk that one party to a financial instrument will cause a financial loss for the other party by failing to discharge an obligation. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Credit Risk [Member]", "terseLabel": "Credit risk" } } }, "localname": "CreditRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CreditrelatedFeeAndCommissionIncome": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "ifrs-full_FeeAndCommissionIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income recognised from credit-related fees and commissions. [Refer: Fee and commission income]" } }, "en-us": { "role": { "label": "Credit-related fee and commission income", "terseLabel": "Facility fees" } } }, "localname": "CreditrelatedFeeAndCommissionIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CurrencyRiskMember": { "auth_ref": [ "r346", "r375", "r376", "r377", "r378" ], "lang": { "en": { "role": { "documentation": "This member stands for a type of market risk representing the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in foreign exchange rates. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Currency Risk [Member]", "terseLabel": "FX risk" } } }, "localname": "CurrencyRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CurrencySwapContractMember": { "auth_ref": [ "r12" ], "lang": { "en": { "role": { "documentation": "This member stands for a currency swap contract. [Refer: Swap contract [member]]" } }, "en-us": { "role": { "label": "Currency Swap Contract [Member]", "terseLabel": "Cross currency swap" } } }, "localname": "CurrencySwapContractMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CurrentDebtInstrumentsIssued": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails": { "order": 1.0, "parentTag": "ifrs-full_DebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of current debt instruments issued. [Refer: Debt instruments issued]" } }, "en-us": { "role": { "label": "Current debt instruments issued", "terseLabel": "Short-term debt" } } }, "localname": "CurrentDebtInstrumentsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CurrentEstimateOfFutureCashOutflowsToBePaidToFulfilObligationMeasurementInputMember": { "auth_ref": [ "r235" ], "lang": { "en": { "role": { "documentation": "This member stands for the current estimate of future cash outflows to be paid to fulfil obligation, used as a measurement input." } }, "en-us": { "role": { "label": "Current Estimate Of Future Cash Outflows To Be Paid To Fulfil Obligation Measurement Input [Member]", "terseLabel": "Cash flows" } } }, "localname": "CurrentEstimateOfFutureCashOutflowsToBePaidToFulfilObligationMeasurementInputMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_CurrentTaxAssets": { "auth_ref": [ "r25" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 8.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The excess of amount paid for current tax in respect of current and prior periods over the amount due for those periods. Current tax is the amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period." } }, "en-us": { "role": { "label": "Current tax assets", "terseLabel": "Current tax assets" } } }, "localname": "CurrentTaxAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods": { "auth_ref": [ "r68" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails": { "order": 1.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of current tax expense (income) and adjustments for the current tax of prior periods. [Refer: Current tax expense (income); Adjustments for current tax of prior periods]" } }, "en-us": { "role": { "label": "Current tax expense (income) and adjustments for current tax of prior periods", "terseLabel": "Current income tax" } } }, "localname": "CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_CurrentTaxLiabilities": { "auth_ref": [ "r25" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 6.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of current tax for current and prior periods to the extent unpaid. Current tax is the amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period." } }, "en-us": { "role": { "label": "Current tax liabilities", "terseLabel": "Current tax liabilities" } } }, "localname": "CurrentTaxLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DebtSecurities": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 5.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of instruments issued by the entity that represent indebtedness." } }, "en-us": { "role": { "label": "Debt instruments issued", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year", "terseLabel": "Debt issues", "totalLabel": "Total debt issues" } } }, "localname": "DebtSecurities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DebtSecuritiesMember": { "auth_ref": [ "r233", "r237" ], "lang": { "en": { "role": { "documentation": "This member stands for instruments held by the entity that represent indebtedness." } }, "en-us": { "role": { "label": "Debt Securities [Member]", "terseLabel": "Debt Securities" } } }, "localname": "DebtSecuritiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_DecreaseThroughClassifiedAsHeldForSaleGoodwill": { "auth_ref": [ "r260" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The decrease in goodwill due to classification as held for sale. [Refer: Goodwill; Disposal groups classified as held for sale [member]]" } }, "en-us": { "role": { "label": "Decrease through classified as held for sale, goodwill", "negatedLabel": "Disposals (refer to Note 36)" } } }, "localname": "DecreaseThroughClassifiedAsHeldForSaleGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DecreaseThroughTransferToLiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSaleOtherProvisions": { "auth_ref": [ "r143" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The decrease in other provisions resulting from the transfer of those provisions to liabilities included in disposal groups classified as held for sale. [Refer: Other provisions; Disposal groups classified as held for sale [member]]" } }, "en-us": { "role": { "label": "Decrease through transfer to liabilities included in disposal groups classified as held for sale, other provisions", "negatedLabel": "Balances reclassified to liabilities held for sale" } } }, "localname": "DecreaseThroughTransferToLiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSaleOtherProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DecreaseThroughWriteoffFinancialAssets": { "auth_ref": [ "r300", "r301", "r339" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The decrease in financial assets resulting from write-off. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Decrease through write-off, financial assets", "negatedLabel": "Write-offs" } } }, "localname": "DecreaseThroughWriteoffFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DeferredTaxAssets": { "auth_ref": [ "r26", "r31", "r74" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails": { "order": 1.0, "parentTag": "ifrs-full_NetDeferredTaxAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]" } }, "en-us": { "role": { "label": "Deferred tax assets", "totalLabel": "Gross deferred tax assets" } } }, "localname": "DeferredTaxAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DeferredTaxExpenseIncome": { "auth_ref": [ "r75" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails": { "order": 2.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]" } }, "en-us": { "role": { "label": "Deferred tax expense (income)", "terseLabel": "Movement in deferred tax" } } }, "localname": "DeferredTaxExpenseIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DeferredTaxLiabilities": { "auth_ref": [ "r26", "r31", "r74" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_NetDeferredTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amounts of income taxes payable in future periods in respect of taxable temporary differences. [Refer: Temporary differences [member]]" } }, "en-us": { "role": { "label": "Deferred tax liabilities", "totalLabel": "Gross deferred tax liabilities" } } }, "localname": "DeferredTaxLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DefinedBenefitObligationAtPresentValue": { "auth_ref": [ "r97" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": 2.0, "parentTag": "ifrs-full_SurplusDeficitInPlan", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value]" } }, "en-us": { "role": { "label": "Defined benefit obligation, at present value", "verboseLabel": "Benefit obligation" } } }, "localname": "DefinedBenefitObligationAtPresentValue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DefinedBenefitPlansAxis": { "auth_ref": [ "r85" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Defined benefit plans [axis]" } } }, "localname": "DefinedBenefitPlansAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DefinedBenefitPlansMember": { "auth_ref": [ "r85" ], "lang": { "en": { "role": { "documentation": "This member stands for post-employment benefit plans other than defined contribution plans. Defined contribution plans are post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods. It also represents the standard value for the 'Defined benefit plans' axis if no other member is used." } }, "en-us": { "role": { "label": "Defined Benefit Plans [Member]", "terseLabel": "Defined benefit plans [member]" } } }, "localname": "DefinedBenefitPlansMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_DerivativeFinancialAssets": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 4.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]" } }, "en-us": { "role": { "label": "Derivative financial assets", "terseLabel": "Derivative financial instruments", "totalLabel": "Total of net derivative assets" } } }, "localname": "DerivativeFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialAssetsHeldForHedging": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of derivative financial assets held for hedging. [Refer: Derivative financial assets]" } }, "en-us": { "role": { "label": "Derivative financial assets held for hedging", "totalLabel": "Total of net derivative assets, hedging", "verboseLabel": "Hedging Asset (carrying amount)" } } }, "localname": "DerivativeFinancialAssetsHeldForHedging", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialAssetsHeldForTrading": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of derivative financial assets held for trading. [Refer: Derivative financial assets; Financial assets at fair value through profit or loss, classified as held for trading]" } }, "en-us": { "role": { "label": "Derivative financial assets held for trading", "totalLabel": "Total of net derivative assets held, trading", "verboseLabel": "Trading Asset (carrying amount)" } } }, "localname": "DerivativeFinancialAssetsHeldForTrading", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialLiabilities": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 4.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]" } }, "en-us": { "role": { "label": "Derivative financial liabilities", "negatedTotalLabel": "Total of net derivative liabilities", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialLiabilitiesHeldForHedging": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of derivative financial liabilities held for hedging. [Refer: Derivative financial liabilities]" } }, "en-us": { "role": { "label": "Derivative financial liabilities held for hedging", "negatedTotalLabel": "Total of net derivative liabilities, hedging", "verboseLabel": "Hedging Liability (carrying amount)" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForHedging", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialLiabilitiesHeldForTrading": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of derivative financial liabilities held for trading. [Refer: Derivative financial liabilities; Financial liabilities at fair value through profit or loss that meet definition of held for trading]" } }, "en-us": { "role": { "label": "Derivative financial liabilities held for trading", "negatedTotalLabel": "Total of net derivative liabilities, trading", "verboseLabel": "Trading Liability (carrying amount)" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForTrading", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativeFinancialLiabilitiesUndiscountedCashFlows": { "auth_ref": [ "r309" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to derivative financial liabilities. [Refer: Derivative financial liabilities]" } }, "en-us": { "role": { "label": "Derivative financial liabilities, undiscounted cash flows", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialLiabilitiesUndiscountedCashFlows", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DerivativesMember": { "auth_ref": [ "r233", "r237", "r319", "r343" ], "lang": { "en": { "role": { "documentation": "This member stands for financial instruments or other contracts within the scope of IFRS 9 with all three of the following characteristics: (a) Their value changes in response to the change in a specified interest rate, financial instrument price, commodity price, foreign exchange rate, index of prices or rates, credit rating or credit index, or other variable, provided in the case of a non-financial variable that the variable is not specific to a party to the contract (sometimes called the \u2018underlying\u2019); (b) They require no initial net investment or an initial net investment that is smaller than would be required for other types of contracts that would be expected to have a similar response to changes in market factors; (c) They are settled at a future date. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Derivatives [Member]", "terseLabel": "Derivatives" } } }, "localname": "DerivativesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForBusinessCombinationsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for business combinations. [Refer: Business combinations [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for business combinations [text block]", "terseLabel": "Business combinations" } } }, "localname": "DescriptionOfAccountingPolicyForBusinessCombinationsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForCashFlowsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for cash flows." } }, "en-us": { "role": { "label": "Description of accounting policy for cash flows [text block]", "terseLabel": "Notes to the cash flow statements" } } }, "localname": "DescriptionOfAccountingPolicyForCashFlowsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForDerivativeFinancialInstrumentsAndHedgingExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for derivative financial instruments and hedging. [Refer: Financial instruments, class [member]; Derivatives [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for derivative financial instruments and hedging [text block]", "terseLabel": "Derivative financial instruments" } } }, "localname": "DescriptionOfAccountingPolicyForDerivativeFinancialInstrumentsAndHedgingExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForEarningsPerShareExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for earnings per share." } }, "en-us": { "role": { "label": "Description of accounting policy for earnings per share [text block]", "terseLabel": "Earnings per share" } } }, "localname": "DescriptionOfAccountingPolicyForEarningsPerShareExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForFairValueMeasurementExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for fair value measurement. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for fair value measurement [text block]", "terseLabel": "Fair values of financial assets and financial liabilities" } } }, "localname": "DescriptionOfAccountingPolicyForFairValueMeasurementExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForFinancialInstrumentsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for financial instruments. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for financial instruments [text block]", "terseLabel": "Financial Assets and Financial Liabilities" } } }, "localname": "DescriptionOfAccountingPolicyForFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForForeignCurrencyTranslationExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for foreign currency translation." } }, "en-us": { "role": { "label": "Description of accounting policy for foreign currency translation [text block]", "terseLabel": "Foreign currency translation" } } }, "localname": "DescriptionOfAccountingPolicyForForeignCurrencyTranslationExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForImpairmentOfAssetsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for the impairment of assets." } }, "en-us": { "role": { "label": "Description of accounting policy for impairment of assets [text block]", "terseLabel": "Impairment charges" } } }, "localname": "DescriptionOfAccountingPolicyForImpairmentOfAssetsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForImpairmentOfFinancialAssetsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for the impairment of financial assets. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Description of accounting policy for impairment of financial assets [text block]", "terseLabel": "Provisions for expected credit losses" } } }, "localname": "DescriptionOfAccountingPolicyForImpairmentOfFinancialAssetsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForIncomeTaxExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for income tax." } }, "en-us": { "role": { "label": "Description of accounting policy for income tax [text block]", "terseLabel": "Income tax" } } }, "localname": "DescriptionOfAccountingPolicyForIncomeTaxExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForInsuranceContracts": { "auth_ref": [ "r13", "r393" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for insurance contracts and related assets, liabilities, income and expense. [Refer: Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for insurance contracts and related assets, liabilities, income and expense [text block]", "terseLabel": "Life insurance assets and life insurance liabilities" } } }, "localname": "DescriptionOfAccountingPolicyForInsuranceContracts", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for intangible assets and goodwill. [Refer: Intangible assets and goodwill]" } }, "en-us": { "role": { "label": "Description of accounting policy for intangible assets and goodwill [text block]", "verboseLabel": "Intangible assets" } } }, "localname": "DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForInterestIncomeAndExpenseExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for income and expense arising from interest." } }, "en-us": { "role": { "label": "Description of accounting policy for interest income and expense [text block]", "terseLabel": "Net interest income" } } }, "localname": "DescriptionOfAccountingPolicyForInterestIncomeAndExpenseExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethodExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for investments other than investments accounted for using the equity method. [Refer: Investments accounted for using equity method; Investments other than investments accounted for using equity method]" } }, "en-us": { "role": { "label": "Description of accounting policy for investments other than investments accounted for using equity method [text block]", "terseLabel": "Investment securities" } } }, "localname": "DescriptionOfAccountingPolicyForInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethodExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForLoansAndReceivablesExplanatory": { "auth_ref": [ "r389" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for loans and receivables. [Refer: Loans and receivables]" } }, "en-us": { "role": { "label": "Description of accounting policy for loans and receivables [text block]", "terseLabel": "Loans" } } }, "localname": "DescriptionOfAccountingPolicyForLoansAndReceivablesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for non-current assets or disposal groups classified as held for sale. [Refer: Non-current assets or disposal groups classified as held for sale]" } }, "en-us": { "role": { "label": "Description of accounting policy for non-current assets or disposal groups classified as held for sale [text block]", "terseLabel": "Assets and liabilities held for sale" } } }, "localname": "DescriptionOfAccountingPolicyForNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForOffsettingOfFinancialInstrumentsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for the offsetting of financial instruments. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for offsetting of financial instruments [text block]", "terseLabel": "Offsetting financial assets and financial liabilities" } } }, "localname": "DescriptionOfAccountingPolicyForOffsettingOfFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForProvisionsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for provisions. [Refer: Provisions]" } }, "en-us": { "role": { "label": "Description of accounting policy for provisions [text block]", "terseLabel": "Provisions, contingent liabilities, contingent assets and credit commitments" } } }, "localname": "DescriptionOfAccountingPolicyForProvisionsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForSegmentReportingExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for segment reporting." } }, "en-us": { "role": { "label": "Description of accounting policy for segment reporting [text block]", "terseLabel": "Segment reporting" } } }, "localname": "DescriptionOfAccountingPolicyForSegmentReportingExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfAccountingPolicyForSharebasedPaymentTransactionsExplanatory": { "auth_ref": [ "r13" ], "lang": { "en": { "role": { "documentation": "The description of the entity's accounting policy for transactions in which the entity: (a) receives goods or services from the supplier of those goods or services (including an employee) in a share-based payment arrangement; or (b) incurs an obligation to settle the transaction with the supplier in a share-based payment arrangement when another group entity receives those goods or services. [Refer: Share-based payment arrangements [member]]" } }, "en-us": { "role": { "label": "Description of accounting policy for share-based payment transactions [text block]", "terseLabel": "Share-based payments" } } }, "localname": "DescriptionOfAccountingPolicyForSharebasedPaymentTransactionsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfExpectedImpactOfInitialApplicationOfNewStandardsOrInterpretations": { "auth_ref": [ "r192" ], "lang": { "en": { "role": { "documentation": "The disclosure of the known or reasonably estimable information relevant to assessing the possible impact that the application of a new IFRS, that has been issued but is not yet effective, will have." } }, "en-us": { "role": { "label": "Disclosure of expected impact of initial application of new standards or interpretations [text block]", "terseLabel": "Future developments in accounting standards" } } }, "localname": "DescriptionOfExpectedImpactOfInitialApplicationOfNewStandardsOrInterpretations", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfExpectedVolatilityShareOptionsGranted": { "auth_ref": [ "r257" ], "lang": { "en": { "role": { "documentation": "The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time." } }, "en-us": { "role": { "label": "Expected volatility, share options granted", "terseLabel": "Volatility rate" } } }, "localname": "DescriptionOfExpectedVolatilityShareOptionsGranted", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_DescriptionOfGrowthRateUsedToExtrapolateCashFlowProjections": { "auth_ref": [ "r134", "r135" ], "lang": { "en": { "role": { "documentation": "The growth rate used to extrapolate cash flow projections beyond the period covered by the most recent budgets/forecasts for a cash-generating unit (group of units). [Refer: Cash-generating units [member]]" } }, "en-us": { "role": { "label": "Growth rate used to extrapolate cash flow projections", "terseLabel": "Terminal growth rate" } } }, "localname": "DescriptionOfGrowthRateUsedToExtrapolateCashFlowProjections", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_DescriptionOfInitialApplicationOfStandardsOrInterpretations": { "auth_ref": [ "r190" ], "lang": { "en": { "role": { "documentation": "The disclosure of the initial application of an IFRS. [Refer: IFRSs [member]]" } }, "en-us": { "role": { "label": "Disclosure of initial application of standards or interpretations [text block]", "verboseLabel": "Standards adopted during the year ended 30 September 2021" } } }, "localname": "DescriptionOfInitialApplicationOfStandardsOrInterpretations", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfManagingLiquidityRisk": { "auth_ref": [ "r310" ], "lang": { "en": { "role": { "documentation": "The disclosure of how the entity manages its liquidity risk. [Refer: Liquidity risk [member]]" } }, "en-us": { "role": { "label": "Disclosure of how entity manages liquidity risk [text block]", "terseLabel": "Summary of the Group's liquid asset holdings" } } }, "localname": "DescriptionOfManagingLiquidityRisk", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DescriptionOfRiskFreeInterestRateShareOptionsGranted": { "auth_ref": [ "r257" ], "lang": { "en": { "role": { "documentation": "The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]" } }, "en-us": { "role": { "label": "Risk free interest rate, share options granted", "terseLabel": "Risk-free rate" } } }, "localname": "DescriptionOfRiskFreeInterestRateShareOptionsGranted", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_DescriptionOfVoluntaryChangeInAccountingPolicy": { "auth_ref": [ "r191" ], "lang": { "en": { "role": { "documentation": "The disclosure of a voluntary change in accounting policy." } }, "en-us": { "role": { "label": "Disclosure of voluntary change in accounting policy [text block]", "terseLabel": "Schedule of change in accounting policy" } } }, "localname": "DescriptionOfVoluntaryChangeInAccountingPolicy", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DilutedEarningsLossPerShare": { "auth_ref": [ "r122" ], "lang": { "en": { "role": { "documentation": "The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator), divided by the weighted average number of ordinary shares outstanding during the period (the denominator), both adjusted for the effects of all dilutive potential ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]" } }, "en-us": { "role": { "label": "Diluted earnings (loss) per share", "terseLabel": "Diluted", "verboseLabel": "Earnings per ordinary share (cents) - Diluted" } } }, "localname": "DilutedEarningsLossPerShare", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "perShareItemType" }, "ifrs-full_DilutiveEffectOfConvertibleInstrumentsOnNumberOfOrdinaryShares": { "auth_ref": [ "r124" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 4.0, "parentTag": "ifrs-full_AdjustedWeightedAverageShares", "weight": 1.0 } }, "lang": { "en": { "role": { "documentation": "The number of dilutive potential ordinary shares that relate to the assumed conversion of the entity's convertible instruments." } }, "en-us": { "role": { "label": "Dilutive effect of convertible instruments on number of ordinary shares", "terseLabel": "Adjustment for potential dilution: Convertible loan capital" } } }, "localname": "DilutiveEffectOfConvertibleInstrumentsOnNumberOfOrdinaryShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "ifrs-full_DilutiveEffectOfShareOptionsOnNumberOfOrdinaryShares": { "auth_ref": [ "r124" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 3.0, "parentTag": "ifrs-full_AdjustedWeightedAverageShares", "weight": 1.0 } }, "lang": { "en": { "role": { "documentation": "The number of dilutive potential ordinary shares that relate to the assumed exercise of the entity's share options." } }, "en-us": { "role": { "label": "Dilutive effect of share options on number of ordinary shares", "terseLabel": "Adjustment for potential dilution: Share-based payments" } } }, "localname": "DilutiveEffectOfShareOptionsOnNumberOfOrdinaryShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "ifrs-full_DisclosureOfAccountingJudgementsAndEstimatesExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of judgements that management has made in the process of applying the entity's accounting policies that have the most significant effect on amounts recognised in the financial statements along with information about the assumptions that the entity makes about the future, and other major sources of estimation uncertainty at the end of the reporting period, that have a significant risk of resulting in a material adjustment to the carrying amounts of assets and liabilities within the next year. [Refer: Carrying amount [member]]" } }, "en-us": { "role": { "label": "Disclosure of accounting judgements and estimates [text block]", "terseLabel": "Critical accounting assumptions and estimates" } } }, "localname": "DisclosureOfAccountingJudgementsAndEstimatesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfAllowanceForCreditLossesExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of the allowance relating to impairments of financial assets due to credit losses. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Disclosure of allowance for credit losses [text block]", "verboseLabel": "Provisions for expected credit losses" } } }, "localname": "DisclosureOfAllowanceForCreditLossesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLosses" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfAmountsArisingFromInsuranceContractsExplanatory": { "auth_ref": [ "r392" ], "lang": { "en": { "role": { "documentation": "The disclosure of information that identifies and explains the amounts in the entity's financial statements arising from insurance contracts. [Refer: Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Disclosure of amounts arising from insurance contracts [text block]", "terseLabel": "Schedule of life insurance assets and life insurance liabilities" } } }, "localname": "DisclosureOfAmountsArisingFromInsuranceContractsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfAmountsToBeRecoveredOrSettledAfterTwelveMonthsForClassesOfAssetsAndLiabilitiesThatContainAmountsToBeRecoveredOrSettledBothNoMoreAndMoreThanTwelveMonthsAfterReportingDateLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of amounts to be recovered or settled after twelve months for classes of assets and liabilities that contain amounts to be recovered or settled both no more and more than twelve months after reporting date [line items]" } } }, "localname": "DisclosureOfAmountsToBeRecoveredOrSettledAfterTwelveMonthsForClassesOfAssetsAndLiabilitiesThatContainAmountsToBeRecoveredOrSettledBothNoMoreAndMoreThanTwelveMonthsAfterReportingDateLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfAmountsToBeRecoveredOrSettledAfterTwelveMonthsForClassesOfAssetsAndLiabilitiesThatContainAmountsToBeRecoveredOrSettledBothNoMoreAndMoreThanTwelveMonthsAfterReportingDateTable": { "auth_ref": [ "r34" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to amounts to be recovered or settled after twelve months for classes of assets and liabilities that contain amounts to be recovered or settled both no more, and more than, twelve months after reporting date." } }, "en-us": { "role": { "label": "Disclosure of amounts to be recovered or settled after twelve months for classes of assets and liabilities that contain amounts to be recovered or settled both no more and more than twelve months after reporting date [table]" } } }, "localname": "DisclosureOfAmountsToBeRecoveredOrSettledAfterTwelveMonthsForClassesOfAssetsAndLiabilitiesThatContainAmountsToBeRecoveredOrSettledBothNoMoreAndMoreThanTwelveMonthsAfterReportingDateTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Assets and liabilities held for sale" } } }, "localname": "DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of analysis of single amount of discontinued operations [line items]" } } }, "localname": "DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsTable": { "auth_ref": [ "r265" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the analysis of the single amount of discontinued operations." } }, "en-us": { "role": { "label": "Disclosure of analysis of single amount of discontinued operations [table]" } } }, "localname": "DisclosureOfAnalysisOfSingleAmountOfDiscontinuedOperationsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfAuditorsRemunerationExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of compensation to the entity's auditors." } }, "en-us": { "role": { "label": "Disclosure of auditors' remuneration [text block]", "verboseLabel": "Auditor's remuneration" } } }, "localname": "DisclosureOfAuditorsRemunerationExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemuneration" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of the basis used for the preparation of the financial statements." } }, "en-us": { "role": { "label": "Disclosure of basis of preparation of financial statements [text block]", "verboseLabel": "Financial statements preparation" } } }, "localname": "DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparation" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfBorrowingsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of borrowings. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Disclosure of borrowings [text block]", "terseLabel": "Schedule of debt issues and movement reconciliation" } } }, "localname": "DisclosureOfBorrowingsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfCashAndBankBalancesAtCentralBanksExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of cash and bank balances at central banks." } }, "en-us": { "role": { "label": "Disclosure of cash and bank balances at central banks [text block]", "terseLabel": "Schedule of cash and balances with central banks" } } }, "localname": "DisclosureOfCashAndBankBalancesAtCentralBanksExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToConsolidatedCashFlowStatementTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfCashFlowStatementExplanatory": { "auth_ref": [ "r189" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for a statement of cash flows." } }, "en-us": { "role": { "label": "Disclosure of cash flow statement [text block]", "terseLabel": "Notes to the cash flow statements" } } }, "localname": "DisclosureOfCashFlowStatementExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatements" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfChangesInAccountingEstimatesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of changes in accounting estimates [line items]", "terseLabel": "Financial statements preparation" } } }, "localname": "DisclosureOfChangesInAccountingEstimatesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfChangesInAccountingEstimatesTable": { "auth_ref": [ "r193" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the changes in accounting estimates." } }, "en-us": { "role": { "label": "Disclosure of changes in accounting estimates [table]" } } }, "localname": "DisclosureOfChangesInAccountingEstimatesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfClassesOfShareCapitalAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Shareholders' equity" } } }, "localname": "DisclosureOfClassesOfShareCapitalAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfClassesOfShareCapitalExplanatory": { "auth_ref": [ "r42" ], "lang": { "en": { "role": { "documentation": "The disclosure of classes of share capital. [Refer: Share capital [member]]" } }, "en-us": { "role": { "label": "Disclosure of classes of share capital [text block]", "terseLabel": "Summary of share capital by class" } } }, "localname": "DisclosureOfClassesOfShareCapitalExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfClassesOfShareCapitalLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of classes of share capital [line items]", "terseLabel": "Shareholders' equity" } } }, "localname": "DisclosureOfClassesOfShareCapitalLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfClassesOfShareCapitalTable": { "auth_ref": [ "r42" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to classes of share capital." } }, "en-us": { "role": { "label": "Disclosure of classes of share capital [table]" } } }, "localname": "DisclosureOfClassesOfShareCapitalTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfCommitmentsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of commitments." } }, "en-us": { "role": { "label": "Disclosure of commitments [text block]", "verboseLabel": "Summary of undrawn credit commitments and maturity analysis" } } }, "localname": "DisclosureOfCommitmentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfContingentLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Contingent liabilities, contingent assets and credit commitments", "terseLabel": "Contingent liabilities" } } }, "localname": "DisclosureOfContingentLiabilitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfContingentLiabilitiesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of contingent liabilities [line items]", "verboseLabel": "Contingent liabilities" } } }, "localname": "DisclosureOfContingentLiabilitiesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfContingentLiabilitiesTable": { "auth_ref": [ "r144" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to contingent liabilities." } }, "en-us": { "role": { "label": "Disclosure of contingent liabilities [table]" } } }, "localname": "DisclosureOfContingentLiabilitiesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfCreditRiskExplanatory": { "auth_ref": [ "r0", "r345" ], "lang": { "en": { "role": { "documentation": "The disclosure of credit risk. [Refer: Credit risk [member]]" } }, "en-us": { "role": { "label": "Disclosure of credit risk [text block]", "terseLabel": "Summary of credit concentrations for each significant class of financial asset" } } }, "localname": "DisclosureOfCreditRiskExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfCreditRiskExposureAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Disclosure of credit risk exposure [abstract]", "terseLabel": "Fair value related to credit risk" } } }, "localname": "DisclosureOfCreditRiskExposureAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfCreditRiskExposureLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of credit risk exposure [line items]", "terseLabel": "Financial risk" } } }, "localname": "DisclosureOfCreditRiskExposureLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfCreditRiskExposureTable": { "auth_ref": [ "r305" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the credit risk exposure." } }, "en-us": { "role": { "label": "Disclosure of credit risk exposure [table]" } } }, "localname": "DisclosureOfCreditRiskExposureTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDeferredTaxesExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of deferred taxes. [Refer: Deferred tax liabilities; Deferred tax assets]" } }, "en-us": { "role": { "label": "Disclosure of deferred taxes [text block]", "terseLabel": "Schedule of temporary differences attributable to deferred tax assets and deferred tax liabilities" } } }, "localname": "DisclosureOfDeferredTaxesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfDefinedBenefitPlansAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Superannuation commitments" } } }, "localname": "DisclosureOfDefinedBenefitPlansAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDefinedBenefitPlansLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of defined benefit plans [line items]", "terseLabel": "Superannuation commitments" } } }, "localname": "DisclosureOfDefinedBenefitPlansLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDefinedBenefitPlansTable": { "auth_ref": [ "r85" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to defined benefit plans." } }, "en-us": { "role": { "label": "Disclosure of defined benefit plans [table]" } } }, "localname": "DisclosureOfDefinedBenefitPlansTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDerivativeFinancialInstrumentsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of derivative financial instruments. [Refer: Derivatives [member]]" } }, "en-us": { "role": { "label": "Disclosure of derivative financial instruments [text block]", "terseLabel": "Derivative financial instruments" } } }, "localname": "DisclosureOfDerivativeFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstruments" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Debt issues" } } }, "localname": "DisclosureOfDetailedInformationAboutBorrowingsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsExplanatory": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "The disclosure of detailed information about borrowings. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Disclosure of detailed information about borrowings [text block]", "verboseLabel": "Debt issues" } } }, "localname": "DisclosureOfDetailedInformationAboutBorrowingsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssues" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of detailed information about borrowings [line items]", "terseLabel": "Debt issues", "verboseLabel": "Loan capital" } } }, "localname": "DisclosureOfDetailedInformationAboutBorrowingsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to details of borrowings." } }, "en-us": { "role": { "label": "Disclosure of detailed information about borrowings [table]" } } }, "localname": "DisclosureOfDetailedInformationAboutBorrowingsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutHedgedItemsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of detailed information about hedged items [line items]", "terseLabel": "Derivative financial instruments" } } }, "localname": "DisclosureOfDetailedInformationAboutHedgedItemsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutHedgedItemsTable": { "auth_ref": [ "r289" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to details of hedged items." } }, "en-us": { "role": { "label": "Disclosure of detailed information about hedged items [table]" } } }, "localname": "DisclosureOfDetailedInformationAboutHedgedItemsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory": { "auth_ref": [ "r282" ], "lang": { "en": { "role": { "documentation": "The disclosure of detailed information about hedging instruments. [Refer: Hedging instruments [member]]" } }, "en-us": { "role": { "label": "Disclosure of detailed information about hedging instruments [text block]", "terseLabel": "Schedule of carrying values, and maturity analysis of notional amounts of hedging instruments" } } }, "localname": "DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfDividendsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of dividends. Dividends are distributions of profits to holders of equity investments in proportion to their holdings of a particular class of capital." } }, "en-us": { "role": { "label": "Disclosure of dividends [text block]", "terseLabel": "Dividends" } } }, "localname": "DisclosureOfDividendsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividends" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfEarningsPerShareExplanatory": { "auth_ref": [ "r125" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for earnings per share." } }, "en-us": { "role": { "label": "Disclosure of earnings per share [text block]", "terseLabel": "Earnings per share" } } }, "localname": "DisclosureOfEarningsPerShareExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShare" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfEmployeeBenefitsExplanatory": { "auth_ref": [ "r98" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for employee benefits." } }, "en-us": { "role": { "label": "Disclosure of employee benefits [text block]", "terseLabel": "Superannuation commitments" } } }, "localname": "DisclosureOfEmployeeBenefitsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitments" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfEntitysReportableSegmentsExplanatory": { "auth_ref": [ "r367" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for operating segments." } }, "en-us": { "role": { "label": "Disclosure of entity's operating segments [text block]", "terseLabel": "Segment reporting" } } }, "localname": "DisclosureOfEntitysReportableSegmentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReporting" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfEventsAfterReportingPeriodExplanatory": { "auth_ref": [ "r66" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for events after the reporting period." } }, "en-us": { "role": { "label": "Disclosure of events after reporting period [text block]", "terseLabel": "Subsequent events" } } }, "localname": "DisclosureOfEventsAfterReportingPeriodExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSubsequentEvents" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfExpensesByNatureExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of expenses by nature. [Refer: Expenses, by nature]" } }, "en-us": { "role": { "label": "Disclosure of expenses by nature [text block]", "terseLabel": "Schedule of operating expenses" } } }, "localname": "DisclosureOfExpensesByNatureExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfExpensesExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of expenses." } }, "en-us": { "role": { "label": "Disclosure of expenses [text block]", "terseLabel": "Operating expenses" } } }, "localname": "DisclosureOfExpensesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpenses" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFairValueMeasurementExplanatory": { "auth_ref": [ "r239" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for fair value measurement." } }, "en-us": { "role": { "label": "Disclosure of fair value measurement [text block]", "verboseLabel": "Fair values of financial assets and financial liabilities" } } }, "localname": "DisclosureOfFairValueMeasurementExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilities" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFairValueOfFinancialInstrumentsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of the fair value of financial instruments. [Refer: Financial instruments, class [member]; At fair value [member]]" } }, "en-us": { "role": { "label": "Disclosure of fair value of financial instruments [text block]", "verboseLabel": "Summary of the attribution of financial instruments measured at fair value to the fair value hierarchy" } } }, "localname": "DisclosureOfFairValueOfFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFairValueOfPlanAssetsExplanatory": { "auth_ref": [ "r88" ], "lang": { "en": { "role": { "documentation": "The disclosure of the fair value of defined benefit plan assets. [Refer: Plan assets [member]; Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Disclosure of fair value of plan assets [text block]", "terseLabel": "Schedule of asset allocation" } } }, "localname": "DisclosureOfFairValueOfPlanAssetsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFinancialAssetsHeldForTradingExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of financial assets classified as held for trading. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Disclosure of financial assets held for trading [text block]", "terseLabel": "Schedule of trading securities and financial assets measured at FVIS" } } }, "localname": "DisclosureOfFinancialAssetsHeldForTradingExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFinancialAssetsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of financial assets [line items]", "terseLabel": "Financial assets" } } }, "localname": "DisclosureOfFinancialAssetsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsTable": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to financial assets." } }, "en-us": { "role": { "label": "Disclosure of financial assets [table]" } } }, "localname": "DisclosureOfFinancialAssetsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of financial assets that are either past due or impaired [line items]", "terseLabel": "Provisions for expected credit losses/impairment charges" } } }, "localname": "DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedTable": { "auth_ref": [ "r410" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to financial assets that are either past due or impaired." } }, "en-us": { "role": { "label": "Disclosure of financial assets that are either past due or impaired [table]" } } }, "localname": "DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Securitisation, covered bonds and other transferred assets" } } }, "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory": { "auth_ref": [ "r316" ], "lang": { "en": { "role": { "documentation": "The disclosure of transferred financial assets that are not derecognised in their entirety. [Refer: Transferred financial assets that are not derecognised in their entirety [member]]" } }, "en-us": { "role": { "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [text block]", "terseLabel": "Schedule of assets transferred and the associated liabilities" } } }, "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [line items]", "terseLabel": "Securitisation, covered bonds and other transferred assets" } } }, "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionTable": { "auth_ref": [ "r316" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to transferred financial assets that are not derecognised in their entirety." } }, "en-us": { "role": { "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [table]" } } }, "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialInstrumentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Derivative financial instruments" } } }, "localname": "DisclosureOfFinancialInstrumentsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialInstrumentsByTypeOfInterestRateExplanatory": { "auth_ref": [ "r311" ], "lang": { "en": { "role": { "documentation": "The disclosure of financial instruments by type of interest rate. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Disclosure of financial instruments by type of interest rate [text block]", "terseLabel": "Schedule of interest rate segmentation of loans maturing after one year" } } }, "localname": "DisclosureOfFinancialInstrumentsByTypeOfInterestRateExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFinancialInstrumentsExplanatory": { "auth_ref": [ "r348" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for financial instruments." } }, "en-us": { "role": { "label": "Disclosure of financial instruments [text block]", "terseLabel": "Investment securities" } } }, "localname": "DisclosureOfFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecurities" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfFinancialInstrumentsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of detailed information about financial instruments [line items]", "terseLabel": "Fair values of financial assets and financial liabilities", "verboseLabel": "Financial instruments" } } }, "localname": "DisclosureOfFinancialInstrumentsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialInstrumentsTable": { "auth_ref": [ "r296", "r304", "r320" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to details of financial instruments." } }, "en-us": { "role": { "label": "Disclosure of detailed information about financial instruments [table]" } } }, "localname": "DisclosureOfFinancialInstrumentsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialLiabilitiesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of financial liabilities [line items]", "terseLabel": "Other financial liabilities" } } }, "localname": "DisclosureOfFinancialLiabilitiesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialLiabilitiesTable": { "auth_ref": [ "r320" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to financial liabilities." } }, "en-us": { "role": { "label": "Disclosure of financial liabilities [table]" } } }, "localname": "DisclosureOfFinancialLiabilitiesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfFinancialRiskManagementExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of the entity's financial risk management practices and policies." } }, "en-us": { "role": { "label": "Disclosure of financial risk management [text block]", "verboseLabel": "Financial risk" } } }, "localname": "DisclosureOfFinancialRiskManagementExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRisk" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfGeographicalAreasExplanatory": { "auth_ref": [ "r365" ], "lang": { "en": { "role": { "documentation": "The disclosure of geographical information." } }, "en-us": { "role": { "label": "Disclosure of geographical areas [text block]", "terseLabel": "Schedule of geographic segments" } } }, "localname": "DisclosureOfGeographicalAreasExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfGeographicalAreasLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of geographical areas [line items]", "terseLabel": "Geographic segments" } } }, "localname": "DisclosureOfGeographicalAreasLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfGeographicalAreasTable": { "auth_ref": [ "r365" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to geographical areas." } }, "en-us": { "role": { "label": "Disclosure of geographical areas [table]" } } }, "localname": "DisclosureOfGeographicalAreasTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfHedgeAccountingExplanatory": { "auth_ref": [ "r403" ], "lang": { "en": { "role": { "documentation": "The disclosure of hedge accounting." } }, "en-us": { "role": { "label": "Disclosure of hedge accounting [text block]", "terseLabel": "Schedule of impact of hedge accounting on the balance sheet and reserves" } } }, "localname": "DisclosureOfHedgeAccountingExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Impairment charges" } } }, "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory": { "auth_ref": [ "r127" ], "lang": { "en": { "role": { "documentation": "The disclosure of impairment loss and the reversal of impairment loss. [Refer: Impairment loss; Reversal of impairment loss]" } }, "en-us": { "role": { "label": "Disclosure of impairment loss and reversal of impairment loss [text block]", "verboseLabel": "Schedule of impairment charges" } } }, "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfImpairmentOfAssetsExplanatory": { "auth_ref": [ "r137" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for the impairment of assets." } }, "en-us": { "role": { "label": "Disclosure of impairment of assets [text block]", "terseLabel": "Impairment charges" } } }, "localname": "DisclosureOfImpairmentOfAssetsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentCharges" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfIncomeTaxExplanatory": { "auth_ref": [ "r77" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for income taxes." } }, "en-us": { "role": { "label": "Disclosure of income tax [text block]", "verboseLabel": "Income tax" } } }, "localname": "DisclosureOfIncomeTaxExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTax" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory": { "auth_ref": [ "r293" ], "lang": { "en": { "role": { "documentation": "The disclosure of information about amounts that affected the statement of comprehensive income as a result of hedge accounting." } }, "en-us": { "role": { "label": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [text block]", "terseLabel": "Schedule of information regarding determination of hedge effectiveness" } } }, "localname": "DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInformationAboutConsolidatedStructuredEntitiesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of information about consolidated structured entities [line items]", "terseLabel": "Structured entities" } } }, "localname": "DisclosureOfInformationAboutConsolidatedStructuredEntitiesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfInformationAboutConsolidatedStructuredEntitiesTable": { "auth_ref": [ "r223" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to consolidated structured entities." } }, "en-us": { "role": { "label": "Disclosure of information about consolidated structured entities [table]" } } }, "localname": "DisclosureOfInformationAboutConsolidatedStructuredEntitiesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory": { "auth_ref": [ "r207" ], "lang": { "en": { "role": { "documentation": "The disclosure of qualitative and quantitative information about the entity's interests in structured entities, including, but not limited to, the nature, purpose, size and activities of the structured entity and how the structured entity is financed." } }, "en-us": { "role": { "label": "Disclosure of information about interests in structured entity [text block]", "terseLabel": "Structured entities" } } }, "localname": "DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntities" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInformationAboutKeyManagementPersonnelExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of information about key management personnel. [Refer: Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Disclosure of information about key management personnel [text block]", "terseLabel": "Schedule of remuneration of KMP" } } }, "localname": "DisclosureOfInformationAboutKeyManagementPersonnelExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInsuranceContractsExplanatory": { "auth_ref": [ "r385", "r402" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for insurance contracts." } }, "en-us": { "role": { "label": "Disclosure of insurance contracts [text block]", "terseLabel": "Life insurance assets and life insurance liabilities" } } }, "localname": "DisclosureOfInsuranceContractsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilities" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfIntangibleAssetsAndGoodwillExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of intangible assets and goodwill. [Refer: Intangible assets and goodwill]" } }, "en-us": { "role": { "label": "Disclosure of intangible assets and goodwill [text block]", "terseLabel": "Intangible assets" } } }, "localname": "DisclosureOfIntangibleAssetsAndGoodwillExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssets" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfIntangibleAssetsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of detailed information about intangible assets [line items]", "terseLabel": "Intangible assets" } } }, "localname": "DisclosureOfIntangibleAssetsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfIntangibleAssetsTable": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to details of intangible assets." } }, "en-us": { "role": { "label": "Disclosure of detailed information about intangible assets [table]" } } }, "localname": "DisclosureOfIntangibleAssetsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfInterestIncomeExpenseExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of interest income and expense. [Refer: Interest income (expense)]" } }, "en-us": { "role": { "label": "Disclosure of interest income (expense) [text block]", "terseLabel": "Net interest income" } } }, "localname": "DisclosureOfInterestIncomeExpenseExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncome" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInterestsInOtherEntitiesExplanatory": { "auth_ref": [ "r200" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for interests in other entities." } }, "en-us": { "role": { "label": "Disclosure of interests in other entities [text block]", "terseLabel": "Investments in subsidiaries and associates" } } }, "localname": "DisclosureOfInterestsInOtherEntitiesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociates" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfInterestsInSubsidiariesExplanatory": { "auth_ref": [ "r206" ], "lang": { "en": { "role": { "documentation": "The disclosure of interests in subsidiaries. [Refer: Subsidiaries [member]]" } }, "en-us": { "role": { "label": "Disclosure of interests in subsidiaries [text block]", "terseLabel": "Summary of ownership percentage of controlled entities" } } }, "localname": "DisclosureOfInterestsInSubsidiariesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfLoansAndAdvancesToCustomersExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of loans and advances to customers. [Refer: Loans and advances to customers]" } }, "en-us": { "role": { "label": "Disclosure of loans and advances to customers [text block]", "terseLabel": "Loans" } } }, "localname": "DisclosureOfLoansAndAdvancesToCustomersExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoans" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of maturity analysis for derivative financial liabilities [line items]", "verboseLabel": "Contractual maturity of financial liabilities" } } }, "localname": "DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesTable": { "auth_ref": [ "r309" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the maturity analysis for derivative financial liabilities." } }, "en-us": { "role": { "label": "Disclosure of maturity analysis for derivative financial liabilities [table]" } } }, "localname": "DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of nature and extent of risks arising from financial instruments [line items]", "terseLabel": "Financial risk" } } }, "localname": "DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable": { "auth_ref": [ "r298", "r299" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the nature and extent of risks arising from financial instruments." } }, "en-us": { "role": { "label": "Disclosure of nature and extent of risks arising from financial instruments [table]" } } }, "localname": "DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory": { "auth_ref": [ "r86" ], "lang": { "en": { "role": { "documentation": "The disclosure of a net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]" } }, "en-us": { "role": { "label": "Disclosure of net defined benefit liability (asset) [text block]", "terseLabel": "Schedule of defined benefit balances recognised" } } }, "localname": "DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Subsequent events" } } }, "localname": "DisclosureOfNonadjustingEventsAfterReportingPeriodAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of non-adjusting events after reporting period [line items]", "terseLabel": "Subsequent events" } } }, "localname": "DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable": { "auth_ref": [ "r65" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to non-adjusting events after the reporting period." } }, "en-us": { "role": { "label": "Disclosure of non-adjusting events after reporting period [table]" } } }, "localname": "DisclosureOfNonadjustingEventsAfterReportingPeriodTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory": { "auth_ref": [ "r267" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for non-current assets held for sale and discontinued operations." } }, "en-us": { "role": { "label": "Disclosure of non-current assets held for sale and discontinued operations [text block]", "terseLabel": "Assets and liabilities held for sale" } } }, "localname": "DisclosureOfNoncurrentAssetsHeldForSaleAndDiscontinuedOperationsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSale" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of non-current assets or disposal groups classified as held for sale. [Refer: Non-current assets or disposal groups classified as held for sale]" } }, "en-us": { "role": { "label": "Disclosure of non-current assets or disposal groups classified as held for sale [text block]", "terseLabel": "Schedule of assets and liabilities that have been presented as held for sale" } } }, "localname": "DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory": { "auth_ref": [ "r14" ], "lang": { "en": { "role": { "documentation": "The disclosure of information that enables users of financial statements to evaluate the entity's objectives, policies and processes for managing capital." } }, "en-us": { "role": { "label": "Disclosure of objectives, policies and processes for managing capital [text block]", "terseLabel": "Shareholders' equity" } } }, "localname": "DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory": { "auth_ref": [ "r347" ], "lang": { "en": { "role": { "documentation": "The disclosure of the offsetting of financial assets and financial liabilities. [Refer: Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Disclosure of offsetting of financial assets and financial liabilities [text block]", "terseLabel": "Offsetting financial assets and financial liabilities" } } }, "localname": "DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilities" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfOperatingSegmentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Segment reporting" } } }, "localname": "DisclosureOfOperatingSegmentsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfOperatingSegmentsExplanatory": { "auth_ref": [ "r355" ], "lang": { "en": { "role": { "documentation": "The disclosure of operating segments. [Refer: Operating segments [member]]" } }, "en-us": { "role": { "label": "Disclosure of operating segments [text block]", "terseLabel": "Schedule of segment results on a cash earnings basis" } } }, "localname": "DisclosureOfOperatingSegmentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfOperatingSegmentsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of operating segments [line items]", "terseLabel": "Segment reporting" } } }, "localname": "DisclosureOfOperatingSegmentsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfOperatingSegmentsTable": { "auth_ref": [ "r355" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to operating segments." } }, "en-us": { "role": { "label": "Disclosure of operating segments [table]" } } }, "localname": "DisclosureOfOperatingSegmentsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfOtherOperatingIncomeExpenseExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of other operating income or expense. [Refer: Other operating income (expense)]" } }, "en-us": { "role": { "label": "Disclosure of other operating income (expense) [text block]", "terseLabel": "Non-interest income" } } }, "localname": "DisclosureOfOtherOperatingIncomeExpenseExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncome" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfOtherProvisionsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Disclosure of other provisions [abstract]", "terseLabel": "Provisions" } } }, "localname": "DisclosureOfOtherProvisionsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfOtherProvisionsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of other provisions [line items]", "terseLabel": "Provisions, contingent liabilities, contingent assets and credit commitments" } } }, "localname": "DisclosureOfOtherProvisionsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfOtherProvisionsTable": { "auth_ref": [ "r143" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to other provisions." } }, "en-us": { "role": { "label": "Disclosure of other provisions [table]" } } }, "localname": "DisclosureOfOtherProvisionsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfProvisionsExplanatory": { "auth_ref": [ "r0" ], "lang": { "en": { "role": { "documentation": "The disclosure of provisions. [Refer: Provisions]" } }, "en-us": { "role": { "label": "Disclosure of provisions [text block]", "terseLabel": "Schedule of changes in provisions" } } }, "localname": "DisclosureOfProvisionsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfReclassificationsOrChangesInPresentationAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Disclosure of reclassifications or changes in presentation [abstract]", "terseLabel": "Reclassifications" } } }, "localname": "DisclosureOfReclassificationsOrChangesInPresentationAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInGoodwillLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in goodwill [line items]", "terseLabel": "Goodwill allocation" } } }, "localname": "DisclosureOfReconciliationOfChangesInGoodwillLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInGoodwillTable": { "auth_ref": [ "r263" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the reconciliation of changes in goodwill." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in goodwill [table]" } } }, "localname": "DisclosureOfReconciliationOfChangesInGoodwillTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "The disclosure of the reconciliation of changes in intangible assets and goodwill. [Refer: Intangible assets and goodwill]" } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in intangible assets and goodwill [text block]", "terseLabel": "Schedule of goodwill and intangible assets" } } }, "localname": "DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in intangible assets and goodwill [line items]", "terseLabel": "Intangible assets" } } }, "localname": "DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillTable": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the reconciliation of changes in intangible assets and goodwill." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in intangible assets and goodwill [table]" } } }, "localname": "DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsExplanatory": { "auth_ref": [ "r300", "r302" ], "lang": { "en": { "role": { "documentation": "The disclosure of the reconciliation of changes in the loss allowance and explanation of changes in the gross carrying amount for financial instruments. Loss allowance is the allowance for expected credit losses on financial assets measured in accordance with paragraph 4.1.2 of IFRS 9, lease receivables and contract assets, the accumulated impairment amount for financial assets measured in accordance with paragraph 4.1.2A of IFRS 9 and the provision for expected credit losses on loan commitments and financial guarantee contracts. [Refer: Gross carrying amount [member]]" } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [text block]", "terseLabel": "Summary and changes in the provision for ECL" } } }, "localname": "DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]", "terseLabel": "Provisions for expected credit losses", "verboseLabel": "Impairment charges" } } }, "localname": "DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsTable": { "auth_ref": [ "r300", "r302" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to the reconciliation of changes in the loss allowance and explanation of changes in the gross carrying amount for financial instruments." } }, "en-us": { "role": { "label": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [table]" } } }, "localname": "DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfRelatedPartyExplanatory": { "auth_ref": [ "r111" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for related parties." } }, "en-us": { "role": { "label": "Disclosure of related party [text block]", "terseLabel": "Related party disclosures" } } }, "localname": "DisclosureOfRelatedPartyExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosures" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfReservesAndOtherEquityInterestExplanatory": { "auth_ref": [ "r43" ], "lang": { "en": { "role": { "documentation": "The disclosure of reserves within equity. [Refer: Other reserves [member]]" } }, "en-us": { "role": { "label": "Disclosure of reserves within equity [text block]", "terseLabel": "Schedule of reconciliation of movement in reserves" } } }, "localname": "DisclosureOfReservesAndOtherEquityInterestExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfReservesWithinEquityLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of reserves within equity [line items]", "terseLabel": "Shareholders' equity" } } }, "localname": "DisclosureOfReservesWithinEquityLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfReservesWithinEquityTable": { "auth_ref": [ "r43" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to reserves within equity." } }, "en-us": { "role": { "label": "Disclosure of reserves within equity [table]" } } }, "localname": "DisclosureOfReservesWithinEquityTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Disclosure of risk management strategy related to hedge accounting [abstract]", "terseLabel": "Determination of hedge effectiveness" } } }, "localname": "DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory": { "auth_ref": [ "r91" ], "lang": { "en": { "role": { "documentation": "The disclosure of a sensitivity analysis for significant actuarial assumptions used to determine the present value of a defined benefit obligation. [Refer: Actuarial assumptions [member]; Defined benefit obligation, at present value]" } }, "en-us": { "role": { "label": "Disclosure of sensitivity analysis of essential assumptions [Table Text Block]", "terseLabel": "Summary of sensitivity analysis of essential assumptions" } } }, "localname": "DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory": { "auth_ref": [ "r44" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for share capital, reserves and other equity interest." } }, "en-us": { "role": { "label": "Disclosure of share capital, reserves and other equity interest [text block]", "verboseLabel": "Shareholders' equity" } } }, "localname": "DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquity" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfSharebasedPaymentArrangementsExplanatory": { "auth_ref": [ "r251" ], "lang": { "en": { "role": { "documentation": "The entire disclosure for share-based payment arrangements." } }, "en-us": { "role": { "label": "Disclosure of share-based payment arrangements [text block]", "terseLabel": "Share-based payments" } } }, "localname": "DisclosureOfSharebasedPaymentArrangementsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPayments" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of subsidiaries [line items]", "terseLabel": "Investments in subsidiaries and associates" } } }, "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable": { "auth_ref": [ "r118", "r120", "r221" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to subsidiaries." } }, "en-us": { "role": { "label": "Disclosure of subsidiaries [table]" } } }, "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of temporary difference, unused tax losses and unused tax credits [line items]", "terseLabel": "Deferred tax assets", "verboseLabel": "Deferred tax liabilities" } } }, "localname": "DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable": { "auth_ref": [ "r76" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to temporary differences, unused tax losses and unused tax credits." } }, "en-us": { "role": { "label": "Disclosure of temporary difference, unused tax losses and unused tax credits [table]" } } }, "localname": "DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Share-based payments" } } }, "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The disclosure of the general terms and conditions of share-based payment arrangements. [Refer: Share-based payment arrangements [member]]" } }, "en-us": { "role": { "label": "Disclosure of terms and conditions of share-based payment arrangement [text block]", "terseLabel": "Summary of terms and conditions of share-based payment arrangements" } } }, "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of terms and conditions of share-based payment arrangement [line items]", "terseLabel": "Share-based payments" } } }, "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to terms and conditions of share-based payment arrangements." } }, "en-us": { "role": { "label": "Disclosure of terms and conditions of share-based payment arrangement [table]" } } }, "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Related party disclosures" } } }, "localname": "DisclosureOfTransactionsBetweenRelatedPartiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesExplanatory": { "auth_ref": [ "r107" ], "lang": { "en": { "role": { "documentation": "The disclosure of transactions between the entity and its related parties. [Refer: Related parties [member]]" } }, "en-us": { "role": { "label": "Disclosure of transactions between related parties [text block]", "terseLabel": "Schedule of loans provided and interest charged to KMP and their related parties" } } }, "localname": "DisclosureOfTransactionsBetweenRelatedPartiesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of transactions between related parties [line items]", "terseLabel": "Related party disclosures", "verboseLabel": "Related party disclosures" } } }, "localname": "DisclosureOfTransactionsBetweenRelatedPartiesLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesTable": { "auth_ref": [ "r109" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to transactions between related parties." } }, "en-us": { "role": { "label": "Disclosure of transactions between related parties [table]" } } }, "localname": "DisclosureOfTransactionsBetweenRelatedPartiesTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTransfersOfFinancialAssetsExplanatory": { "auth_ref": [ "r349" ], "lang": { "en": { "role": { "documentation": "The disclosure of transfers of financial assets. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Disclosure of transfers of financial assets [text block]", "terseLabel": "Securitisation, covered bonds and other transferred assets" } } }, "localname": "DisclosureOfTransfersOfFinancialAssetsExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssets" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfTypesOfInsuranceContractsLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of types of insurance contracts [line items]", "terseLabel": "Investments held directly and in unit trusts", "verboseLabel": "Life insurance liabilities" } } }, "localname": "DisclosureOfTypesOfInsuranceContractsLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfTypesOfInsuranceContractsTable": { "auth_ref": [ "r402" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to types of insurance contracts." } }, "en-us": { "role": { "label": "Disclosure of types of insurance contracts [table]" } } }, "localname": "DisclosureOfTypesOfInsuranceContractsTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfUnconsolidatedStructuredEntitiesExplanatory": { "auth_ref": [ "r222" ], "lang": { "en": { "role": { "documentation": "The disclosure of unconsolidated structured entities. [Refer: Unconsolidated structured entities [member]]" } }, "en-us": { "role": { "label": "Disclosure of unconsolidated structured entities [text block]", "terseLabel": "Schedule of the Group's interests in unconsolidated structured entities and its maximum exposure to loss in relation to those interests" } } }, "localname": "DisclosureOfUnconsolidatedStructuredEntitiesExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_DisclosureOfVoluntaryChangeInAccountingPolicyLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Disclosure of voluntary change in accounting policy [line items]", "terseLabel": "Financial statements preparation" } } }, "localname": "DisclosureOfVoluntaryChangeInAccountingPolicyLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DisclosureOfVoluntaryChangeInAccountingPolicyTable": { "auth_ref": [ "r191" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to a voluntary change in accounting policy." } }, "en-us": { "role": { "label": "Disclosure of voluntary change in accounting policy [table]" } } }, "localname": "DisclosureOfVoluntaryChangeInAccountingPolicyTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_DiscountRateMeasurementInputMember": { "auth_ref": [ "r226" ], "lang": { "en": { "role": { "documentation": "This member stands for a discount rate used as a measurement input used in valuation techniques based on a present value calculation." } }, "en-us": { "role": { "label": "Discount Rate Measurement Input [Member]", "terseLabel": "Discount rate" } } }, "localname": "DiscountRateMeasurementInputMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_DividendsPaid": { "auth_ref": [ "r10" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 2.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of dividends recognised as distributions to owners." } }, "en-us": { "role": { "label": "Dividends recognised as distributions to owners", "negatedLabel": "Dividends on ordinary shares" } } }, "localname": "DividendsPaid", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DividendsPaidClassifiedAsFinancingActivities": { "auth_ref": [ "r184" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 11.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for dividends paid by the entity, classified as financing activities." } }, "en-us": { "role": { "label": "Dividends paid, classified as financing activities", "negatedLabel": "Payment of dividends" } } }, "localname": "DividendsPaidClassifiedAsFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DividendsPaidToNoncontrollingInterestsClassifiedAsFinancingActivities": { "auth_ref": [ "r178" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 12.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for dividends paid to non-controlling interests, classified as financing activities. [Refer: Non-controlling interests; Dividends paid to non-controlling interests]" } }, "en-us": { "role": { "label": "Dividends paid to non-controlling interests, classified as financing activities", "negatedLabel": "Dividends paid to NCI" } } }, "localname": "DividendsPaidToNoncontrollingInterestsClassifiedAsFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners": { "auth_ref": [ "r15", "r64" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDividendsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en": { "role": { "documentation": "The amount of dividends proposed or declared after the reporting period but before financial statements are authorised for issue. Such dividends are not recognised as a liability at the end of the reporting period because no obligation exists at that time." } }, "en-us": { "role": { "label": "Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners", "totalLabel": "Total dividends not recognised at year end", "verboseLabel": "Proposed dividend" } } }, "localname": "DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwnersPerShare": { "auth_ref": [ "r15" ], "lang": { "en": { "role": { "documentation": "The amount, per share, of dividends proposed or declared before financial statements were authorised for issue but not recognised as distribution to owners." } }, "en-us": { "role": { "label": "Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners per share", "terseLabel": "Final dividend per share" } } }, "localname": "DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwnersPerShare", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "perShareItemType" }, "ifrs-full_DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToCurrentYear": { "auth_ref": [ "r8" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of dividends relating to the current year, recognised as distributions to owners of the parent. [Refer: Parent [member]]" } }, "en-us": { "role": { "label": "Dividends recognised as distributions to owners of parent, relating to current year", "terseLabel": "Interim dividend" } } }, "localname": "DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToCurrentYear", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical" ], "xbrltype": "monetaryItemType" }, "ifrs-full_DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears": { "auth_ref": [ "r8" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDividendsDetails": { "order": 1.0, "parentTag": "ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of dividends relating to prior years, recognised as distributions to owners of the parent. [Refer: Parent [member]]" } }, "en-us": { "role": { "label": "Dividends recognised as distributions to owners of parent, relating to prior years", "terseLabel": "Final dividend", "verboseLabel": "Final dividend 60 cents per share (2020: 31 cents, 2019: 80 cents) all fully franked at 30%" } } }, "localname": "DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EarningsPerShareAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Earnings per share", "terseLabel": "Earnings per share (cents)" } } }, "localname": "EarningsPerShareAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "stringItemType" }, "ifrs-full_EarningsPerShareExplanatory": { "auth_ref": [ "r122" ], "lang": { "en": { "role": { "documentation": "The disclosure of earnings per share." } }, "en-us": { "role": { "label": "Earnings per share [text block]", "terseLabel": "Schedule of earnings per share" } } }, "localname": "EarningsPerShareExplanatory", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents": { "auth_ref": [ "r182", "r183" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The effect of exchange rate changes on cash and cash equivalents held or due in a foreign currency. [Refer: Cash and cash equivalents]" } }, "en-us": { "role": { "label": "Effect of exchange rate changes on cash and cash equivalents", "terseLabel": "Effect of exchange rate changes on cash and balances with central banks" } } }, "localname": "EffectOfExchangeRateChangesOnCashAndCashEquivalents", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EmployeeBenefitsExpense": { "auth_ref": [ "r1", "r3", "r62" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 1.0, "parentTag": "ifrs-full_OperatingExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The expense of all forms of consideration given by an entity in exchange for a service rendered by employees or for the termination of employment." } }, "en-us": { "role": { "label": "Employee benefits expense", "totalLabel": "Total staff expenses" } } }, "localname": "EmployeeBenefitsExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EmployeeContributions": { "auth_ref": [ "r113" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of employee contributions to retirement benefit plans." } }, "en-us": { "role": { "label": "Employee contributions", "terseLabel": "Member contributions" } } }, "localname": "EmployeeContributions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EmployerContributions": { "auth_ref": [ "r112" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of employer contributions to retirement benefit plans." } }, "en-us": { "role": { "label": "Employer contributions", "terseLabel": "Employer contributions" } } }, "localname": "EmployerContributions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EntitysTotalForConsolidatedStructuredEntitiesMember": { "auth_ref": [ "r223" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Consolidated structured entities' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Consolidated Structured Entities [Member]", "terseLabel": "Entity's total for consolidated structured entities [member]" } } }, "localname": "EntitysTotalForConsolidatedStructuredEntitiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForImpairmentOfFinancialAssetsMember": { "auth_ref": [ "r410" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Impairment of financial assets' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Impairment Of Financial Assets [Member]", "terseLabel": "Entity's total for impairment of financial assets [member]" } } }, "localname": "EntitysTotalForImpairmentOfFinancialAssetsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForIndividualAssetsOrCashgeneratingUnitsMember": { "auth_ref": [ "r132" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Individual assets or cash-generating units' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Individual Assets Or Cashgenerating Units [Member]", "terseLabel": "Entity's total for individual assets or cash-generating units [member]" } } }, "localname": "EntitysTotalForIndividualAssetsOrCashgeneratingUnitsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForInternalCreditGradesMember": { "auth_ref": [ "r305", "r340", "r396", "r407", "r412" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Internal credit grades' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Internal Credit Grades [Member]", "terseLabel": "Entity's total for internal credit grades [member]" } } }, "localname": "EntitysTotalForInternalCreditGradesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForRelatedPartiesMember": { "auth_ref": [ "r109" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Categories of related parties' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Related Parties [Member]", "terseLabel": "Entity's total for related parties [member]" } } }, "localname": "EntitysTotalForRelatedPartiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForSegmentConsolidationItemsMember": { "auth_ref": [ "r361" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Segment consolidation items' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Segment Consolidation Items [Member]", "terseLabel": "Entity's total for segment consolidation items [member]" } } }, "localname": "EntitysTotalForSegmentConsolidationItemsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForSubsidiariesMember": { "auth_ref": [ "r118", "r120", "r221" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Subsidiaries' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Subsidiaries [Member]", "terseLabel": "Entity's total for subsidiaries [member]" } } }, "localname": "EntitysTotalForSubsidiariesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EntitysTotalForUnconsolidatedSubsidiariesMember": { "auth_ref": [ "r205" ], "lang": { "en": { "role": { "documentation": "This member stands for the standard value for the 'Unconsolidated subsidiaries' axis if no other member is used." } }, "en-us": { "role": { "label": "Entitys Total For Unconsolidated Subsidiaries [Member]", "terseLabel": "Entity's total for unconsolidated subsidiaries [member]" } } }, "localname": "EntitysTotalForUnconsolidatedSubsidiariesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Equity": { "auth_ref": [ "r30", "r38", "r194", "r196", "r224", "r225", "r229" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of residual interest in the assets of the entity after deducting all its liabilities." } }, "en-us": { "role": { "label": "Equity.", "periodEndLabel": "Balance", "periodStartLabel": "Balance", "totalLabel": "Total shareholders' equity and NCI" } } }, "localname": "Equity", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Equity", "terseLabel": "Shareholders' equity" } } }, "localname": "EquityAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "stringItemType" }, "ifrs-full_EquityAttributableToOwnersOfParent": { "auth_ref": [ "r29" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "ifrs-full_Equity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of equity attributable to the owners of the parent. This specifically excludes non-controlling interest." } }, "en-us": { "role": { "label": "Equity attributable to owners of parent", "terseLabel": "Total equity attributable to owners of WBC", "totalLabel": "Total equity attributable to owners of WBC" } } }, "localname": "EquityAttributableToOwnersOfParent", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EquityAttributableToOwnersOfParentMember": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "This member stands for equity attributable to the owners of the parent." } }, "en-us": { "role": { "label": "Equity Attributable To Owners Of Parent [Member]", "terseLabel": "Total equity attributable to owners of WBC" } } }, "localname": "EquityAttributableToOwnersOfParentMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_EquityMember": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "This member stands for the residual interest in the assets of the entity after deducting all its liabilities. It also represents the standard value for the 'Components of equity' axis if no other member is used." } }, "en-us": { "role": { "label": "Equity [Member]", "terseLabel": "Equity [member]" } } }, "localname": "EquityMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_EquityPriceRiskMember": { "auth_ref": [ "r312", "r342" ], "lang": { "en": { "role": { "documentation": "This member stands for a component of other price risk that represents the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in equity prices. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Equity Price Risk [Member]", "terseLabel": "Equity risk" } } }, "localname": "EquityPriceRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_EstimateOfContributionsExpectedToBePaidToPlan": { "auth_ref": [ "r92", "r94" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The estimate of the expected contributions to be made to a defined benefit plan for the next annual reporting period. [Refer: Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Estimate of contributions expected to be paid to plan for next annual reporting period", "terseLabel": "Expected contribution from the employer" } } }, "localname": "EstimateOfContributionsExpectedToBePaidToPlan", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_EstimatedFinancialEffectOfContingentAssets": { "auth_ref": [ "r147" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of the estimated financial effect of possible assets that arise from past events and whose existence will be confirmed only by the occurrence or non-occurrence of one or more uncertain future events not wholly within control of the entity." } }, "en-us": { "role": { "label": "Estimated financial effect of contingent assets", "terseLabel": "Earn-out payments" } } }, "localname": "EstimatedFinancialEffectOfContingentAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ExchangeDifferencesOnTranslationAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Exchange differences on translation [abstract]", "terseLabel": "Foreign currency translation reserve" } } }, "localname": "ExchangeDifferencesOnTranslationAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ExpectedCreditLossesCollectivelyAssessedMember": { "auth_ref": [ "r300", "r302", "r339" ], "lang": { "en": { "role": { "documentation": "This member stands for expected credit losses that are collectively assessed. [Refer: Method of assessment of expected credit losses [member]]" } }, "en-us": { "role": { "label": "Expected Credit Losses Collectively Assessed [Member]", "terseLabel": "Collectively assessed" } } }, "localname": "ExpectedCreditLossesCollectivelyAssessedMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ExpectedCreditLossesIndividuallyAssessedMember": { "auth_ref": [ "r300", "r302", "r339" ], "lang": { "en": { "role": { "documentation": "This member stands for expected credit losses that are individually assessed. [Refer: Method of assessment of expected credit losses [member]]" } }, "en-us": { "role": { "label": "Expected Credit Losses Individually Assessed [Member]", "terseLabel": "Individually assessed" } } }, "localname": "ExpectedCreditLossesIndividuallyAssessedMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ExpenseArisingFromInsuranceContracts": { "auth_ref": [ "r394" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 3.0, "parentTag": "wbk_NetWealthManagementAndInsuranceIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense arising from insurance contracts. [Refer: Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Expense arising from insurance contracts", "negatedTotalLabel": "Total insurance claims, changes in insurance liabilities and other expenses" } } }, "localname": "ExpenseArisingFromInsuranceContracts", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ExpenseByNatureAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Expenses by nature [abstract]", "terseLabel": "Other expenses" } } }, "localname": "ExpenseByNatureAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 3.0, "parentTag": "ifrs-full_EmployeeBenefitsExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense from share-based payment transactions with employees." } }, "en-us": { "role": { "label": "Expense from share-based payment transactions with employees", "terseLabel": "Share-based payments" } } }, "localname": "ExpenseFromSharebasedPaymentTransactionsWithEmployees", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ExpenseIncomeIncludedInProfitOrLossLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued": { "auth_ref": [ "r395", "r401" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in liabilities under insurance contracts and reinsurance contracts issued resulting from expense or income included in profit or loss. [Refer: Liabilities under insurance contracts and reinsurance contracts issued]" } }, "en-us": { "role": { "label": "Expense (income) included in profit or loss, liabilities under insurance contracts and reinsurance contracts issued", "terseLabel": "Movements in policy liabilities reflected in the income statement" } } }, "localname": "ExpenseIncomeIncludedInProfitOrLossLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ExpenseOfRestructuringActivities": { "auth_ref": [ "r60" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 4.0, "parentTag": "ifrs-full_EmployeeBenefitsExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense relating to restructuring. Restructuring is a programme that is planned and controlled by management and materially changes either the scope of a business undertaken by an entity or the manner in which that business is conducted. Such programmes include: (a) the sale or termination of a line of business; (b) closure of business locations in a country or region or the relocation of activities from one country or region to another; (c) changes in management structure; and (d) fundamental reorganisations that have a material effect on the nature and focus of the entity's operations." } }, "en-us": { "role": { "label": "Expense of restructuring activities", "terseLabel": "Restructuring costs" } } }, "localname": "ExpenseOfRestructuringActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FairValueHedgesMember": { "auth_ref": [ "r159", "r282", "r289", "r293" ], "lang": { "en": { "role": { "documentation": "This member stands for hedges of the exposure to changes in fair value of a recognised asset or liability or an unrecognised firm commitment, or an identified portion of such an asset, liability or firm commitment, that is attributable to a particular risk and could affect profit or loss. [Refer: Hedges [member]]" } }, "en-us": { "role": { "label": "Fair Value Hedges [Member]", "terseLabel": "Fair value hedges" } } }, "localname": "FairValueHedgesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FairValueOfAssociatedFinancialLiabilities": { "auth_ref": [ "r314" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The fair value of financial liabilities associated with transferred financial assets that are not derecognised in their entirety. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Fair value of associated financial liabilities", "terseLabel": "Fair value of associated liabilities" } } }, "localname": "FairValueOfAssociatedFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety": { "auth_ref": [ "r314" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The difference between the fair value of transferred financial assets that have not been derecognised in their entirety and their associated liabilities. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Fair value of transferred financial assets (associated financial liabilities) that are not derecognised in their entirety", "terseLabel": "Net fair value position" } } }, "localname": "FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FairValueOfTransferredFinancialAssetsThatAreNotDerecognisedInTheirEntirety": { "auth_ref": [ "r314" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The fair value of transferred financial assets that are not derecognised in their entirety. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Fair value of transferred financial assets that are not derecognised in their entirety", "terseLabel": "Fair value of transferred assets" } } }, "localname": "FairValueOfTransferredFinancialAssetsThatAreNotDerecognisedInTheirEntirety", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FeeAndCommissionExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "ifrs-full_FeeAndCommissionIncomeExpense", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense relating to fees and commissions." } }, "en-us": { "role": { "label": "Fee and commission expense", "negatedTotalLabel": "Fee expenses" } } }, "localname": "FeeAndCommissionExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FeeAndCommissionIncome": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "ifrs-full_FeeAndCommissionIncomeExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income relating to fees and commissions." } }, "en-us": { "role": { "label": "Fee and commission income", "totalLabel": "Fee income" } } }, "localname": "FeeAndCommissionIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FeeAndCommissionIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Fee and commission income [abstract]", "verboseLabel": "Net fee income" } } }, "localname": "FeeAndCommissionIncomeAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_FeeAndCommissionIncomeExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "wbk_NonInterestIncomeExpense", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 2.0, "parentTag": "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income or expense relating to fees and commissions." } }, "en-us": { "role": { "label": "Net fee income", "terseLabel": "Net fee income", "totalLabel": "Net fee income", "verboseLabel": "Net fee income" } } }, "localname": "FeeAndCommissionIncomeExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssets": { "auth_ref": [ "r295", "r300", "r302", "r305", "r306" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity\u2019s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity\u2019s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity\u2019s own equity instruments. For this purpose the entity\u2019s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity\u2019s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]" } }, "en-us": { "role": { "label": "Financial assets", "periodEndLabel": "Balance at the end of the year", "periodStartLabel": "Balance at the beginning of the year", "terseLabel": "Provisions for expected credit losses", "verboseLabel": "Financial assets" } } }, "localname": "FinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember": { "auth_ref": [ "r322" ], "lang": { "en": { "role": { "documentation": "This member stands for the financial assets at amortised cost category. [Refer: Financial assets at amortised cost]" } }, "en-us": { "role": { "label": "Financial Assets At Amortised Cost Category [Member]", "terseLabel": "Amortised cost" } } }, "localname": "FinancialAssetsAtAmortisedCostCategoryMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsAtFairValue": { "auth_ref": [ "r295" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The fair value of financial assets. [Refer: At fair value [member]; Financial assets]" } }, "en-us": { "role": { "label": "Financial assets, at fair value", "terseLabel": "Financial assets measured at fair value", "verboseLabel": "Financial assets, Fair Value" } } }, "localname": "FinancialAssetsAtFairValue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember": { "auth_ref": [ "r323" ], "lang": { "en": { "role": { "documentation": "This member stands for the financial assets at fair value through other comprehensive income category. [Refer: Financial assets at fair value through other comprehensive income]" } }, "en-us": { "role": { "label": "Financial Assets At Fair Value Through Other Comprehensive Income Category [Member]", "terseLabel": "FVOCI" } } }, "localname": "FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss": { "auth_ref": [ "r321" ], "calculation": { "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails": { "order": 3.0, "parentTag": "wbk_TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatement", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]" } }, "en-us": { "role": { "label": "Financial assets at fair value through profit or loss", "verboseLabel": "Other financial assets measured at FVIS" } } }, "localname": "FinancialAssetsAtFairValueThroughProfitOrLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssetsCategoryMember": { "auth_ref": [ "r324" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated categories of financial assets. It also represents the standard value for the 'Categories of financial assets' axis if no other member is used. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial Assets Category [Member]", "terseLabel": "Financial assets, category [member]" } } }, "localname": "FinancialAssetsCategoryMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsHeldForManagingLiquidityRisk": { "auth_ref": [ "r330" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets held for managing liquidity risk (for example, financial assets that are readily saleable or expected to generate cash inflows to meet cash outflows on financial liabilities). [Refer: Liquidity risk [member]; Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Financial assets held for managing liquidity risk", "terseLabel": "Liquid assets" } } }, "localname": "FinancialAssetsHeldForManagingLiquidityRisk", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssetsImpairedMember": { "auth_ref": [ "r410" ], "lang": { "en": { "role": { "documentation": "This member stands for financial assets that have been impaired. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial Assets Impaired [Member]", "terseLabel": "Impaired exposures" } } }, "localname": "FinancialAssetsImpairedMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsMember": { "auth_ref": [ "r318", "r319", "r370", "r384", "r386" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated classes of financial assets. It also represents the standard value for the 'Classes of financial assets' axis if no other member is used. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial Assets [Member]", "terseLabel": "Financial assets" } } }, "localname": "FinancialAssetsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities": { "auth_ref": [ "r274" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets that the entity has pledged as collateral for liabilities or contingent liabilities, including amounts that have been reclassified in accordance with paragraph 3.2.23(a) of IFRS 9. [Refer: Contingent liabilities [member]; Financial assets]" } }, "en-us": { "role": { "label": "Financial assets pledged as collateral for liabilities or contingent liabilities", "terseLabel": "Financial assets pledged to secure liabilities" } } }, "localname": "FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialAssetsTypeMember": { "auth_ref": [ "r337", "r338" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated types of financial assets. It also represents the standard value for the 'Types of financial assets' axis if no other member is used. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial Assets Type [Member]", "terseLabel": "Financial assets, type [member]" } } }, "localname": "FinancialAssetsTypeMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialAssetsWhichDoNotQualifyForDerecognitionAxis": { "auth_ref": [ "r316" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Transferred financial assets that are not derecognised in their entirety [axis]" } } }, "localname": "FinancialAssetsWhichDoNotQualifyForDerecognitionAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_FinancialAssetsWhichDoNotQualifyForDerecognitionMember": { "auth_ref": [ "r316" ], "lang": { "en": { "role": { "documentation": "This member stands for transferred financial assets that are not derecognised in their entirety. It also represents the standard value for the 'Transferred financial assets that are not derecognised in their entirety' axis if no other member is used. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial Assets Which Do Not Qualify For Derecognition [Member]", "terseLabel": "Transferred financial assets that are not derecognised in their entirety [member]" } } }, "localname": "FinancialAssetsWhichDoNotQualifyForDerecognitionMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": { "auth_ref": [ "r271", "r344" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of financial instruments subject to an enforceable master netting arrangement or similar agreement that are not set off against financial assets. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Financial instruments subject to enforceable master netting arrangement or similar agreement not set off against financial assets", "negatedTerseLabel": "Other recognised financial instruments" } } }, "localname": "FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": { "auth_ref": [ "r271", "r344" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial instruments subject to an enforceable master netting arrangement or similar agreement that are not set off against financial liabilities. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Financial instruments subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities", "negatedTerseLabel": "Other recognised financial instruments" } } }, "localname": "FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialLiabilities": { "auth_ref": [ "r295" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity\u2019s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity\u2019s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity\u2019s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity\u2019s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity\u2019s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity\u2019s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]" } }, "en-us": { "role": { "label": "Financial liabilities", "periodEndLabel": "Balance at the end of the year", "periodStartLabel": "Balance at the beginning of the year", "verboseLabel": "Financial liabilities" } } }, "localname": "FinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialLiabilitiesAtFairValue": { "auth_ref": [ "r295" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]" } }, "en-us": { "role": { "label": "Financial liabilities, at fair value", "terseLabel": "Financial liabilities measured at fair value", "verboseLabel": "Financial liabilities, Fair Value" } } }, "localname": "FinancialLiabilitiesAtFairValue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_FinancialLiabilitiesMember": { "auth_ref": [ "r318", "r319", "r370" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated classes financial liabilities. It also represents the standard value for the 'Classes of financial liabilities' axis if no other member is used. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Financial Liabilities [Member]", "terseLabel": "Financial liabilities, class [member]" } } }, "localname": "FinancialLiabilitiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FixedInterestRateMember": { "auth_ref": [ "r311" ], "lang": { "en": { "role": { "documentation": "This member stands for a fixed interest rate. [Refer: Interest rate risk [member]]" } }, "en-us": { "role": { "label": "Fixed Interest Rate [Member]", "terseLabel": "Fixed interest rate" } } }, "localname": "FixedInterestRateMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_FloatingInterestRateMember": { "auth_ref": [ "r311" ], "lang": { "en": { "role": { "documentation": "This member stands for a non-fixed interest rate. [Refer: Interest rate risk [member]]" } }, "en-us": { "role": { "label": "Floating Interest Rate [Member]", "terseLabel": "Variable Interest Rates" } } }, "localname": "FloatingInterestRateMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ForeignCountriesMember": { "auth_ref": [ "r363", "r364" ], "lang": { "en": { "role": { "documentation": "This member stands for countries outside the entity's country of domicile. [Refer: Country of domicile [member]]" } }, "en-us": { "role": { "label": "Foreign Countries [Member]", "terseLabel": "Overseas" } } }, "localname": "ForeignCountriesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ForwardContractMember": { "auth_ref": [ "r12" ], "lang": { "en": { "role": { "documentation": "This member stands for a contract between two parties for the purchase or sale of an underlying asset at a specified future date for a settlement price determined in advance." } }, "en-us": { "role": { "label": "Forward Contract [Member]", "terseLabel": "Forward contracts" } } }, "localname": "ForwardContractMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_GainLossOnChangeInFairValueOfHedgedItemUsedAsBasisForRecognisingHedgeIneffectiveness": { "auth_ref": [ "r285", "r287" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gain (loss) on the change in fair value of the hedged item used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item." } }, "en-us": { "role": { "label": "Gain (loss) on change in fair value of hedged item used as basis for recognising hedge ineffectiveness", "terseLabel": "Change in value of the hedged item used for calculating ineffectiveness" } } }, "localname": "GainLossOnChangeInFairValueOfHedgedItemUsedAsBasisForRecognisingHedgeIneffectiveness", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness": { "auth_ref": [ "r280" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gain (loss) on the change in fair value of the hedging instrument used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item." } }, "en-us": { "role": { "label": "Gain (loss) on change in fair value of hedging instrument used as basis for recognising hedge ineffectiveness", "terseLabel": "Change in fair value of hedging instrument used for calculating ineffectiveness" } } }, "localname": "GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainLossOnHedgeIneffectivenessRecognisedInProfitOrLoss": { "auth_ref": [ "r290", "r292" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gain (loss) recognised in profit or loss on hedge ineffectiveness. [Refer: Gain (loss) on hedge ineffectiveness]" } }, "en-us": { "role": { "label": "Interest Income on Net Ineffectiveness on Qualifying Hedges", "terseLabel": "Net ineffectiveness on qualifying hedges" } } }, "localname": "GainLossOnHedgeIneffectivenessRecognisedInProfitOrLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff": { "auth_ref": [ "r55" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gain on the recovery of loans and advances previously written off." } }, "en-us": { "role": { "label": "Gain on recovery of loans and advances previously written off", "negatedLabel": "Recoveries" } } }, "localname": "GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnCashFlowHedgesBeforeTax": { "auth_ref": [ "r58", "r404" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 2.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on cash flow hedges, before tax. [Refer: Cash flow hedges [member]]" } }, "en-us": { "role": { "label": "Gains (losses) on cash flow hedges, before tax", "terseLabel": "Cash flow hedging instruments", "verboseLabel": "Net gains/(losses) from changes in fair value" } } }, "localname": "GainsLossesOnCashFlowHedgesBeforeTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnChangeInFairValueOfDerivatives": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 7.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]]" } }, "en-us": { "role": { "label": "Gains (losses) on change in fair value of derivatives", "terseLabel": "Net gain/(loss) on derivatives held for risk management purposes" } } }, "localname": "GainsLossesOnChangeInFairValueOfDerivatives", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnDisposalsOfNoncurrentAssets": { "auth_ref": [ "r12" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) on disposals of non-current assets. [Refer: Non-current assets]" } }, "en-us": { "role": { "label": "Gains (losses) on disposals of non-current assets", "verboseLabel": "Gain/(loss) on disposal" } } }, "localname": "GainsLossesOnDisposalsOfNoncurrentAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnDisposalsOfPropertyPlantAndEquipment": { "auth_ref": [ "r61" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 5.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) on disposals of property, plant and equipment. [Refer: Property, plant and equipment]" } }, "en-us": { "role": { "label": "Gains (losses) on disposals of property, plant and equipment", "terseLabel": "Net gain/(loss) on disposal of assets" } } }, "localname": "GainsLossesOnDisposalsOfPropertyPlantAndEquipment", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationNetOfTax": { "auth_ref": [ "r57" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on exchange differences on the translation of financial statements of foreign operations, net of tax. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Gains (losses) on exchange differences on translation, net of tax", "verboseLabel": "Exchange differences on translation of foreign operations" } } }, "localname": "GainsLossesOnExchangeDifferencesOnTranslationNetOfTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax": { "auth_ref": [ "r58", "r275" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 1.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on financial assets measured at fair value through other comprehensive income, before tax. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]" } }, "en-us": { "role": { "label": "Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax", "terseLabel": "Debt securities measured at fair value through other comprehensive income (FVOCI)" } } }, "localname": "GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax": { "auth_ref": [ "r57", "r158", "r291", "r294", "r369" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on hedges of net investments in foreign operations, net of tax. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Gains (losses) on hedges of net investments in foreign operations, net of tax", "verboseLabel": "Gains/(losses) on net investment hedges" } } }, "localname": "GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedInOtherComprehensiveIncomeExcludingExchangeDifferencesFairValueMeasurementAssets": { "auth_ref": [ "r228" ], "lang": { "en": { "role": { "documentation": "The gains (losses) excluding exchange differences, recognised in other comprehensive income, on the fair value measurement of assets. [Refer: At fair value [member]; Other comprehensive income]" } }, "en-us": { "role": { "label": "Gains (losses) recognised in other comprehensive income excluding exchange differences, fair value measurement, assets", "terseLabel": "OCI" } } }, "localname": "GainsLossesRecognisedInOtherComprehensiveIncomeExcludingExchangeDifferencesFairValueMeasurementAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement": { "auth_ref": [ "r230" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in profit or loss for assets measured at fair value that are attributable to the change in unrealised gains or losses relating to those assets held at the end of the reporting period. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "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", "terseLabel": "Unrealised gains/(losses) recognised in the income statements for financial instruments held as at end of year" } } }, "localname": "GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForLiabilitiesHeldAtEndOfPeriodFairValueMeasurement": { "auth_ref": [ "r230" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in profit or loss for liabilities measured at fair value that are attributable to the change in unrealised gains or losses relating to those liabilities held at the end of the reporting period. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "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", "terseLabel": "Unrealised gains/(losses) recognised in the income statements for financial instruments held as at end of year" } } }, "localname": "GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForLiabilitiesHeldAtEndOfPeriodFairValueMeasurement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedInProfitOrLossExcludingExchangeDifferencesFairValueMeasurementAssets": { "auth_ref": [ "r227" ], "lang": { "en": { "role": { "documentation": "The gains (losses) excluding exchange differences, recognised in profit or loss, on the fair value measurement of assets. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "Gains (losses) recognised in profit or loss excluding exchange differences, fair value measurement, assets", "terseLabel": "Income statements" } } }, "localname": "GainsLossesRecognisedInProfitOrLossExcludingExchangeDifferencesFairValueMeasurementAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedInProfitOrLossExcludingExchangeDifferencesFairValueMeasurementLiabilities": { "auth_ref": [ "r227" ], "lang": { "en": { "role": { "documentation": "The gains (losses) excluding exchange differences, recognised in profit or loss, on the fair value measurement of liabilities. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "Gains (losses) recognised in profit or loss excluding exchange differences, fair value measurement, liabilities", "negatedLabel": "Income statements" } } }, "localname": "GainsLossesRecognisedInProfitOrLossExcludingExchangeDifferencesFairValueMeasurementLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GainsLossesRecognisedWhenControlInSubsidiaryIsLost": { "auth_ref": [ "r203" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 9.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gains (losses) recognised in association with the loss of control over a subsidiary, which are attributable to the former controlling interest." } }, "en-us": { "role": { "label": "Gains (losses) recognised when control of subsidiary is lost", "terseLabel": "Net gain/(loss) on disposal of controlled entities and other businesses", "verboseLabel": "Gain (loss) on businesses disposed during the year" } } }, "localname": "GainsLossesRecognisedWhenControlInSubsidiaryIsLost", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails", "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GeographicalAreasAxis": { "auth_ref": [ "r83", "r244", "r365", "r382" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Geographical areas [axis]" } } }, "localname": "GeographicalAreasAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_GeographicalAreasMember": { "auth_ref": [ "r83", "r244", "r365", "r382" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregated geographical areas. It also represents the standard value for the 'Geographical areas' axis if no other member is used." } }, "en-us": { "role": { "label": "Geographical Areas [Member]", "terseLabel": "Geographical areas [member]" } } }, "localname": "GeographicalAreasMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Goodwill": { "auth_ref": [ "r18", "r133", "r136", "r263" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails": { "order": 1.0, "parentTag": "ifrs-full_IntangibleAssetsAndGoodwill", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of assets representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognised. [Refer: Business combinations [member]]" } }, "en-us": { "role": { "label": "Goodwill", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year", "terseLabel": "Goodwill" } } }, "localname": "Goodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GoodwillMember": { "auth_ref": [ "r128" ], "lang": { "en": { "role": { "documentation": "This member stands for goodwill. [Refer: Goodwill]" } }, "en-us": { "role": { "label": "Goodwill [Member]", "terseLabel": "Goodwill" } } }, "localname": "GoodwillMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_GrossCarryingAmountMember": { "auth_ref": [ "r79", "r150", "r164", "r167", "r263", "r302", "r305", "r306", "r409", "r419" ], "lang": { "en": { "role": { "documentation": "This member stands for the amount at which an asset is recognised before deducting any accumulated depreciation (amortisation) and accumulated impairment losses thereon. [Refer: Depreciation and amortisation expense; Impairment loss]" } }, "en-us": { "role": { "label": "Gross Carrying Amount [Member]", "terseLabel": "Gross amount" } } }, "localname": "GrossCarryingAmountMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_GrossFinancialAssetsSetOffAgainstFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r269" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets set off against financial liabilities when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis, or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Gross financial assets set off against financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements", "negatedTerseLabel": "Amounts offset" } } }, "localname": "GrossFinancialAssetsSetOffAgainstFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r268" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The gross amount of recognised financial assets that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Gross financial assets subject to offsetting, enforceable master netting arrangements or similar agreements", "terseLabel": "Gross amounts" } } }, "localname": "GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GrossFinancialLiabilitiesSetOffAgainstFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r269" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of financial liabilities set off against financial assets when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Gross financial liabilities set off against financial assets subject to offsetting, enforceable master netting arrangements or similar agreements", "negatedLabel": "Amounts offset" } } }, "localname": "GrossFinancialLiabilitiesSetOffAgainstFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r268" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The gross amount of recognised financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Gross financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements", "terseLabel": "Gross amounts" } } }, "localname": "GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_HedgedItemAssets": { "auth_ref": [ "r283" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of a hedged item, recognised as an asset. [Refer: Hedged items [member]]" } }, "en-us": { "role": { "label": "Hedged item, assets", "terseLabel": "Carrying value of hedged assets" } } }, "localname": "HedgedItemAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_HedgedItemLiabilities": { "auth_ref": [ "r283" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of a hedged item, recognised as a liability. [Refer: Hedged items [member]]" } }, "en-us": { "role": { "label": "Hedged item, liabilities", "negatedLabel": "Carrying value of hedged liabilities" } } }, "localname": "HedgedItemLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_HedgedItemsAxis": { "auth_ref": [ "r289" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Hedged items [axis]" } } }, "localname": "HedgedItemsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_HedgedItemsMember": { "auth_ref": [ "r289" ], "lang": { "en": { "role": { "documentation": "This member stands for hedged items. A hedged item can be a recognised asset or liability, an unrecognised firm commitment, a forecast transaction or a net investment in a foreign operation. The hedged item can be: (a) a single item; or (b) a group of items (subject to paragraphs 6.6.1\u20136.6.6 and B6.6.1\u2013B6.6.16 of IFRS 9). A hedged item can also be a component of such an item or group of items (see paragraphs 6.3.7 and B6.3.7\u2013B6.3.25 of IFRS 9). This member also represents the standard value for the 'Hedged items' axis if no other member is used." } }, "en-us": { "role": { "label": "Hedged Items [Member]", "terseLabel": "Hedged items [member]" } } }, "localname": "HedgedItemsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_HedgesOfNetInvestmentInForeignOperationsMember": { "auth_ref": [ "r161", "r282", "r289", "r293" ], "lang": { "en": { "role": { "documentation": "This member stands for hedges of the entity's monetary items that are receivable from or payable to a foreign operation, for which settlement is neither planned nor likely to occur in the foreseeable future. A foreign operation is an entity that is a subsidiary, associate, joint venture or branch of a reporting entity, the activities of which are based or conducted in a country or currency other than those of the reporting entity." } }, "en-us": { "role": { "label": "Hedges Of Net Investment In Foreign Operations [Member]", "terseLabel": "Net investment hedges" } } }, "localname": "HedgesOfNetInvestmentInForeignOperationsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_HedgingInstrumentAssets": { "auth_ref": [ "r279" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of a hedging instrument, recognised as an asset. [Refer: Hedging instruments [member]]" } }, "en-us": { "role": { "label": "Hedging instrument, assets", "totalLabel": "Carrying value, hedged assets" } } }, "localname": "HedgingInstrumentAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_HedgingInstrumentLiabilities": { "auth_ref": [ "r279" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [member]]" } }, "en-us": { "role": { "label": "Hedging instrument, liabilities", "negatedTotalLabel": "Carrying value, hedged liabilities" } } }, "localname": "HedgingInstrumentLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_HedgingInstrumentsAxis": { "auth_ref": [ "r277", "r282" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Hedging instruments [axis]" } } }, "localname": "HedgingInstrumentsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_HedgingInstrumentsMember": { "auth_ref": [ "r277", "r282" ], "lang": { "en": { "role": { "documentation": "This member stands for hedging instruments. A hedging instrument can be a designated: (a) derivative measured at fair value through profit or loss, except for some written options (see paragraph B6.2.4 of IFRS 9); (b) non-derivative financial asset or non-derivative financial liability measured at fair value through profit or loss, unless it is a financial liability designated as at fair value through profit or loss for which the amount of its change in fair value that is attributable to changes in the credit risk of that liability is presented in other comprehensive income in accordance with paragraph 5.7.7 of IFRS 9. For a hedge of foreign currency risk, the foreign currency risk component of a non-derivative financial asset or a non-derivative financial liability may be designated as a hedging instrument provided that it is not an investment in an equity instrument for which an entity has elected to present changes in fair value in other comprehensive income in accordance with paragraph 5.7.5 of IFRS 9. This member also represents the standard value for the 'Hedging instruments' axis if no other member is used." } }, "en-us": { "role": { "label": "Hedging Instruments [Member]", "terseLabel": "Hedging instruments [member]" } } }, "localname": "HedgingInstrumentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ImpairmentLoss": { "auth_ref": [ "r130", "r131" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount recognised as a reduction of the carrying amount of an asset or cash-generating unit to its recoverable amount. [Refer: Carrying amount [member]]" } }, "en-us": { "role": { "label": "Impairment loss", "terseLabel": "Impairment expenses" } } }, "localname": "ImpairmentLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossImpairmentGainAndReversalOfImpairmentLossDeterminedInAccordanceWithIFRS9": { "auth_ref": [ "r53" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 3.0, "parentTag": "ifrs-full_ProfitLossBeforeTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of impairment loss, impairment gain or reversal of impairment loss that is recognised in profit or loss in accordance with paragraph 5.5.8 of IFRS 9 and that arises from applying the impairment requirements in Section 5.5 of IFRS 9." } }, "en-us": { "role": { "label": "Impairment loss (impairment gain and reversal of impairment loss) determined in accordance with IFRS 9", "negatedLabel": "Impairment (charges)/benefits", "terseLabel": "Impairment (charges)/benefits", "verboseLabel": "Impairment charges (Note 6)" } } }, "localname": "ImpairmentLossImpairmentGainAndReversalOfImpairmentLossDeterminedInAccordanceWithIFRS9", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossRecognisedInProfitOrLoss": { "auth_ref": [ "r126", "r129" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of impairment loss recognised in profit or loss. [Refer: Impairment loss; Profit (loss)]" } }, "en-us": { "role": { "label": "Impairment loss recognised in profit or loss", "terseLabel": "Provisions raised/(released)", "verboseLabel": "Impairment expense" } } }, "localname": "ImpairmentLossRecognisedInProfitOrLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossRecognisedInProfitOrLossGoodwill": { "auth_ref": [ "r261" ], "lang": { "en": { "role": { "documentation": "The amount of impairment loss recognised in profit or loss for goodwill. [Refer: Impairment loss recognised in profit or loss; Goodwill]" } }, "en-us": { "role": { "label": "Impairment loss recognised in profit or loss, goodwill", "negatedLabel": "Impairment", "terseLabel": "Impairment of goodwill" } } }, "localname": "ImpairmentLossRecognisedInProfitOrLossGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsAndGoodwill": { "auth_ref": [ "r152" ], "lang": { "en": { "role": { "documentation": "The amount of impairment loss recognised in profit or loss for intangible assets and goodwill. [Refer: Impairment loss recognised in profit or loss; Intangible assets and goodwill]" } }, "en-us": { "role": { "label": "Impairment loss recognised in profit or loss, intangible assets and goodwill", "terseLabel": "Impairment of intangible assets, including goodwill" } } }, "localname": "ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsAndGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r152" ], "lang": { "en": { "role": { "documentation": "The amount of impairment loss recognised in profit or loss for intangible assets other than goodwill. [Refer: Impairment loss recognised in profit or loss; Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Impairment loss recognised in profit or loss, intangible assets other than goodwill", "negatedLabel": "Impairment", "terseLabel": "Impairment", "verboseLabel": "Impairment of intangible assets" } } }, "localname": "ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossRecognisedInProfitOrLossLoansAndAdvances": { "auth_ref": [ "r55" ], "lang": { "en": { "role": { "documentation": "The amount of impairment loss recognised in profit or loss for loans and advances. [Refer: Impairment loss recognised in profit or loss]" } }, "en-us": { "role": { "label": "Impairment loss recognised in profit or loss, loans and advances", "verboseLabel": "Impairment" } } }, "localname": "ImpairmentLossRecognisedInProfitOrLossLoansAndAdvances", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvancesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Impairment loss (reversal of impairment loss) recognised in profit or loss, loans and advances [abstract]", "terseLabel": "Reconciliation of impairment charges" } } }, "localname": "ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvancesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ImpairmentOfFinancialAssetsAxis": { "auth_ref": [ "r410" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Impairment of financial assets [axis]" } } }, "localname": "ImpairmentOfFinancialAssetsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_IncomeStatementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Income statements" } } }, "localname": "IncomeStatementAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_IncomeTaxExpenseContinuingOperations": { "auth_ref": [ "r54", "r67", "r70", "r71", "r115", "r216", "r354" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails": { "order": 2.0, "parentTag": "wbk_ProfitLossFromOperationsBeforeCashEarningsAdjustment", "weight": -1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 2.0, "parentTag": "ifrs-full_ProfitLoss", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]" } }, "en-us": { "role": { "label": "Tax expense (income), continuing operations", "negatedLabel": "Income tax (expense)/benefit", "negatedTerseLabel": "Income tax expense", "totalLabel": "Total income tax expense" } } }, "localname": "IncomeTaxExpenseContinuingOperations", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncomeTaxRelatingToCashFlowHedgesOfOtherComprehensiveIncome": { "auth_ref": [ "r56", "r69" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 9.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income in relation to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]" } }, "en-us": { "role": { "label": "Income tax relating to cash flow hedges of other comprehensive income", "negatedLabel": "Cash flow hedging instruments" } } }, "localname": "IncomeTaxRelatingToCashFlowHedgesOfOtherComprehensiveIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract]", "terseLabel": "Income tax on items taken to or transferred from equity:" } } }, "localname": "IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_IncomeTaxRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": { "auth_ref": [ "r56", "r69" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 8.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income in relation to financial assets measured at fair value through other comprehensive income. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]" } }, "en-us": { "role": { "label": "Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income", "negatedLabel": "Debt instruments measured at FVOCI" } } }, "localname": "IncomeTaxRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges": { "auth_ref": [ "r186" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in cash and cash equivalents before the effect of exchange rate changes on cash and cash equivalents held in foreign currencies. [Refer: Cash and cash equivalents; Effect of exchange rate changes on cash and cash equivalents]" } }, "en-us": { "role": { "label": "Increase (decrease) in cash and cash equivalents before effect of exchange rate changes", "totalLabel": "Net increase/(decrease) in cash and balances with central banks" } } }, "localname": "IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption": { "auth_ref": [ "r90" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption", "terseLabel": "Increase in obligation" } } }, "localname": "IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughForeignExchangeAndOtherMovementsFinancialAssets": { "auth_ref": [ "r300", "r339" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in financial assets resulting from foreign exchange and other movements. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Increase (decrease) through foreign exchange and other movements, financial assets", "terseLabel": "Exchange rate and other adjustments" } } }, "localname": "IncreaseDecreaseThroughForeignExchangeAndOtherMovementsFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions": { "auth_ref": [ "r7" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 5.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in equity resulting from share-based payment transactions. [Refer: Equity]" } }, "en-us": { "role": { "label": "Increase (decrease) through share-based payment transactions, equity", "terseLabel": "Share-based payment arrangements", "verboseLabel": "Share-based payment expense" } } }, "localname": "IncreaseDecreaseThroughSharebasedPaymentTransactions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughTransactionsWithOwners": { "auth_ref": [ "r8" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in equity resulting from transactions with owners." } }, "en-us": { "role": { "label": "Increase (decrease) through transactions with owners, equity", "terseLabel": "Transactions with owners" } } }, "localname": "IncreaseDecreaseThroughTransactionsWithOwners", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesEquity": { "auth_ref": [ "r8" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 8.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in equity resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Equity]" } }, "en-us": { "role": { "label": "Increase (decrease) through other changes, equity", "terseLabel": "Other" } } }, "localname": "IncreaseDecreaseThroughTransfersAndOtherChangesEquity", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesGoodwill": { "auth_ref": [ "r262" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in goodwill resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Goodwill]" } }, "en-us": { "role": { "label": "Increase (decrease) through other changes, goodwill", "terseLabel": "Other adjustments" } } }, "localname": "IncreaseDecreaseThroughTransfersAndOtherChangesGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesIntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r154" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in intangible assets other than goodwill resulting from transfers and changes that the entity does not separately disclose in the same statement or note. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Increase (decrease) through transfers and other changes, intangible assets other than goodwill", "terseLabel": "Other adjustments" } } }, "localname": "IncreaseDecreaseThroughTransfersAndOtherChangesIntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IncreaseDecreaseThroughTreasuryShareTransactions": { "auth_ref": [ "r8" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 7.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase (decrease) in equity resulting from treasury share transactions. [Refer: Equity; Treasury shares]" } }, "en-us": { "role": { "label": "Increase (decrease) through treasury share transactions, equity", "terseLabel": "Net acquisition of treasury shares" } } }, "localname": "IncreaseDecreaseThroughTreasuryShareTransactions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis": { "auth_ref": [ "r132" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Individual assets or cash-generating units [axis]" } } }, "localname": "IndividualAssetsOrCashgeneratingUnitsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_InitiallyAppliedIFRSsAxis": { "auth_ref": [ "r190" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Initially applied IFRSs [axis]" } } }, "localname": "InitiallyAppliedIFRSsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_InitiallyAppliedIFRSsMember": { "auth_ref": [ "r190" ], "lang": { "en": { "role": { "documentation": "This member stands for IFRSs that have been initially applied by the entity. It also represents the standard value for the 'Initially applied IFRSs' axis if no other member is used. [Refer: IFRSs [member]]" } }, "en-us": { "role": { "label": "Initially Applied I F R Ss [Member]", "terseLabel": "Initially applied IFRSs [member]" } } }, "localname": "InitiallyAppliedIFRSsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InsuranceContractsMember": { "auth_ref": [ "r402" ], "lang": { "en": { "role": { "documentation": "This member stands for contracts under which one party (the insurer) accepts significant insurance risk from another party (the policyholder) by agreeing to compensate the policyholder if a specified uncertain future event (the insured event) adversely affects the policyholder. It also represents the standard value for the 'Types of insurance contracts' axis if no other member is used." } }, "en-us": { "role": { "label": "Insurance Contracts [Member]", "terseLabel": "Types of insurance contracts [member]" } } }, "localname": "InsuranceContractsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_IntangibleAssetsAndGoodwill": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 15.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of intangible assets and goodwill held by the entity. [Refer: Goodwill; Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Intangible assets and goodwill", "totalLabel": "Total intangible assets, including goodwill", "verboseLabel": "Intangible assets" } } }, "localname": "IntangibleAssetsAndGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IntangibleAssetsAndGoodwillAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Intangible assets" } } }, "localname": "IntangibleAssetsAndGoodwillAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_IntangibleAssetsAndGoodwillMember": { "auth_ref": [ "r155" ], "lang": { "en": { "role": { "documentation": "This member stands for intangible assets and goodwill. It also represents the standard value for the 'Classes of intangible assets and goodwill' axis if no other member is used. [Refer: Goodwill; Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Intangible Assets And Goodwill [Member]", "terseLabel": "Intangible assets and goodwill [member]" } } }, "localname": "IntangibleAssetsAndGoodwillMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_IntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r18", "r154" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails": { "order": 2.0, "parentTag": "ifrs-full_IntangibleAssetsAndGoodwill", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of identifiable non-monetary assets without physical substance. This amount does not include goodwill. [Refer: Goodwill]" } }, "en-us": { "role": { "label": "Intangible assets other than goodwill", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year", "terseLabel": "Intangible assets" } } }, "localname": "IntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IntangibleAssetsOtherThanGoodwillMember": { "auth_ref": [ "r128", "r155", "r247" ], "lang": { "en": { "role": { "documentation": "This member stands for intangible assets other than goodwill. It also represents the standard value for the 'Classes of intangible assets other than goodwill' axis if no other member is used. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Intangible Assets Other Than Goodwill [Member]", "terseLabel": "Intangible assets" } } }, "localname": "IntangibleAssetsOtherThanGoodwillMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InterestExpense": { "auth_ref": [ "r215", "r353", "r360" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 1.0, "parentTag": "ifrs-full_InterestRevenueExpense", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense arising from interest." } }, "en-us": { "role": { "label": "Interest expense", "negatedLabel": "Interest expense", "negatedTerseLabel": "Total interest expense", "terseLabel": "Interest expense" } } }, "localname": "InterestExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestExpenseOnDebtInstrumentsIssued": { "auth_ref": [ "r12" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of interest expense on debt instruments issued. [Refer: Interest expense; Debt instruments issued]" } }, "en-us": { "role": { "label": "Interest expense on debt instruments issued", "negatedLabel": "Debt issues" } } }, "localname": "InterestExpenseOnDebtInstrumentsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestExpenseOnOtherFinancialLiabilities": { "auth_ref": [ "r12" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of interest expense on other financial liabilities. [Refer: Interest expense; Other financial liabilities]" } }, "en-us": { "role": { "label": "Interest expense on other financial liabilities", "negatedTerseLabel": "Other financial liabilities" } } }, "localname": "InterestExpenseOnOtherFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestIncomeOnCashAndBankBalancesAtCentralBanks": { "auth_ref": [ "r12" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of interest income on cash and bank balances at central banks. [Refer: Interest income; Cash and bank balances at central banks]" } }, "en-us": { "role": { "label": "Interest income on cash and bank balances at central banks", "terseLabel": "Cash and balances with central banks" } } }, "localname": "InterestIncomeOnCashAndBankBalancesAtCentralBanks", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestIncomeOnLoansAndReceivables": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of interest income on loans and receivables. [Refer: Interest income; Loans and receivables]" } }, "en-us": { "role": { "label": "Interest income on loans and receivables", "terseLabel": "Loans" } } }, "localname": "InterestIncomeOnLoansAndReceivables", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestIncomeOnOtherFinancialAssets": { "auth_ref": [ "r12" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of interest income on other financial assets. [Refer: Interest income; Other financial assets]" } }, "en-us": { "role": { "label": "Interest income on other financial assets", "terseLabel": "Other financial assets" } } }, "localname": "InterestIncomeOnOtherFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestPaidClassifiedAsOperatingActivities": { "auth_ref": [ "r184" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 2.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for interest paid, classified as operating activities." } }, "en-us": { "role": { "label": "Interest paid, classified as operating activities", "negatedLabel": "Interest paid" } } }, "localname": "InterestPaidClassifiedAsOperatingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestPayable": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of interest recognised as a liability." } }, "en-us": { "role": { "label": "Interest payable", "verboseLabel": "Accrued interest payable" } } }, "localname": "InterestPayable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestRateRiskMember": { "auth_ref": [ "r346", "r375", "r376", "r377", "r378" ], "lang": { "en": { "role": { "documentation": "This member stands for the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market interest rates. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Interest Rate Risk [Member]", "terseLabel": "Interest rate risk" } } }, "localname": "InterestRateRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InterestRateSwapContractMember": { "auth_ref": [ "r12" ], "lang": { "en": { "role": { "documentation": "This member stands for an interest rate swap contract. [Refer: Swap contract [member]]" } }, "en-us": { "role": { "label": "Interest Rate Swap Contract [Member]", "terseLabel": "Interest rate swap" } } }, "localname": "InterestRateSwapContractMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InterestRateTypesMember": { "auth_ref": [ "r311" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of interest rates. It also represents the standard value for the 'Types of interest rates' axis if no other member is used. [Refer: Interest rate risk [member]]" } }, "en-us": { "role": { "label": "Interest Rate Types [Member]", "terseLabel": "Interest rate types [member]" } } }, "localname": "InterestRateTypesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InterestReceivable": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 1.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of interest recognised as a receivable." } }, "en-us": { "role": { "label": "Interest receivable", "terseLabel": "Accrued interest receivable" } } }, "localname": "InterestReceivable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestReceivedClassifiedAsOperatingActivities": { "auth_ref": [ "r184" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 1.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from interest received, classified as operating activities." } }, "en-us": { "role": { "label": "Interest received, classified as operating activities", "terseLabel": "Interest received" } } }, "localname": "InterestReceivedClassifiedAsOperatingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod": { "auth_ref": [ "r52", "r371" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 1.0, "parentTag": "ifrs-full_RevenueFromInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of interest revenue calculated using the effective interest method. Effective interest method is the method that is used in the calculation of the amortised cost of a financial asset or a financial liability and in the allocation and recognition of the interest revenue or interest expense in profit or loss over the relevant period. [Refer: Revenue]" } }, "en-us": { "role": { "label": "Interest revenue calculated using effective interest method", "terseLabel": "Calculated using the effective interest rate method", "verboseLabel": "Total interest income calculated using the effective interest rate method" } } }, "localname": "InterestRevenueCalculatedUsingEffectiveInterestMethod", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InterestRevenueExpense": { "auth_ref": [ "r55", "r355", "r360" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 1.0, "parentTag": "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income or expense arising from interest. [Refer: Interest expense; Interest income]" } }, "en-us": { "role": { "label": "Interest income (expense)", "terseLabel": "Net interest income", "totalLabel": "Net interest income" } } }, "localname": "InterestRevenueExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InternalCreditGradesAxis": { "auth_ref": [ "r305", "r340", "r396", "r407", "r412" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Internal credit grades [axis]" } } }, "localname": "InternalCreditGradesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_InvestmentFundsMember": { "auth_ref": [ "r220" ], "lang": { "en": { "role": { "documentation": "This member stands for investment funds." } }, "en-us": { "role": { "label": "Investment Funds [Member]", "terseLabel": "Group Managed Funds" } } }, "localname": "InvestmentFundsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_InvestmentsInAssociates": { "auth_ref": [ "r116" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 12.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of investments in associates in an entity's separate financial statements. [Refer: Associates [member]]" } }, "en-us": { "role": { "label": "Investments in associates", "terseLabel": "Investment in associates" } } }, "localname": "InvestmentsInAssociates", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InvestmentsInSubsidiaries": { "auth_ref": [ "r116" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 11.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of investments in subsidiaries in an entity's separate financial statements. [Refer: Subsidiaries [member]]" } }, "en-us": { "role": { "label": "Investments in subsidiaries", "terseLabel": "Investment in subsidiaries" } } }, "localname": "InvestmentsInSubsidiaries", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_InvestmentsInSubsidiariesJointVenturesAndAssociatesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Investments in subsidiaries and associates" } } }, "localname": "InvestmentsInSubsidiariesJointVenturesAndAssociatesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 5.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of investments other than investments accounted for using the equity method. [Refer: Investments accounted for using equity method]" } }, "en-us": { "role": { "label": "Investments other than investments accounted for using equity method", "terseLabel": "Investment securities" } } }, "localname": "InvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IssueOfEquity": { "auth_ref": [ "r7" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 1.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The increase in equity through the issue of equity instruments." } }, "en-us": { "role": { "label": "Issue of equity", "terseLabel": "Share issuances" } } }, "localname": "IssueOfEquity", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IssuedCapital": { "auth_ref": [ "r38" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails": { "order": 1.0, "parentTag": "wbk_IssuedCapitalNetOfTreasuryShares", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "ifrs-full_EquityAttributableToOwnersOfParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The nominal value of capital issued." } }, "en-us": { "role": { "label": "Issued capital", "terseLabel": "Ordinary share capital", "verboseLabel": "Ordinary share capital, fully paid" } } }, "localname": "IssuedCapital", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_IssuedCapitalMember": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "This member stands for a component of equity representing issued capital." } }, "en-us": { "role": { "label": "Issued Capital [Member]", "terseLabel": "Share capital" } } }, "localname": "IssuedCapitalMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_KeyManagementPersonnelCompensation": { "auth_ref": [ "r105" ], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of compensation to key management personnel. [Refer: Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Key management personnel compensation", "totalLabel": "Total" } } }, "localname": "KeyManagementPersonnelCompensation", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_KeyManagementPersonnelCompensationPostemploymentBenefits": { "auth_ref": [ "r102" ], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": 2.0, "parentTag": "ifrs-full_KeyManagementPersonnelCompensation", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of compensation to key management personnel in the form of post-employment benefits. [Refer: Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Key management personnel compensation, post-employment benefits", "terseLabel": "Post employment benefits" } } }, "localname": "KeyManagementPersonnelCompensationPostemploymentBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_KeyManagementPersonnelCompensationSharebasedPayment": { "auth_ref": [ "r104" ], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": 5.0, "parentTag": "ifrs-full_KeyManagementPersonnelCompensation", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of compensation to key management personnel in the form of share-based payments. [Refer: Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Key management personnel compensation, share-based payment", "terseLabel": "Share-based payments" } } }, "localname": "KeyManagementPersonnelCompensationSharebasedPayment", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_KeyManagementPersonnelCompensationShorttermEmployeeBenefits": { "auth_ref": [ "r101" ], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": 1.0, "parentTag": "ifrs-full_KeyManagementPersonnelCompensation", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of compensation to key management personnel in the form of short-term employee benefits. [Refer: Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Key management personnel compensation, short-term employee benefits", "terseLabel": "Short-term benefits" } } }, "localname": "KeyManagementPersonnelCompensationShorttermEmployeeBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_KeyManagementPersonnelCompensationTerminationBenefits": { "auth_ref": [ "r103" ], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": 4.0, "parentTag": "ifrs-full_KeyManagementPersonnelCompensation", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of compensation to key management personnel in the form of termination benefits. [Refer: Termination benefits expense; Key management personnel of entity or parent [member]]" } }, "en-us": { "role": { "label": "Key management personnel compensation, termination benefits", "terseLabel": "Termination benefits" } } }, "localname": "KeyManagementPersonnelCompensationTerminationBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_KeyManagementPersonnelOfEntityOrParentMember": { "auth_ref": [ "r108" ], "lang": { "en": { "role": { "documentation": "This member stands for those persons having authority and responsibility for planning, directing and controlling the activities of the entity, directly or indirectly, including any director (whether executive or otherwise) of that entity." } }, "en-us": { "role": { "label": "Key Management Personnel Of Entity Or Parent [Member]", "terseLabel": "Key management personnel" } } }, "localname": "KeyManagementPersonnelOfEntityOrParentMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanFiveYearsAndNotLaterThanTenYearsMember": { "auth_ref": [ "r12", "r329", "r341" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than five years and not later than ten years." } }, "en-us": { "role": { "label": "Later Than Five Years And Not Later Than Ten Years [Member]", "terseLabel": "Over 5 Years to 10 Years" } } }, "localname": "LaterThanFiveYearsAndNotLaterThanTenYearsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanFiveYearsMember": { "auth_ref": [ "r249", "r250", "r329", "r335", "r341", "r380" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than five years." } }, "en-us": { "role": { "label": "Later Than Five Years [Member]", "terseLabel": "Over 5 years" } } }, "localname": "LaterThanFiveYearsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanOneMonthAndNotLaterThanThreeMonthsMember": { "auth_ref": [ "r326", "r332", "r341" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than one month and not later than three months." } }, "en-us": { "role": { "label": "Later Than One Month And Not Later Than Three Months [Member]", "terseLabel": "Over 1 month to 3 months" } } }, "localname": "LaterThanOneMonthAndNotLaterThanThreeMonthsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember": { "auth_ref": [ "r328", "r341" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than one year and not later than five years." } }, "en-us": { "role": { "label": "Later Than One Year And Not Later Than Five Years [Member]", "terseLabel": "Over 1 year to 5 years" } } }, "localname": "LaterThanOneYearAndNotLaterThanFiveYearsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanOneYearMember": { "auth_ref": [ "r33", "r408", "r416" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than one year." } }, "en-us": { "role": { "label": "Later Than One Year [Member]", "terseLabel": "Over 1 year" } } }, "localname": "LaterThanOneYearMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanSixMonthsAndNotLaterThanOneYearMember": { "auth_ref": [ "r329", "r334", "r341", "r408", "r415" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than six months and not later than one year." } }, "en-us": { "role": { "label": "Later Than Six Months And Not Later Than One Year [Member]", "terseLabel": "Over 6 months to 1 year" } } }, "localname": "LaterThanSixMonthsAndNotLaterThanOneYearMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanTenYearsMember": { "auth_ref": [ "r12", "r329", "r341" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than ten years." } }, "en-us": { "role": { "label": "Later Than Ten Years [Member]", "terseLabel": "Over 10 Years" } } }, "localname": "LaterThanTenYearsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanThreeMonthsAndNotLaterThanOneYearMember": { "auth_ref": [ "r327" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than three months and not later than one year." } }, "en-us": { "role": { "label": "Later Than Three Months And Not Later Than One Year [Member]", "terseLabel": "Over 3 months to 1 year" } } }, "localname": "LaterThanThreeMonthsAndNotLaterThanOneYearMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LaterThanThreeMonthsAndNotLaterThanSixMonthsMember": { "auth_ref": [ "r329", "r333", "r341", "r408", "r414" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of later than three months and not later than six months." } }, "en-us": { "role": { "label": "Later Than Three Months And Not Later Than Six Months [Member]", "terseLabel": "Over 3 to 6 months" } } }, "localname": "LaterThanThreeMonthsAndNotLaterThanSixMonthsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LegalProceedingsProvision": { "auth_ref": [ "r145", "r148" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of provision for legal proceedings. [Refer: Other provisions]" } }, "en-us": { "role": { "label": "Legal proceedings provision", "terseLabel": "Legal proceedings provision" } } }, "localname": "LegalProceedingsProvision", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_LegalProceedingsProvisionMember": { "auth_ref": [ "r145", "r148" ], "lang": { "en": { "role": { "documentation": "This member stands for a provision for legal proceedings. [Refer: Other provisions [member]]" } }, "en-us": { "role": { "label": "Legal Proceedings Provision [Member]", "terseLabel": "AUSTRAC proceedings" } } }, "localname": "LegalProceedingsProvisionMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Level1OfFairValueHierarchyMember": { "auth_ref": [ "r88", "r225" ], "lang": { "en": { "role": { "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are quoted prices (unadjusted) in active markets for identical assets or liabilities that the entity can access at the measurement date." } }, "en-us": { "role": { "label": "Level1 Of Fair Value Hierarchy [Member]", "terseLabel": "Level 1" } } }, "localname": "Level1OfFairValueHierarchyMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Level2OfFairValueHierarchyMember": { "auth_ref": [ "r225" ], "lang": { "en": { "role": { "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly." } }, "en-us": { "role": { "label": "Level2 Of Fair Value Hierarchy [Member]", "terseLabel": "Level 2" } } }, "localname": "Level2OfFairValueHierarchyMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_Level3OfFairValueHierarchyMember": { "auth_ref": [ "r225" ], "lang": { "en": { "role": { "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are unobservable inputs for the asset or liability. Unobservable inputs are inputs for which market data are not available and that are developed using the best information available about the assumptions that the market participants would use when pricing the asset or liability." } }, "en-us": { "role": { "label": "Level3 Of Fair Value Hierarchy [Member]", "terseLabel": "Level 3" } } }, "localname": "Level3OfFairValueHierarchyMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LevelsOfFairValueHierarchyAxis": { "auth_ref": [ "r88", "r225" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Levels of fair value hierarchy [axis]" } } }, "localname": "LevelsOfFairValueHierarchyAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_Liabilities": { "auth_ref": [ "r30", "r224", "r225", "r229", "r355", "r359" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "ifrs-full_NetAssetsLiabilities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of a present obligation of the entity to transfer an economic resource as a result of past events. Economic resource is a right that has the potential to produce economic benefits." } }, "en-us": { "role": { "label": "Liabilities", "totalLabel": "Total liabilities" } } }, "localname": "Liabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_LiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Liabilities [abstract]", "terseLabel": "Liabilities", "verboseLabel": "Liabilities:" } } }, "localname": "LiabilitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "stringItemType" }, "ifrs-full_LiabilitiesArisingFromInsuranceContracts": { "auth_ref": [ "r390", "r394", "r395", "r397", "r398" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 7.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities under insurance contracts and reinsurance contracts issued. [Refer: Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Liabilities under insurance contracts and reinsurance contracts issued", "terseLabel": "Life insurance liabilities" } } }, "localname": "LiabilitiesArisingFromInsuranceContracts", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale": { "auth_ref": [ "r27", "r266" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 12.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities included in disposal groups classified as held for sale. [Refer: Liabilities; Disposal groups classified as held for sale [member]]" } }, "en-us": { "role": { "label": "Liabilities included in disposal groups classified as held for sale", "terseLabel": "Liabilities held for sale", "verboseLabel": "Total liabilities held for sale" } } }, "localname": "LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_LiabilitiesMember": { "auth_ref": [ "r232" ], "lang": { "en": { "role": { "documentation": "This member stands for a present obligation of the entity to transfer an economic resource as a result of past events. Economic resource is a right that has the potential to produce economic benefits. It also represents the standard value for the 'Classes of liabilities' axis if no other member is used. [Refer: Liabilities]" } }, "en-us": { "role": { "label": "Liabilities [Member]", "terseLabel": "Liabilities [member]" } } }, "localname": "LiabilitiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LifeInsuranceContractsMember": { "auth_ref": [ "r402" ], "lang": { "en": { "role": { "documentation": "This member stands for life insurance contracts. [Refer: Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Life Insurance Contracts [Member]", "terseLabel": "Life insurance contracts" } } }, "localname": "LifeInsuranceContractsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LiquidityRiskMember": { "auth_ref": [ "r297", "r375", "r376", "r377" ], "lang": { "en": { "role": { "documentation": "This member stands for the risk that an entity will encounter difficulty in meeting obligations associated with financial liabilities that are settled by delivering cash or another financial asset. [Refer: Financial assets; Financial liabilities]" } }, "en-us": { "role": { "label": "Liquidity Risk [Member]", "terseLabel": "Liquidity risk" } } }, "localname": "LiquidityRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_LoansAndReceivables": { "auth_ref": [ "r411" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 6.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of non-derivative financial assets with fixed or determinable payments that are not quoted in an active market, other than: (a) those that the entity intends to sell immediately or in the near term, which shall be classified as held for trading, and those that the entity, upon initial recognition, designates as at fair value through profit or loss; (b) those that the entity, upon initial recognition, designates as available for sale; or (c) those for which the holder may not recover substantially all of its initial investment, other than because of credit deterioration, which shall be classified as available for sale. An interest acquired in a pool of assets that are not loans or receivables (for example, an interest in a mutual fund or a similar fund) is not a loan or receivable. [Refer: Derivative financial assets]" } }, "en-us": { "role": { "label": "Loans and receivables", "terseLabel": "Loans" } } }, "localname": "LoansAndReceivables", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_MajorComponentsOfTaxExpenseIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Income tax" } } }, "localname": "MajorComponentsOfTaxExpenseIncomeAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_MandatoryReserveDepositsAtCentralBanks": { "auth_ref": [ "r12" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of reserve that is kept in deposit at a central bank to fulfil regulatory reserve requirements." } }, "en-us": { "role": { "label": "Mandatory reserve deposits at central banks", "verboseLabel": "Restricted cash included in cash and balances with central banks" } } }, "localname": "MandatoryReserveDepositsAtCentralBanks", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_MarketRiskMember": { "auth_ref": [ "r297", "r375", "r376", "r377", "r378" ], "lang": { "en": { "role": { "documentation": "This member stands for the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices. Market risk comprises three types of risk: currency risk, interest rate risk and other price risk. [Refer: Currency risk [member]; Interest rate risk [member]; Other price risk [member]; Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Market Risk [Member]", "terseLabel": "Net market risk" } } }, "localname": "MarketRiskMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_MaterialReconcilingItemsMember": { "auth_ref": [ "r361" ], "lang": { "en": { "role": { "documentation": "This member stands for material adjustments used to reconcile items in the entity's financial statements." } }, "en-us": { "role": { "label": "Material Reconciling Items [Member]", "terseLabel": "Net cash earnings adjustment" } } }, "localname": "MaterialReconcilingItemsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_MaturityAnalysisForNonderivativeFinancialLiabilities": { "auth_ref": [ "r308" ], "lang": { "en": { "role": { "documentation": "The disclosure of a maturity analysis for non-derivative financial liabilities (including issued financial guarantee contracts) that shows the remaining contractual maturities. [Refer: Derivative financial liabilities]" } }, "en-us": { "role": { "label": "Disclosure of maturity analysis for non-derivative financial liabilities [text block]", "terseLabel": "Schedule of contractual maturities of financial liabilities" } } }, "localname": "MaturityAnalysisForNonderivativeFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "ifrs-full_MaturityAxis": { "auth_ref": [ "r34", "r242", "r249", "r250", "r278", "r317", "r329", "r372", "r374", "r380" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Maturity [axis]" } } }, "localname": "MaturityAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_MaximumExposureToCreditRisk": { "auth_ref": [ "r303", "r406" ], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en": { "role": { "documentation": "The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]]" } }, "en-us": { "role": { "label": "Maximum exposure to credit risk", "totalLabel": "Total gross credit risk" } } }, "localname": "MaximumExposureToCreditRisk", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities": { "auth_ref": [ "r208" ], "calculation": { "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en": { "role": { "documentation": "The amount that best represents the entity's maximum exposure to loss from its interests in structured entities. [Refer: Unconsolidated structured entities [member]]" } }, "en-us": { "role": { "label": "Maximum exposure to loss from interests in structured entities", "totalLabel": "Maximum exposure to loss" } } }, "localname": "MaximumExposureToLossFromInterestsInStructuredEntities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_MeasurementAxis": { "auth_ref": [ "r162", "r166", "r224" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Measurement [axis]" } } }, "localname": "MeasurementAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_MethodOfAssessmentOfExpectedCreditLossesAxis": { "auth_ref": [ "r300", "r302", "r339" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Method of assessment of expected credit losses [axis]" } } }, "localname": "MethodOfAssessmentOfExpectedCreditLossesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_MethodOfAssessmentOfExpectedCreditLossesMember": { "auth_ref": [ "r300", "r302", "r339" ], "lang": { "en": { "role": { "documentation": "This member stands for all methods of assessment of expected credit losses. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights. This member also represents the standard value for the 'Method of assessment of expected credit losses' axis if no other member is used." } }, "en-us": { "role": { "label": "Method Of Assessment Of Expected Credit Losses [Member]", "terseLabel": "Method of assessment of expected credit losses [member]" } } }, "localname": "MethodOfAssessmentOfExpectedCreditLossesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_MiscellaneousOtherOperatingExpense": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 7.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of miscellaneous other operating expenses. [Refer: Other operating income (expense)]" } }, "en-us": { "role": { "label": "Miscellaneous other operating expense", "verboseLabel": "Other" } } }, "localname": "MiscellaneousOtherOperatingExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetAssetsLiabilities": { "auth_ref": [ "r12", "r198" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of assets less the amount of liabilities." } }, "en-us": { "role": { "label": "Assets (liabilities)", "totalLabel": "Net assets" } } }, "localname": "NetAssetsLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetDeferredTaxAssets": { "auth_ref": [ "r74" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 14.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of deferred tax assets net of deferred tax liabilities, when the absolute amount of deferred tax assets is greater than the absolute amount of deferred tax liabilities. [Refer: Deferred tax assets; Deferred tax liabilities]" } }, "en-us": { "role": { "label": "Net deferred tax assets", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year", "totalLabel": "Net deferred tax assets", "verboseLabel": "Deferred tax assets" } } }, "localname": "NetDeferredTaxAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetDeferredTaxLiabilities": { "auth_ref": [ "r74" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 10.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of deferred tax liabilities net of deferred tax assets, when the absolute amount of deferred tax liabilities is greater than the absolute amount of deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]" } }, "en-us": { "role": { "label": "Net deferred tax liabilities", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year", "terseLabel": "Deferred tax liabilities", "totalLabel": "Net deferred tax liabilities" } } }, "localname": "NetDeferredTaxLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r273" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial assets, from the net amount of financial assets subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position." } }, "en-us": { "role": { "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements", "totalLabel": "Net amount" } } }, "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements [abstract]", "terseLabel": "Assets" } } }, "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition": { "auth_ref": [ "r270" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The net amount of financial assets that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement, presented in the statement of financial position. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position", "totalLabel": "Net amounts reported on the balance sheet" } } }, "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract]", "terseLabel": "Effects of offsetting in the balance sheet" } } }, "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [ "r273" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial liabilities, from the net amount of financial liabilities subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position." } }, "en-us": { "role": { "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements", "totalLabel": "Net amount" } } }, "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements [abstract]", "terseLabel": "Liabilities" } } }, "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition": { "auth_ref": [ "r270" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The net amount of financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement, presented in the statement of financial position. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position", "totalLabel": "Net amounts reported on the balance sheet" } } }, "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract]", "terseLabel": "Effects of offsetting in the balance sheet" } } }, "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_NetworkInfrastructureMember": { "auth_ref": [ "r78" ], "lang": { "en": { "role": { "documentation": "This member stands for a class of property, plant and equipment representing network infrastructure. [Refer: Property, plant and equipment]" } }, "en-us": { "role": { "label": "Network Infrastructure [Member]", "terseLabel": "IT equipment" } } }, "localname": "NetworkInfrastructureMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NominalAmountOfHedgingInstrument": { "auth_ref": [ "r278", "r281" ], "lang": { "en": { "role": { "documentation": "The nominal amount of a hedging instrument. [Refer: Hedging instruments [member]]" } }, "en-us": { "role": { "label": "Nominal amount of hedging instrument", "terseLabel": "Notional amounts", "verboseLabel": "Hedging (notional amount)" } } }, "localname": "NominalAmountOfHedgingInstrument", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NonadjustingEventsAfterReportingPeriodAxis": { "auth_ref": [ "r65" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Non-adjusting events after reporting period [axis]" } } }, "localname": "NonadjustingEventsAfterReportingPeriodAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_NonadjustingEventsMember": { "auth_ref": [ "r65" ], "lang": { "en": { "role": { "documentation": "This member stands for events that occur between the end of the reporting period and the date when the financial statements are authorised for issue and are indicative of conditions that arose after the reporting period. It also represents the standard value for the 'Non-adjusting events after reporting period' axis if no other member is used." } }, "en-us": { "role": { "label": "Nonadjusting Events [Member]", "terseLabel": "Non-adjusting events after reporting period [member]" } } }, "localname": "NonadjustingEventsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NoncontrollingInterests": { "auth_ref": [ "r28", "r199", "r202" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "ifrs-full_Equity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of equity in a subsidiary not attributable, directly or indirectly, to a parent. [Refer: Subsidiaries [member]]" } }, "en-us": { "role": { "label": "Non-controlling interests", "terseLabel": "NCI" } } }, "localname": "NoncontrollingInterests", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NoncontrollingInterestsMember": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "This member stands for equity in a subsidiary not attributable, directly or indirectly, to the parent." } }, "en-us": { "role": { "label": "Noncontrolling Interests [Member]", "terseLabel": "NCI" } } }, "localname": "NoncontrollingInterestsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_NoncurrentAssetsHeldForSaleMember": { "auth_ref": [ "r233", "r237", "r266" ], "lang": { "en": { "role": { "documentation": "This member stands for non-current assets that are available for immediate sale in their present condition, subject only to terms that are usual and customary for sales of such assets, and for which sale is highly probable. [Refer: Non-current assets]" } }, "en-us": { "role": { "label": "Noncurrent Assets Held For Sale [Member]", "terseLabel": "Assets held for sale" } } }, "localname": "NoncurrentAssetsHeldForSaleMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners": { "auth_ref": [ "r21" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 17.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of non-current assets or disposal groups classified as held for sale or as held for distribution to owners. [Refer: Non-current assets or disposal groups classified as held for distribution to owners; Non-current assets or disposal groups classified as held for sale]" } }, "en-us": { "role": { "label": "Non-current assets or disposal groups classified as held for sale or as held for distribution to owners", "terseLabel": "Assets held for sale", "verboseLabel": "Total assets held for sale" } } }, "localname": "NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NoncurrentAssetsOtherThanFinancialInstrumentsDeferredTaxAssetsPostemploymentBenefitAssetsAndRightsArisingUnderInsuranceContracts": { "auth_ref": [ "r364" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of non-current assets other than financial instruments, deferred tax assets, post-employment benefit assets and rights arising under insurance contracts. [Refer: Deferred tax assets; Financial instruments, class [member]; Non-current assets; Types of insurance contracts [member]]" } }, "en-us": { "role": { "label": "Non-current assets other than financial instruments, deferred tax assets, post-employment benefit assets, and rights arising under insurance contracts", "terseLabel": "Non-current assets" } } }, "localname": "NoncurrentAssetsOtherThanFinancialInstrumentsDeferredTaxAssetsPostemploymentBenefitAssetsAndRightsArisingUnderInsuranceContracts", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NoncurrentDebtInstrumentsIssued": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails": { "order": 2.0, "parentTag": "ifrs-full_DebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of non-current debt instruments issued. [Refer: Debt instruments issued]" } }, "en-us": { "role": { "label": "Non-current debt instruments issued", "terseLabel": "Long-term debt" } } }, "localname": "NoncurrentDebtInstrumentsIssued", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NotLaterThanOneMonthMember": { "auth_ref": [ "r325", "r331", "r341" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of not later than one month." } }, "en-us": { "role": { "label": "Not Later Than One Month [Member]", "terseLabel": "Up to 1 month" } } }, "localname": "NotLaterThanOneMonthMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NotLaterThanOneYearMember": { "auth_ref": [ "r32", "r249", "r250", "r329", "r341", "r380" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of not later than one year." } }, "en-us": { "role": { "label": "Not Later Than One Year [Member]", "terseLabel": "Up to 1 year" } } }, "localname": "NotLaterThanOneYearMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NotLaterThanThreeMonthsMember": { "auth_ref": [ "r12", "r408", "r413" ], "lang": { "en": { "role": { "documentation": "This member stands for a time band of not later than three months." } }, "en-us": { "role": { "label": "Not Later Than Three Months [Member]", "terseLabel": "Up to 3 months" } } }, "localname": "NotLaterThanThreeMonthsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember": { "auth_ref": [ "r234" ], "lang": { "en": { "role": { "documentation": "This member stands for items not measured at fair value in the statement of financial position but for which fair value is disclosed. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "Not Measured At Fair Value In Statement Of Financial Position But For Which Fair Value Is Disclosed [Member]", "terseLabel": "Not measured at fair value" } } }, "localname": "NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_NotionalAmount": { "auth_ref": [ "r12" ], "lang": { "en": { "role": { "documentation": "The nominal or face amount of a financial instrument, used to calculate payments made on that instrument." } }, "en-us": { "role": { "label": "Notional amount", "terseLabel": "Principal amount" } } }, "localname": "NotionalAmount", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted": { "auth_ref": [ "r256", "r258" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments granted in share-based payment arrangement", "terseLabel": "Granted during the year", "verboseLabel": "Total number of shares allocated" } } }, "localname": "NumberOfInstrumentsOtherEquityInstrumentsGranted", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOtherEquityInstrumentsExercisableInSharebasedPaymentArrangement": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) exercisable in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments exercisable in share-based payment arrangement", "terseLabel": "Outstanding and exercisable at the end of the year" } } }, "localname": "NumberOfOtherEquityInstrumentsExercisableInSharebasedPaymentArrangement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOtherEquityInstrumentsExercisedOrVestedInSharebasedPaymentArrangement": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) exercised or vested in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments exercised or vested in share-based payment arrangement", "terseLabel": "Exercised during the year" } } }, "localname": "NumberOfOtherEquityInstrumentsExercisedOrVestedInSharebasedPaymentArrangement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOtherEquityInstrumentsExpiredInSharebasedPaymentArrangement": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) expired in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments expired in share-based payment arrangement", "terseLabel": "Lapsed during the year" } } }, "localname": "NumberOfOtherEquityInstrumentsExpiredInSharebasedPaymentArrangement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) forfeited in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments forfeited in share-based payment arrangement", "terseLabel": "Forfeited during the year" } } }, "localname": "NumberOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The number of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of other equity instruments outstanding in share-based payment arrangement", "periodEndLabel": "Outstanding at the end of the year", "periodStartLabel": "Outstanding at the beginning of the year", "terseLabel": "Number of Share Rights" } } }, "localname": "NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfOutstandingShareOptions": { "auth_ref": [ "r252", "r253", "r255" ], "lang": { "en": { "role": { "documentation": "The number of share options outstanding in a share-based payment arrangement." } }, "en-us": { "role": { "label": "Number of share options outstanding in share-based payment arrangement", "periodEndLabel": "Outstanding at the end of the year", "periodStartLabel": "Outstanding at the beginning of the year", "terseLabel": "Number of options outstanding" } } }, "localname": "NumberOfOutstandingShareOptions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "ifrs-full_NumberOfSharesOutstanding": { "auth_ref": [ "r41" ], "lang": { "en": { "role": { "documentation": "The number of shares that have been authorised and issued, reduced by treasury shares held. [Refer: Treasury shares]" } }, "en-us": { "role": { "label": "Number of shares outstanding", "periodEndLabel": "Closing balance", "periodStartLabel": "Opening balance" } } }, "localname": "NumberOfSharesOutstanding", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "ifrs-full_OccupancyExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 2.0, "parentTag": "ifrs-full_OperatingExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense arising from occupancy services received by the entity." } }, "en-us": { "role": { "label": "Occupancy expense", "totalLabel": "Total occupancy expenses" } } }, "localname": "OccupancyExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OperatingExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 2.0, "parentTag": "ifrs-full_ProfitLossBeforeTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of all operating expenses." } }, "en-us": { "role": { "label": "Operating expense", "negatedLabel": "Operating expenses", "totalLabel": "Total operating expenses" } } }, "localname": "OperatingExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OperatingLeaseIncome": { "auth_ref": [ "r248" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 10.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of operating lease income. Operating lease is a lease that does not transfer substantially all the risks and rewards incidental to ownership of an underlying asset." } }, "en-us": { "role": { "label": "Operating lease income", "terseLabel": "Rental income on operating leases" } } }, "localname": "OperatingLeaseIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OperatingSegmentsMember": { "auth_ref": [ "r361" ], "lang": { "en": { "role": { "documentation": "This member stands for operating segments. An operating segment is a component of an entity: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same entity); (b) whose operating results are regularly reviewed by the entity\u2019s chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance; and (c) for which discrete financial information is available. [Refer: Revenue]" } }, "en-us": { "role": { "label": "Operating Segments [Member]", "terseLabel": "Operating segments" } } }, "localname": "OperatingSegmentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_OrdinarySharesMember": { "auth_ref": [ "r42", "r122" ], "lang": { "en": { "role": { "documentation": "This member stands for equity instruments that are subordinate to all other classes of equity instruments. It also represents the standard value for the 'Classes of ordinary shares' axis if no other member is used." } }, "en-us": { "role": { "label": "Ordinary Shares [Member]", "terseLabel": "Ordinary shares" } } }, "localname": "OrdinarySharesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_OtherAdjustmentsForNoncashItems": { "auth_ref": [ "r180" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 8.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "Adjustments for non-cash items to reconcile profit (loss) to net cash flow from (used in) operating activities that the entity does not separately disclose in the same statement or note. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Other adjustments for non-cash items", "terseLabel": "Other non-cash items" } } }, "localname": "OtherAdjustmentsForNoncashItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherAssets": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 16.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of assets that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other assets.", "terseLabel": "Other assets", "verboseLabel": "Other assets" } } }, "localname": "OtherAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherAssetsMember": { "auth_ref": [ "r247" ], "lang": { "en": { "role": { "documentation": "This member stands for assets that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other Assets [Member]", "terseLabel": "Other assets" } } }, "localname": "OtherAssetsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_OtherComprehensiveIncome": { "auth_ref": [ "r6", "r46", "r57", "r212" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 2.0, "parentTag": "ifrs-full_ComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income and expense (including reclassification adjustments) that is not recognised in profit or loss as required or permitted by IFRSs. [Refer: IFRSs [member]]" } }, "en-us": { "role": { "label": "Other comprehensive income", "totalLabel": "Other comprehensive income (expense) for the year (net of tax)", "verboseLabel": "Net other comprehensive income/(expense)" } } }, "localname": "OtherComprehensiveIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherComprehensiveIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Other comprehensive income [abstract]", "verboseLabel": "Other comprehensive income/(expense)" } } }, "localname": "OtherComprehensiveIncomeAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "ifrs-full_OtherComprehensiveIncomeNetOfTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability": { "auth_ref": [ "r35", "r57" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 11.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of other comprehensive income, net of tax, related to changes in the fair value of financial liabilities attributable to the changes in the credit risk of those liabilities. [Refer: Other comprehensive income; Credit risk [member]; Financial liabilities]" } }, "en-us": { "role": { "label": "Other comprehensive income, net of tax, change in fair value of financial liability attributable to change in credit risk of liability", "terseLabel": "Own credit adjustment on financial liabilities designated at fair value (net of tax)" } } }, "localname": "OtherComprehensiveIncomeNetOfTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments": { "auth_ref": [ "r35", "r57" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 10.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of other comprehensive income, net of tax, related to gains (losses) from changes in the fair value of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Other comprehensive income, net of tax, gains (losses) from investments in equity instruments", "terseLabel": "Gains/(losses) on equity instruments measured at FVOCI (net of tax)" } } }, "localname": "OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans": { "auth_ref": [ "r35", "r57" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 12.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of other comprehensive income, net of tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)]" } }, "en-us": { "role": { "label": "Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans", "terseLabel": "Remeasurement of defined benefit obligation recognised in equity (net of tax)" } } }, "localname": "OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherEquitySecuritiesMember": { "auth_ref": [ "r233", "r237" ], "lang": { "en": { "role": { "documentation": "This member stands for equity instruments that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other Equity Securities [Member]", "terseLabel": "Equity securities" } } }, "localname": "OtherEquitySecuritiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_OtherExpenseByNature": { "auth_ref": [ "r1", "r62" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 4.0, "parentTag": "ifrs-full_OperatingExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expenses that the entity does not separately disclose in the same statement or note when the entity uses the 'nature of expense' form for its analysis of expenses. [Refer: Expenses, by nature]" } }, "en-us": { "role": { "label": "Other expenses, by nature", "totalLabel": "Total other expenses" } } }, "localname": "OtherExpenseByNature", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherFeeAndCommissionExpense": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "ifrs-full_FeeAndCommissionExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of fee and commission expense that the entity does not separately disclose in the same statement or note. [Refer: Fee and commission expense]" } }, "en-us": { "role": { "label": "Other fee and commission expense", "negatedLabel": "Transaction fee related expenses" } } }, "localname": "OtherFeeAndCommissionExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherFinancialAssets": { "auth_ref": [ "r19" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 7.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of financial assets that the entity does not separately disclose in the same statement or note. [Refer: Financial assets]" } }, "en-us": { "role": { "label": "Other financial assets.", "terseLabel": "Other financial assets", "totalLabel": "Total other financial assets" } } }, "localname": "OtherFinancialAssets", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherFinancialLiabilities": { "auth_ref": [ "r24" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 3.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of financial liabilities that the entity does not separately disclose in the same statement or note. [Refer: Financial liabilities]" } }, "en-us": { "role": { "label": "Other financial liabilities.", "terseLabel": "Other financial liabilities", "totalLabel": "Total other financial liabilities" } } }, "localname": "OtherFinancialLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherIncome": { "auth_ref": [ "r1", "r2", "r114" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 4.0, "parentTag": "wbk_NonInterestIncomeExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of operating income that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other income", "totalLabel": "Total other income" } } }, "localname": "OtherIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherLiabilities": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 11.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other liabilities.", "terseLabel": "Other liabilities" } } }, "localname": "OtherLiabilities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherLongtermBenefits": { "auth_ref": [ "r95" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of long-term employee benefits other than post-employment benefits and termination benefits. Such benefits may include long-term paid absences, jubilee or other long-service benefits, long-term disability benefits, long-term profit-sharing and bonuses and long-term deferred remuneration. [Refer: Employee benefits expense]" } }, "en-us": { "role": { "label": "Other long-term employee benefits", "terseLabel": "Other employee benefits" } } }, "localname": "OtherLongtermBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherOperatingIncomeExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 5.0, "parentTag": "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of operating income (expense) that the entity does not separately disclose in the same statement or note." } }, "en-us": { "role": { "label": "Other operating income (expense)", "terseLabel": "Other income" } } }, "localname": "OtherOperatingIncomeExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherProvisions": { "auth_ref": [ "r37", "r139" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of provisions other than provisions for employee benefits. [Refer: Provisions]" } }, "en-us": { "role": { "label": "Other provisions", "periodEndLabel": "Balance at end of the year", "periodStartLabel": "Balance at beginning of year" } } }, "localname": "OtherProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherProvisionsMember": { "auth_ref": [ "r143" ], "lang": { "en": { "role": { "documentation": "This member stands for provisions other than provisions for employee benefits. It also represents the standard value for the 'Classes of other provisions' axis if no other member is used. [Refer: Provisions]" } }, "en-us": { "role": { "label": "Other Provisions [Member]", "terseLabel": "Other provisions" } } }, "localname": "OtherProvisionsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_OtherReserves": { "auth_ref": [ "r38" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 3.0, "parentTag": "ifrs-full_EquityAttributableToOwnersOfParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing reserves within equity, not including retained earnings. [Refer: Retained earnings]" } }, "en-us": { "role": { "label": "Other reserves", "terseLabel": "Reserves", "totalLabel": "Total reserves" } } }, "localname": "OtherReserves", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_OtherReservesMember": { "auth_ref": [ "r9", "r43" ], "lang": { "en": { "role": { "documentation": "This member stands for a component of equity representing reserves within equity, not including retained earnings. It also represents the standard value for the 'Reserves within equity' axis if no other member is used. [Refer: Retained earnings]" } }, "en-us": { "role": { "label": "Other Reserves [Member]", "terseLabel": "Reserves" } } }, "localname": "OtherReservesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_OtherTaxEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome": { "auth_ref": [ "r70" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 10.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that the entity does not separately disclose in the same statement or note. [Refer: Accounting profit; Applicable tax rate]" } }, "en-us": { "role": { "label": "Other tax effects for reconciliation between accounting profit and tax expense (income)", "terseLabel": "Other items" } } }, "localname": "OtherTaxEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ParValuePerShare": { "auth_ref": [ "r40" ], "lang": { "en": { "role": { "documentation": "The nominal value per share." } }, "en-us": { "role": { "label": "Par value per share", "terseLabel": "Par value" } } }, "localname": "ParValuePerShare", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "ifrs-full_PaymentsForPremiumsAndClaimsAnnuitiesAndOtherPolicyBenefits": { "auth_ref": [ "r391" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 10.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for premiums and claims, annuities and other policy benefits." } }, "en-us": { "role": { "label": "Payments for premiums and claims, annuities and other policy benefits", "negatedLabel": "Payments to policyholders and suppliers" } } }, "localname": "PaymentsForPremiumsAndClaimsAnnuitiesAndOtherPolicyBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities": { "auth_ref": [ "r177" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 3.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for payment of lease liabilities, classified as financing activities. [Refer: Lease liabilities]" } }, "en-us": { "role": { "label": "Payments of lease liabilities, classified as financing activities", "negatedLabel": "Payments for the principal portion of lease liabilities" } } }, "localname": "PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PaymentsToSuppliersForGoodsAndServicesAndToAndOnBehalfOfEmployees": { "auth_ref": [ "r170" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 5.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for payments to suppliers for goods and services and to, and on behalf of, employees." } }, "en-us": { "role": { "label": "Payments to suppliers for goods and services and to and on behalf of employees", "negatedLabel": "Operating expenses paid" } } }, "localname": "PaymentsToSuppliersForGoodsAndServicesAndToAndOnBehalfOfEmployees", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PercentageOfReasonablyPossibleDecreaseInActuarialAssumption": { "auth_ref": [ "r90" ], "lang": { "en": { "role": { "documentation": "The reasonably possible percentage of the decrease in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Percentage of reasonably possible decrease in actuarial assumption", "terseLabel": "Decrease in actuarial assumption (as a percent)" } } }, "localname": "PercentageOfReasonablyPossibleDecreaseInActuarialAssumption", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_PercentageOfReasonablyPossibleIncreaseInActuarialAssumption": { "auth_ref": [ "r90" ], "lang": { "en": { "role": { "documentation": "The reasonably possible percentage of the increase in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [member]]" } }, "en-us": { "role": { "label": "Percentage of reasonably possible increase in actuarial assumption", "terseLabel": "Increase in actuarial assumption (as a percent)" } } }, "localname": "PercentageOfReasonablyPossibleIncreaseInActuarialAssumption", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_PlanAssetsAtFairValue": { "auth_ref": [ "r97" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": 1.0, "parentTag": "ifrs-full_SurplusDeficitInPlan", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]" } }, "en-us": { "role": { "label": "Plan assets, at fair value", "verboseLabel": "Fair value of plan assets" } } }, "localname": "PlanAssetsAtFairValue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PortfolioAndOtherManagementFeeIncome": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "wbk_NetWealthManagementAndInsuranceIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income recognised from portfolio and other management fees." } }, "en-us": { "role": { "label": "Portfolio and other management fee income", "terseLabel": "Net wealth management income" } } }, "localname": "PortfolioAndOtherManagementFeeIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PostemploymentBenefitExpenseDefinedBenefitPlans": { "auth_ref": [ "r96" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of post-employment benefit expense relating to defined benefit plans. [Refer: Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Post-employment benefit expense, defined benefit plans", "totalLabel": "Total defined benefit expense" } } }, "localname": "PostemploymentBenefitExpenseDefinedBenefitPlans", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities": { "auth_ref": [ "r175" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 1.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from borrowings obtained. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Proceeds from borrowings, classified as financing activities", "verboseLabel": "Proceeds from debt issues (net of issue costs)" } } }, "localname": "ProceedsFromBorrowingsClassifiedAsFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromDisposalOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations": { "auth_ref": [ "r173" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails": { "order": 1.0, "parentTag": "wbk_TotalConsiderationFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails": { "order": 2.0, "parentTag": "wbk_ProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperationsNetOfCashDeconsolidated", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from the disposal of non-current assets or disposal groups classified as held for sale and discontinued operations. [Refer: Discontinued operations [member]; Disposal groups classified as held for sale [member]; Non-current assets or disposal groups classified as held for sale]" } }, "en-us": { "role": { "label": "Proceeds from disposal of non-current assets or disposal groups classified as held for sale and discontinued operations", "verboseLabel": "Cash proceeds received (net of transaction costs)" } } }, "localname": "ProceedsFromDisposalOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromIssuingShares": { "auth_ref": [ "r174" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 6.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from issuing shares." } }, "en-us": { "role": { "label": "Proceeds from issuing shares", "terseLabel": "Proceeds from issuances of shares" } } }, "localname": "ProceedsFromIssuingShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromSalesOfInterestsInAssociates": { "auth_ref": [ "r173" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 6.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from sales of interests in associates. [Refer: Associates [member]]" } }, "en-us": { "role": { "label": "Proceeds from sales of interests in associates", "terseLabel": "Proceeds from disposal of associates" } } }, "localname": "ProceedsFromSalesOfInterestsInAssociates", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromSalesOfInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod": { "auth_ref": [ "r173" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 1.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from sales of investments other than investments accounted for using the equity method. [Refer: Investments accounted for using equity method; Investments other than investments accounted for using equity method]" } }, "en-us": { "role": { "label": "Proceeds from sales of investments other than investments accounted for using equity method", "terseLabel": "Proceeds from investment securities" } } }, "localname": "ProceedsFromSalesOfInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities": { "auth_ref": [ "r172" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 8.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from sales of property, plant and equipment, classified as investing activities. [Refer: Property, plant and equipment]" } }, "en-us": { "role": { "label": "Proceeds from sales of property, plant and equipment, classified as investing activities", "terseLabel": "Proceeds from disposal of property and equipment" } } }, "localname": "ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProductsAndServicesAxis": { "auth_ref": [ "r243", "r362" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Products and services [axis]" } } }, "localname": "ProductsAndServicesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ProductsAndServicesMember": { "auth_ref": [ "r243", "r362" ], "lang": { "en": { "role": { "documentation": "This member stands for the entity's products and services. It also represents the standard value for the 'Products and services' axis if no other member is used." } }, "en-us": { "role": { "label": "Products And Services [Member]", "terseLabel": "Products and services [member]" } } }, "localname": "ProductsAndServicesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ProfitLoss": { "auth_ref": [ "r5", "r45", "r179", "r195", "r197", "r209", "r355", "r357", "r373", "r387" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 1.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementConsolidatedIncomeStatementCalc2": { "order": 1.0, "parentTag": "ifrs-full_ProfitLossAttributableToOwnersOfParent", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 1.0, "parentTag": "ifrs-full_ComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Profit (loss)", "terseLabel": "Net profit", "totalLabel": "Net profit", "verboseLabel": "Net profit for the year" } } }, "localname": "ProfitLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProfitLossAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Profit (loss) [abstract]", "verboseLabel": "Income statements" } } }, "localname": "ProfitLossAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "stringItemType" }, "ifrs-full_ProfitLossAttributableToNoncontrollingInterests": { "auth_ref": [ "r48", "r201" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails": { "order": 3.0, "parentTag": "wbk_ProfitLossFromOperationsBeforeCashEarningsAdjustment", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementConsolidatedIncomeStatementCalc2": { "order": 2.0, "parentTag": "ifrs-full_ProfitLossAttributableToOwnersOfParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The profit (loss) from continuing and discontinued operations attributable to non-controlling interests. [Refer: Profit (loss); Non-controlling interests]" } }, "en-us": { "role": { "label": "Profit (loss), attributable to non-controlling interests", "terseLabel": "Net profit attributable to NCI", "verboseLabel": "Net profit attributable to non-controlling interests (NCI)" } } }, "localname": "ProfitLossAttributableToNoncontrollingInterests", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity": { "auth_ref": [ "r123" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The profit (loss) attributable to ordinary equity holders of the parent entity. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Profit (loss), attributable to ordinary equity holders of parent entity", "totalLabel": "Adjusted net profit attributable to owners of WBC - Basic" } } }, "localname": "ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects": { "auth_ref": [ "r123" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The profit (loss) attributable to ordinary equity holders of the parent entity, adjusted for the effects of all dilutive potential ordinary shares. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Profit (loss), attributable to ordinary equity holders of parent entity including dilutive effects", "totalLabel": "Adjusted net profit attributable to owners of WBC - Diluted" } } }, "localname": "ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProfitLossAttributableToOwnersOfParent": { "auth_ref": [ "r49" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 2.0, "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementConsolidatedIncomeStatementCalc2": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The profit (loss) from continuing and discontinued operations attributable to owners of the parent. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Profit (loss), attributable to owners of parent", "totalLabel": "Net profit attributable to owners of Westpac Banking Corporation (WBC)", "verboseLabel": "Net profit attributable to owners of WBC" } } }, "localname": "ProfitLossAttributableToOwnersOfParent", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ProfitLossBeforeTax": { "auth_ref": [ "r1", "r2", "r264", "r355", "r357" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails": { "order": 1.0, "parentTag": "wbk_ProfitLossFromOperationsBeforeCashEarningsAdjustment", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 1.0, "parentTag": "ifrs-full_ProfitLoss", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The profit (loss) before tax expense or income. [Refer: Profit (loss)]" } }, "en-us": { "role": { "label": "Profit (loss) before tax", "totalLabel": "Profit before income tax (expense)/benefit" } } }, "localname": "ProfitLossBeforeTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PropertyPlantAndEquipment": { "auth_ref": [ "r17", "r80" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 13.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period." } }, "en-us": { "role": { "label": "Property, plant and equipment", "terseLabel": "Property and equipment" } } }, "localname": "PropertyPlantAndEquipment", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PropertyPlantAndEquipmentMember": { "auth_ref": [ "r81", "r128", "r247" ], "lang": { "en": { "role": { "documentation": "This member stands for property, plant and equipment. It also represents the standard value for the 'Classes of property, plant and equipment' axis if no other member is used. [Refer: Property, plant and equipment]" } }, "en-us": { "role": { "label": "Property Plant And Equipment [Member]", "terseLabel": "Property and equipment" } } }, "localname": "PropertyPlantAndEquipmentMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ProportionOfOwnershipInterestInSubsidiary": { "auth_ref": [ "r117", "r119", "r204" ], "lang": { "en": { "role": { "documentation": "The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Subsidiaries [member]]" } }, "en-us": { "role": { "label": "Proportion of ownership interest in subsidiary", "terseLabel": "Percentage owned" } } }, "localname": "ProportionOfOwnershipInterestInSubsidiary", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "percentItemType" }, "ifrs-full_ProvisionForCreditCommitmentsMember": { "auth_ref": [ "r143" ], "lang": { "en": { "role": { "documentation": "This member stands for a provision for credit commitments entered into by the entity. [Refer: Other provisions [member]]" } }, "en-us": { "role": { "label": "Provision For Credit Commitments [Member]", "terseLabel": "Provision for ECL on credit commitments" } } }, "localname": "ProvisionForCreditCommitmentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ProvisionUsedOtherProvisions": { "auth_ref": [ "r141" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount used (ie incurred and charged against the provision) for other provisions. [Refer: Other provisions]" } }, "en-us": { "role": { "label": "Provision used, other provisions", "negatedLabel": "Utilisation" } } }, "localname": "ProvisionUsedOtherProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_Provisions": { "auth_ref": [ "r23" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 9.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of liabilities of uncertain timing or amount." } }, "en-us": { "role": { "label": "Provisions.", "terseLabel": "Provisions" } } }, "localname": "Provisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities": { "auth_ref": [ "r171" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 10.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for the purchases of intangible assets, classified as investing activities. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Purchase of intangible assets, classified as investing activities", "negatedLabel": "Purchase of intangible assets" } } }, "localname": "PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PurchaseOfInterestsInAssociates": { "auth_ref": [ "r173" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 7.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for the purchase of interests in associates. [Refer: Associates [member]]" } }, "en-us": { "role": { "label": "Purchase of interests in associates", "negatedLabel": "Purchase of associates" } } }, "localname": "PurchaseOfInterestsInAssociates", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PurchaseOfInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod": { "auth_ref": [ "r173" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 2.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for the purchase of investments other than investments accounted for using equity method. [Refer: Investments accounted for using equity method; Investments other than investments accounted for using equity method]" } }, "en-us": { "role": { "label": "Purchase of investments other than investments accounted for using equity method", "negatedLabel": "Purchase of investment securities" } } }, "localname": "PurchaseOfInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities": { "auth_ref": [ "r171" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 9.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow for the purchases of property, plant and equipment, classified as investing activities. [Refer: Property, plant and equipment]" } }, "en-us": { "role": { "label": "Purchase of property, plant and equipment, classified as investing activities", "negatedLabel": "Purchase of property and equipment" } } }, "localname": "PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RangeAxis": { "auth_ref": [ "r236", "r238", "r240", "r255", "r320", "r374" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Range [axis]" } } }, "localname": "RangeAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_RangesMember": { "auth_ref": [ "r236", "r238", "r240", "r255", "r320", "r374" ], "lang": { "en": { "role": { "documentation": "This member stands for aggregate ranges. It also represents the standard value for the 'Range' axis if no other member is used." } }, "en-us": { "role": { "label": "Ranges [Member]", "terseLabel": "Ranges [member]" } } }, "localname": "RangesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ReceiptsFromPremiumsAndClaimsAnnuitiesAndOtherPolicyBenefits": { "auth_ref": [ "r391" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 7.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from premiums and claims, annuities and other policy benefits." } }, "en-us": { "role": { "label": "Receipts from premiums and claims, annuities and other policy benefits", "terseLabel": "Receipts from policyholders and customers" } } }, "localname": "ReceiptsFromPremiumsAndClaimsAnnuitiesAndOtherPolicyBenefits", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReceiptsFromRoyaltiesFeesCommissionsAndOtherRevenue": { "auth_ref": [ "r169" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 4.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The cash inflow from royalties, fees, commissions and other revenue. [Refer: Other revenue]" } }, "en-us": { "role": { "label": "Receipts from royalties, fees, commissions and other revenue", "terseLabel": "Other non-interest income received" } } }, "localname": "ReceiptsFromRoyaltiesFeesCommissionsAndOtherRevenue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax": { "auth_ref": [ "r59", "r405" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 4.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of reclassification adjustments related to cash flow hedges, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Cash flow hedges [member]; Other comprehensive income]" } }, "en-us": { "role": { "label": "Reclassification adjustments on cash flow hedges, before tax", "negatedLabel": "Cash flow hedging instruments", "negatedTerseLabel": "Transferred to income statements" } } }, "localname": "ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax": { "auth_ref": [ "r59", "r99" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 5.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of reclassification adjustments related to exchange differences when the financial statements of foreign operations are translated, net of tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Reclassification adjustments on exchange differences on translation, net of tax", "negatedLabel": "Foreign currency translation reserve", "negatedTerseLabel": "Transferred to income statements" } } }, "localname": "ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax": { "auth_ref": [ "r59", "r275" ], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 3.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of reclassification adjustments related to financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]" } }, "en-us": { "role": { "label": "Reclassification adjustments on financial assets measured at fair value through other comprehensive income, before tax", "negatedLabel": "Debt securities measured at FVOCI", "negatedTerseLabel": "Transferred to income statement" } } }, "localname": "ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RecognisedAssetsDefinedBenefitPlan": { "auth_ref": [ "r30" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Net defined benefit asset", "verboseLabel": "Defined benefit surplus included in other assets" } } }, "localname": "RecognisedAssetsDefinedBenefitPlan", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RecognisedLiabilitiesDefinedBenefitPlan": { "auth_ref": [ "r30" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of deficit in a defined benefit plan. [Refer: Defined benefit plans [member]]" } }, "en-us": { "role": { "label": "Net defined benefit liability", "negatedLabel": "Defined benefit deficit included in other liabilities" } } }, "localname": "RecognisedLiabilitiesDefinedBenefitPlan", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReconciliationOfAccountingProfitMultipliedByApplicableTaxRatesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of accounting profit multiplied by applicable tax rates [abstract]", "terseLabel": "Income tax expense reconciled to profit before income tax expense" } } }, "localname": "ReconciliationOfAccountingProfitMultipliedByApplicableTaxRatesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInFairValueMeasurementAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in fair value measurement, assets [abstract]", "terseLabel": "Assets" } } }, "localname": "ReconciliationOfChangesInFairValueMeasurementAssetsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInFairValueMeasurementLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in fair value measurement, liabilities [abstract]", "terseLabel": "Liabilities" } } }, "localname": "ReconciliationOfChangesInFairValueMeasurementLiabilitiesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInGoodwillAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in goodwill [abstract]", "terseLabel": "Goodwill" } } }, "localname": "ReconciliationOfChangesInGoodwillAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in intangible assets other than goodwill [abstract]", "terseLabel": "Intangible assets other than goodwill" } } }, "localname": "ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssuedAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in liabilities under insurance contracts and reinsurance contracts issued [abstract]", "terseLabel": "Reconciliation of movements in policy liabilities" } } }, "localname": "ReconciliationOfChangesInLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssuedAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfChangesInOtherProvisionsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of changes in other provisions" } } }, "localname": "ReconciliationOfChangesInOtherProvisionsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_ReconciliationOfNumberOfSharesOutstandingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Reconciliation of number of shares outstanding [abstract]", "terseLabel": "Reconciliation of movement in number of ordinary shares" } } }, "localname": "ReconciliationOfNumberOfSharesOutstandingAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_RecurringFairValueMeasurementMember": { "auth_ref": [ "r224" ], "lang": { "en": { "role": { "documentation": "This member stands for fair value measurements which other IFRSs require or permit in the statement of financial position at the end of each reporting period. [Refer: IFRSs [member]]" } }, "en-us": { "role": { "label": "Recurring Fair Value Measurement [Member]", "terseLabel": "Recurring" } } }, "localname": "RecurringFairValueMeasurementMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_RentalExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 1.0, "parentTag": "ifrs-full_OccupancyExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense recognised on rental activities." } }, "en-us": { "role": { "label": "Rental expense", "terseLabel": "Lease expense" } } }, "localname": "RentalExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities": { "auth_ref": [ "r176" ], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 2.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The cash outflow to settle borrowings, classified as financing activities. [Refer: Borrowings]" } }, "en-us": { "role": { "label": "Repayments of borrowings, classified as financing activities", "negatedLabel": "Redemption of debt issues" } } }, "localname": "RepaymentsOfBorrowingsClassifiedAsFinancingActivities", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfCashFlowHedges": { "auth_ref": [ "r38", "r368" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 2.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing the accumulated portion of gain (loss) on a hedging instrument that is determined to be an effective hedge for cash flow hedges. [Refer: Cash flow hedges [member]]" } }, "en-us": { "role": { "label": "Reserve of cash flow hedges", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveOfCashFlowHedges", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied": { "auth_ref": [ "r288" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing the reserve of cash flow hedges in relation to hedging relationships for which hedge accounting is no longer applied. [Refer: Reserve of cash flow hedges]" } }, "en-us": { "role": { "label": "Reserve of cash flow hedges, hedging relationships for which hedge accounting is no longer applied", "negatedLabel": "Losses in cash flow hedge reserve relating to hedge relationships for which hedge accounting is no longer applied" } } }, "localname": "ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfExchangeDifferencesOnTranslation": { "auth_ref": [ "r100" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 3.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing exchange differences on translation of financial statements of foreign operations recognised in other comprehensive income and accumulated in equity. [Refer: Other comprehensive income]" } }, "en-us": { "role": { "label": "Reserve of exchange differences on translation", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveOfExchangeDifferencesOnTranslation", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfGainsAndLossesFromInvestmentsInEquityInstruments": { "auth_ref": [ "r38" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 5.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing accumulated gains and losses from investments in equity instruments that the entity has designated at fair value through other comprehensive income." } }, "en-us": { "role": { "label": "Reserve of gains and losses from investments in equity instruments", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveOfGainsAndLossesFromInvestmentsInEquityInstruments", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfGainsAndLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": { "auth_ref": [ "r38" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 6.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing the reserve of gains and losses on financial assets measured at fair value through other comprehensive income. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]" } }, "en-us": { "role": { "label": "Reserve of gains and losses on financial assets measured at fair value through other comprehensive income", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveOfGainsAndLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReserveOfSharebasedPayments": { "auth_ref": [ "r38" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 1.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity resulting from share-based payments." } }, "en-us": { "role": { "label": "Reserve of share-based payments", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveOfSharebasedPayments", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RestructuringProvisionMember": { "auth_ref": [ "r138" ], "lang": { "en": { "role": { "documentation": "This member stands for a provision for restructuring, such as the sale or termination of a line of business; closure of business locations in a country or region or relocation of activities from one country or region to another; changes in management structure; and fundamental reorganisations that have a material effect on the nature and focus of the entity's operations. [Refer: Other provisions [member]]" } }, "en-us": { "role": { "label": "Restructuring Provision [Member]", "terseLabel": "Restructuring provisions" } } }, "localname": "RestructuringProvisionMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_RetainedEarnings": { "auth_ref": [ "r38", "r63" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 4.0, "parentTag": "ifrs-full_EquityAttributableToOwnersOfParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "A component of equity representing the entity's cumulative undistributed earnings or deficit." } }, "en-us": { "role": { "label": "Retained earnings", "terseLabel": "Retained profits" } } }, "localname": "RetainedEarnings", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RetainedEarningsMember": { "auth_ref": [ "r9", "r11" ], "lang": { "en": { "role": { "documentation": "This member stands for a component of equity representing an entity's cumulative undistributed earnings or deficit." } }, "en-us": { "role": { "label": "Retained Earnings [Member]", "terseLabel": "Retained profits" } } }, "localname": "RetainedEarningsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "domainItemType" }, "ifrs-full_Revenue": { "auth_ref": [ "r1", "r2", "r52", "r209", "r211", "r264", "r351", "r356", "r362", "r363", "r366" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims." } }, "en-us": { "role": { "label": "Revenue", "terseLabel": "Revenue" } } }, "localname": "Revenue", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RevenueFromInterest": { "auth_ref": [ "r12", "r214", "r352", "r360" ], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 2.0, "parentTag": "ifrs-full_InterestRevenueExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income arising from interest." } }, "en-us": { "role": { "label": "Interest income", "terseLabel": "Interest income", "totalLabel": "Total interest income", "verboseLabel": "Total interest income" } } }, "localname": "RevenueFromInterest", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed": { "auth_ref": [ "r30" ], "calculation": { "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails": { "order": 2.0, "parentTag": "wbk_TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatement", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of instruments purchased for resale in reverse repurchase agreements and cash collateral on securities borrowed. [Refer: Repurchase agreements and cash collateral on securities lent]" } }, "en-us": { "role": { "label": "Reverse repurchase agreements and cash collateral on securities borrowed", "verboseLabel": "Reverse repurchase agreements" } } }, "localname": "ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_RiskDiversificationEffectMember": { "auth_ref": [ "r297" ], "lang": { "en": { "role": { "documentation": "This member stands for the effect of the diversification of risks arising from financial instruments. [Refer: Financial instruments, class [member]]" } }, "en-us": { "role": { "label": "Risk Diversification Effect [Member]", "terseLabel": "Diversification effect" } } }, "localname": "RiskDiversificationEffectMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_RiskExposuresAxis": { "auth_ref": [ "r379" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Risk exposures [axis]" } } }, "localname": "RiskExposuresAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_RiskExposuresMember": { "auth_ref": [ "r379" ], "lang": { "en": { "role": { "documentation": "This member stands for the risk exposures. It also represents the standard value for the 'Risk exposures' axis if no other member is used." } }, "en-us": { "role": { "label": "Risk Exposures [Member]", "terseLabel": "Risk exposures [member]" } } }, "localname": "RiskExposuresMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_SecuritisationVehiclesMember": { "auth_ref": [ "r218" ], "lang": { "en": { "role": { "documentation": "This member stands for vehicles used for the process of securitisation, whereby individual assets are pooled together and sold to a special purpose vehicle that issues debt instruments backed by the pool of assets." } }, "en-us": { "role": { "label": "Securitisation Vehicles [Member]", "terseLabel": "Financing to Securitisation Vehicles" } } }, "localname": "SecuritisationVehiclesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_SegmentConsolidationItemsAxis": { "auth_ref": [ "r355" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Segment consolidation items [axis]" } } }, "localname": "SegmentConsolidationItemsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_SegmentsAxis": { "auth_ref": [ "r84", "r131", "r241", "r355", "r383" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Segments [axis]" } } }, "localname": "SegmentsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_SegmentsMember": { "auth_ref": [ "r84", "r131", "r241", "r361", "r383" ], "lang": { "en": { "role": { "documentation": "This member stands for all segments of an entity. It also represents the standard value for the 'Segments' axis if no other member is used." } }, "en-us": { "role": { "label": "Segments [Member]", "terseLabel": "Segments [member]" } } }, "localname": "SegmentsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod": { "auth_ref": [ "r217" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 11.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The entity's share of the profit (loss) from continuing operations of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Continuing operations [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss) from continuing operations]" } }, "en-us": { "role": { "label": "Share of profit (loss) from continuing operations of associates and joint ventures accounted for using equity method", "terseLabel": "Share of associates' net profit/(loss)" } } }, "localname": "ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_SharebasedPaymentArrangementsMember": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "This member stands for an agreement between the entity or another group entity or any shareholder of the group entity and another party (including an employee) that entitles the other party to receive (a) cash or other assets of the entity for amounts that are based on the price (or value) of equity instruments (including shares or share options) of the entity or another group entity; or (b) equity instruments (including shares or share options) of the entity or another group entity, provided that the specified vesting conditions, if any, are met. It also represents the standard value for the 'Types of share-based payment arrangements' axis if no other member is used." } }, "en-us": { "role": { "label": "Sharebased Payment Arrangements [Member]", "terseLabel": "Share-based payment arrangements [member]" } } }, "localname": "SharebasedPaymentArrangementsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_ShorttermEmployeeBenefitsExpense": { "auth_ref": [ "r12" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 1.0, "parentTag": "ifrs-full_EmployeeBenefitsExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of expense from employee benefits (other than termination benefits) that are expected to be settled wholly within twelve months after the end of the annual reporting period in which the employees render the related services." } }, "en-us": { "role": { "label": "Short-term employee benefits expense", "terseLabel": "Employee remuneration, entitlements and on-costs" } } }, "localname": "ShorttermEmployeeBenefitsExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_SignificantInvestmentsInSubsidiariesAxis": { "auth_ref": [ "r118", "r120", "r221" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Subsidiaries [axis]" } } }, "localname": "SignificantInvestmentsInSubsidiariesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_StatementOfCashFlowsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Cash flow statements" } } }, "localname": "StatementOfCashFlowsAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_StatementOfChangesInEquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Statements of changes in equity" } } }, "localname": "StatementOfChangesInEquityAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_StatementOfChangesInEquityLineItems": { "auth_ref": [], "lang": { "en": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table." } }, "en-us": { "role": { "label": "Statement of changes in equity [line items]", "terseLabel": "Statements of changes in equity" } } }, "localname": "StatementOfChangesInEquityLineItems", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "stringItemType" }, "ifrs-full_StatementOfChangesInEquityTable": { "auth_ref": [ "r9" ], "lang": { "en": { "role": { "documentation": "Schedule disclosing information related to changes in equity." } }, "en-us": { "role": { "label": "Statement of changes in equity [table]" } } }, "localname": "StatementOfChangesInEquityTable", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "stringItemType" }, "ifrs-full_StatementOfComprehensiveIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Statements of comprehensive income" } } }, "localname": "StatementOfComprehensiveIncomeAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_StatementOfFinancialPositionAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Balance sheets" } } }, "localname": "StatementOfFinancialPositionAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "xbrltype": "stringItemType" }, "ifrs-full_SurplusDeficitInPlan": { "auth_ref": [ "r97" ], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]]" } }, "en-us": { "role": { "label": "Surplus (deficit) in plan", "totalLabel": "Net surplus/(deficit)" } } }, "localname": "SurplusDeficitInPlan", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_SurplusDeficitInPlanAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Surplus (deficit) in plan [abstract]", "terseLabel": "Defined benefit balances recognised" } } }, "localname": "SurplusDeficitInPlanAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TaxEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss": { "auth_ref": [ "r70" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 7.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to expenses not deductible in determining taxable profit (tax loss). [Refer: Accounting profit]" } }, "en-us": { "role": { "label": "Tax effect of expense not deductible in determining taxable profit (tax loss)", "terseLabel": "Other non-deductible items" } } }, "localname": "TaxEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TaxEffectOfForeignTaxRates": { "auth_ref": [ "r70" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 8.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to foreign tax rates. [Refer: Accounting profit]" } }, "en-us": { "role": { "label": "Tax effect of foreign tax rates", "terseLabel": "Adjustment for overseas tax rates" } } }, "localname": "TaxEffectOfForeignTaxRates", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TaxEffectOfRevenuesExemptFromTaxation2011": { "auth_ref": [ "r70" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 6.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": -1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to revenues that are exempt from taxation. [Refer: Accounting profit]" } }, "en-us": { "role": { "label": "Tax effect of revenues exempt from taxation", "negatedLabel": "Other non-assessable items" } } }, "localname": "TaxEffectOfRevenuesExemptFromTaxation2011", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TaxExpenseIncomeAtApplicableTaxRate": { "auth_ref": [ "r70" ], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 1.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The product of the accounting profit multiplied by the applicable tax rate(s). [Refer: Accounting profit; Applicable tax rate]" } }, "en-us": { "role": { "label": "Tax expense (income) at applicable tax rate", "terseLabel": "Tax at the Australian company tax rate of 30%" } } }, "localname": "TaxExpenseIncomeAtApplicableTaxRate", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis": { "auth_ref": [ "r76" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Temporary difference, unused tax losses and unused tax credits [axis]" } } }, "localname": "TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsMember": { "auth_ref": [ "r76" ], "lang": { "en": { "role": { "documentation": "This member stands for temporary differences, unused tax losses and unused tax credits. It also represents the standard value for the 'Temporary difference, unused tax losses and unused tax credits' axis if no other member is used. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]" } }, "en-us": { "role": { "label": "Temporary Difference Unused Tax Losses And Unused Tax Credits [Member]", "terseLabel": "Temporary difference, unused tax losses and unused tax credits [member]" } } }, "localname": "TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures": { "auth_ref": [ "r73" ], "lang": { "en": { "role": { "documentation": "The aggregate amount of temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements, for which deferred tax liabilities have not been recognised as a result of satisfying both of the following conditions: (a) the parent, investor, joint venturer or joint operator is able to control the timing of the reversal of the temporary difference; and (b) it is probable that the temporary difference will not reverse in the foreseeable future. [Refer: Associates [member]; Subsidiaries [member]; Temporary differences [member]; Investments in subsidiaries]" } }, "en-us": { "role": { "label": "Temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements for which deferred tax liabilities have not been recognised", "terseLabel": "Unrecognised deferred tax liability: Gross retained earnings of subsidiaries which the Parent Entity does not intend to distribute in the foreseeable future" } } }, "localname": "TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TopOfRangeMember": { "auth_ref": [ "r236", "r238", "r240", "r255", "r320", "r374" ], "lang": { "en": { "role": { "documentation": "This member stands for top of a range." } }, "en-us": { "role": { "label": "Top Of Range [Member]", "terseLabel": "Maximum" } } }, "localname": "TopOfRangeMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TradeAndOtherPayables": { "auth_ref": [ "r22" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 8.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of trade payables and other payables. [Refer: Trade payables; Other payables]" } }, "en-us": { "role": { "label": "Trade and other payables", "verboseLabel": "Trade creditors and other accrued expenses" } } }, "localname": "TradeAndOtherPayables", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TradeAndOtherPayablesToRelatedParties": { "auth_ref": [ "r39" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 8.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of payables due to related parties. [Refer: Related parties [member]]" } }, "en-us": { "role": { "label": "Payables to related parties", "terseLabel": "Due to subsidiaries" } } }, "localname": "TradeAndOtherPayablesToRelatedParties", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TradeAndOtherReceivablesDueFromRelatedParties": { "auth_ref": [ "r36" ], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 10.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount of receivables due from related parties. [Refer: Related parties [member]]" } }, "en-us": { "role": { "label": "Receivables due from related parties", "terseLabel": "Due from subsidiaries" } } }, "localname": "TradeAndOtherReceivablesDueFromRelatedParties", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TradeReceivables": { "auth_ref": [ "r36" ], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 3.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount due from customers for goods and services sold." } }, "en-us": { "role": { "label": "Trade receivables", "terseLabel": "Trade debtors" } } }, "localname": "TradeReceivables", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TradingEquitySecuritiesMember": { "auth_ref": [ "r233", "r237" ], "lang": { "en": { "role": { "documentation": "This member stands for equity instruments that (a) are acquired or incurred principally for the purpose of selling or repurchasing it in the near term; or (b) on initial recognition are part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking." } }, "en-us": { "role": { "label": "Trading Equity Securities [Member]", "terseLabel": "Equity securities" } } }, "localname": "TradingEquitySecuritiesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TradingIncomeExpense": { "auth_ref": [ "r55" ], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 3.0, "parentTag": "wbk_NonInterestIncomeExpense", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 4.0, "parentTag": "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "weight": 1.0 } }, "crdr": "credit", "lang": { "en": { "role": { "documentation": "The amount of income (expense) relating to trading assets and liabilities." } }, "en-us": { "role": { "label": "Trading income (expense)", "terseLabel": "Trading income" } } }, "localname": "TradingIncomeExpense", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TreasuryShares": { "auth_ref": [ "r38", "r121" ], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails": { "order": 2.0, "parentTag": "wbk_IssuedCapitalNetOfTreasuryShares", "weight": -1.0 }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "ifrs-full_EquityAttributableToOwnersOfParent", "weight": -1.0 } }, "crdr": "debit", "lang": { "en": { "role": { "documentation": "An entity\u2019s own equity instruments, held by the entity or other members of the consolidated group." } }, "en-us": { "role": { "label": "Treasury shares", "negatedLabel": "Treasury shares and Restricted Share Plan (RSP) treasury shares", "negatedTotalLabel": "Total treasury shares" } } }, "localname": "TreasuryShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "ifrs-full_TypesOfContractsAxis": { "auth_ref": [ "r246", "r381" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of contracts [axis]" } } }, "localname": "TypesOfContractsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfContractsMember": { "auth_ref": [ "r246", "r381" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of contracts with customers. It also represents the standard value for the 'Types of contracts' axis if no other member is used." } }, "en-us": { "role": { "label": "Types Of Contracts [Member]", "terseLabel": "Types of contracts [member]" } } }, "localname": "TypesOfContractsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TypesOfCustomersAxis": { "auth_ref": [ "r245" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of customers [axis]" } } }, "localname": "TypesOfCustomersAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfCustomersMember": { "auth_ref": [ "r245" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of customers. It also represents the standard value for the 'Types of customers' axis if no other member is used." } }, "en-us": { "role": { "label": "Types Of Customers [Member]", "terseLabel": "Types of customers [member]" } } }, "localname": "TypesOfCustomersMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TypesOfFinancialAssetsAxis": { "auth_ref": [ "r337", "r338" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of financial assets [axis]" } } }, "localname": "TypesOfFinancialAssetsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfHedgesAxis": { "auth_ref": [ "r282", "r289", "r293", "r403" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of hedges [axis]" } } }, "localname": "TypesOfHedgesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfHedgesMember": { "auth_ref": [ "r282", "r289", "r293", "r403" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of hedges. It also represents the standard value for the 'Types of hedges' axis if no other member is used." } }, "en-us": { "role": { "label": "Types Of Hedges [Member]", "terseLabel": "Hedges [member]" } } }, "localname": "TypesOfHedgesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TypesOfInsuranceContractsAxis": { "auth_ref": [ "r402" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of insurance contracts [axis]" } } }, "localname": "TypesOfInsuranceContractsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfInterestRatesAxis": { "auth_ref": [ "r311" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of interest rates [axis]" } } }, "localname": "TypesOfInterestRatesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfRisksAxis": { "auth_ref": [ "r276", "r298", "r299", "r375", "r376", "r377", "r379" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of risks [axis]" } } }, "localname": "TypesOfRisksAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_TypesOfRisksMember": { "auth_ref": [ "r276", "r298", "r299", "r375", "r376", "r377", "r379" ], "lang": { "en": { "role": { "documentation": "This member stands for all types of risks. It also represents the standard value for the 'Types of risks' axis if no other member is used." } }, "en-us": { "role": { "label": "Types Of Risks [Member]", "terseLabel": "Risks [member]" } } }, "localname": "TypesOfRisksMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_TypesOfSharebasedPaymentArrangementsAxis": { "auth_ref": [ "r256" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Types of share-based payment arrangements [axis]" } } }, "localname": "TypesOfSharebasedPaymentArrangementsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_UnconsolidatedSubsidiariesAxis": { "auth_ref": [ "r205" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Unconsolidated subsidiaries [axis]" } } }, "localname": "UnconsolidatedSubsidiariesAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_UnconsolidatedSubsidiariesMember": { "auth_ref": [ "r205" ], "lang": { "en": { "role": { "documentation": "This member stands for unconsolidated subsidiaries. [Refer: Subsidiaries [member]]" } }, "en-us": { "role": { "label": "Unconsolidated Subsidiaries [Member]", "terseLabel": "Non-consolidated entities" } } }, "localname": "UnconsolidatedSubsidiariesMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_UnobservableInputsAxis": { "auth_ref": [ "r226", "r231" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Unobservable inputs [axis]" } } }, "localname": "UnobservableInputsAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_UnobservableInputsMember": { "auth_ref": [ "r226", "r231" ], "lang": { "en": { "role": { "documentation": "This member stands for all the unobservable inputs. It also represents the standard value for the 'Unobservable inputs' axis if no other member is used." } }, "en-us": { "role": { "label": "Unobservable Inputs [Member]", "terseLabel": "Unobservable inputs [member]" } } }, "localname": "UnobservableInputsMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_UnusedProvisionReversedOtherProvisions": { "auth_ref": [ "r142" ], "crdr": "debit", "lang": { "en": { "role": { "documentation": "The amount reversed for unused other provisions. [Refer: Other provisions]" } }, "en-us": { "role": { "label": "Unused provision reversed, other provisions", "negatedLabel": "Reversal of unutilised provisions" } } }, "localname": "UnusedProvisionReversedOtherProvisions", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised": { "auth_ref": [ "r72" ], "lang": { "en": { "role": { "documentation": "The amount of unused tax losses for which no deferred tax asset is recognised in the statement of financial position. [Refer: Unused tax losses [member]]" } }, "en-us": { "role": { "label": "Unused tax losses for which no deferred tax asset recognised", "verboseLabel": "Unrecognised deferred tax asset: Tax losses on revenue account" } } }, "localname": "UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill": { "auth_ref": [ "r149" ], "lang": { "en": { "role": { "documentation": "The useful life, measured as period of time, used for intangible assets other than goodwill. [Refer: Intangible assets other than goodwill]" } }, "en-us": { "role": { "label": "Useful life measured as period of time, intangible assets other than goodwill", "terseLabel": "Useful life (in years)" } } }, "localname": "UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsUsefulLifeDetails" ], "xbrltype": "durationItemType" }, "ifrs-full_ValueAtRisk": { "auth_ref": [ "r313" ], "lang": { "en": { "role": { "documentation": "The measure of a potential loss exposure as a result of future market movements, based on a specified confidence interval and measurement horizon." } }, "en-us": { "role": { "label": "Value at risk" } } }, "localname": "ValueAtRisk", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_VoluntaryChangesInAccountingPolicyAxis": { "auth_ref": [ "r191" ], "lang": { "en": { "role": { "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table." } }, "en-us": { "role": { "label": "Voluntary changes in accounting policy [axis]" } } }, "localname": "VoluntaryChangesInAccountingPolicyAxis", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "stringItemType" }, "ifrs-full_VoluntaryChangesInAccountingPolicyMember": { "auth_ref": [ "r191" ], "lang": { "en": { "role": { "documentation": "This member stands for changes in accounting policy that result in the financial statements providing reliable and more relevant information about the effects of transactions, other events or conditions on the entity\u2019s financial position, financial performance or cash flows. Early application of an IFRS is not considered a voluntary change in accounting policy. It also represents the standard value for the 'Voluntary changes in accounting policy' axis if no other member is used." } }, "en-us": { "role": { "label": "Voluntary Changes In Accounting Policy [Member]", "terseLabel": "Voluntary changes in accounting policy [member]" } } }, "localname": "VoluntaryChangesInAccountingPolicyMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_WeightedAverageDurationOfDefinedBenefitObligation2019": { "auth_ref": [ "r93" ], "lang": { "en": { "role": { "documentation": "The weighted average duration of a defined benefit obligation. [Refer: Weighted average [member]]" } }, "en-us": { "role": { "label": "Weighted average duration of defined benefit obligation", "terseLabel": "Average duration of the defined benefit obligation" } } }, "localname": "WeightedAverageDurationOfDefinedBenefitObligation2019", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "durationItemType" }, "ifrs-full_WeightedAverageFairValueAtMeasurementDateOtherEquityInstrumentsGranted": { "auth_ref": [ "r258" ], "crdr": "credit", "lang": { "en": { "role": { "documentation": "The weighted average fair value at the measurement date of granted equity instruments other than share options. [Refer: Weighted average [member]]" } }, "en-us": { "role": { "label": "Weighted average fair value at measurement date, other equity instruments granted", "terseLabel": "Weighted average fair value at grant date" } } }, "localname": "WeightedAverageFairValueAtMeasurementDateOtherEquityInstrumentsGranted", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "monetaryItemType" }, "ifrs-full_WeightedAverageMember": { "auth_ref": [ "r236", "r238", "r240", "r320", "r374" ], "lang": { "en": { "role": { "documentation": "This member stands for an average in which each quantity to be averaged is assigned a weight that determines the relative effect of each quantity on the average." } }, "en-us": { "role": { "label": "Weighted Average [Member]", "terseLabel": "Average" } } }, "localname": "WeightedAverageMember", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "ifrs-full_WeightedAverageSharePrice2019": { "auth_ref": [ "r254" ], "lang": { "en": { "role": { "documentation": "The weighted average share price. [Refer: Weighted average [member]]" } }, "en-us": { "role": { "label": "Weighted average share price", "terseLabel": "Average share price, ordinary shares" } } }, "localname": "WeightedAverageSharePrice2019", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "ifrs-full_WeightedAverageShares": { "auth_ref": [ "r124" ], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en": { "role": { "documentation": "The number of ordinary shares outstanding at the beginning of the period, adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time-weighting factor." } }, "en-us": { "role": { "label": "Weighted average number of ordinary shares outstanding", "totalLabel": "Adjusted weighted average number of ordinary shares - Basic" } } }, "localname": "WeightedAverageShares", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "ifrs-full_WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Weighted average ordinary shares and adjusted weighted average ordinary shares [abstract]", "terseLabel": "Weighted average number of ordinary shares (millions)" } } }, "localname": "WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract", "nsuri": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "stringItemType" }, "srt_CondensedFinancialStatementsCaptionsLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Condensed Financial Statements, Captions [Line Items]", "terseLabel": "Consolidated financial statements" } } }, "localname": "CondensedFinancialStatementsCaptionsLineItems", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementCashFlowStatements", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "srt_ConsolidatedEntitiesAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Consolidated Entities [Axis]" } } }, "localname": "ConsolidatedEntitiesAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails", "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails", "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementCashFlowStatements", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "srt_ConsolidatedEntitiesDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Consolidated Entities [Domain]", "terseLabel": "Consolidated Entities [Domain]" } } }, "localname": "ConsolidatedEntitiesDomain", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails", "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails", "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementCashFlowStatements", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "domainItemType" }, "srt_CurrencyAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Currency [Axis]" } } }, "localname": "CurrencyAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "stringItemType" }, "srt_ParentCompanyMember": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Parent Company [Member]", "terseLabel": "Parent Entity" } } }, "localname": "ParentCompanyMember", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails", "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsChangesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails", "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails", "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementCashFlowStatements", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "domainItemType" }, "srt_RangeAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Statistical Measurement [Axis]" } } }, "localname": "RangeAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "stringItemType" }, "srt_RangeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Range [Member]", "terseLabel": "Statistical Measurement [Domain]" } } }, "localname": "RangeMember", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "domainItemType" }, "srt_RestatementAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Revision of Prior Period [Axis]" } } }, "localname": "RestatementAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "srt_RestatementDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Restatement [Domain]", "terseLabel": "Revision of Prior Period [Domain]" } } }, "localname": "RestatementDomain", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "srt_RevisionOfPriorPeriodChangeInAccountingPrincipleAdjustmentMember": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Revision Of Prior Period Change In Accounting Principle Adjustment [Member]", "terseLabel": "Change in accounting policy adjustment" } } }, "localname": "RevisionOfPriorPeriodChangeInAccountingPrincipleAdjustmentMember", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "srt_RevisionOfPriorPeriodReclassificationAdjustmentMember": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Revision Of Prior Period Reclassification Adjustment [Member]", "terseLabel": "Reclassification adjustment" } } }, "localname": "RevisionOfPriorPeriodReclassificationAdjustmentMember", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "srt_ScenarioForecastMember": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Scenario Forecast [Member]", "terseLabel": "Forecast" } } }, "localname": "ScenarioForecastMember", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "domainItemType" }, "srt_ScenarioUnspecifiedDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Scenario Unspecified [Domain]", "terseLabel": "Scenario [Domain]" } } }, "localname": "ScenarioUnspecifiedDomain", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "domainItemType" }, "srt_ScheduleOfCondensedFinancialStatementsTable": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Condensed Financial Statements [Table]" } } }, "localname": "ScheduleOfCondensedFinancialStatementsTable", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementBalanceSheets", "http://www.westpac.com.au/role/StatementCashFlowStatements", "http://www.westpac.com.au/role/StatementIncomeStatements", "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "srt_StatementScenarioAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Scenario [Axis]" } } }, "localname": "StatementScenarioAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails", "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "stringItemType" }, "srt_TitleOfIndividualAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Title of Individual [Axis]" } } }, "localname": "TitleOfIndividualAxis", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "stringItemType" }, "srt_TitleOfIndividualWithRelationshipToEntityDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Title Of Individual With Relationship To Entity [Domain]", "terseLabel": "Title of Individual [Domain]" } } }, "localname": "TitleOfIndividualWithRelationshipToEntityDomain", "nsuri": "http://fasb.org/srt/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancialInstrumentAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Financial Instrument [Axis]" } } }, "localname": "FinancialInstrumentAxis", "nsuri": "http://fasb.org/us-gaap/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "label": "Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain]", "terseLabel": "Financial Instruments [Domain]" } } }, "localname": "TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain", "nsuri": "http://fasb.org/us-gaap/2020-01-31", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_AccommodationCafesAndRestaurantsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for accommodation, cafes and restaurants.", "label": "Accommodation Cafes And Restaurants [Member]", "terseLabel": "Accommodation, cafes and restaurants" } } }, "localname": "AccommodationCafesAndRestaurantsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_AccruedIncomeOtherThanContractAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 6.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of assets representing income that has been earned but is not yet a receivable, other than contract assets.", "label": "Accrued income other than contract assets", "terseLabel": "Accrued fees and commissions" } } }, "localname": "AccruedIncomeOtherThanContractAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AcquisitionAndIssuesFairValueMeasurementAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase in the fair value measurement of assets resulting from acquisition and issues of those assets.", "label": "Acquisition And Issues, Fair Value Measurement, Assets", "terseLabel": "Acquisition and issues" } } }, "localname": "AcquisitionAndIssuesFairValueMeasurementAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AcquisitionAndIssuesFairValueMeasurementLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase in the fair value measurement of liabilities resulting from acquisition and issues of those liabilities.", "label": "Acquisition And Issues, Fair Value Measurement, Liabilities", "terseLabel": "Acquisition and issues" } } }, "localname": "AcquisitionAndIssuesFairValueMeasurementLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ActuarialAssessmentLiability": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liability based on an actuarial assessment as a self-insurer.", "label": "Actuarial Assessment Liability", "terseLabel": "Assessed liabilities" } } }, "localname": "ActuarialAssessmentLiability", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ActuarialAssumptionOfLifeExpectancyAfterRetirementOfFemale": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The life expectancy after retirement of a female used as a significant actuarial assumption to determine the present value of a defined benefit obligation.", "label": "Actuarial Assumption Of Life Expectancy After Retirement Of Female", "terseLabel": "Life expectancy of a 60-year-old female" } } }, "localname": "ActuarialAssumptionOfLifeExpectancyAfterRetirementOfFemale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "durationItemType" }, "wbk_ActuarialAssumptionOfLifeExpectancyAfterRetirementOfMale": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The life expectancy after retirement of a male used as a significant actuarial assumption to determine the present value of a defined benefit obligation.", "label": "Actuarial Assumption Of Life Expectancy After Retirement Of Male", "terseLabel": "Life expectancy of a 60-year-old male" } } }, "localname": "ActuarialAssumptionOfLifeExpectancyAfterRetirementOfMale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSignificantAssumptionsDetails" ], "xbrltype": "durationItemType" }, "wbk_AdditionalAllowanceRecognisedInProfitOrLossAllowanceAccountForCreditLossesOfFinancialAssetsOtherThanLoansAndAdvances": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 5.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of additional allowance recognised in profit or loss for credit losses of financial assets other than loans and advances.", "label": "Additional allowance recognised in profit or loss, allowance account for credit losses of financial assets other than loans and advances", "terseLabel": "Non-lending losses" } } }, "localname": "AdditionalAllowanceRecognisedInProfitOrLossAllowanceAccountForCreditLossesOfFinancialAssetsOtherThanLoansAndAdvances", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdditionalTierOneLoanCapitalMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Additional Tier 1 (AT1) loan capital.", "label": "Additional Tier One Loan Capital [Member]", "terseLabel": "Additional Tier 1 (AT1) loan capital" } } }, "localname": "AdditionalTierOneLoanCapitalMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables" ], "xbrltype": "domainItemType" }, "wbk_AdjustmentDueToChangeInAccountingPolicy": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) due to a change in accounting policy.", "label": "Adjustment Due to Change in Accounting Policy", "negatedLabel": "Impact from a change in accounting policy" } } }, "localname": "AdjustmentDueToChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentImpactOnCurrentYearMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the impact to the current year of an adjustment.", "label": "Adjustment Impact On Current Year [Member]", "terseLabel": "Impact for 2021" } } }, "localname": "AdjustmentImpactOnCurrentYearMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "wbk_AdjustmentToProfitLossForDilutiveEffectOfConvertibleInstruments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 3.0, "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Adjustment to profit (loss) for distributions to convertible instrument holders to calculate profit (loss) attributable to ordinary equity holders of the parent equity including dilutive effects.", "label": "Adjustment to profit (loss) for dilutive effect of convertible instruments", "terseLabel": "Adjustment for potential dilution: Distributions to convertible loan capital holders" } } }, "localname": "AdjustmentToProfitLossForDilutiveEffectOfConvertibleInstruments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentToProfitLossForRestrictedSharePlanDividends": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 1.0, "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustment to profit (loss) for restricted share plan dividends to calculate profit (loss) attributable to ordinary equity holders of the parent equity.", "label": "Adjustment to profit (loss) for restricted share plan dividends", "negatedLabel": "Adjustment for RSP dividends - Basic" } } }, "localname": "AdjustmentToProfitLossForRestrictedSharePlanDividends", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentToProfitLossForRestrictedSharePlanDividendsDilutiveEffects": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 1.0, "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustment to profit (loss) for restricted share plan dividends to calculate profit (loss) attributable to ordinary equity holders of the parent equity, adjusted for the effects of all dilutive potential ordinary shares.", "label": "Adjustment To Profit (Loss) For Restricted Share Plan Dividends, Dilutive Effects", "negatedLabel": "Adjustment for RSP dividends - Diluted" } } }, "localname": "AdjustmentToProfitLossForRestrictedSharePlanDividendsDilutiveEffects", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForCurrentAndDeferredTaxOfPriorPeriods": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails": { "order": 3.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 9.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments of tax expense (income) recognised in the period for current and deferred tax of prior periods.", "label": "Adjustments for current and deferred tax of prior periods", "verboseLabel": "Income tax (over)/under provided in prior years" } } }, "localname": "AdjustmentsForCurrentAndDeferredTaxOfPriorPeriods", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForDecreaseIncreaseInDerivativeFinancialInstruments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 4.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in derivative financial instruments to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Adjustments for decrease (increase) in derivative financial instruments", "terseLabel": "Derivative financial instruments" } } }, "localname": "AdjustmentsForDecreaseIncreaseInDerivativeFinancialInstruments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForDecreaseIncreaseInFinancialAssetsAtFairValueThroughProfitOrLoss": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 3.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in financial assets at fair value through profit or loss to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Trading securities and financial assets measured at FVIS.", "terseLabel": "Trading securities and financial assets measured at FVIS", "verboseLabel": "Trading securities and other financial assets measured at FVIS" } } }, "localname": "AdjustmentsForDecreaseIncreaseInFinancialAssetsAtFairValueThroughProfitOrLoss", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForDecreaseIncreaseInLifeInsuranceAssetsAndLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 7.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in life insurance assets and liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Adjustments for decrease (increase) in life insurance assets and liabilities", "terseLabel": "Life insurance assets and life insurance liabilities" } } }, "localname": "AdjustmentsForDecreaseIncreaseInLifeInsuranceAssetsAndLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForDecreaseIncreaseInLoansAndReceivables": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 5.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in loans and receivables to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Adjustments for decrease (increase) in loans and receivables", "terseLabel": "Loans" } } }, "localname": "AdjustmentsForDecreaseIncreaseInLoansAndReceivables", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForIncreaseDecreaseInDepositsAndOtherBorrowings": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 10.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for increase (decrease) in deposits and other borrowings to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Adjustments for increase (decrease) in deposits and other borrowings", "terseLabel": "Deposits and other borrowings" } } }, "localname": "AdjustmentsForIncreaseDecreaseInDepositsAndOtherBorrowings", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForIncreaseDecreaseInLeaseLiability": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for increase (decrease) in lease liability in non cash financing activity.", "label": "Adjustments For Increase (Decrease) In Lease Liability", "terseLabel": "Increase in lease liabilities" } } }, "localname": "AdjustmentsForIncreaseDecreaseInLeaseLiability", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AdjustmentsForIncreaseDecreaseInOtherFinancialLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 11.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for increase (decrease) in other financial liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Adjustments for Increase (Decrease) in Other Financial Liabilities", "terseLabel": "Other financial liabilities" } } }, "localname": "AdjustmentsForIncreaseDecreaseInOtherFinancialLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_AgreementForDistributionOfLifeInsuranceProductsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for an agreement for the distribution of life insurance products.", "label": "Agreement For Distribution Of Life Insurance Products [Member]", "terseLabel": "Agreement for the distribution of life insurance products" } } }, "localname": "AgreementForDistributionOfLifeInsuranceProductsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_AgreementForProvisionOfLifeInsuranceProductsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the provision of life insurance products.", "label": "Agreement For Provision Of Life Insurance Products [Member]", "terseLabel": "Strategic alliance for the provision of life insurance products" } } }, "localname": "AgreementForProvisionOfLifeInsuranceProductsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_AgricultureForestryAndFishingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for agriculture, forestry and fishing.", "label": "Agriculture Forestry And Fishing [Member]", "terseLabel": "Agriculture, forestry and fishing" } } }, "localname": "AgricultureForestryAndFishingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_AlastairWelshMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to group executive Alastair Welsh.", "label": "Alastair Welsh [Member]", "terseLabel": "Alastair Welsh" } } }, "localname": "AlastairWelshMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_AllOtherAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 13.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of assets that the entity does not separately disclose in relation to expected maturities, including property and equipment, deferred tax assets, intangible assets and other.", "label": "All Other Assets", "terseLabel": "All other assets" } } }, "localname": "AllOtherAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AllOtherAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for all other assets.", "label": "All Other Assets [Member]", "terseLabel": "All other assets" } } }, "localname": "AllOtherAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_AllOtherAssetsNotSeparatelyDisclosedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for all other assets not separately disclosed.", "label": "All Other Assets Not Separately Disclosed [Member]", "terseLabel": "All other assets" } } }, "localname": "AllOtherAssetsNotSeparatelyDisclosedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_AllOtherLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 9.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities that the entity does not separately disclose in relation to expected maturities, including provisions, tax liabilities and other.", "label": "All Other Liabilities", "terseLabel": "All other liabilities" } } }, "localname": "AllOtherLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AllOtherLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for all other liabilities.", "label": "All Other Liabilities [Member]", "terseLabel": "All other liabilities" } } }, "localname": "AllOtherLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_AllOtherLiabilitiesNotSeparatelyDisclosedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member all other liabilities not separately disclosed.", "label": "All Other Liabilities Not Separately Disclosed [Member]", "terseLabel": "All other liabilities" } } }, "localname": "AllOtherLiabilitiesNotSeparatelyDisclosedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "domainItemType" }, "wbk_AllOtherSignificantCashGeneratingUnitsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for all other significant cash-generating units.", "label": "All Other Significant Cash Generating Units [Member]", "terseLabel": "All other significant CGUs" } } }, "localname": "AllOtherSignificantCashGeneratingUnitsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "wbk_AllianzAgreementDistributionOfGeneralInsuranceProductsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for an agreement with Allianz for the distribution of general insurance products to be provided to the Company's customers.", "label": "Allianz Agreement Distribution Of General Insurance Products [Member]", "terseLabel": "Allianz agreement, distribution of general insurance products" } } }, "localname": "AllianzAgreementDistributionOfGeneralInsuranceProductsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_AmortisationAndImpairmentOfInformationTechnologyEquipment": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 2.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense for amortisation and impairment of technology equipment.", "label": "Amortisation and Impairment of Information Technology Equipment", "terseLabel": "Depreciation and impairment of IT equipment" } } }, "localname": "AmortisationAndImpairmentOfInformationTechnologyEquipment", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmortisationAndImpairmentOfIntangibleAssetsAndDeferredExpenditure": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 2.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense for amortisation and impairment of intangible assets and deferred expenditure.", "label": "Amortisation and Impairment of Intangible Assets and Deferred Expenditure", "terseLabel": "Amortisation and impairment of intangible assets and deferred expenditure" } } }, "localname": "AmortisationAndImpairmentOfIntangibleAssetsAndDeferredExpenditure", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmortisationAndImpairmentOfSoftwareAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 1.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense for amortisation and impairment of software assets.", "label": "Amortisation and Impairment of Software Assets", "terseLabel": "Amortisation and impairment of software assets" } } }, "localname": "AmortisationAndImpairmentOfSoftwareAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmountOfExistingRetailAutoLoans": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of existing Retail Auto loans.", "label": "Amount of Existing Retail Auto Loans", "terseLabel": "Amount of existing retail auto loans not included in sale" } } }, "localname": "AmountOfExistingRetailAutoLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmountOfWestpacCapitalNotesFourTransferredToNominatedParty": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of WCN4 transferred to the nominated party pursuant to the WCN7 reinvestment offer.", "label": "Amount of Westpac Capital Notes Four Transferred to the Nominated Party", "terseLabel": "Amount of WCN4 transferred to the nominated party" } } }, "localname": "AmountOfWestpacCapitalNotesFourTransferredToNominatedParty", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmountOfWestpacCapitalNotesThreeRedeemedAndCancelled": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of WCN3 redeemed and cancelled.", "label": "Amount of Westpac Capital Notes Three Redeemed and Cancelled", "terseLabel": "Amount of WCN3 redeemed and cancelled" } } }, "localname": "AmountOfWestpacCapitalNotesThreeRedeemedAndCancelled", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmountOfWestpacCapitalNotesThreeTransferredToNominatedParty": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of WCN3 transferred to the nominated party pursuant to the WCN7 reinvestment offer.", "label": "Amount of Westpac Capital Notes Three Transferred to the Nominated Party", "terseLabel": "Amount of WCN3 transferred to the nominated party" } } }, "localname": "AmountOfWestpacCapitalNotesThreeTransferredToNominatedParty", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AmountPerNoteOfWestpacCapitalNotesFourTransferredToNominatedParty": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount per note of WCN4 transferred to the nominated party pursuant to the WCN8 reinvestment offer.", "label": "Amount Per Note of Westpac Capital Notes Four Transferred To Nominated Party", "terseLabel": "Amount per note of WCN4 transferred to the nominated party" } } }, "localname": "AmountPerNoteOfWestpacCapitalNotesFourTransferredToNominatedParty", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "perShareItemType" }, "wbk_AmountPerNoteOfWestpacCapitalNotesThreeRedeemedAndCancelled": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount per note of WCN3 redeemed and cancelled.", "label": "Amount Per Note of Westpac Capital Notes Three Redeemed and Cancelled", "terseLabel": "Amount per note of WCN3 redeemed and cancelled" } } }, "localname": "AmountPerNoteOfWestpacCapitalNotesThreeRedeemedAndCancelled", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "perShareItemType" }, "wbk_AmountPerNoteOfWestpacCapitalNotesThreeTransferredToNominatedParty": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount per note of WCN3 transferred to the nominated party pursuant to the WCN7 reinvestment offer.", "label": "Amount Per Note of Westpac Capital Notes Three Transferred To Nominated Party", "terseLabel": "Amount per note of WCN3 transferred to the nominated party" } } }, "localname": "AmountPerNoteOfWestpacCapitalNotesThreeTransferredToNominatedParty", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "perShareItemType" }, "wbk_AnalysisOfExpectedMaturitiesForFinancialAssetsAndFinancialLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tabular disclosure of analysis of expected maturities for financial assets and financial liabilities, based on historical behaviours.", "label": "Analysis of Expected Maturities For Financial Assets and Financial Liabilities [Table Text Block]", "terseLabel": "Schedule of expected maturities of financial assets and financial liabilities" } } }, "localname": "AnalysisOfExpectedMaturitiesForFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_AnnualImpairmentTestingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for annual impairment testing.", "label": "Annual Impairment Testing [Member]", "terseLabel": "Annual impairment testing" } } }, "localname": "AnnualImpairmentTestingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "wbk_AnnualImpairmentTestingOtherAssetsWrittenDown": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of other assets written down due to results of annual impairment testing.", "label": "Annual Impairment Testing, Other Assets Written Down", "terseLabel": "Other assets written down due to results of annual impairment testing" } } }, "localname": "AnnualImpairmentTestingOtherAssetsWrittenDown", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AnnualLeaveAndOtherEmployeeBenefitsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a provision for annual leave and other employee benefits.", "label": "Annual Leave And Other Employee Benefits [Member]", "terseLabel": "Annual leave and other employee benefits" } } }, "localname": "AnnualLeaveAndOtherEmployeeBenefitsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "wbk_AnthonyMillerMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Anthony Miller.", "label": "Anthony Miller [Member]", "terseLabel": "Anthony Miller" } } }, "localname": "AnthonyMillerMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_AscalonCapitalManagersAsiaLimitedAndAscalonCapitalManagersLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Ascalon Capital Managers (Asia) limited and Ascalon Capital Managers Limited.", "label": "Ascalon Capital Managers Asia Limited And Ascalon Capital Managers Limited [Member]", "terseLabel": "Ascalon Capital Managers (Asia) Limited and Ascalon Capital Managers Limited" } } }, "localname": "AscalonCapitalManagersAsiaLimitedAndAscalonCapitalManagersLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_AssetsClassifiedAsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for assets classified as held for sale.", "label": "Assets Classified As Held For Sale [Member]", "terseLabel": "Assets held for sale" } } }, "localname": "AssetsClassifiedAsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_AssetsHeldForSaleAgreementsAndLoans": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of assets held for sale classified as agreements and loans.", "label": "Assets Held for Sale, Agreements and Loans", "terseLabel": "Auto dealer and introducer agreements together with wholesale dealer loans" } } }, "localname": "AssetsHeldForSaleAgreementsAndLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AssetsHeldForSaleBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 12.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Assets held sale, based on expected maturities.", "label": "Assets Held for Sale Based on Expected Maturities", "terseLabel": "Assets held for sale" } } }, "localname": "AssetsHeldForSaleBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AssetsHeldForSaleSeparationAndTransactionCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of separation and transaction costs associated with assets held for sale.", "label": "Assets Held for Sale, Separation and Transaction Costs", "terseLabel": "Separation and transaction costs" } } }, "localname": "AssetsHeldForSaleSeparationAndTransactionCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AssetsIncludingGoodwillAndOtherIntangibleAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for assets (including goodwill and other intangible assets.", "label": "Assets Including Goodwill And Other Intangible Assets [Member]", "terseLabel": "Assets including goodwill and other intangible assets" } } }, "localname": "AssetsIncludingGoodwillAndOtherIntangibleAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_AssetsPledgedAsCollateralAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Assets Pledged as Collateral [Abstract]", "terseLabel": "Assets pledged as collateral" } } }, "localname": "AssetsPledgedAsCollateralAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails" ], "xbrltype": "stringItemType" }, "wbk_AuditorsRemunerationForAuditAndAuditRelatedServices": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails": { "order": 1.0, "parentTag": "ifrs-full_AuditorsRemuneration", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors for auditing and audit-related services.", "label": "Auditors Remuneration for Audit and Audit Related Services", "totalLabel": "Total audit and audit-related fees" } } }, "localname": "AuditorsRemunerationForAuditAndAuditRelatedServices", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AuditorsRemunerationForAuditRelatedServices": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails": { "order": 1.0, "parentTag": "wbk_AuditorsRemunerationForAuditAndAuditRelatedServices", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors for audit-related services.", "label": "Auditors Remuneration for Audit Related Services", "terseLabel": "Audit-related fees" } } }, "localname": "AuditorsRemunerationForAuditRelatedServices", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AuditorsRemunerationFromRelatedParties": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of fees paid or payable to the entity's auditors by non-consolidated related party entities.", "label": "Auditors remuneration from related parties", "terseLabel": "Fees received by auditor from various entities related to Westpac" } } }, "localname": "AuditorsRemunerationFromRelatedParties", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AustraliaAndNewZealandMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Australia and New Zealand.", "label": "Australia And New Zealand [Member]", "terseLabel": "Australia and New Zealand" } } }, "localname": "AustraliaAndNewZealandMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_AustralianAccountingStandard16LeasesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Australian Accounting Standard (AASB) 16 Leases.", "label": "Australian Accounting Standard16 Leases [Member]", "terseLabel": "AASB 16 Leases" } } }, "localname": "AustralianAccountingStandard16LeasesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_AustralianCapitalTerritoryMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of Australian Capital Territory.", "label": "Australian Capital Territory [Member]", "terseLabel": "Australian Capital Territory" } } }, "localname": "AustralianCapitalTerritoryMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_AustralianPrudentialRegulationAuthorityProposedChangesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Australian Prudential Regulation Authority (APRA) proposed changes.", "label": "Australian Prudential Regulation Authority Proposed Changes [Member]", "terseLabel": "APRA Proposed Changes" } } }, "localname": "AustralianPrudentialRegulationAuthorityProposedChangesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_AustralianPrudentialRegulationAuthorityRevisedStandardsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Australian Prudential Regulation Authority revised standards.", "label": "Australian Prudential Regulation Authority Revised Standards [Member]", "terseLabel": "APRA Revised Standards" } } }, "localname": "AustralianPrudentialRegulationAuthorityRevisedStandardsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_AustralianPrudentialRegulationAuthorityStandardsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Australian Prudential Regulation Authority standards.", "label": "Australian Prudential Regulation Authority Standards [Member]", "terseLabel": "APRA Prudential Standards" } } }, "localname": "AustralianPrudentialRegulationAuthorityStandardsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_AverageBalanceOfInterestBearingLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 1.0, "parentTag": "wbk_AverageBalanceOfTotalLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of interest bearing liabilities during the period.", "label": "Average Balance Of Interest Bearing Liabilities", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfInterestBearingLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfInterestEarningAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails": { "order": 1.0, "parentTag": "wbk_AverageBalanceOfTotalAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of interest earning assets during the period.", "label": "Average Balance Of Interest Earning Assets", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfInterestEarningAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfNonControllingInterests": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 2.0, "parentTag": "wbk_AverageBalanceOfTotalEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of non-controlling interests during the period.", "label": "Average Balance Of Non-Controlling Interests", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfNonControllingInterests", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfNonInterestBearingLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 2.0, "parentTag": "wbk_AverageBalanceOfTotalLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of non-interest bearing liabilities during the period.", "label": "Average Balance Of Non Interest Bearing Liabilities", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfNonInterestBearingLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfNonInterestEarningAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails": { "order": 2.0, "parentTag": "wbk_AverageBalanceOfTotalAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of non-interest earning assets during the period.", "label": "Average Balance Of Non Interest Earning Assets", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfNonInterestEarningAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfShareholdersEquity": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 1.0, "parentTag": "wbk_AverageBalanceOfTotalEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of the shareholders' equity during the period.", "label": "Average Balance Of Shareholders Equity", "terseLabel": "Average balance" } } }, "localname": "AverageBalanceOfShareholdersEquity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfTotalAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of total assets, including both interest earning and non-interest earning assets.", "label": "Average Balance Of Total Assets", "totalLabel": "Average balance" } } }, "localname": "AverageBalanceOfTotalAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfTotalEquity": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 2.0, "parentTag": "wbk_AverageBalanceOfTotalLiabilitiesAndEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of total equity during the period.", "label": "Average Balance Of Total Equity", "totalLabel": "Average balance" } } }, "localname": "AverageBalanceOfTotalEquity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfTotalLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": 1.0, "parentTag": "wbk_AverageBalanceOfTotalLiabilitiesAndEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of total liabilities, including both interest bearing and non-interest bearing liabilities.", "label": "Average Balance Of Total Liabilities", "totalLabel": "Average balance" } } }, "localname": "AverageBalanceOfTotalLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceOfTotalLiabilitiesAndEquity": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of daily average balance of total liabilities and equity during the period.", "label": "Average Balance Of Total Liabilities And Equity", "totalLabel": "Average balance" } } }, "localname": "AverageBalanceOfTotalLiabilitiesAndEquity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageBalanceSheetAndInterestRatesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Average balance sheet and interest rates" } } }, "localname": "AverageBalanceSheetAndInterestRatesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_AverageBalanceSheetAndInterestRatesLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Average Balance Sheet And Interest Rates [Line items]", "terseLabel": "Average balance sheet and interest rates" } } }, "localname": "AverageBalanceSheetAndInterestRatesLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "stringItemType" }, "wbk_AverageBalanceSheetAndInterestRatesTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to average balances and interest rates.", "label": "Average Balance Sheet And Interest Rates [Table]" } } }, "localname": "AverageBalanceSheetAndInterestRatesTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "stringItemType" }, "wbk_AverageBalanceSheetAndInterestRatesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of average daily balances of assets and liabilities, with average interest rates and related interest income or expense for interest earning assets and interest bearing liabilities.", "label": "Average Balance Sheet And Interest Rates [Table Text Block]", "terseLabel": "Summary of the average daily balances of the Group's interest earning assets and interest bearing liabilities" } } }, "localname": "AverageBalanceSheetAndInterestRatesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesTables" ], "xbrltype": "textBlockItemType" }, "wbk_AverageBalancesAndInterestRatesTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure of average daily balances, including average interest rates and related interest income or expense for interest earning assets and interest bearing liabilities.", "label": "Average Balances and Interest Rates [Text Block]", "terseLabel": "Average balance sheet and interest rates" } } }, "localname": "AverageBalancesAndInterestRatesTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRates" ], "xbrltype": "textBlockItemType" }, "wbk_AverageBalancesOfDeposits": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of average balance of deposits.", "label": "Average Balances of Deposits", "terseLabel": "Average balance" } } }, "localname": "AverageBalancesOfDeposits", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_AverageInterestRateOnDeposits": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The average rate of interest on the deposits.", "label": "Average Interest Rate on Deposits", "terseLabel": "Average rate (as a percent)" } } }, "localname": "AverageInterestRateOnDeposits", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails" ], "xbrltype": "percentItemType" }, "wbk_AverageRateOnInterestBearingLiabilities": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The average interest rate on interest bearing liabilities during the period.", "label": "Average Rate On Interest Bearing Liabilities", "terseLabel": "Average rate %" } } }, "localname": "AverageRateOnInterestBearingLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "percentItemType" }, "wbk_AverageRateOnInterestEarningAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The average interest rate on interest earning assets during the period.", "label": "Average Rate On Interest Earning Assets", "terseLabel": "Average rate %" } } }, "localname": "AverageRateOnInterestEarningAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "percentItemType" }, "wbk_AwardsGrantedIn20172018And2019Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for awards granted in 2017, 2018 and 2019.", "label": "Awards Granted In20172018 And2019 [Member]", "terseLabel": "2017, 2018 and 2019 awards" } } }, "localname": "AwardsGrantedIn20172018And2019Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "domainItemType" }, "wbk_AwardsGrantedIn2020And2021Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for awards granted in 2020 and 2021.", "label": "Awards Granted In2020 And2021 [Member]", "terseLabel": "2020 and 2021 awards" } } }, "localname": "AwardsGrantedIn2020And2021Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "domainItemType" }, "wbk_BalanceSheetAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Balance Sheet [Abstract]", "terseLabel": "Balance sheet" } } }, "localname": "BalanceSheetAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "wbk_BalanceSheetExposureToLossFromInterestsInStructuredEntities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that best represents the entity's balance sheet exposure to loss from its interests in structured entities.", "label": "Balance Sheet Exposure to Loss from Interests in Structured Entities", "terseLabel": "Total on-balance sheet exposures" } } }, "localname": "BalanceSheetExposureToLossFromInterestsInStructuredEntities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_BalanceSheetLoanReceivables": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of loan receivables.", "label": "Balance Sheet, Loan Receivables", "terseLabel": "Loans" } } }, "localname": "BalanceSheetLoanReceivables", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_BalancesReclassifiedToAssetsHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount reclassified to assets held for sale.", "label": "Balances Reclassified to Assets Held for Sale", "terseLabel": "Balances reclassified to assets held for sale" } } }, "localname": "BalancesReclassifiedToAssetsHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_BankLevyExpense": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense from the major bank levy, included in interest expense.", "label": "Bank levy expense", "negatedLabel": "Bank levy" } } }, "localname": "BankLevyExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_BaseCaseScenarioMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Base Case Scenario.", "label": "Base Case Scenario [Member]", "terseLabel": "Base case scenario" } } }, "localname": "BaseCaseScenarioMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_BusinessBankMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Business Bank reportable segment.", "label": "Business Bank [Member]", "terseLabel": "Business" } } }, "localname": "BusinessBankMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_BusinessLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for business loans and finance leases.", "label": "Business Loans [Member]", "terseLabel": "Business" } } }, "localname": "BusinessLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "domainItemType" }, "wbk_CapitalConservationBuffer": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Percentage of capital conservation on buffer the company is required to maintain above the risk based capital requirements.", "label": "Capital Conservation Buffer", "terseLabel": "Capital conservation buffer" } } }, "localname": "CapitalConservationBuffer", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_CapitalConservationBufferSurcharge": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Percentage of capital conservation buffer surcharge the company is required to maintain above the risk based capital requirements.", "label": "Capital Conservation Buffer Surcharge", "terseLabel": "Capital conservation buffer, surcharge" } } }, "localname": "CapitalConservationBufferSurcharge", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_CapitalManagementStrategyMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac's capital management strategy.", "label": "Capital Management Strategy [Member]", "terseLabel": "Capital management strategy" } } }, "localname": "CapitalManagementStrategyMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_CapitalRequiredForMinimumReservesToRiskWeightedAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Capital ratio required for minimum reserves purposes under the regulatory framework.", "label": "Capital Required for Minimum Reserves to Risk Weighted Assets", "terseLabel": "Minimum requirement of Total Regulatory Capital ratio" } } }, "localname": "CapitalRequiredForMinimumReservesToRiskWeightedAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_CapitalTriggerThresholdPercentageCommonEquityTierOneCapitalRatio": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "A capital trigger event occurs when Common Equity Tier 1 Capital ratio is equal to or less than the threshold percentage.", "label": "Capital Trigger Threshold Percentage, Common Equity Tier One Capital Ratio", "terseLabel": "Common Equity Tier 1 Capital ratio threshold percentage" } } }, "localname": "CapitalTriggerThresholdPercentageCommonEquityTierOneCapitalRatio", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "wbk_CarolynMccannMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Carolyn McCann.", "label": "Carolyn Mccann [Member]", "terseLabel": "Carolyn McCann" } } }, "localname": "CarolynMccannMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_CashAndBalancesWithCentralBanksIncludedInAssetsHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash and balances with central banks included in assets held for sale.", "label": "Cash and Balances with Central Banks Included in Assets Held for Sale", "terseLabel": "Cash and balances with central banks included in assets held for sale" } } }, "localname": "CashAndBalancesWithCentralBanksIncludedInAssetsHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_CashAndBalancesWithCentralBanksMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cash and bank balances held at central banks.", "label": "Cash And Balances With Central Banks [Member]", "terseLabel": "Cash and balances with central banks" } } }, "localname": "CashAndBalancesWithCentralBanksMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "wbk_CashAndBankBalancesAtCentralBanksAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Cash And Bank Balances At Central Banks [Abstract]", "terseLabel": "Cash and balances with central banks" } } }, "localname": "CashAndBankBalancesAtCentralBanksAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "stringItemType" }, "wbk_CashAndBankBalancesAtCentralBanksBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash and bank balances held at central banks, based on expected maturities.", "label": "Cash And Bank Balances At Central Banks, Based on Expected Maturities", "terseLabel": "Cash and balances with central banks" } } }, "localname": "CashAndBankBalancesAtCentralBanksBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CashCollateralSubjectToEnforceableNettingArrangementsWithDerivativeFinancialAssetsAndReverseRepurchaseAgreements": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash collateral, subject to enforceable netting arrangements with derivative financial assets and reverse repurchase agreements", "label": "Cash collateral, subject to enforceable netting arrangements with derivative financial assets and reverse repurchase agreements", "terseLabel": "Cash collateral, subject to enforceable netting arrangements with derivative financial assets and reverse repurchase agreements" } } }, "localname": "CashCollateralSubjectToEnforceableNettingArrangementsWithDerivativeFinancialAssetsAndReverseRepurchaseAgreements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CashCollateralSubjectToEnforceableNettingArrangementsWithDerivativeFinancialLiabilitiesAndReverseRepurchaseAgreements": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of cash collateral, subject to enforceable netting arrangements with derivative financial liabilities and reverse repurchase agreements", "label": "Cash collateral, subject to enforceable netting arrangements with derivative financial liabilities and reverse repurchase agreements", "terseLabel": "Cash collateral, subject to enforceable netting arrangements with derivative financial liabilities and reverse repurchase agreements" } } }, "localname": "CashCollateralSubjectToEnforceableNettingArrangementsWithDerivativeFinancialLiabilitiesAndReverseRepurchaseAgreements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CashDeconsolidatedOnDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails": { "order": 1.0, "parentTag": "wbk_ProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperationsNetOfCashDeconsolidated", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of cash deconsolidated on disposal of non-current assets or disposal groups classified as held for sale and discontinued operations.", "label": "Cash deconsolidated on disposal of non-current assets or disposal groups classified as held for sale and discontinued operations", "negatedLabel": "Less: Cash deconsolidated" } } }, "localname": "CashDeconsolidatedOnDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CashDepositOnStockBorrowedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cash deposit on stock borrowed.", "label": "Cash Deposit On Stock Borrowed [Member]", "terseLabel": "Cash deposit on stock borrowed" } } }, "localname": "CashDepositOnStockBorrowedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails" ], "xbrltype": "domainItemType" }, "wbk_CashFlowHedgesAndNetInvestmentHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cash flow hedges and net investment hedges.", "label": "Cash Flow Hedges And Net Investment Hedges [Member]", "terseLabel": "Cash Flow and Net Investment Hedges" } } }, "localname": "CashFlowHedgesAndNetInvestmentHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "domainItemType" }, "wbk_CashPrimarilyForDerivativesOtherCollateral": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails": { "order": 1.0, "parentTag": "wbk_CollateralHeldAgainstFinancialAssetsOtherThanLoansTotal", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash held as collateral, primarily for derivatives.", "label": "Cash Primarily for Derivatives, Other Collateral", "terseLabel": "Cash primarily for derivatives" } } }, "localname": "CashPrimarilyForDerivativesOtherCollateral", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CertificatesOfDepositsMoreThanUs100000": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of certificate of deposit liabilities, in denominations of more than US$100,000.", "label": "Certificates of Deposits, More than US$100,000", "terseLabel": "Certificates of deposit in excess of insured amounts" } } }, "localname": "CertificatesOfDepositsMoreThanUs100000", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest expense versus the prior period.", "label": "Change In Interest Expense", "totalLabel": "Total change in interest expense" } } }, "localname": "ChangeInInterestExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestExpenseDueToVolume": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 2.0, "parentTag": "wbk_ChangeInNetInterestIncomeDueToVolume", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest expense versus the prior period that is related to the change in the average balances of interest bearing liabilities.", "label": "Change in Interest Expense Due to Volume", "terseLabel": "Interest expense - Change Due to Volume" } } }, "localname": "ChangeInInterestExpenseDueToVolume", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestExpensesDueToInterestRates": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 1.0, "parentTag": "wbk_ChangeInNetInterestIncomeDueToInterestRates", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest expense versus the prior period that is related to the change in the average interest rates of interest bearing liabilities.", "label": "Change In Interest Expenses Due To Interest Rates", "terseLabel": "Interest expense - Change Due to Rate" } } }, "localname": "ChangeInInterestExpensesDueToInterestRates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest income versus the prior period.", "label": "Change In Interest Income", "totalLabel": "Total change in interest income" } } }, "localname": "ChangeInInterestIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestIncomeDueToInterestRates": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 2.0, "parentTag": "wbk_ChangeInNetInterestIncomeDueToInterestRates", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest income versus the prior period that is related to the change in the average interest rates of interest earning assets.", "label": "Change In Interest Income Due To Interest Rates", "terseLabel": "Interest income - Change Due to Rate" } } }, "localname": "ChangeInInterestIncomeDueToInterestRates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInInterestIncomeDueToVolume": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 1.0, "parentTag": "wbk_ChangeInNetInterestIncomeDueToVolume", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in interest income versus the prior period that is related to the change in the average balances of interest earning assets.", "label": "Change in Interest Income Due to Volume", "terseLabel": "Interest income - Change Due to Volume" } } }, "localname": "ChangeInInterestIncomeDueToVolume", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInNetInterestIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in net interest income versus the prior period.", "label": "Change In Net Interest Income", "totalLabel": "Total change in net interest income" } } }, "localname": "ChangeInNetInterestIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInNetInterestIncomeDueToInterestRates": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 1.0, "parentTag": "wbk_ChangeInNetInterestIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of change in net interest income due to change in interest rate.", "label": "Change In Net Interest Income Due To Interest Rates", "totalLabel": "Net interest income - Change Due to Rate" } } }, "localname": "ChangeInNetInterestIncomeDueToInterestRates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangeInNetInterestIncomeDueToVolume": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails": { "order": 2.0, "parentTag": "wbk_ChangeInNetInterestIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the change in net interest income versus the prior period that is related to the change in the average balances of interest earning assets and interest bearing liabilities.", "label": "Change in Net Interest Income Due to Volume", "totalLabel": "Net interest income - Change Due to Volume" } } }, "localname": "ChangeInNetInterestIncomeDueToVolume", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ChangesInAccountingPolicyImpactToBalanceSheetAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Changes in Accounting Policy, Impact to Balance Sheet [Abstract]", "terseLabel": "Balance sheets" } } }, "localname": "ChangesInAccountingPolicyImpactToBalanceSheetAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "wbk_ChangesInAccountingPolicyImpactToIncomeStatementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Changes in Accounting Policy, Impact to Income Statement [Abstract]", "terseLabel": "Income statements" } } }, "localname": "ChangesInAccountingPolicyImpactToIncomeStatementAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "stringItemType" }, "wbk_ChrisDeBruinMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Chris De Bruin.", "label": "Chris De Bruin [Member]", "terseLabel": "Chris De Bruin" } } }, "localname": "ChrisDeBruinMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_ChristineParkerMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Christine Parker.", "label": "Christine Parker [Member]", "terseLabel": "Christine Parker" } } }, "localname": "ChristineParkerMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_ClearingAndSettlementBalances": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 5.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of clearing and settlement balances.", "label": "Clearing and Settlement Balances", "terseLabel": "Clearing and settlement balances" } } }, "localname": "ClearingAndSettlementBalances", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ClosingBalanceOfUnrecognisedDayOneProfit": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of closing balance of unrecognised day one profit for both the consolidated and the parent entity.", "label": "Closing Balance Of Unrecognised Day One Profit", "terseLabel": "Closing balance of unrecognised day one profit (loss)" } } }, "localname": "ClosingBalanceOfUnrecognisedDayOneProfit", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralHeldAgainstFinancialAssetsOtherThanLoansTotal": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of collateral held against financial assets other than loans.", "label": "Collateral Held Against Financial Assets Other Than Loans, Total", "totalLabel": "Total other collateral held" } } }, "localname": "CollateralHeldAgainstFinancialAssetsOtherThanLoansTotal", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralPaid": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Cumulative amount of collateral paid.", "label": "Collateral Paid", "terseLabel": "Collateral paid" } } }, "localname": "CollateralPaid", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralPaidBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Cumulative amount of collateral paid, based on expected maturities.", "label": "Collateral Paid, Based on Expected Maturities", "terseLabel": "Collateral paid" } } }, "localname": "CollateralPaidBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralPaidMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cumulative collateral paid.", "label": "Collateral Paid [Member]", "terseLabel": "Collateral paid" } } }, "localname": "CollateralPaidMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_CollateralPaidRelatedToFuturesMargin": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Collateral paid related to futures margin.", "label": "Collateral Paid Related To Futures Margin", "terseLabel": "Futures margin" } } }, "localname": "CollateralPaidRelatedToFuturesMargin", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralReceived": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Cumulative amount of collateral received.", "label": "Collateral Received", "terseLabel": "Collateral received" } } }, "localname": "CollateralReceived", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralReceivedBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Cumulative amount of collateral received, based on expected maturities.", "label": "Collateral Received, Based on Expected Maturities", "terseLabel": "Collateral received" } } }, "localname": "CollateralReceivedBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CollateralReceivedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cumulative collateral received.", "label": "Collateral Received [Member]", "terseLabel": "Collateral received" } } }, "localname": "CollateralReceivedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_CommitmentsToCustomersButNotYetBeenAccepted": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amounts of commitments to customers, which had not yet been accepted.", "label": "Commitments to Customers But Not Yet Been Accepted", "terseLabel": "Letters of credit and guarantees, commitments to customers which had not yet been accepted" } } }, "localname": "CommitmentsToCustomersButNotYetBeenAccepted", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CommitmentsToExtendCredit": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails": { "order": 2.0, "parentTag": "wbk_UndrawnCreditCommitments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of commitments to extend credit.", "label": "Commitments to Extend Credit", "terseLabel": "Commitments to extend credit" } } }, "localname": "CommitmentsToExtendCredit", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CommitmentsToExtendCreditsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for commitments to extend credit.", "label": "Commitments To Extend Credits [Member]", "terseLabel": "Commitments to extend credit" } } }, "localname": "CommitmentsToExtendCreditsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_CommittedLiquidityFacilityUsage": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of committed liquidity facility usage", "label": "Committed Liquidity Facility Usage", "terseLabel": "Committed Liquidity Facility usage" } } }, "localname": "CommittedLiquidityFacilityUsage", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The minimum Common Equity Tier One Capital Ratio (Common Equity Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.", "label": "Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets", "terseLabel": "Minimum requirement of Common Equity Tier 1 (CET1)" } } }, "localname": "CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_ComplianceRegulationAndRemediationProvisionsIncludedInOperatingExpenses": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of compliance, regulation and remediation provisions included in operating expenses.", "label": "Compliance Regulation and Remediation Provisions Included in Operating Expenses", "terseLabel": "Compliance, regulation and remediation costs" } } }, "localname": "ComplianceRegulationAndRemediationProvisionsIncludedInOperatingExpenses", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ComplianceRegulationAndRemediationProvisionsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a provision related to compliance, regulation and remediation matters.", "label": "Compliance Regulation And Remediation Provisions [Member]", "terseLabel": "Compliance, regulation and remediation provisions" } } }, "localname": "ComplianceRegulationAndRemediationProvisionsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "wbk_ComplianceRegulationAndRemediationProvisionsRelatingToCustomerRefunds": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of compliance, regulation and remediation provisions relating to customer refunds included in other non-risk fee income.", "label": "Compliance, regulation and Remediation Provisions Relating to Customer Refunds", "terseLabel": "Estimated compliance, regulation and remediation costs recognised as a reduction in non-risk fee income, net wealth management income and other income" } } }, "localname": "ComplianceRegulationAndRemediationProvisionsRelatingToCustomerRefunds", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ConfidenceLevelForVar": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of confidence level used for Value at Risk.", "label": "Confidence Level for VaR", "terseLabel": "Confidence level" } } }, "localname": "ConfidenceLevelForVar", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "percentItemType" }, "wbk_ConsumerBankMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Consumer Bank reportable segment.", "label": "Consumer Bank [Member]", "terseLabel": "Consumer" } } }, "localname": "ConsumerBankMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_ContingentAssetTerm": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The period over which possible assets that arise from past events and whose existence will be confirmed only by the occurrence or non-occurrence of future events may be earned.", "label": "Contingent Asset, Term", "terseLabel": "Earn-out period" } } }, "localname": "ContingentAssetTerm", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "durationItemType" }, "wbk_ContingentLiabilitiesAndCommitmentsUndiscountedCashFlows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to contingent liabilities and commitments.", "label": "Contingent Liabilities and Commitments, Undiscounted Cash Flows", "terseLabel": "Total undiscounted contingent liabilities and commitments" } } }, "localname": "ContingentLiabilitiesAndCommitmentsUndiscountedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ContractualOutstandingAmountsPayableAtMaturity": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The contractual outstanding amount payable at maturity.", "label": "Contractual Outstanding Amounts Payable at Maturity", "terseLabel": "Contractual outstanding amount payable at maturity" } } }, "localname": "ContractualOutstandingAmountsPayableAtMaturity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ContributionsToPlanByEmployerDefinedContributionPlans": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of contributions made by the entity to defined contribution plans.", "label": "Contributions to plan by employer, defined contribution plans", "terseLabel": "Group contributions to defined contribution plans" } } }, "localname": "ContributionsToPlanByEmployerDefinedContributionPlans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresSuperannuationPlansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CountercyclicalCapitalBuffer": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Percentage of countercyclical buffer surcharge the company is required to maintain above the risk based capital requirements.", "label": "Countercyclical Capital Buffer", "terseLabel": "Countercyclical capital buffer" } } }, "localname": "CountercyclicalCapitalBuffer", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "pureItemType" }, "wbk_CoveredBondsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for covered bonds issued by the entity.", "label": "Covered Bonds [Member]", "terseLabel": "Covered bonds" } } }, "localname": "CoveredBondsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails", "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_Covid19Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for COVID-19.", "label": "Covid19 [Member]", "terseLabel": "COVID-19" } } }, "localname": "Covid19Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditCardLoyaltyProgramsFeeExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "ifrs-full_FeeAndCommissionExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense recognized for fees related to credit card loyalty programs.", "label": "Credit Card Loyalty Programs Fee Expense", "negatedLabel": "Credit card loyalty programs" } } }, "localname": "CreditCardLoyaltyProgramsFeeExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_CreditCardLoyaltyProgramsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit card loyalty programs.", "label": "Credit Card Loyalty Programs [Member]", "terseLabel": "Credit card loyalty programs" } } }, "localname": "CreditCardLoyaltyProgramsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditCommitmentsExcludingCreditCommitmentsIncludedInAssetsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit commitments, excluding credit commitments included in assets held for sale.", "label": "Credit Commitments Excluding Credit Commitments Included In Assets Held For Sale [Member]", "terseLabel": "Credit commitments, excluding credit commitments included in assets held for sale" } } }, "localname": "CreditCommitmentsExcludingCreditCommitmentsIncludedInAssetsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditCommitmentsIncludedInLiabilitiesHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit commitments included in liabilities held for sale.", "label": "Credit Commitments Included In Liabilities Held For Sale [Member]", "terseLabel": "Credit commitments included in liabilities held for sale" } } }, "localname": "CreditCommitmentsIncludedInLiabilitiesHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit commitments.", "label": "Credit Commitments [Member]", "terseLabel": "Credit commitments" } } }, "localname": "CreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditProtectionBoughtMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit protection bought through the use of credit default swaps.", "label": "Credit Protection Bought [Member]", "terseLabel": "Credit protection bought" } } }, "localname": "CreditProtectionBoughtMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_CreditProtectionSoldMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for credit protection sold through the use of credit default swaps.", "label": "Credit Protection Sold [Member]", "terseLabel": "Credit protection sold" } } }, "localname": "CreditProtectionSoldMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairChineseYuanToAustralianDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Chinese Yuan (CHN) to Australian Dollars (AUD).", "label": "Currency To Currency Pair Chinese Yuan To Australian Dollars [Member]", "terseLabel": "CNH:AUD" } } }, "localname": "CurrencyToCurrencyPairChineseYuanToAustralianDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairEuroToAustralianDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Euro (EUR) to Australian Dollars (AUD).", "label": "Currency To Currency Pair Euro To Australian Dollars [Member]", "terseLabel": "EUR:AUD" } } }, "localname": "CurrencyToCurrencyPairEuroToAustralianDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairEuroToNewZealandDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Euro (EUR) to New Zealand Dollars (NZD).", "label": "Currency To Currency Pair Euro To New Zealand Dollars [Member]", "terseLabel": "EUR:NZD" } } }, "localname": "CurrencyToCurrencyPairEuroToNewZealandDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairHongKongDollarsToNewZealandDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Hong Kong Dollars (HKD) to New Zealand Dollars (NZD).", "label": "Currency To Currency Pair Hong Kong Dollars To New Zealand Dollars [Member]", "terseLabel": "HKD:NZD" } } }, "localname": "CurrencyToCurrencyPairHongKongDollarsToNewZealandDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairJapaneseYenToAustralianDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Japanese Yen (JPY) to Australian Dollars (AUD).", "label": "Currency To Currency Pair Japanese Yen To Australian Dollars [Member]", "terseLabel": "JPY:AUD" } } }, "localname": "CurrencyToCurrencyPairJapaneseYenToAustralianDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairNewZealandDollarsToAustralianDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: New Zealand Dollars (NZD) to Australian Dollars (AUD).", "label": "Currency To Currency Pair New Zealand Dollars To Australian Dollars [Member]", "terseLabel": "NZD:AUD" } } }, "localname": "CurrencyToCurrencyPairNewZealandDollarsToAustralianDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairSwissFrancToAustralianDollarsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: Swiss Franc (CHF) to Australian Dollars (AUD).", "label": "Currency To Currency Pair Swiss Franc To Australian Dollars [Member]", "terseLabel": "CHF:AUD" } } }, "localname": "CurrencyToCurrencyPairSwissFrancToAustralianDollarsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrencyToCurrencyPairUnitedStatesDollarToGreatBritainPoundMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the currency to currency pair: United States Dollar (USD) to Great Britain Pound (GBP).", "label": "Currency To Currency Pair United States Dollar To Great Britain Pound [Member]", "terseLabel": "USD:GBP" } } }, "localname": "CurrencyToCurrencyPairUnitedStatesDollarToGreatBritainPoundMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_CurrentTaxLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for current tax liabilities.", "label": "Current Tax Liabilities [Member]", "terseLabel": "Current tax liabilities" } } }, "localname": "CurrentTaxLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails" ], "xbrltype": "domainItemType" }, "wbk_CurtZuberMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to group executive Curt Zuber.", "label": "Curt Zuber [Member]", "terseLabel": "Curt Zuber" } } }, "localname": "CurtZuberMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_DataProcessingExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 6.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from data processing.", "label": "Data Processing Expense", "terseLabel": "Data processing" } } }, "localname": "DataProcessingExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DavidMcleanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for David McLean.", "label": "David Mclean [Member]", "terseLabel": "David McLean" } } }, "localname": "DavidMcleanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_DavidStephenMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for David Stephen.", "label": "David Stephen [Member]", "terseLabel": "David Stephen" } } }, "localname": "DavidStephenMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_DayOneProfitOrLossAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The closing balance of unrecognised day one profit for both Group and the Parent Entity.", "label": "Day One Profit Or Loss [Abstract]", "terseLabel": "Day one profit or loss" } } }, "localname": "DayOneProfitOrLossAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "wbk_DebtInstrumentWithEquityCharacteristicsIncludedInInvestmentInSubsidiaries": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of debt instruments with equity characteristics included in investments in subsidiaries.", "label": "Debt Instrument with Equity Characteristics Included in Investment in Subsidiaries", "terseLabel": "Long-term debt instruments with equity characteristics included in investments in subsidiaries" } } }, "localname": "DebtInstrumentWithEquityCharacteristicsIncludedInInvestmentInSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DebtInstrumentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt instruments.", "label": "Debt Instruments [Member]", "terseLabel": "Debt instruments" } } }, "localname": "DebtInstrumentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtIssuesAndLoanCapitalMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt issues and loan capital.", "label": "Debt Issues And Loan Capital [Member]", "terseLabel": "Debt issues and loan capital" } } }, "localname": "DebtIssuesAndLoanCapitalMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtIssuesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for instruments issued by the entity that represent indebtedness.", "label": "Debt Issues [Member]", "terseLabel": "Debt issues" } } }, "localname": "DebtIssuesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtSecuritiesAtAmortisedCostMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt securities at amortised cost.", "label": "Debt Securities At Amortised Cost [Member]", "terseLabel": "Debt securities at amortised cost" } } }, "localname": "DebtSecuritiesAtAmortisedCostMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtSecuritiesAtFairValueThroughOtherComprehensiveIncomeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt securities at fair value through other comprehensive income.", "label": "Debt Securities At Fair Value Through Other Comprehensive Income [Member]", "terseLabel": "Debt securities at FVOCI" } } }, "localname": "DebtSecuritiesAtFairValueThroughOtherComprehensiveIncomeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtSecuritiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 5.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of instruments issued by the entity that represent indebtedness, based on expected maturities.", "label": "Debt Securities, Based on Expected Maturities", "terseLabel": "Debt issues" } } }, "localname": "DebtSecuritiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DebtSecuritiesIssuancesPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for the issuance of debt securities.", "label": "Debt Securities Issuances [Policy Text Block]", "terseLabel": "Debt issues" } } }, "localname": "DebtSecuritiesIssuancesPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DebtSecuritiesMeasuredAtAmortisedCostMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt securities measured at amortised cost.", "label": "Debt Securities Measured At Amortised Cost [Member]", "terseLabel": "Debt securities measured at amortised cost" } } }, "localname": "DebtSecuritiesMeasuredAtAmortisedCostMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_DebtSecuritiesReserveAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Debt Securities Reserve Abstract", "terseLabel": "Debt securities at FVOCI reserve" } } }, "localname": "DebtSecuritiesReserveAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "wbk_DecreaseInInterestIncomeRelatedToComplianceRegulationAndRemediationCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of decrease in interest income related to compliance, regulation and remediation costs.", "label": "Decrease in Interest Income Related to Compliance, Regulation and Remediation Costs", "terseLabel": "Reduction in interest income related to compliance, regulation and remediation costs" } } }, "localname": "DecreaseInInterestIncomeRelatedToComplianceRegulationAndRemediationCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DecreaseInLifeInsuranceLiabilitiesDueToBalancesReclassifiedToLiabilitiesHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of decrease in life insurance liabilities due to balances reclassified to liabilities held for sale.", "label": "Decrease in Life Insurance Liabilities Due to Balances Reclassified to Liabilities Held for Sale", "negatedLabel": "Balances reclassified to liabilities held for sale (refer to Note 37)" } } }, "localname": "DecreaseInLifeInsuranceLiabilitiesDueToBalancesReclassifiedToLiabilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DecreaseThroughAcquisitionOrRedemptionOfEntitysSharesNetOfIssueCost": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 6.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The decrease in equity resulting from the acquisition or redemption of the entity's shares, net of associated share issue cost.", "label": "Decrease through acquisition or redemption of entity's shares, net of issue cost", "negatedLabel": "Purchase of shares" } } }, "localname": "DecreaseThroughAcquisitionOrRedemptionOfEntitysSharesNetOfIssueCost", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_DecreaseThroughChangeInInvestmentSchemesLiabilitiesUnderInsuranceContractsAndReinsuranceContractIssued": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The decrease in liabilities under insurance contracts and reinsurance contracts issued resulting from change in external unit holders of managed investment schemes.", "label": "Decrease Through Change in Investment Schemes Liabilities Under Insurance Contracts and Reinsurance Contract Issued", "negatedLabel": "Change in external unit holders of managed investment schemes" } } }, "localname": "DecreaseThroughChangeInInvestmentSchemesLiabilitiesUnderInsuranceContractsAndReinsuranceContractIssued", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DecreaseThroughContractFeesExpensesAndTaxRecoveriesLiabilitiesUnderInsuranceContractsAndReinsuranceContractIssued": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The decrease in liabilities under insurance contracts and reinsurance contracts issued resulting from contract fees, expenses and tax recoveries.", "label": "Decrease Through Contract Fees Expenses and Tax Recoveries Liabilities Under Insurance Contracts and Reinsurance Contract Issued", "negatedLabel": "Contract fees, expenses and tax recoveries" } } }, "localname": "DecreaseThroughContractFeesExpensesAndTaxRecoveriesLiabilitiesUnderInsuranceContractsAndReinsuranceContractIssued", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferralPackagesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for deferral packages.", "label": "Deferral Packages [Member]", "terseLabel": "Deferral packages" } } }, "localname": "DeferralPackagesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "domainItemType" }, "wbk_DeferredConsideration": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails": { "order": 3.0, "parentTag": "wbk_TotalConsiderationFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of deferred consideration.", "label": "Deferred Consideration", "terseLabel": "Deferred consideration" } } }, "localname": "DeferredConsideration", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredIncomeIncludingContractLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities representing income that has been received (or the amount is due) but is not yet earned, including contract liabilities.", "label": "Deferred Income Including Contract Liabilities", "terseLabel": "Deferred income" } } }, "localname": "DeferredIncomeIncludingContractLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxAssetsBalancesTransferredToPurchasesOnSettlementOfAssetsAndLiabilitiesHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The changes in deferred tax assets resulting from the amount transferred to purchase upon settlement of assets and liabilities held for sale.", "label": "Deferred Tax Assets, Balances Transferred to Purchases on Settlement of Assets and Liabilities Held for Sale", "terseLabel": "Balances disposed of on sale of businesses" } } }, "localname": "DeferredTaxAssetsBalancesTransferredToPurchasesOnSettlementOfAssetsAndLiabilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for deferred tax assets.", "label": "Deferred Tax Assets [Member]", "terseLabel": "Deferred tax assets" } } }, "localname": "DeferredTaxAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails" ], "xbrltype": "domainItemType" }, "wbk_DeferredTaxExpenseIncomeRecognisedInOtherComprehensiveIncomeDeferredTaxAssets": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of tax expense or income relating to changes in deferred tax assets, recognised in other comprehensive income.", "label": "Deferred tax expense (income) recognised in other comprehensive income, deferred tax assets", "negatedLabel": "Recognised in OCI" } } }, "localname": "DeferredTaxExpenseIncomeRecognisedInOtherComprehensiveIncomeDeferredTaxAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxExpenseIncomeRecognisedInOtherComprehensiveIncomeDeferredTaxLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of tax expense or income relating to changes in deferred tax liabilities, recognised in other comprehensive income.", "label": "Deferred tax expense (income) recognised in other comprehensive income, deferred tax liabilities", "terseLabel": "Recognised in OCI" } } }, "localname": "DeferredTaxExpenseIncomeRecognisedInOtherComprehensiveIncomeDeferredTaxLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxExpenseIncomeRecognisedInProfitOrLossDeferredTaxAssets": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of tax expense or income relating to changes in deferred tax assets, recognised in profit or loss.", "label": "Deferred tax expense (income) recognised in profit or loss, deferred tax assets", "negatedLabel": "Recognised in the income statements" } } }, "localname": "DeferredTaxExpenseIncomeRecognisedInProfitOrLossDeferredTaxAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxExpenseIncomeRecognisedInProfitOrLossDeferredTaxLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of tax expense or income relating to changes in deferred tax liabilities, recognised in profit or loss.", "label": "Deferred tax expense (income) recognised in profit or loss, deferred tax liabilities", "terseLabel": "Recognised in the income statements" } } }, "localname": "DeferredTaxExpenseIncomeRecognisedInProfitOrLossDeferredTaxLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxExpenseIncomeSetOffOfDeferredTaxAssetsAndLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of tax expense or income relating to changes that are set-off between deferred tax liabilities and deferred tax assets.", "label": "Deferred tax expense (income), set-off of deferred tax assets and liabilities", "terseLabel": "Set-off of deferred tax assets and deferred tax liabilities" } } }, "localname": "DeferredTaxExpenseIncomeSetOffOfDeferredTaxAssetsAndLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxLiabilitiesBalancesReclassifiedToLiabilitiesHeldForSale": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The changes in deferred tax liabilities resulting from the amounts reclassified to liabilities held for sale.", "label": "Deferred Tax Liabilities, Balances Reclassified to Liabilities Held for Sale", "terseLabel": "Balances reclassified to liabilities held for sale" } } }, "localname": "DeferredTaxLiabilitiesBalancesReclassifiedToLiabilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DeferredTaxLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for deferred tax liabilities.", "label": "Deferred Tax Liabilities [Member]", "terseLabel": "Deferred tax liabilities" } } }, "localname": "DeferredTaxLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails" ], "xbrltype": "domainItemType" }, "wbk_DefinedBenefitObligationIncreaseInTermOfLifeExpectancy": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the increase in the term of life expectancy of the actuarial assumption.", "label": "Defined Benefit Obligation, Increase In The Term Of Life Expectancy", "terseLabel": "Increase in term of life expectancy" } } }, "localname": "DefinedBenefitObligationIncreaseInTermOfLifeExpectancy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsSensitivityToChangesInSignificantAssumptionsDetails" ], "xbrltype": "durationItemType" }, "wbk_DefinedBenefitPlanFundingSurplus": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Represents the funding surplus under the defined benefit plan.", "label": "Defined Benefit Plan, Funding Surplus", "terseLabel": "Funding surplus" } } }, "localname": "DefinedBenefitPlanFundingSurplus", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DefinedBenefitPlanPercentageOfPlanAssetAllocation": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.", "label": "Defined Benefit Plan, Percentage Of Plan Asset Allocation", "terseLabel": "Asset allocation percentage" } } }, "localname": "DefinedBenefitPlanPercentageOfPlanAssetAllocation", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "percentItemType" }, "wbk_DefinedBenefitPlansNetInterestCost": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": 2.0, "parentTag": "ifrs-full_PostemploymentBenefitExpenseDefinedBenefitPlans", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of net interest cost recognized related to defined benefit plan.", "label": "Defined Benefit Plans Net Interest Cost", "terseLabel": "Net interest cost on net benefit liability" } } }, "localname": "DefinedBenefitPlansNetInterestCost", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DefinedBenefitPlansServiceCost": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails": { "order": 1.0, "parentTag": "ifrs-full_PostemploymentBenefitExpenseDefinedBenefitPlans", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Amount of service cost expense recognized related to defined benefit plan.", "label": "Defined Benefit Plans Service Cost", "terseLabel": "Current service cost" } } }, "localname": "DefinedBenefitPlansServiceCost", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsContributionsAndExpenseRecognisedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DepositsAndOtherBorrowings": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapital", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of deposits and other borrowings.", "label": "Deposits and other borrowings.", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DepositsAndOtherBorrowings", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_DepositsAndOtherBorrowingsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of deposits and other borrowings, based on expected maturities.", "label": "Deposits And Other Borrowings, Based on Expected Maturities", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DepositsAndOtherBorrowingsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DepositsAndOtherBorrowingsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for deposits and other borrowings.", "label": "Deposits And Other Borrowings [Member]", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DepositsAndOtherBorrowingsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DepreciationAndImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 2.0, "parentTag": "ifrs-full_OccupancyExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of depreciation and impairment loss recognised in profit or loss for property, plant and equipment.", "label": "Depreciation and Impairment Loss Recognised in Profit or Loss, Property, Plant and Equipment", "terseLabel": "Depreciation and impairment of property and equipment" } } }, "localname": "DepreciationAndImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeAssetsHeldForHedgingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Derivative Assets Held for Hedging [Abstract]", "terseLabel": "Derivative Assets Held for Hedging" } } }, "localname": "DerivativeAssetsHeldForHedgingAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_DerivativeAssetsHeldForTradingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Derivative Assets Held for Trading [Abstract]", "terseLabel": "Derivative Assets Held for Trading" } } }, "localname": "DerivativeAssetsHeldForTradingAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_DerivativeFinancialAssetsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 4.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of financial assets classified as derivative instruments, based on expected maturities.", "label": "Derivative Financial Assets, Based on Expected Maturities", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialAssetsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial assets before netting arrangements.", "label": "Derivative Financial Assets Before Netting Arrangements", "terseLabel": "Gross derivative assets" } } }, "localname": "DerivativeFinancialAssetsBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsHeldForHedgingBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialAssetsHeldForHedging", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial assets held for hedging before netting arrangements.", "label": "Derivative Financial assets Held for Hedging Before Netting Arrangements", "terseLabel": "Gross derivative assets, hedging" } } }, "localname": "DerivativeFinancialAssetsHeldForHedgingBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsHeldForHedgingImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialAssetsHeldForHedging", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative assets held for hedging due to the impacts of netting arrangements.", "label": "Derivative Financial Assets Held for Hedging, Impact of Netting Arrangements", "terseLabel": "Impact of netting arrangements on derivative assets, hedging" } } }, "localname": "DerivativeFinancialAssetsHeldForHedgingImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsHeldForTradingBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialAssetsHeldForTrading", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial assets held for trading before netting arrangements.", "label": "Derivative Financial Assets Held for Trading Before Netting Arrangements", "terseLabel": "Gross derivative assets, trading" } } }, "localname": "DerivativeFinancialAssetsHeldForTradingBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsHeldForTradingImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialAssetsHeldForTrading", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative assets held for trading due to the impacts of netting arrangements.", "label": "Derivative Financial Assets Held for Trading, Impact of Netting Arrangements", "terseLabel": "Impact of netting arrangements on derivative assets, trading" } } }, "localname": "DerivativeFinancialAssetsHeldForTradingImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative assets due to the impacts of netting arrangements.", "label": "Derivative Financial Assets, Impact of Netting Arrangements", "terseLabel": "Impact of netting arrangements on derivative assets" } } }, "localname": "DerivativeFinancialAssetsImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for derivative financial assets.", "label": "Derivative Financial Assets [Member]", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DerivativeFinancialLiabilitiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 4.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of financial liabilities classified as derivative instruments, based on expected maturities.", "label": "Derivative Financial Liabilities, Based on Expected Maturities", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialLiabilitiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial liabilities before netting arrangements.", "label": "Derivative Financial Liabilities Before Netting Arrangements", "negatedLabel": "Gross derivative liabilities" } } }, "localname": "DerivativeFinancialLiabilitiesBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForHedgingBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilitiesHeldForHedging", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial liabilities held for hedging before netting arrangements. Total of net derivative liabilities held for trading.", "label": "Derivative Financial Liabilities Held for Hedging Before Netting Arrangements", "negatedLabel": "Gross derivative liabilities, hedging" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForHedgingBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForHedgingGrossSettledMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for derivative financial liabilities held for hedging and gross settled.", "label": "Derivative Financial Liabilities Held For Hedging Gross Settled [Member]", "terseLabel": "Derivative financial instruments: Held for hedging purposes (gross settled)" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForHedgingGrossSettledMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForHedgingImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilitiesHeldForHedging", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative liabilities held for hedging due to the impacts of netting arrangements.", "label": "Derivative Financial Liabilities Held for Hedging, Impact of Netting Arrangements", "negatedLabel": "Impact of netting arrangements on derivative liabilities, hedging" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForHedgingImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForHedgingNetSettledMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for derivative financial liabilities held for hedging and net settled.", "label": "Derivative Financial Liabilities Held For Hedging Net Settled [Member]", "terseLabel": "Derivative financial instruments: Held for hedging purposes (net settled)" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForHedgingNetSettledMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForTradingBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilitiesHeldForTrading", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of derivative financial liabilities held for trading before netting arrangements.", "label": "Derivative Financial Liabilities Held for Trading Before Netting Arrangements", "negatedLabel": "Gross derivative liabilities, trading" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForTradingBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForTradingImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilitiesHeldForTrading", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative liabilities held for trading due to the impacts of netting arrangements.", "label": "Derivative Financial Liabilities Held for Trading, Impact of Netting Arrangements", "negatedLabel": "Impact of netting arrangements on derivative liabilities, trading" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForTradingImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesHeldForTradingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for derivative financial liabilities held for trading.", "label": "Derivative Financial Liabilities Held For Trading [Member]", "terseLabel": "Derivative financial instruments: Held for trading" } } }, "localname": "DerivativeFinancialLiabilitiesHeldForTradingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DerivativeFinancialLiabilitiesImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_DerivativeFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in derivative liabilities due to the impacts of netting arrangements.", "label": "Derivative Financial Liabilities, Impact of Netting Arrangements", "negatedLabel": "Impact of netting arrangements on derivative liabilities" } } }, "localname": "DerivativeFinancialLiabilitiesImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for derivative financial liabilities.", "label": "Derivative Financial Liabilities [Member]", "terseLabel": "Derivative financial instruments" } } }, "localname": "DerivativeFinancialLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_DerivativeFinancialLiabilitiesUndiscountedCashInflows": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash inflows in relation to gross-settled derivative financial liabilities held for hedging purposes.", "label": "Derivative financial liabilities, undiscounted cash inflows", "negatedLabel": "Derivative financial instruments: Cash inflow" } } }, "localname": "DerivativeFinancialLiabilitiesUndiscountedCashInflows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeFinancialLiabilitiesUndiscountedCashOutflows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash outflows in relation to gross-settled derivative financial liabilities held for hedging purposes.", "label": "Derivative financial liabilities, undiscounted cash outflows", "terseLabel": "Derivative financial instruments: Cash outflow" } } }, "localname": "DerivativeFinancialLiabilitiesUndiscountedCashOutflows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DerivativeLiabilitiesHeldForHedgingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Derivative Liabilities Held for Hedging [Abstract]", "terseLabel": "Derivative Liabilities Held for Hedging" } } }, "localname": "DerivativeLiabilitiesHeldForHedgingAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_DerivativeLiabilitiesHeldForTradingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Derivative Liabilities Held for Trading [Abstract]", "terseLabel": "Derivative Liabilities Held for Trading" } } }, "localname": "DerivativeLiabilitiesHeldForTradingAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_DescriptionOfAccountingPolicyForBasisOfAccountingPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for basis of accounting.", "label": "Description of Accounting Policy for Basis of Accounting [Policy Text Block]", "verboseLabel": "Basis of accounting" } } }, "localname": "DescriptionOfAccountingPolicyForBasisOfAccountingPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForComparativeRevisionsPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for comparative revisions.", "label": "Description of Accounting Policy for Comparative Revisions [Policy Text Block]", "terseLabel": "Comparative revisions" } } }, "localname": "DescriptionOfAccountingPolicyForComparativeRevisionsPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForDepositsAndOtherBorrowingsPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for deposits and other borrowings.", "label": "Description of Accounting Policy for Deposits and Other Borrowings [Policy Text Block]", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DescriptionOfAccountingPolicyForDepositsAndOtherBorrowingsPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForHistoricalCostConventionPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for historical cost convention.", "label": "Description of Accounting Policy for Historical Cost Convention [Policy Text Block]", "terseLabel": "Historical cost convention" } } }, "localname": "DescriptionOfAccountingPolicyForHistoricalCostConventionPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForInterestsInOtherEntitiesPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for interests in other entities.", "label": "Description of Accounting Policy for Interests in Other Entities [Policy Text Block]", "terseLabel": "Investments in subsidiaries and associates" } } }, "localname": "DescriptionOfAccountingPolicyForInterestsInOtherEntitiesPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForLoanCapitalPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for capital requirement for depository and lending institutions. Institutions include, but not are not limited to, finance company, insured depository institution, bank holding company, savings and loan association holding company, bank and savings institution not federally insured, mortgage company, foreign financial institution and credit union.", "label": "Description of Accounting Policy for Loan Capital [Policy Text Block]", "terseLabel": "Loan Capital" } } }, "localname": "DescriptionOfAccountingPolicyForLoanCapitalPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForNonInterestIncomePolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for non-interest income.", "label": "Description of Accounting Policy for Non Interest Income [Policy Text Block]", "terseLabel": "Non-interest income" } } }, "localname": "DescriptionOfAccountingPolicyForNonInterestIncomePolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForOtherFinancialLiabilitiesPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for other financial liabilities.", "label": "Description of Accounting Policy for Other Financial Liabilities [Policy Text Block]", "terseLabel": "Other financial liabilities" } } }, "localname": "DescriptionOfAccountingPolicyForOtherFinancialLiabilitiesPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForStructuredEntitiesPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for structured entities.", "label": "Description of Accounting Policy for Structured Entities [Policy Text Block]", "terseLabel": "Structured entities" } } }, "localname": "DescriptionOfAccountingPolicyForStructuredEntitiesPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForSuperannuationCommitmentsPolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for superannuation commitments.", "label": "Description of Accounting Policy for Superannuation Commitments [Policy Text Block]", "terseLabel": "Superannuation commitments" } } }, "localname": "DescriptionOfAccountingPolicyForSuperannuationCommitmentsPolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DescriptionOfAccountingPolicyForTradingSecuritiesAndFinancialAssetsDesignatedAtFairValuePolicyTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The description of the entity's accounting policy for trading securities and financial assets designated at fair value.", "label": "Description of Accounting Policy for Trading Securities and Financial Assets Designated at Fair Value [Policy Text Block]", "terseLabel": "Trading securities and financial assets designated at fair value" } } }, "localname": "DescriptionOfAccountingPolicyForTradingSecuritiesAndFinancialAssetsDesignatedAtFairValuePolicyTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationPolicies" ], "xbrltype": "textBlockItemType" }, "wbk_DetailsOfAssetsAndLiabilitiesOverWhichControlCeasedAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Details of the Assets and Liabilities Over Which Control Ceased [Abstract]", "terseLabel": "Details of the assets and liabilities over which control ceased" } } }, "localname": "DetailsOfAssetsAndLiabilitiesOverWhichControlCeasedAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfAssetsPledgedAsCollateralExplanatoryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of assets pledged as collateral.", "label": "Disclosure of Assets Pledged as Collateral Explanatory [Table Text Block]", "terseLabel": "Summary of financial assets pledged as collateral" } } }, "localname": "DisclosureOfAssetsPledgedAsCollateralExplanatoryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfAuditorRemunerationLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Auditor Remuneration [Line Items]", "terseLabel": "Auditor's remuneration" } } }, "localname": "DisclosureOfAuditorRemunerationLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfAuditorRemunerationTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to auditor's remuneration.", "label": "Disclosure of Auditor Remuneration [Table]" } } }, "localname": "DisclosureOfAuditorRemunerationTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfAuditorsRemunerationTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of detailed information related to auditor's remuneration.", "label": "Disclosure of Auditors Remuneration [Table Text Block]", "terseLabel": "Schedule of fees payable to the auditor" } } }, "localname": "DisclosureOfAuditorsRemunerationTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of average balances and average rates for major categories of deposits.", "label": "Disclosure of Average Balances and Average Rates for Major Categories of Deposits [Table Text Block]", "terseLabel": "Schedule of average balances and average rates for major categories of deposits" } } }, "localname": "DisclosureOfAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfCollateralHeldTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of collateral held.", "label": "Disclosure of Collateral Held [Table Text Block]", "terseLabel": "Summary of collateral held" } } }, "localname": "DisclosureOfCollateralHeldTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfContractualMaturityDistributionOfLoansByIndustryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of contractual maturity distribution of all loans by industry.", "label": "Disclosure of Contractual Maturity Distribution Of Loans By Industry [Table Text Block]", "terseLabel": "Schedule of contractual maturity distribution of loans" } } }, "localname": "DisclosureOfContractualMaturityDistributionOfLoansByIndustryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfCreditQualityOfGrossCreditRiskExposuresTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of credit quality of gross credit risk exposures.", "label": "Disclosure Of Credit Quality of Gross Credit Risk Exposures [Table Text Block]", "terseLabel": "Schedule of credit quality of gross credit risk exposures" } } }, "localname": "DisclosureOfCreditQualityOfGrossCreditRiskExposuresTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfCreditRiskRatingsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the entity's internal credit risk ratings system and corresponding external ratings.", "label": "Disclosure of Credit Risk Ratings [Table Text Block]", "terseLabel": "Schedule of high level CRGs and corresponding external rating" } } }, "localname": "DisclosureOfCreditRiskRatingsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDebtIssuesByTypeAndCurrencyTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of debt issues by type and currency.", "label": "Disclosure Of Debt Issues By Type And Currency [Table Text Block]", "terseLabel": "Schedule of debt issues by type and currency" } } }, "localname": "DisclosureOfDebtIssuesByTypeAndCurrencyTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDefinedBenefitPlanContributionTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tabular disclosure of defined benefit plan contribution by employer and member.", "label": "Disclosure Of Defined Benefit Plan Contribution [Table Text Block]", "terseLabel": "Schedule of contributions" } } }, "localname": "DisclosureOfDefinedBenefitPlanContributionTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDefinedBenefitPlanExpenseTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tabular disclosure of defined benefit plan expenses.", "label": "Disclosure Of Defined Benefit Plan Expense [Table Text Block]", "terseLabel": "Summary of expenses recognised" } } }, "localname": "DisclosureOfDefinedBenefitPlanExpenseTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDefinedBenefitPlanSignificantAssumptionsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tabular disclosure of defined benefit plan significant assumptions.", "label": "Disclosure Of Defined Benefit Plan Significant Assumptions [Table Text Block]", "terseLabel": "Schedule of defined benefit plan significant assumptions" } } }, "localname": "DisclosureOfDefinedBenefitPlanSignificantAssumptionsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDepositsAndOtherBorrowingsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Deposits and other borrowings" } } }, "localname": "DisclosureOfDepositsAndOtherBorrowingsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfDepositsAndOtherBorrowingsLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Deposits and Other Borrowings [Line Items]", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DisclosureOfDepositsAndOtherBorrowingsLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfDepositsAndOtherBorrowingsTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to Deposits and other borrowings.", "label": "Disclosure of Deposits and Other Borrowings [Table]" } } }, "localname": "DisclosureOfDepositsAndOtherBorrowingsTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfDepositsAndOtherBorrowingsTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure of deposits and other borrowings.", "label": "Disclosure of Deposits and Other Borrowings [Text Block]", "terseLabel": "Deposits and other borrowings" } } }, "localname": "DisclosureOfDepositsAndOtherBorrowingsTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowings" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDerivativeFinancialInstrumentsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of derivative financial instruments.", "label": "Disclosure of Derivative Financial Instruments [Table Text Block]", "terseLabel": "Summary of carrying values of derivative instruments" } } }, "localname": "DisclosureOfDerivativeFinancialInstrumentsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDetailedInformationAboutDepositsAndOtherBorrowingsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of detailed information about deposits and other borrowings.", "label": "Disclosure of Detailed Information about Deposits and Other Borrowings [Table Text Block]", "terseLabel": "Schedule of deposits and other borrowings" } } }, "localname": "DisclosureOfDetailedInformationAboutDepositsAndOtherBorrowingsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfDividendsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "N/A.", "label": "Dividends" } } }, "localname": "DisclosureOfDividendsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfDividendsLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Dividends [Line Items]", "terseLabel": "Dividends" } } }, "localname": "DisclosureOfDividendsLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfDividendsTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information relating to dividends.", "label": "Disclosure of Dividends [Table]" } } }, "localname": "DisclosureOfDividendsTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of a schedule that shows the effects of any changes in the parent's ownership interest in subsidiaries that result in a loss of control on the assets and liabilities of those subsidiaries.", "label": "Disclosure of Effects of Changes in Parent's Ownership Interest in Subsidiaries that Result in Loss of Control on Assets and Liabilities [Table Text Block]", "terseLabel": "Summary of the assets and liabilities over which control ceased" } } }, "localname": "DisclosureOfEffectsOfChangesInParentSOwnershipInterestInSubsidiariesThatResultInLossOfControlOnAssetsAndLiabilitiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToConsolidatedCashFlowStatementTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfFairValueMeasurementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Fair values of financial assets and financial liabilities" } } }, "localname": "DisclosureOfFairValueMeasurementAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfFinancialInstrumentsNotMeasuredAtFairValueTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of financial instruments not measured at fair value.", "label": "Disclosure of Financial Instruments Not Measured At Fair Value [Table Text Block]", "terseLabel": "Schedule of estimated fair value and fair value hierarchy of financial instruments not measured at fair value" } } }, "localname": "DisclosureOfFinancialInstrumentsNotMeasuredAtFairValueTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfFundingCompositionTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the entity's funding composition.", "label": "Disclosure of Funding Composition [Table Text Block]", "terseLabel": "Summary of Group's funding composition" } } }, "localname": "DisclosureOfFundingCompositionTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfGainsLossesOnAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Gains (Losses) on Assets [Abstract]", "terseLabel": "Gains/(losses) on assets/(gains)/losses on liabilities recognised in:" } } }, "localname": "DisclosureOfGainsLossesOnAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfGainsLossesOnLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of (Gains) Losses on Liabilities [Abstract]", "terseLabel": "Gains/(losses) on assets/(gains)/losses on liabilities recognised in:" } } }, "localname": "DisclosureOfGainsLossesOnLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfGrossCreditRiskByGeographicLocationTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of gross credit risk by geographic location.", "label": "Disclosure Of Gross Credit Risk, By Geographic Location [Table Text Block]", "terseLabel": "Schedule of gross credit risk" } } }, "localname": "DisclosureOfGrossCreditRiskByGeographicLocationTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfIncomeStatementDetailLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Income Statement Detail [Line Items]", "terseLabel": "Non-interest income" } } }, "localname": "DisclosureOfIncomeStatementDetailLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfIncomeStatementDetailTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing detailed information related to the income statement.", "label": "Disclosure of Income Statement Detail [Table]" } } }, "localname": "DisclosureOfIncomeStatementDetailTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfInformationAboutStructuredEntitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition is available.", "label": "Structured entities" } } }, "localname": "DisclosureOfInformationAboutStructuredEntitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfInsuranceContractsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Life insurance assets and life insurance liabilities" } } }, "localname": "DisclosureOfInsuranceContractsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfInterestIncomeAndExpenseTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the components interest income and expense.", "label": "Disclosure of Interest Income and Expense [Table Text Block]", "terseLabel": "Schedule of net interest income" } } }, "localname": "DisclosureOfInterestIncomeAndExpenseTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfInterestIncomeExpenseNetAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Interest Income (Expense), Net [Abstract]", "terseLabel": "Net interest income" } } }, "localname": "DisclosureOfInterestIncomeExpenseNetAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfInterestRateRiskInBankingBookNonTradedMarketRiskExplanatoryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of interest rate risk in the banking book as a component of non-traded market risk.", "label": "Disclosure of Interest Rate Risk in Banking Book, Non Traded Market Risk Explanatory [Table Text Block]", "terseLabel": "Summary of VaR for IRRBB as it relates to non-traded market risk" } } }, "localname": "DisclosureOfInterestRateRiskInBankingBookNonTradedMarketRiskExplanatoryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfInterestsInMateriallyControlledEntitiesWhichAreNotWhollyOwnedTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of interests in materially controlled entities which are not wholly owned.", "label": "Disclosure of Interests in Materially Controlled Entities which are not Wholly Owned [Table Text Block]", "terseLabel": "Summary of material controlled entities which are not wholly owned" } } }, "localname": "DisclosureOfInterestsInMateriallyControlledEntitiesWhichAreNotWhollyOwnedTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfInvestmentSecuritiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of investment securities.", "label": "Disclosure of Investment Securities [Table Text Block]", "terseLabel": "Schedule of investment securities" } } }, "localname": "DisclosureOfInvestmentSecuritiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfInvestmentsDebtAndEquitySecuritiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Disclosure of Investments Debt And Equity Securities [Abstract]", "terseLabel": "Maturities of the Group's investment securities" } } }, "localname": "DisclosureOfInvestmentsDebtAndEquitySecuritiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfLoanCapitalAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Loan capital" } } }, "localname": "DisclosureOfLoanCapitalAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfLoanCapitalTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure for loan capital.", "label": "Disclosure of Loan Capital [Text Block]", "terseLabel": "Loan capital" } } }, "localname": "DisclosureOfLoanCapitalTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapital" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfLoansAndAdvancesToCustomersAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Loans" } } }, "localname": "DisclosureOfLoansAndAdvancesToCustomersAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfMacroeconomicScenarioWeightingsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tabular disclosure of macroeconomic scenario weightings.", "label": "Disclosure of Macroeconomic Scenario Weightings [Table Text Block]", "terseLabel": "Summary of macroeconomic scenario weightings" } } }, "localname": "DisclosureOfMacroeconomicScenarioWeightingsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfMaturityProfileOfCertificatesOfDepositsAndTermDepositsMoreThanUs100000TableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the maturity profile of certificates of deposit and term deposits greater than US$100,000.", "label": "Disclosure of Maturity Profile of Certificates of Deposits and Term Deposits, More than US$100,000 [Table Text Block]", "terseLabel": "Schedule of balances of uninsured certificates of deposit and term deposits by remaining maturity" } } }, "localname": "DisclosureOfMaturityProfileOfCertificatesOfDepositsAndTermDepositsMoreThanUs100000TableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfNetInterestIncomeAtRiskNonTradedMarketRiskExplanatoryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of net interest income at risk as a component of non-traded market risk.", "label": "Disclosure of Net Interest Income at Risk, Non Traded Market Risk Explanatory [Table Text Block]", "terseLabel": "Summary of net interest income-at-risk (NaR) as it relates to non-traded market risk" } } }, "localname": "DisclosureOfNetInterestIncomeAtRiskNonTradedMarketRiskExplanatoryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfNonControllingInterestAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Non-Controlling Interest [Abstract]", "terseLabel": "NCI" } } }, "localname": "DisclosureOfNonControllingInterestAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfNonInterestIncomeTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the components of non-interest income.", "label": "Disclosure of Non-Interest Income [Table Text Block]", "terseLabel": "Schedule of non-interest income" } } }, "localname": "DisclosureOfNonInterestIncomeTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Offsetting financial assets and financial liabilities" } } }, "localname": "DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure Of Offsetting Of Financial Assets And Financial Liabilities [Line Items]", "terseLabel": "Offsetting financial assets and financial liabilities" } } }, "localname": "DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to the offsetting of financial assets and financial liabilities.", "label": "Disclosure Of Offsetting Of Financial Assets And Financial Liabilities [Table]" } } }, "localname": "DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfOperatingExpensesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Operating Expenses [Abstract]", "terseLabel": "Operating expenses" } } }, "localname": "DisclosureOfOperatingExpensesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfOtherAssetsLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Other Assets [Line Items]", "terseLabel": "Other financial assets" } } }, "localname": "DisclosureOfOtherAssetsLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfOtherAssetsTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to other assets.", "label": "Disclosure of Other Assets [Table]" } } }, "localname": "DisclosureOfOtherAssetsTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfOtherFinancialAssetsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of other financial assets.", "label": "Disclosure of Other Financial Assets [Table Text Block]", "terseLabel": "Schedule of other financial assets" } } }, "localname": "DisclosureOfOtherFinancialAssetsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfOtherFinancialAssetsTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure of other financial assets.", "label": "Disclosure of Other Financial Assets [Text Block]", "terseLabel": "Other financial assets" } } }, "localname": "DisclosureOfOtherFinancialAssetsTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssets" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfOtherFinancialLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of other financial liabilities.", "label": "Disclosure of Other Financial Liabilities [Table Text Block]", "terseLabel": "Schedule of other financial liabilities" } } }, "localname": "DisclosureOfOtherFinancialLiabilitiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfOtherFinancialLiabilitiesTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure of other financial liabilities.", "label": "Disclosure of Other Financial Liabilities [Text Block]", "terseLabel": "Other financial liabilities" } } }, "localname": "DisclosureOfOtherFinancialLiabilitiesTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilities" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfParentEntityCreditRatingsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of external credit ratings for the parent entity.", "label": "Disclosure of Parent Entity Credit Ratings [Table Text Block]", "terseLabel": "Schedule of Parent Entity's credit ratings" } } }, "localname": "DisclosureOfParentEntityCreditRatingsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of pretax impact of cash flow and net investment hedges on reserves.", "label": "Disclosure of Pre-Tax Impact of Cash flow and Net Investment Hedges on Reserves [Table Text Block]", "terseLabel": "Schedule of pre-tax impact of cash flow and net investment hedges on reserves" } } }, "localname": "DisclosureOfPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfProvisionForExpectedCreditLossesOnLoansAndCreditCommitmentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Provision for Expected Credit Losses on Loans and Credit Commitments [Abstract]", "terseLabel": "Loans and credit commitments" } } }, "localname": "DisclosureOfProvisionForExpectedCreditLossesOnLoansAndCreditCommitmentsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Provisions, contingent liabilities, contingent assets and credit commitments" } } }, "localname": "DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure of provisions, contingent liabilities, contingent assets and credit commitments.", "label": "Disclosure Of Provisions, Contingent Liabilities, Contingent Assets And Credit Commitments [Text Block]", "terseLabel": "Provisions, contingent liabilities, contingent assets and credit commitments" } } }, "localname": "DisclosureOfProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitments" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfQuantitativeInformationAboutFinancialInstrumentsThatHaveYetToTransitionToAlternativeBenchmarkRateTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of quantitative information about financial instruments that have yet to transition to an alternative benchmark rate.", "label": "Disclosure of quantitative information about financial instruments that have yet to transition to alternative benchmark rate [text block]", "terseLabel": "Schedule of financial instruments impacted by IBOR reform and yet to transition to ARR" } } }, "localname": "DisclosureOfQuantitativeInformationAboutFinancialInstrumentsThatHaveYetToTransitionToAlternativeBenchmarkRateTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfReconciliationOfCashEarningsToNetProfitExplanatoryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of reconciliation of cash earnings to net profit.", "label": "Disclosure of Reconciliation of Cash Earnings to Net Profit Explanatory [Table Text Block]", "verboseLabel": "Schedule of reconciliation of cash earnings to net profit" } } }, "localname": "DisclosureOfReconciliationOfCashEarningsToNetProfitExplanatoryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfReconciliationOfNetCashInOperatingActivitiesToNetProfitTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the reconciliation of net cash provided by/(used in) operating activities to net profit or loss.", "label": "Disclosure Of Reconciliation Of Net Cash In Operating Activities To Net Profit [Table Text Block]", "terseLabel": "Summary of reconciliation of net cash provided by/(used in) operating activities to net profit for the year" } } }, "localname": "DisclosureOfReconciliationOfNetCashInOperatingActivitiesToNetProfitTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToConsolidatedCashFlowStatementTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfRegulatoryCapitalRequirementsUnderBankingRegulationsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition is available.", "label": "Capital adequacy" } } }, "localname": "DisclosureOfRegulatoryCapitalRequirementsUnderBankingRegulationsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_DisclosureOfRestrictedCashAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Restricted Cash [Abstract]", "terseLabel": "Restricted cash" } } }, "localname": "DisclosureOfRestrictedCashAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfShareCapitalAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Disclosure of Share Capital [Abstract]", "terseLabel": "Share capital" } } }, "localname": "DisclosureOfShareCapitalAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfSharebasedPaymentArrangementActivityTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of share-based payment arrangement activity.", "label": "Disclosure Of Share-Based Payment Arrangement Activity [Table Text Block]", "terseLabel": "Schedule of share-based payment schemes" } } }, "localname": "DisclosureOfSharebasedPaymentArrangementActivityTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfFinancialInstrumentsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of significant inputs for which market data are not available and that are developed using the best information available about the assumptions that market participants would use when measuring the fair value of financial instruments.", "label": "Disclosure of Significant Unobservable Inputs Used In Fair Value Measurement of Financial Instruments [Table Text Block]", "terseLabel": "Summary of the changes in financial instruments measured at fair value derived from non-market observable valuation techniques (Level 3)" } } }, "localname": "DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfFinancialInstrumentsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfTradedMarketRiskExplanatoryTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of traded market risk.", "label": "Disclosure of Traded Market Risk Explanatory [Table Text Block]", "terseLabel": "Summary of aggregate VaR, by risk type as it relates to traded market risk" } } }, "localname": "DisclosureOfTradedMarketRiskExplanatoryTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Disclosure of Trading Securities And Financial Assets Measured At Fair Value Through Income Statement [Line Items]", "terseLabel": "Trading securities and financial assets measured at FVIS" } } }, "localname": "DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Disclosure of trading securities and financial assets measured at fair value through income statement (FVIS).", "label": "Disclosure of Trading Securities And Financial Assets Measured At Fair Value Through Income Statement [Table]" } } }, "localname": "DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "stringItemType" }, "wbk_DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure for trading securities and financial assets measured at fair value through income statement (FVIS).", "label": "Disclosure of Trading Securities and Financial Assets Measured Fair Value Through Income Statement [Text Block]", "terseLabel": "Trading securities and financial assets measured at FVIS" } } }, "localname": "DisclosureOfTradingSecuritiesAndFinancialAssetsMeasuredFairValueThroughIncomeStatementTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvis" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfUnrecognisedDeferredTaxBalancesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of unrecognised deferred tax balances.", "label": "Disclosure of Unrecognised Deferred Tax Balances [Table Text Block]", "terseLabel": "Schedule of unrecognised deferred tax balances" } } }, "localname": "DisclosureOfUnrecognisedDeferredTaxBalancesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfValuationAssumptionsUsedToCalculateValueAtRiskTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the significant assumptions used during the year to calculate value at risk (VaR).", "label": "Disclosure of Valuation Assumptions Used To Calculate Value At Risk [Table Text Block]", "terseLabel": "Summary of key parameters of VaR" } } }, "localname": "DisclosureOfValuationAssumptionsUsedToCalculateValueAtRiskTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_DisclosureOfWriteOffsNetOfRecoveriesToAverageLoansTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The disclosure of write-offs of net recoveries to average loans.", "label": "Disclosure of Write-Offs of Net Recoveries to Average Loans [Table Text Block]", "terseLabel": "Schedule of write-offs net of recoveries to average loans" } } }, "localname": "DisclosureOfWriteOffsNetOfRecoveriesToAverageLoansTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_DiscontinuedOperationsPreTaxGainOnSale": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of pre-tax gain on sale of a discontinued operation.", "label": "Discontinued Operations, Pre-Tax Gain on Sale", "terseLabel": "Pre-tax gain on sale" } } }, "localname": "DiscontinuedOperationsPreTaxGainOnSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DiscontinuedOperationsPreTaxGainOnSaleNetOfTransactionAndSeparationCosts": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of pre-tax gain on sale of a discontinued operation, net of transaction and separation costs.", "label": "Discontinued Operations, Pre-Tax Gain On Sale, Net of Transaction and Separation Costs", "terseLabel": "Pre-tax gain on sale, net of transaction and separation costs" } } }, "localname": "DiscontinuedOperationsPreTaxGainOnSaleNetOfTransactionAndSeparationCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DiscountRateOnSharePriceUponConversion": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of discount rate on share price upon conversion.", "label": "Discount Rate on Share Price Upon Conversion", "terseLabel": "Discount rate on share price upon conversion" } } }, "localname": "DiscountRateOnSharePriceUponConversion", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "wbk_DiscountRateOnSharePriceWhichDeterminedBasedOnCapitalTriggerEventDateOrNonViabilityTriggerEventDate": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of discount rate on share price which determined based on capital trigger event date or non-viability trigger event date.", "label": "Discount Rate on Share Price Which Determined Based on Capital Trigger Event Date or Non-viability Trigger Event Date", "terseLabel": "Discount rate on share price determined based on capital trigger event date or non-viability trigger event date" } } }, "localname": "DiscountRateOnSharePriceWhichDeterminedBasedOnCapitalTriggerEventDateOrNonViabilityTriggerEventDate", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "wbk_DisposalAndSettlementsFairValueMeasurementAssets": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The decrease in the fair value measurement of assets resulting from disposal and settlements.", "label": "Disposal And Settlements, Fair Value Measurement, Assets", "negatedLabel": "Disposal and settlements" } } }, "localname": "DisposalAndSettlementsFairValueMeasurementAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DisposalAndSettlementsFairValueMeasurementLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The decrease in the fair value measurement of liabilities resulting from disposal and settlements.", "label": "Disposal And Settlements, Fair Value Measurement, Liabilities", "negatedLabel": "Disposal and settlements" } } }, "localname": "DisposalAndSettlementsFairValueMeasurementLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DisposalGroupIncludingDiscontinuedOperationTotalConsideration": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Total amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation", "label": "Disposal Group, Including Discontinued Operation, Total Consideration", "terseLabel": "Sale price" } } }, "localname": "DisposalGroupIncludingDiscontinuedOperationTotalConsideration", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DisposalGroupNameDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Name of disposal group.", "label": "Disposal Group Name [Domain]", "terseLabel": "Disposal Group Name [Domain]" } } }, "localname": "DisposalGroupNameDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_DisposalOfAssetsReversalOfFairValueAdjustment": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of fair value adjustment reversed for assets held for sale.", "label": "Disposal of Assets, Reversal of Fair Value Adjustment", "terseLabel": "Write back recognised upon termination of sale agreement" } } }, "localname": "DisposalOfAssetsReversalOfFairValueAdjustment", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DividendIncomeFromOtherEntities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 3.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of dividends from entities other than subsidiaries, recognised as income.", "label": "Dividend income from other entities", "terseLabel": "Dividends received from other entities" } } }, "localname": "DividendIncomeFromOtherEntities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DividendIncomeFromSubsidiaries": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of dividends from subsidiaries, recognised as income.", "label": "Dividend income from subsidiaries", "terseLabel": "Dividends received from subsidiaries" } } }, "localname": "DividendIncomeFromSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_DividendReinvestmentPlanNumberOfSharesPurchasedFromMarketForTransferToParticipants": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of shares purchased from the market for transfer to participants in the dividend reinvestment plan.", "label": "Dividend Reinvestment Plan, Number of Shares Purchased from Market for Transfer to Participants", "terseLabel": "DRP - number of shares purchased for transfer to participants" } } }, "localname": "DividendReinvestmentPlanNumberOfSharesPurchasedFromMarketForTransferToParticipants", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_DividendsPaidOrdinarySharesPerShareRelatingToCurrentYear": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount of dividends paid per ordinary share, relating to the current year.", "label": "Dividends paid, ordinary shares per share, relating to current year", "terseLabel": "Interim dividend (in dollars per share)" } } }, "localname": "DividendsPaidOrdinarySharesPerShareRelatingToCurrentYear", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical" ], "xbrltype": "perShareItemType" }, "wbk_DividendsPaidOrdinarySharesPerShareRelatingToPriorYears": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount of dividends paid per ordinary share, relating to prior years.", "label": "Dividends paid, ordinary shares per share, relating to prior years", "terseLabel": "Final dividend (in dollars per share)" } } }, "localname": "DividendsPaidOrdinarySharesPerShareRelatingToPriorYears", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical" ], "xbrltype": "perShareItemType" }, "wbk_DividendsProposedOrDeclaredTradingPeriodToDetermineNumberOfSharesForDividendReinvestmentPlan": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "For dividends proposed or declared after the reporting period but before financial statements are authorised for issue, the trading period over which the market price will be used to determine shares to be issued to participants in the dividend reinvestment plan.", "label": "Dividends proposed or declared, trading period to determine number of shares for dividend reinvestment plan", "terseLabel": "Trading period to determine number of shares for dividend reinvestment plan" } } }, "localname": "DividendsProposedOrDeclaredTradingPeriodToDetermineNumberOfSharesForDividendReinvestmentPlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "durationItemType" }, "wbk_DividendsReceivedClassifiedAsOperatingActivitiesExcludingLifeBusiness": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 3.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from dividends received, classified as operating activities, excluding dividends related to life insurance business.", "label": "Dividends received, classified as operating activities, excluding life business", "terseLabel": "Dividends received excluding life business" } } }, "localname": "DividendsReceivedClassifiedAsOperatingActivitiesExcludingLifeBusiness", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_DividendsReceivedClassifiedAsOperatingActivitiesLifeBusiness": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 9.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from dividends received, classified as operating activities, related to life insurance business.", "label": "Dividends received, classified as operating activities, life business", "terseLabel": "Dividends received" } } }, "localname": "DividendsReceivedClassifiedAsOperatingActivitiesLifeBusiness", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_DownsideScenarioMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the downside scenario. The downside scenario is a fixed severity scenario with expected credit losses approximately 80% higher than those under the current base scenario.", "label": "Downside Scenario [Member]", "terseLabel": "Downside scenario" } } }, "localname": "DownsideScenarioMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails" ], "xbrltype": "domainItemType" }, "wbk_DueFromSubsidiariesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for receivables due from subsidiaries.", "label": "Due From Subsidiaries [Member]", "terseLabel": "Due from subsidiaries" } } }, "localname": "DueFromSubsidiariesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "wbk_DueToSubsidiariesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for payables due to subsidiaries.", "label": "Due To Subsidiaries [Member]", "terseLabel": "Due to subsidiaries" } } }, "localname": "DueToSubsidiariesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_EmployeeSharePlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to employee share plan.", "label": "Employee Share Plan [Member]", "terseLabel": "Employee Share Plan (ESP)" } } }, "localname": "EmployeeSharePlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_EntitiesOverWhichControlHasCeasedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for entities over which control has ceased.", "label": "Entities Over Which Control Has Ceased [Member]", "terseLabel": "Assets and liabilities over which control ceased" } } }, "localname": "EntitiesOverWhichControlHasCeasedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "domainItemType" }, "wbk_EquityAdjustedBalance": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of residual interest in the assets of the entity after deducting all its liabilities, after the cumulative effect adjustment of a new accounting principle applied in the period of adoption.", "label": "Equity, Adjusted Balance", "terseLabel": "Restated opening balance" } } }, "localname": "EquityAdjustedBalance", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_EquityInstrumentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for equity instruments.", "label": "Equity Instruments [Member]", "terseLabel": "Equity instruments" } } }, "localname": "EquityInstrumentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "wbk_EquityInstrumentsOtherThanOptionsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Equity Instruments Other Than Options [Abstract]", "terseLabel": "Equity instruments other than options" } } }, "localname": "EquityInstrumentsOtherThanOptionsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "stringItemType" }, "wbk_EquitySecuritiesReserveAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Equity Securities Reserve [Abstract]", "terseLabel": "Equity securities at FVOCI reserve" } } }, "localname": "EquitySecuritiesReserveAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "wbk_EstimateOfUnemploymentRatePercentage": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The estimated unemployment rate percentage used in sensitivity analysis.", "label": "Estimate of Unemployment Rate Percentage", "terseLabel": "Unemployment rate, percentage forecast" } } }, "localname": "EstimateOfUnemploymentRatePercentage", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "percentItemType" }, "wbk_EstimatedCostsOfLegalProceedings": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The estimated costs of legal proceedings.", "label": "Estimated Costs of Legal Proceedings", "terseLabel": "Estimated costs associated with AUSTRAC proceedings" } } }, "localname": "EstimatedCostsOfLegalProceedings", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExchangeDifferencesRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in the reserve of gains and losses on financial assets measured at fair value through other comprehensive income resulting from exchange differences.", "label": "Exchange differences relating to financial assets measured at fair value through other comprehensive income", "terseLabel": "Exchange differences" } } }, "localname": "ExchangeDifferencesRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExchangeSettlementAccounts": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails": { "order": 2.0, "parentTag": "ifrs-full_CashAndBankBalancesAtCentralBanks", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash classified as exchange settlement accounts", "label": "Exchange Settlement Accounts", "terseLabel": "Exchange settlement accounts" } } }, "localname": "ExchangeSettlementAccounts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExclusiveSupplyAgreementMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for an exclusive supply agreement.", "label": "Exclusive Supply Agreement [Member]", "terseLabel": "Exclusive supply agreement" } } }, "localname": "ExclusiveSupplyAgreementMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_ExpectedCreditLossCovid19AggregateProvision": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The aggregate amount of provision for expected credit loss (ECL) related to COVID-19.", "label": "Expected Credit Loss, COVID19, Aggregate Provision", "totalLabel": "Total provision for ECL" } } }, "localname": "ExpectedCreditLossCovid19AggregateProvision", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpectedCreditLossCovid19ModelledProvisionUsingEconomicInputs": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails": { "order": 1.0, "parentTag": "wbk_ExpectedCreditLossCovid19AggregateProvision", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of provision for expected credit loss (ECL) for economic uncertainties, modelled using updated inputs and weightings, related to COVID-19.", "label": "Expected Credit Loss, COVID19, Modelled Provision Using Economic Inputs", "terseLabel": "Modelled provision for ECL" } } }, "localname": "ExpectedCreditLossCovid19ModelledProvisionUsingEconomicInputs", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpectedCreditLossEconomicOverlay": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails": { "order": 2.0, "parentTag": "wbk_ExpectedCreditLossCovid19AggregateProvision", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of provision for expected credit loss (ECL) for economic overlay.", "label": "Expected Credit Loss, Economic Overlay", "terseLabel": "Portfolio Overlays" } } }, "localname": "ExpectedCreditLossEconomicOverlay", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfPortfolioOverlaysOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpectedCreditLossStagingSensitivityPercentageOfStageOneReflectedInStageTwo": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "In sensitivity analysis, the percentage of stage 1 gross exposure from loans and credit commitments (calculated on a 12 month ECL) reflected in stage 2 (calculated on a lifetime ECL).", "label": "Expected Credit Loss, Staging Sensitivity, Percentage of Stage One Reflected in Stage Two", "terseLabel": "Percentage of gross exposure from loans and credit commitments stage 1 reflected in stage 2" } } }, "localname": "ExpectedCreditLossStagingSensitivityPercentageOfStageOneReflectedInStageTwo", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "percentItemType" }, "wbk_ExpectedLossOnSaleOfSubsidiaryBeforeTax": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The expected loss on sale of subsidiary, before tax.", "label": "Expected Loss On Sale of Subsidiary, Before tax", "terseLabel": "Expected loss on sale, pre-tax" } } }, "localname": "ExpectedLossOnSaleOfSubsidiaryBeforeTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpectedReceivableCompletionSettlement": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails": { "order": 2.0, "parentTag": "wbk_TotalConsiderationFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expected receivable from completion settlement.", "label": "Expected Receivable, Completion Settlement", "terseLabel": "Expected receivable (completion settlement)" } } }, "localname": "ExpectedReceivableCompletionSettlement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpenseArisingFromInsuranceContractsGeneralInsuranceClaimsAndLendersMortgageInsuranceClaimsAndOtherExpenses": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "ifrs-full_ExpenseArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from insurance contracts classified as general insurance claims and lenders mortgage (LMI) claims and other expenses.", "label": "Expense Arising From Insurance Contracts, General Insurance Claims and Lenders Mortgage Insurance Claims And Other Expenses", "negatedLabel": "General insurance and LMI claims and other expenses" } } }, "localname": "ExpenseArisingFromInsuranceContractsGeneralInsuranceClaimsAndLendersMortgageInsuranceClaimsAndOtherExpenses", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ExpenseArisingFromInsuranceContractsLifeInsuranceClaimsAndChangesInInsuranceLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "ifrs-full_ExpenseArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from insurance contracts classified as life insurance claims and changes to insurance liabilities.", "label": "Expense Arising From Insurance Contracts, Life Insurance Claims and Changes in Insurance Liabilities", "negatedLabel": "Life insurance claims and changes in life insurance liabilities" } } }, "localname": "ExpenseArisingFromInsuranceContractsLifeInsuranceClaimsAndChangesInInsuranceLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FairValueAssumptionsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Fair Value Assumptions [Abstract]", "terseLabel": "Fair value assumptions" } } }, "localname": "FairValueAssumptionsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails" ], "xbrltype": "stringItemType" }, "wbk_FinanceAndInsuranceMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for finance and insurance.", "label": "Finance And Insurance [Member]", "terseLabel": "Finance and insurance" } } }, "localname": "FinanceAndInsuranceMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_FinanceLeaseTransactionMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for finance lease transactions.", "label": "Finance Lease Transaction [Member]", "terseLabel": "Finance lease transactions" } } }, "localname": "FinanceLeaseTransactionMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "FINANCIAL ASSETS AND FINANCIAL LIABILITIES" } } }, "localname": "FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure for the general accounting policies related to financial assets and financial liabilities.", "label": "Financial Assets and Financial Liabilities, Policy Disclosure [Text Block]", "terseLabel": "FINANCIAL ASSETS AND FINANCIAL LIABILITIES" } } }, "localname": "FinancialAssetsAndFinancialLiabilitiesPolicyDisclosureTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialAssetsAndFinancialLiabilities" ], "xbrltype": "textBlockItemType" }, "wbk_FinancialAssetsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "wbk_FinancialAssetsLiabilitiesBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of financial assets based on expected maturities.", "label": "Financial Assets, Based On Expected Maturities", "totalLabel": "Total assets" } } }, "localname": "FinancialAssetsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialAssetsLiabilitiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of financial assets (liabilities) based on expected maturities.", "label": "Financial Assets (Liabilities), Based On Expected Maturities", "totalLabel": "Net assets/(net liabilities)" } } }, "localname": "FinancialAssetsLiabilitiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialAssetsNotSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount financial assets not subject to offsetting, enforceable master netting arrangements or similar agreements.", "label": "Financial Assets Not Subject to Offsetting, Enforceable Master Netting Arrangements or Similar Agreements", "terseLabel": "Financial assets not subject to offsetting" } } }, "localname": "FinancialAssetsNotSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialInstrumentCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 4.0, "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of financial instrument collateral received that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial assets.", "label": "Financial Instrument Collateral Received Subject To Enforceable Master Netting Arrangement Or Similar Agreement Not Set Off Against Financial Assets", "negatedLabel": "Financial instrument collateral" } } }, "localname": "FinancialInstrumentCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialInstrumentPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 4.0, "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of financial instrument collateral pledged that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial liabilities.", "label": "Financial Instrument Pledged Subject To Enforceable Master Netting Arrangement Or Similar Agreement Not Set Off Against Financial Liabilities", "negatedLabel": "Financial instrument collateral" } } }, "localname": "FinancialInstrumentPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialInstrumentsExcludingDerivativesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for financial instruments excluding derivatives.", "label": "Financial Instruments Excluding Derivatives [Member]", "terseLabel": "Non-derivative financial instruments" } } }, "localname": "FinancialInstrumentsExcludingDerivativesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_FinancialInstrumentsImpactedByInterbankOfferingRateReformAndYetToTransitionToAlternativeReferenceRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for financial instruments impacted by IBOR reform and yet to transition to ARR.", "label": "Financial Instruments Impacted By Interbank Offering Rate Reform And Yet To Transition To Alternative Reference Rate [Member]", "terseLabel": "Financial instruments impacted by IBOR reform post transition date" } } }, "localname": "FinancialInstrumentsImpactedByInterbankOfferingRateReformAndYetToTransitionToAlternativeReferenceRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_FinancialLiabilitiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "wbk_FinancialAssetsLiabilitiesBasedOnExpectedMaturities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of financial liabilities based on expected maturities.", "label": "Financial Liabilities, Based On Expected Maturities", "totalLabel": "Total liabilities" } } }, "localname": "FinancialLiabilitiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to financial liabilities, excluding loan capital.", "label": "Financial Liabilities, Excluding Loan Capital, Undiscounted Cash Flows", "terseLabel": "Total financial liabilities excluding loan capital" } } }, "localname": "FinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialLiabilitiesNotSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount financial liabilities not subject to offsetting, enforceable master netting arrangements or similar agreements.", "label": "Financial Liabilities Not Subject to Offsetting, Enforceable Master Netting Arrangements or Similar Agreements", "terseLabel": "Financial liabilities not subject to offsetting" } } }, "localname": "FinancialLiabilitiesNotSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialLiabilitiesUndiscountedCashFlows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to financial liabilities.", "label": "Financial Liabilities, Undiscounted Cash Flows", "terseLabel": "Total undiscounted financial liabilities" } } }, "localname": "FinancialLiabilitiesUndiscountedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FinancialRiskAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Financial risk" } } }, "localname": "FinancialRiskAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_FinancialStatementsPreparationAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Financial statements preparation" } } }, "localname": "FinancialStatementsPreparationAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_FiveYearAudSemiQuarterlyMidSwapReferenceRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for five year AUD semi-quarterly mid-swap reference rate.", "label": "Five Year Aud Semi Quarterly Mid Swap Reference Rate [Member]", "terseLabel": "Five year AUD semi-quarterly mid-swap reference rate" } } }, "localname": "FiveYearAudSemiQuarterlyMidSwapReferenceRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearEurMidMarketSwapRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for 5-year EUR mid-market swap rate.", "label": "Five Year Eur Mid Market Swap Rate [Member]", "terseLabel": "Five-year EUR mid-market swap rate" } } }, "localname": "FiveYearEurMidMarketSwapRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearHkdMidSwapRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for five year HKD mid-swap rate.", "label": "Five Year Hkd Mid Swap Rate [Member]", "terseLabel": "Five year HKD mid-swap rate" } } }, "localname": "FiveYearHkdMidSwapRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearJpyMidSwapRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for five year JPY mid-swap rate.", "label": "Five Year Jpy Mid Swap Rate [Member]", "terseLabel": "Five year JPY mid-swap rate" } } }, "localname": "FiveYearJpyMidSwapRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearSgdSwapOfferRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for five year SGD swap offer rate.", "label": "Five Year Sgd Swap Offer Rate [Member]", "terseLabel": "Five year SGD swap offer rate" } } }, "localname": "FiveYearSgdSwapOfferRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearUsTreasuryRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for 5-year US Treasury rate.", "label": "Five Year Us Treasury Rate [Member]", "terseLabel": "Five-year USD treasury rate" } } }, "localname": "FiveYearUsTreasuryRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FiveYearUsdMidMarketSwapRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for 5-year USD mid-market swap rate.", "label": "Five Year Usd Mid Market Swap Rate [Member]", "terseLabel": "Five-year USD mid-market swap rate" } } }, "localname": "FiveYearUsdMidMarketSwapRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_FloatingNinetyDayBankBillRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for floating 90 day bank bill rate.", "label": "Floating Ninety Day Bank Bill Rate [Member]", "terseLabel": "Floating 90 day bank bill rate" } } }, "localname": "FloatingNinetyDayBankBillRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_ForeignExchangeContractsCrossCurrencySwapAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for foreign exchange cross currency swap agreements.", "label": "Foreign Exchange Contracts Cross Currency Swap Agreements [Member]", "terseLabel": "Cross currency swap agreements" } } }, "localname": "ForeignExchangeContractsCrossCurrencySwapAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_ForeignExchangeSpotAndForwardContractsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for foreign exchange spot and forward contracts.", "label": "Foreign Exchange Spot And Forward Contracts [Member]", "terseLabel": "Spot and forward contracts" } } }, "localname": "ForeignExchangeSpotAndForwardContractsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_FormerGroupExecutiveMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Former Group Executive.", "label": "Former Group Executive [Member]", "terseLabel": "Former Group Executive" } } }, "localname": "FormerGroupExecutiveMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_FourYearVestingPeriodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to four year vesting period.", "label": "Four Year Vesting Period [Member]", "terseLabel": "Four-year vesting period" } } }, "localname": "FourYearVestingPeriodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_FrankingCreditsAvailableAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of franking credits available amount.", "label": "Franking Credits Available Amount", "terseLabel": "Franking credits" } } }, "localname": "FrankingCreditsAvailableAmount", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_FullySecuredLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans for which the secured loan to collateral value ratio is less than or equal to 100%.", "label": "Fully Secured Loans [Member]", "terseLabel": "Fully secured" } } }, "localname": "FullySecuredLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "domainItemType" }, "wbk_FundingForLendingProgramMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Funding for Lending Programme (FLP) issued by the Reserve Bank of New Zealand.", "label": "Funding For Lending Program [Member]", "terseLabel": "Funding for Lending Programme (FLP)" } } }, "localname": "FundingForLendingProgramMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "domainItemType" }, "wbk_GainLossOnDisposalOfInvestmentsInAssociates": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 4.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of gain (loss) on disposal of investment in associates.", "label": "Gain (Loss) on Disposal of Investments in Associates", "terseLabel": "Net gain/(loss) on sale/derecognition of associates" } } }, "localname": "GainLossOnDisposalOfInvestmentsInAssociates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainLossOnHedgeIneffectivenessRecognisedInInterestIncome": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gain (loss) recognised in interest income on hedge ineffectiveness.", "label": "Gain (Loss) on Hedge Ineffectiveness Recognised in Interest Income", "terseLabel": "Hedge ineffectiveness recognised in interest income" } } }, "localname": "GainLossOnHedgeIneffectivenessRecognisedInInterestIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainLossOnHedgeIneffectivenessRecognisedInOperatingIncome": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gain (loss) recognised in operating income on hedge ineffectiveness.", "label": "Gain (Loss) on Hedge Ineffectiveness Recognised in Operating Income", "terseLabel": "Hedge ineffectiveness recognised in non-interest income" } } }, "localname": "GainLossOnHedgeIneffectivenessRecognisedInOperatingIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgeEffectivenessDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesFromChangeInFairValueOfNetInvestmentHedges": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gain (losses) from changes in fair value of net investment hedges.", "label": "Gains (Losses) from Change in Fair Value of Net Investment Hedges", "terseLabel": "Net gains (losses) from changes in fair value of net investment hedges" } } }, "localname": "GainsLossesFromChangeInFairValueOfNetInvestmentHedges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnCashFlowHedgesTax": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on cash flow hedges, tax.", "label": "Gains (Losses) on Cash Flow Hedges Tax", "terseLabel": "Income tax effect" } } }, "localname": "GainsLossesOnCashFlowHedgesTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnExchangeDifferencesOnTranslationNetOfAssociatedHedges": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 7.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on exchange differences on the translation of financial statements of foreign operations, net of associated hedges, net of tax.", "label": "Gains Losses On Exchange Differences On Translation Net Of Associated Hedges", "terseLabel": "Exchange differences on translation of foreign operations (net of associated hedges)" } } }, "localname": "GainsLossesOnExchangeDifferencesOnTranslationNetOfAssociatedHedges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxExcludingExchangeDifferences": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) recognised in other comprehensive income on financial assets measured at fair value through other comprehensive income, before tax and excluding exchange differences.", "label": "Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax, excluding exchange differences", "terseLabel": "Net gains/(losses) from changes in fair value" } } }, "localname": "GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxExcludingExchangeDifferences", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeTax": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The income tax effect of gains (losses) recognised in other comprehensive income on financial assets measured at fair value through other comprehensive income.", "label": "Gains (losses) on financial assets measured at fair value through other comprehensive income, tax", "negatedLabel": "Income tax effect" } } }, "localname": "GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnFinancialInstrumentsAtFairValueThroughProfitOrLoss": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 8.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) on financial instruments at fair value through profit or loss.", "label": "Gains (losses) on financial instruments at fair value through profit or loss", "terseLabel": "Net gain/(loss) on financial assets measured at fair value" } } }, "localname": "GainsLossesOnFinancialInstrumentsAtFairValueThroughProfitOrLoss", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsRecognisedInProfitOrLoss": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 6.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) recognised in profit or loss on hedges of net investments in foreign operations.", "label": "Gains (losses) on hedges of net investments in foreign operations recognised in profit or loss", "terseLabel": "Net gain/(loss) on hedging overseas operations" } } }, "localname": "GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsRecognisedInProfitOrLoss", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GainsLossesOnHedgingInstrumentDiscontinuedHedges": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gains (losses) on hedging instruments in fair value hedges attributable to discontinued hedges.", "label": "Gains (Losses) on Hedging Instrument, Discontinued Hedges", "negatedLabel": "Loss relating to discontinued hedges" } } }, "localname": "GainsLossesOnHedgingInstrumentDiscontinuedHedges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GaryThursbyMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Gary Thursby.", "label": "Gary Thursby [Member]", "terseLabel": "Gary Thursby" } } }, "localname": "GaryThursbyMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_GoodOrSatisfactoryCreditGradeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for good or satisfactory credit grade.", "label": "Good Or Satisfactory Credit Grade [Member]", "terseLabel": "Good/satisfactory" } } }, "localname": "GoodOrSatisfactoryCreditGradeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_GoodwillImpairmentTestingScheduleOfSignificantAssumptionsUsedTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of significant assumptions used in goodwill impairment testing.", "label": "Goodwill Impairment Testing, Schedule of Significant Assumptions Used [Table Text Block]", "terseLabel": "Summary of significant assumptions used in goodwill impairment testing" } } }, "localname": "GoodwillImpairmentTestingScheduleOfSignificantAssumptionsUsedTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsTables" ], "xbrltype": "textBlockItemType" }, "wbk_GovernmentAdministrationAndDefenceMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for government, administration and defence.", "label": "Government Administration And Defence [Member]", "terseLabel": "Government, administration and defence" } } }, "localname": "GovernmentAdministrationAndDefenceMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_GovernmentAndSemiGovernmentSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for government and semi-government debt securities held by the entity.", "label": "Government And Semi Government Securities [Member]", "terseLabel": "Government and semi-government debt securities" } } }, "localname": "GovernmentAndSemiGovernmentSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "domainItemType" }, "wbk_GrossDeferredTaxAssetsRecognisedInIncomeStatementsAndOpeningRetainedProfitsDueToAdoptionOfNewAccountingStandards": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails": { "order": 1.0, "parentTag": "ifrs-full_DeferredTaxAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The gross amount of deferred tax assets recognised in the income statement and opening retained profits due to adoption of new accounting standards.", "label": "Gross Deferred Tax Assets, Recognised in Income Statements and Opening Retained Profits due to Adoption of New Accounting Standards", "terseLabel": "Amounts recognised in the income statements and opening retained profits" } } }, "localname": "GrossDeferredTaxAssetsRecognisedInIncomeStatementsAndOpeningRetainedProfitsDueToAdoptionOfNewAccountingStandards", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GrossDeferredTaxAssetsRecognisedInOtherComprehensiveIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails": { "order": 2.0, "parentTag": "ifrs-full_DeferredTaxAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The gross amount of deferred tax assets recognised directly in other comprehensive income.", "label": "Gross Deferred Tax Assets Recognised in Other Comprehensive Income", "terseLabel": "Amounts recognised directly in OCI" } } }, "localname": "GrossDeferredTaxAssetsRecognisedInOtherComprehensiveIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GrossDeferredTaxLiabilitiesRecognisedInIncomeStatement": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_DeferredTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gross amount of deferred tax liabilities recognised in the income statement.", "label": "Gross Deferred Tax Liabilities Recognised in Income Statement", "terseLabel": "Amounts recognised in the income statements and opening retained profits" } } }, "localname": "GrossDeferredTaxLiabilitiesRecognisedInIncomeStatement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GrossDeferredTaxLiabilitiesRecognisedInOtherComprehensiveIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_DeferredTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The gross amount of deferred tax liabilities recognised directly in other comprehensive income.", "label": "Gross Deferred Tax Liabilities Recognised in Other Comprehensive Income", "terseLabel": "Amounts recognised directly in OCI" } } }, "localname": "GrossDeferredTaxLiabilitiesRecognisedInOtherComprehensiveIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GrossLoansAndCreditCommitments": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The gross amount of loans and credit commitments.", "label": "Gross Loans and Credit Commitments", "terseLabel": "Gross loans and credit commitments" } } }, "localname": "GrossLoansAndCreditCommitments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GrossLoansAndCreditCommitmentsProvisionForExpectedCreditLossesCoverageRatio": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount of provision for expected credit losses as a percentage of gross amount of loans and credit commitments.", "label": "Gross Loans and Credit Commitments, Provision for Expected Credit Losses, Coverage Ratio", "terseLabel": "Coverage ratio (%)" } } }, "localname": "GrossLoansAndCreditCommitmentsProvisionForExpectedCreditLossesCoverageRatio", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "percentItemType" }, "wbk_GrossProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from the disposal of non-current assets or disposal groups classified as held for sale and discontinued operations.", "label": "Gross Proceeds From Disposal of Non-Current Assets or Disposal Groups Classified as Held-For-Sale and Discontinued Operations", "terseLabel": "Cash proceeds received from sale of business" } } }, "localname": "GrossProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_GroupExecutiveMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Group Executive.", "label": "Group Executive [Member]", "terseLabel": "Group Executive" } } }, "localname": "GroupExecutiveMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_GuaranteesTrancheOneMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for tranche one of guarantees.", "label": "Guarantees Tranche One [Member]", "terseLabel": "Guarantees capped at $20 million per year" } } }, "localname": "GuaranteesTrancheOneMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_GuaranteesTrancheTwoMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for tranche two of guarantees.", "label": "Guarantees Tranche Two [Member]", "terseLabel": "Guarantees capped at $2 million per year" } } }, "localname": "GuaranteesTrancheTwoMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_GuilhermeLimaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Guilherme Lima.", "label": "Guilherme Lima [Member]", "terseLabel": "Guil Lima" } } }, "localname": "GuilhermeLimaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_HedgingInstrumentAssetsBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_HedgingInstrumentAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of a hedging instrument, recognised as an asset before netting arrangements.", "label": "Hedging Instrument, Assets, Before Netting Arrangements", "terseLabel": "Gross hedged assets" } } }, "localname": "HedgingInstrumentAssetsBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_HedgingInstrumentAssetsImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_HedgingInstrumentAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in hedged assets due to the impacts of netting arrangements.", "label": "Hedging Instrument, Assets, Impact of Netting Arrangements", "terseLabel": "Impact of netting arrangements on hedged assets" } } }, "localname": "HedgingInstrumentAssetsImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_HedgingInstrumentLiabilitiesBeforeNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": 1.0, "parentTag": "ifrs-full_HedgingInstrumentLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of a hedging instrument, recognised as a liability before netting arrangements.", "label": "Hedging Instrument, Liabilities, Before Netting Arrangements", "negatedLabel": "Gross hedged liabilities" } } }, "localname": "HedgingInstrumentLiabilitiesBeforeNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_HedgingInstrumentLiabilitiesImpactOfNettingArrangements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails": { "order": 2.0, "parentTag": "ifrs-full_HedgingInstrumentLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in hedged liabilities due to the impacts of netting arrangements.", "label": "Hedging Instrument, Liabilities, Impact of Netting Arrangements", "negatedLabel": "Impact of netting arrangements on hedged liabilities" } } }, "localname": "HedgingInstrumentLiabilitiesImpactOfNettingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_HoldingPeriodForVar": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The period of historical data used for Value at Risk.", "label": "Holding Period for VaR", "terseLabel": "Holding period" } } }, "localname": "HoldingPeriodForVar", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "durationItemType" }, "wbk_HousingLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for housing loans.", "label": "Housing Loans [Member]", "terseLabel": "Housing" } } }, "localname": "HousingLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "domainItemType" }, "wbk_HundredPercentBaseCaseEclMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to 100% base case ECL.", "label": "Hundred Percent Base Case Ecl [Member]", "terseLabel": "100% base case ECL" } } }, "localname": "HundredPercentBaseCaseEclMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "domainItemType" }, "wbk_HundredPercentDownsideEclMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to 100% downside ECL.", "label": "Hundred Percent Downside Ecl [Member]", "terseLabel": "100% downside ECL" } } }, "localname": "HundredPercentDownsideEclMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsAwardDateAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by date or year of grant, pertaining to equity-based compensation arrangements.", "label": "IFRS Award Date [Axis]" } } }, "localname": "IfrsAwardDateAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsAwardDateDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Date or year of grant of equity-based compensation.", "label": "Ifrs Award Date [Domain]", "terseLabel": "IFRS Award Date [Domain]" } } }, "localname": "IfrsAwardDateDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsAwardTypeAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by award type pertaining to equity-based compensation.", "label": "IFRS Award Type [Axis]" } } }, "localname": "IfrsAwardTypeAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsBalanceSheetLocationAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by location on balance sheet (statement of financial position).", "label": "IFRS Balance Sheet Location [Axis]" } } }, "localname": "IfrsBalanceSheetLocationAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsBalanceSheetLocationDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Location in the balance sheet (statement of financial position).", "label": "Ifrs Balance Sheet Location [Domain]", "terseLabel": "IFRS Balance Sheet Location [Domain]" } } }, "localname": "IfrsBalanceSheetLocationDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsBankingRegulationRiskWeightedAssetsCalculationMethodologyAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by approach for calculating risk-weighted assets as defined by regulatory framework.", "label": "IFRS Banking Regulation, Risk-Weighted Assets Calculation Methodology [Axis]" } } }, "localname": "IfrsBankingRegulationRiskWeightedAssetsCalculationMethodologyAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsBankingRegulationRiskWeightedAssetsCalculationMethodologyDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Approach for calculating risk-weighted assets as defined by regulatory framework.", "label": "Ifrs Banking Regulation Risk Weighted Assets Calculation Methodology [Domain]", "terseLabel": "IFRS Banking Regulation, Risk-Weighted Assets Calculation Methodology [Domain]" } } }, "localname": "IfrsBankingRegulationRiskWeightedAssetsCalculationMethodologyDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsCashMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits.", "label": "Ifrs Cash [Member]", "terseLabel": "Cash" } } }, "localname": "IfrsCashMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsCertificatesOfDepositMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Short to medium-term investment available at banks and savings and loan institutions where a customer agrees to lend money to the institution for a certain amount of time and is paid a predetermined rate of interest. Certificates of deposit (CD) are typically Federal Deposit Insurance Corporation (FDIC) insured.", "label": "Ifrs Certificates Of Deposit [Member]", "terseLabel": "Certificates of deposit" } } }, "localname": "IfrsCertificatesOfDepositMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsCommodityContractMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to commodity prices.", "label": "Ifrs Commodity Contract [Member]", "terseLabel": "Commodity contracts" } } }, "localname": "IfrsCommodityContractMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "IFRS Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]", "terseLabel": "Capital adequacy" } } }, "localname": "IfrsComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsConstructionMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Building or developing real estate. Includes, but is not limited to, improvement to land for drainage, utilities, grading and subdividing.", "label": "Ifrs Construction [Member]", "terseLabel": "Construction" } } }, "localname": "IfrsConstructionMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsCreditDefaultSwapMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "A type of swap transaction used as a credit derivative in which one party makes periodic payments to the other and receives the promise of a pay-off if a third party defaults.", "label": "Ifrs Credit Default Swap [Member]", "terseLabel": "Credit default swaps" } } }, "localname": "IfrsCreditDefaultSwapMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsCumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.", "label": "IFRS Cumulative Effect of New Accounting Principle in Period of Adoption", "terseLabel": "Impact on adoption of new accounting standards" } } }, "localname": "IfrsCumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_IfrsDebtInstrumentTerm": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "IFRS Debt Instrument, Term", "terseLabel": "Term of lending facility" } } }, "localname": "IfrsDebtInstrumentTerm", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "durationItemType" }, "wbk_IfrsDerivativeContractDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Financial instrument or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.", "label": "Ifrs Derivative Contract [Domain]", "terseLabel": "IFRS Derivative Contract [Domain]" } } }, "localname": "IfrsDerivativeContractDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsDerivativeInstrumentAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by type of derivative contract.", "label": "IFRS Derivative Instrument [Axis]" } } }, "localname": "IfrsDerivativeInstrumentAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsDiscontinuedOperationsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Component or group of components classified as held-for-sale and representing a strategic shift that has or will have a major effect on operations and financial results. Includes a business or nonprofit activity on acquisition classified as held-for-sale.", "label": "Ifrs Discontinued Operations Held For Sale [Member]", "terseLabel": "Assets and liabilities held for sale" } } }, "localname": "IfrsDiscontinuedOperationsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsDisposalGroupClassificationAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by disposal group classification.", "label": "IFRS Disposal Group Classification [Axis]" } } }, "localname": "IfrsDisposalGroupClassificationAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsDisposalGroupClassificationDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Component or group of components disposed of, including but not limited to, disposal group held-for-sale or disposed of by sale, disposed of by means other than sale, and discontinued operations.", "label": "Ifrs Disposal Group Classification [Domain]", "terseLabel": "IFRS Disposal Group Classification [Domain]" } } }, "localname": "IfrsDisposalGroupClassificationDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsDisposalGroupNameAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by name of disposal group.", "label": "IFRS Disposal Group Name [Axis]" } } }, "localname": "IfrsDisposalGroupNameAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsEquityAwardDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Equity-based compensation award.", "label": "Ifrs Equity Award [Domain]", "terseLabel": "IFRS Equity Award [Domain]" } } }, "localname": "IfrsEquityAwardDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsEquityContractMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to share prices.", "label": "Ifrs Equity Contract [Member]", "terseLabel": "Equities" } } }, "localname": "IfrsEquityContractMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsFinancialInstrumentPerformanceStatusAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by category of performance or non-performance status of financial instruments.", "label": "IFRS Financial Instrument Performance Status [Axis]" } } }, "localname": "IfrsFinancialInstrumentPerformanceStatusAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsFinancialInstrumentPerformanceStatusDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Category of performance or non-performance status of financial instruments, including but not limited to, financing receivables, loans, debt, and investments.", "label": "Ifrs Financial Instrument Performance Status [Domain]", "terseLabel": "IFRS Financial Instrument Performance Status [Domain]" } } }, "localname": "IfrsFinancialInstrumentPerformanceStatusDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsFinancingReceivableCreditQualityIndicatorsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of financing receivables by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics.", "label": "IFRS Financing Receivable Credit Quality Indicators [Table Text Block]", "terseLabel": "Summary of non-performing loans and credit commitments" } } }, "localname": "IfrsFinancingReceivableCreditQualityIndicatorsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTables" ], "xbrltype": "textBlockItemType" }, "wbk_IfrsForeignExchangeContractMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to foreign exchange rates.", "label": "Ifrs Foreign Exchange Contract [Member]", "terseLabel": "FX contracts" } } }, "localname": "IfrsForeignExchangeContractMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsForeignExchangeOptionMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "An option that allows the holder to buy (if call) or sell (if put) an underlying currency at a fixed exercise rate, expressed as an exchange, during a specified period (an American option) or at a specified date (a European option).", "label": "Ifrs Foreign Exchange Option [Member]", "terseLabel": "Fx options" } } }, "localname": "IfrsForeignExchangeOptionMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsIncomeStatementLocationAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by location in the income statement.", "label": "IFRS Income Statement Location [Axis]" } } }, "localname": "IfrsIncomeStatementLocationAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsIncomeStatementLocationDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Location in the income statement.", "label": "Ifrs Income Statement Location [Domain]", "terseLabel": "IFRS Income Statement Location [Domain]" } } }, "localname": "IfrsIncomeStatementLocationDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsIncreaseDecreaseInCustomerDeposits": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) during the period in the amount of customer money held in customer accounts, including security deposits, collateral for a current or future transactions, initial payment of the cost of acquisition or for the right to enter into a contract or agreement.", "label": "IFRS Increase (Decrease) In Customer Deposits", "terseLabel": "Increase in customer deposits, amount" } } }, "localname": "IfrsIncreaseDecreaseInCustomerDeposits", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IfrsInterestExpenseAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Ifrs Interest Expense [Abstract]", "terseLabel": "Interest expense" } } }, "localname": "IfrsInterestExpenseAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsInterestRateContractMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to the right to receive or pay a sum of money at a given interest rate.", "label": "Ifrs Interest Rate Contract [Member]", "terseLabel": "Interest rate contracts" } } }, "localname": "IfrsInterestRateContractMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsInvestmentInterestRate": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Rate of interest on investment.", "label": "IFRS Investment Interest Rate", "terseLabel": "Weighted average yield" } } }, "localname": "IfrsInvestmentInterestRate", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "percentItemType" }, "wbk_IfrsInvestmentsDebtAndEquitySecuritiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Investment securities" } } }, "localname": "IfrsInvestmentsDebtAndEquitySecuritiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_IfrsLineOfCreditFacilityMaximumBorrowingCapacity": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.", "label": "IFRS Line of Credit Facility, Maximum Borrowing Capacity", "terseLabel": "Total allowance" } } }, "localname": "IfrsLineOfCreditFacilityMaximumBorrowingCapacity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IfrsLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "When a lender gives money or property over other debt securities sold by the issuer. In the event the issuer goes bankrupt, senior debt holders receive priority for [must receive] repayment [prior] relative to junior and unsecured (general) creditors.", "label": "Ifrs Loans [Member]", "terseLabel": "Loans" } } }, "localname": "IfrsLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsLoansReceivableMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "An amount of money or property, or a portion thereof, leant to a borrower (debtor) in exchange for a promise to repay the amount borrowed plus interest at a date certain in the future.", "label": "Ifrs Loans Receivable [Member]", "terseLabel": "Loans" } } }, "localname": "IfrsLoansReceivableMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsNonInterestIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Non-interest income" } } }, "localname": "IfrsNonInterestIncomeAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_IfrsOperatingExpenseMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Primary financial statement caption encompassing expenses associated with normal operations.", "label": "Ifrs Operating Expense [Member]", "terseLabel": "Operating expenses" } } }, "localname": "IfrsOperatingExpenseMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsOperatingExpensesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Operating expenses" } } }, "localname": "IfrsOperatingExpensesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_IfrsOtherIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Ifrs Other Income [Abstract]", "terseLabel": "Other income" } } }, "localname": "IfrsOtherIncomeAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsOtherLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Primary financial statement caption encompassing other liabilities.", "label": "Ifrs Other Liabilities [Member]", "terseLabel": "Other liabilities" } } }, "localname": "IfrsOtherLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The entire disclosure for regulatory capital requirement for depository and lending institutions. Institutions include, but not are not limited to, finance company, insured depository institution, bank holding company, savings and loan association holding company, bank and savings institution not federally insured, mortgage company, foreign financial institution and credit union.", "label": "IFRS Regulatory Capital Requirements under Banking Regulations [Text Block]", "terseLabel": "Capital adequacy" } } }, "localname": "IfrsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacy" ], "xbrltype": "textBlockItemType" }, "wbk_IfrsRepurchaseAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Investments represented by an agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Such agreements are generally short-term in nature.", "label": "Ifrs Repurchase Agreements [Member]", "terseLabel": "Repurchase agreements" } } }, "localname": "IfrsRepurchaseAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "A table disclosing the capital amounts and ratios as of the balance sheet date indicating whether the entity or entities are in compliance with regulatory capital requirements, by entity.", "label": "IFRS Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table]" } } }, "localname": "IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the capital amounts and ratios as of the balance sheet date, indicating whether the entity or entities are in compliance with regulatory capital requirements, by entity.", "label": "IFRS Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]", "terseLabel": "Schedule of loan capital" } } }, "localname": "IfrsScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTables" ], "xbrltype": "textBlockItemType" }, "wbk_IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pre-tax income from continuing operations.", "label": "Ifrs Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]", "terseLabel": "Schedule of income tax reconciled to profit before income tax" } } }, "localname": "IfrsScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxTables" ], "xbrltype": "textBlockItemType" }, "wbk_IfrsSharePrice": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Price of a single share of a number of saleable stocks of a company.", "label": "IFRS Share Price", "terseLabel": "Average price per share for share issuance" } } }, "localname": "IfrsSharePrice", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "wbk_IfrsStockIssuedDuringPeriodValueDividendReinvestmentPlan": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 3.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Value of stock issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the holder of the stock to reinvest dividends paid to them by the entity on new issues of stock by the entity.", "label": "Ifrs Stock Issued During Period, Value, Dividend Reinvestment Plan", "terseLabel": "Dividend reinvestment plan", "verboseLabel": "Shares issued under the dividend reinvestment plan" } } }, "localname": "IfrsStockIssuedDuringPeriodValueDividendReinvestmentPlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails", "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_IfrsStockRepurchaseProgramAuthorizedAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of stock repurchase plan authorized.", "label": "IFRS Stock Repurchase Program, Authorized Amount", "terseLabel": "Maximum value of shares authorized for buy back" } } }, "localname": "IfrsStockRepurchaseProgramAuthorizedAmount", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IfrsUnusualOrInfrequentItemOrBothAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by an event or transaction that is unusual in nature or infrequent in occurrence, or both.", "label": "IFRS Unusual or Infrequent Item, or Both [Axis]" } } }, "localname": "IfrsUnusualOrInfrequentItemOrBothAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsUnusualOrInfrequentItemOrBothDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Event or transaction that is unusual in nature or infrequent in occurrence, or both.", "label": "Ifrs Unusual Or Infrequent Item Or Both [Domain]", "terseLabel": "IFRS Unusual or Infrequent Item, or Both [Domain]" } } }, "localname": "IfrsUnusualOrInfrequentItemOrBothDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "domainItemType" }, "wbk_IfrsVestingAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Information by vesting schedule for share-based compensation.", "label": "IFRS Vesting [Axis]" } } }, "localname": "IfrsVestingAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "stringItemType" }, "wbk_IfrsVestingDomain": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Vesting schedule for share-based compensation.", "label": "Ifrs Vesting [Domain]", "terseLabel": "IFRS Vesting [Domain]" } } }, "localname": "IfrsVestingDomain", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_ImpactOnNetDeferredTaxAssetsDueToAdoptionOfNewAccountingPolicies": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of impact to deferred tax assets upon adoption of new accounting policies.", "label": "Impact On Net Deferred Tax Assets Due To Adoption Of New Accounting Policies", "terseLabel": "Impact on adoption of new accounting standards" } } }, "localname": "ImpactOnNetDeferredTaxAssetsDueToAdoptionOfNewAccountingPolicies", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ImpactOnNetDeferredTaxLiabilitiesDueToAdoptionOfNewAccountingPolicies": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of impact to deferred tax liabilities upon adoption of new accounting policies.", "label": "Impact On Net Deferred Tax Liabilities Due To Adoption Of New Accounting Policies", "terseLabel": "Impact on adoption of new accounting standards" } } }, "localname": "ImpactOnNetDeferredTaxLiabilitiesDueToAdoptionOfNewAccountingPolicies", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ImpairmentChargesForDebtSecuritiesAtAmortisedCostMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for impairment charges for debt securities at amortised cost.", "label": "Impairment Charges For Debt Securities At Amortised Cost [Member]", "terseLabel": "Impairment charges for debt securities at amortised cost" } } }, "localname": "ImpairmentChargesForDebtSecuritiesAtAmortisedCostMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_ImpairmentChargesForDebtSecuritiesAtFairValueThroughOtherComprehensiveIncomeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for impairment charges for debt securities at Fair Value through Other Comprehensive Income (FVOCI).", "label": "Impairment Charges For Debt Securities At Fair Value Through Other Comprehensive Income [Member]", "terseLabel": "Impairment charges for debt securities at FVOCI" } } }, "localname": "ImpairmentChargesForDebtSecuritiesAtFairValueThroughOtherComprehensiveIncomeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_ImpairmentLossRecognizedInOtherComprehensiveIncomeDebtSecurities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of impairment loss recognised in other comprehensive income for debt securities.", "label": "Impairment loss recognized in other comprehensive income, debt securities", "negatedLabel": "Loss allowance on debt securities measured at FVOCI" } } }, "localname": "ImpairmentLossRecognizedInOtherComprehensiveIncomeDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossInvestmentsInSubsidiaries": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 6.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of impairment loss or reversal of impairment loss recognised in profit or loss for investments in subsidiaries.", "label": "Impairment loss (reversal of impairment loss) recognised in profit or loss, investments in subsidiaries", "terseLabel": "Impairment on investments in subsidiaries" } } }, "localname": "ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossInvestmentsInSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ImputationCreditsAvailableAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of imputation credits available.", "label": "Imputation Credits Available Amount", "terseLabel": "Imputation credits" } } }, "localname": "ImputationCreditsAvailableAmount", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ImputationCreditsPerShare": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The per share amount of imputation credits.", "label": "Imputation Credits Per Share", "terseLabel": "Imputation credits per share" } } }, "localname": "ImputationCreditsPerShare", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "perShareItemType" }, "wbk_IncomeArisingFromInsuranceContractsGeneralInsuranceAndLendersMortgageInsurance": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 4.0, "parentTag": "wbk_NetEarnedPremiumAndIncomeArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of income arising from general insurance and lenders mortgage (LMI) contracts.", "label": "Income Arising From Insurance Contracts, General Insurance And Lenders Mortgage Insurance", "terseLabel": "General insurance and LMI investment and other income" } } }, "localname": "IncomeArisingFromInsuranceContractsGeneralInsuranceAndLendersMortgageInsurance", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncomeArisingFromInsuranceContractsLifeInsurance": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 3.0, "parentTag": "wbk_NetEarnedPremiumAndIncomeArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of income arising from life insurance contracts.", "label": "Income Arising From Insurance Contracts, Life Insurance", "terseLabel": "Life insurance investment and other income" } } }, "localname": "IncomeArisingFromInsuranceContractsLifeInsurance", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncomeFromTransactionsWithSubsidiaries": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of income from transactions with subsidiaries.", "label": "Income from Transactions with Subsidiaries", "terseLabel": "Transactions with subsidiaries" } } }, "localname": "IncomeFromTransactionsWithSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncomeTaxAnalysisAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Income Tax Analysis [Abstract]", "terseLabel": "Income tax expense comprises:" } } }, "localname": "IncomeTaxAnalysisAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails" ], "xbrltype": "stringItemType" }, "wbk_IncomeTaxDisclosureLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represents concepts include in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Income Tax Disclosure [Line Items]", "terseLabel": "Income tax" } } }, "localname": "IncomeTaxDisclosureLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "stringItemType" }, "wbk_IncomeTaxDisclosureTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to income tax disclosures.", "label": "Income Tax Disclosure [Table]" } } }, "localname": "IncomeTaxDisclosureTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxAnalysisDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "stringItemType" }, "wbk_IncomeTaxesPaidClassifiedAsOperatingActivitiesExcludingLifeBusiness": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 6.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow for income taxes paid, classified as operating activities, excluding income taxes related to life insurance business.", "label": "Income taxes paid, classified as operating activities, excluding life business", "negatedLabel": "Income tax paid excluding life business" } } }, "localname": "IncomeTaxesPaidClassifiedAsOperatingActivitiesExcludingLifeBusiness", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_IncomeTaxesPaidClassifiedAsOperatingActivitiesLifeBusiness": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 11.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow for income taxes paid, classified as operating activities, related to life insurance business.", "label": "Income taxes paid, classified as operating activities, life business", "negatedLabel": "Income tax paid" } } }, "localname": "IncomeTaxesPaidClassifiedAsOperatingActivitiesLifeBusiness", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInAccruedInterestPayable": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 6.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in accrued interest payable.", "label": "Increase (Decrease) in Accrued Interest Payable", "terseLabel": "(Decrease)/increase in accrued interest payable" } } }, "localname": "IncreaseDecreaseInAccruedInterestPayable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInAccruedInterestReceivable": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails": { "order": 5.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in accrued interest receivable.", "label": "Increase (Decrease) in Accrued Interest Receivable", "negatedLabel": "(Increase)/decrease in accrued interest receivable" } } }, "localname": "IncreaseDecreaseInAccruedInterestReceivable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInAmountOfCollateralPaid": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 2.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in collateral paid to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Increase Decrease in Amount of Collateral Paid", "terseLabel": "Collateral paid" } } }, "localname": "IncreaseDecreaseInAmountOfCollateralPaid", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInCollateralReceived": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 9.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for increase (decrease) in collateral received to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Increase Decrease in Collateral Received", "terseLabel": "Collateral received" } } }, "localname": "IncreaseDecreaseInCollateralReceived", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInDeferredTaxAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in a deferred tax asset.", "label": "Increase (Decrease) in Deferred Tax Assets", "terseLabel": "Increase in deferred tax assets" } } }, "localname": "IncreaseDecreaseInDeferredTaxAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInDeferredTaxAssetsChangeInAccountingPolicy": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in deferred tax assets related to a change in accounting policy.", "label": "Increase (Decrease) in Deferred Tax Assets, Change in Accounting Policy", "terseLabel": "Deferred tax assets" } } }, "localname": "IncreaseDecreaseInDeferredTaxAssetsChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInDeferredTaxLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in a deferred tax liabilities.", "label": "Increase (Decrease) in Deferred Tax Liabilities", "terseLabel": "Increase in deferred tax liabilities" } } }, "localname": "IncreaseDecreaseInDeferredTaxLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInEquityDueToChangesInAccountingPolicy": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease in equity due to changes in accounting policy.", "label": "Increase (Decrease) in Equity Due to Changes in Accounting Policy", "terseLabel": "Impact from a change in accounting policy" } } }, "localname": "IncreaseDecreaseInEquityDueToChangesInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInFairValueOfFinancialLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cumulative change in fair value of financial liabilities.", "label": "Increase (Decrease) in Fair Value of Financial Liabilities", "terseLabel": "Increase in fair value of financial liabilities" } } }, "localname": "IncreaseDecreaseInFairValueOfFinancialLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInFundingFromEquity": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in funding from equity.", "label": "Increase (Decrease) in Funding from Equity", "terseLabel": "Increase in funding from equity" } } }, "localname": "IncreaseDecreaseInFundingFromEquity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInFundingThroughWholesaleTermFunding": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in funding through wholesale term funding.", "label": "Increase (Decrease) in Funding through Wholesale Term Funding", "terseLabel": "New capital securities raised" } } }, "localname": "IncreaseDecreaseInFundingThroughWholesaleTermFunding", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInIncomeTaxExpenseChangeInAccountingPolicy": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in income tax expense, related to a change in accounting policy.", "label": "Increase (Decrease) in Income Tax Expense, Change in Accounting Policy", "terseLabel": "Tax expense" } } }, "localname": "IncreaseDecreaseInIncomeTaxExpenseChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInIntangibleAssetsComputerSoftware": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in intangible assets classified as computer software related to a change in accounting policy.", "label": "Increase (Decrease) in Intangible Assets, Computer Software", "terseLabel": "Intangible assets - computer software" } } }, "localname": "IncreaseDecreaseInIntangibleAssetsComputerSoftware", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInNetProfitAfterTaxChangeInAccountingPolicy": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in net profit after tax, related to a change in accounting policy.", "label": "Increase (Decrease) in Net Profit After Tax, Change in Accounting Policy", "terseLabel": "Net profit after tax" } } }, "localname": "IncreaseDecreaseInNetProfitAfterTaxChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInOperatingExpensesChangeInAccountingPolicy": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in operating expenses, related to a change in accounting policy.", "label": "Increase (Decrease) in Operating Expenses, Change in Accounting Policy", "terseLabel": "Operating expenses" } } }, "localname": "IncreaseDecreaseInOperatingExpensesChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInOperatingExpensesRelatedToChangeInAccountingEstimate": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in operating expenses related to change in accounting estimate.", "label": "Increase (Decrease) in Operating Expenses Related to Change in Accounting Estimate", "terseLabel": "Increase in operating expenses" } } }, "localname": "IncreaseDecreaseInOperatingExpensesRelatedToChangeInAccountingEstimate", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInOtherFinancialAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 6.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Adjustments for decrease (increase) in other financial assets to reconcile profit (loss) to net cash flow from (used in) operating activities.", "label": "Increase Decrease in Other Financial Assets", "terseLabel": "Other financial assets" } } }, "localname": "IncreaseDecreaseInOtherFinancialAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInProfitLossRelatedToChangeInAccountingEstimate": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in net profit (loss) related to change in accounting estimate.", "label": "Increase (Decrease) in Profit (Loss) Related to Change in Accounting Estimate", "negatedLabel": "Reduced profit before income tax" } } }, "localname": "IncreaseDecreaseInProfitLossRelatedToChangeInAccountingEstimate", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseInRetainedEarningsChangeInAccountingPolicy": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount increase (decrease) in retained earnings, related to a change in accounting policy.", "label": "Increase (Decrease) in Retained Earnings, Change in Accounting Policy", "terseLabel": "Opening retained earnings" } } }, "localname": "IncreaseDecreaseInRetainedEarningsChangeInAccountingPolicy", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughCashMovementsDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from cash movements.", "label": "Increase (Decrease) through Cash Movements, Debt Securities", "totalLabel": "Total cash movements" } } }, "localname": "IncreaseDecreaseThroughCashMovementsDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughChangesInModelsRiskParametersOrModificationOfContractualCashFlowsFinancialAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in financial assets resulting from changes in models, risk parameters, or modification of contractual cash flows.", "label": "Increase (Decrease) Through Changes in Models, Risk Parameters, or Modification of Contractual Cash Flows, Financial Assets", "terseLabel": "Net remeasurement of provision for ECL" } } }, "localname": "IncreaseDecreaseThroughChangesInModelsRiskParametersOrModificationOfContractualCashFlowsFinancialAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughFairValueAdjustmentsDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 1.0, "parentTag": "wbk_IncreaseDecreaseThroughNonCashMovementsDebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from fair value adjustments.", "label": "Increase (Decrease) through Fair Value Adjustments, Debt Securities", "terseLabel": "Fair value adjustments" } } }, "localname": "IncreaseDecreaseThroughFairValueAdjustmentsDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughFairValueHedgeAccountingAdjustmentsDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 2.0, "parentTag": "wbk_IncreaseDecreaseThroughNonCashMovementsDebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from fair value hedge accounting adjustments.", "label": "Increase (Decrease) through Fair Value Hedge Accounting Adjustments, Debt Securities", "terseLabel": "Fair value hedge accounting adjustments" } } }, "localname": "IncreaseDecreaseThroughFairValueHedgeAccountingAdjustmentsDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughNetExchangeDifferencesDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 3.0, "parentTag": "wbk_IncreaseDecreaseThroughNonCashMovementsDebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from foreign exchange translation.", "label": "Increase (Decrease) through Net Exchange Differences, Debt Securities", "terseLabel": "FX translation impact" } } }, "localname": "IncreaseDecreaseThroughNetExchangeDifferencesDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughNonCashMovementsDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from non-cash movements.", "label": "Increase (Decrease) through Non-Cash Movements, Debt Securities", "totalLabel": "Total non-cash movements" } } }, "localname": "IncreaseDecreaseThroughNonCashMovementsDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughOriginationOrPurchaseFinancialAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in financial assets resulting from origination or purchase.", "label": "Increase (Decrease) Through Origination or Purchase, Financial Assets", "terseLabel": "Business activity during the year" } } }, "localname": "IncreaseDecreaseThroughOriginationOrPurchaseFinancialAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughOtherAdjustmentsDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 4.0, "parentTag": "wbk_IncreaseDecreaseThroughNonCashMovementsDebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase (decrease) in debt instruments issued by the entity resulting from amortisation of bond issue costs and other non-cash movements not separately identified.", "label": "Increase (Decrease) through Other Adjustments, Debt Securities", "terseLabel": "Other (amortisation of bond issue costs, etc.)" } } }, "localname": "IncreaseDecreaseThroughOtherAdjustmentsDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughTransfersFinancialAssetsStageOne": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in financial assets resulting from transfers in or out of Stage One.", "label": "Increase (Decrease) Through Transfers, Financial Assets, Stage One", "terseLabel": "Transfers to Stage 1" } } }, "localname": "IncreaseDecreaseThroughTransfersFinancialAssetsStageOne", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughTransfersFinancialAssetsStageThree": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in financial assets resulting from transfers in or out of Stage Three.", "label": "Increase (Decrease) Through Transfers, Financial Assets, Stage Three", "terseLabel": "Transfers to Stage 3" } } }, "localname": "IncreaseDecreaseThroughTransfersFinancialAssetsStageThree", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseThroughTransfersFinancialAssetsStageTwo": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in financial assets resulting from transfers in or out of Stage Two.", "label": "Increase (Decrease) Through Transfers, Financial Assets, Stage Two", "terseLabel": "Transfers to Stage 2" } } }, "localname": "IncreaseDecreaseThroughTransfersFinancialAssetsStageTwo", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseDecreaseToCreditExposuresDueToStagingMethodologyChanges": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) to credit exposures due to staging methodology changes.", "label": "Increase (Decrease) to Credit Exposures Due to Staging Methodology Changes", "terseLabel": "Increase (decrease) to due to staging methodology changes" } } }, "localname": "IncreaseDecreaseToCreditExposuresDueToStagingMethodologyChanges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseInInterestIncomeRelatedToComplianceRegulationAndRemediationCosts": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase in interest income related to compliance, regulation and remediation costs.", "label": "Increase in Interest Income Related to Compliance, Regulation and Remediation Costs", "terseLabel": "Addition in interest income related to compliance, regulation and remediation costs" } } }, "localname": "IncreaseInInterestIncomeRelatedToComplianceRegulationAndRemediationCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IncreaseThroughDividendReinvestmentPlan": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The increase in equity resulting from the dividend reinvestment plan.", "label": "Increase through Dividend Reinvestment Plan", "terseLabel": "Dividend reinvestment plan" } } }, "localname": "IncreaseThroughDividendReinvestmentPlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_IncreaseThroughDividendReinvestmentPlan.UnderwritersOption": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The increase in equity shares resulting from the underwriters option to the dividend reinvestment plan.", "label": "Increase Through Dividend Reinvestment Plan. Underwriters Option", "terseLabel": "Dividend reinvestment plan underwrite" } } }, "localname": "IncreaseThroughDividendReinvestmentPlan.UnderwritersOption", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_IntangibleAssetsComputerSoftwareMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for intangible assets classified as computer software.", "label": "Intangible Assets Computer Software [Member]", "terseLabel": "Intangible assets - computer software" } } }, "localname": "IntangibleAssetsComputerSoftwareMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "wbk_InterbankLending": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 4.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount due from other financial institutions as a result of interbank lending.", "label": "Interbank Lending", "terseLabel": "Interbank lending" } } }, "localname": "InterbankLending", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterbankPlacements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of interbank placements.", "label": "Interbank Placements", "terseLabel": "Interbank placements" } } }, "localname": "InterbankPlacements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestBearingLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Interest Bearing Liabilities [Abstract]", "terseLabel": "Interest bearing liabilities" } } }, "localname": "InterestBearingLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_InterestEarningAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Interest Earning Assets [Abstract]", "terseLabel": "Interest earning assets and interest income" } } }, "localname": "InterestEarningAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_InterestExpenseOnAmountsDueToSubsidiaries": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense on the amounts due to subsidiaries.", "label": "Interest Expense on Amounts Due to Subsidiaries", "negatedLabel": "Due to subsidiaries" } } }, "localname": "InterestExpenseOnAmountsDueToSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestExpenseOnCollateralReceived": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense on collateral received.", "label": "Interest Expense on Collateral Received", "negatedLabel": "Collateral received" } } }, "localname": "InterestExpenseOnCollateralReceived", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestExpenseOnDepositsAndOtherBorrowings": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense on deposits and other borrowings.", "label": "Interest Expense on Deposits and Other Borrowings", "negatedLabel": "Deposits and other borrowings" } } }, "localname": "InterestExpenseOnDepositsAndOtherBorrowings", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestExpenseOnFinancialLiabilitiesHeldForTradingNetOfImpactOfTreasuryBalanceSheetManagementActivities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense on financial liabilities held for trading, net of impact of Treasury balance sheet management activities.", "label": "Interest Expense On Financial Liabilities Held For Trading, Net Of Impact Of Treasury Balance Sheet Management Activities", "negatedLabel": "Trading liabilities" } } }, "localname": "InterestExpenseOnFinancialLiabilitiesHeldForTradingNetOfImpactOfTreasuryBalanceSheetManagementActivities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestExpenseOnLiabilitiesHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense from liabilities held for sale.", "label": "Interest Expense on Liabilities Held for Sale", "negatedLabel": "Liabilities held for sale" } } }, "localname": "InterestExpenseOnLiabilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestExpenseOnLoanCapital": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense on loan capital.", "label": "Interest Expense on Loan Capital", "negatedLabel": "Loan capital" } } }, "localname": "InterestExpenseOnLoanCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestInOtherStructuredEntitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest in other structured entities.", "label": "Interest In Other Structured Entities [Member]", "terseLabel": "Interest in Other Structured Entities" } } }, "localname": "InterestInOtherStructuredEntitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Interest Income [Abstract]", "terseLabel": "Interest income" } } }, "localname": "InterestIncomeAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "wbk_InterestIncomeAndExpensesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Net interest income" } } }, "localname": "InterestIncomeAndExpensesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_InterestIncomeExpenseCalculatedUsingEffectiveInterestRateMethodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest income (expense) calculated using the effective interest rate method.", "label": "Interest Income Expense Calculated Using Effective Interest Rate Method [Member]", "terseLabel": "Calculated using the effective interest rate method" } } }, "localname": "InterestIncomeExpenseCalculatedUsingEffectiveInterestRateMethodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestIncomeExpenseExcludingInterestCalculatedUsingEffectiveInterestRateMethodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest income (expense) excluding income interest calculated using the effective interest rate method.", "label": "Interest Income Expense Excluding Interest Calculated Using Effective Interest Rate Method [Member]", "terseLabel": "Other" } } }, "localname": "InterestIncomeExpenseExcludingInterestCalculatedUsingEffectiveInterestRateMethodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestIncomeOnAmountsDueFromSubsidiaries": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interest income on the amounts due from subsidiaries.", "label": "Interest Income on Amounts Due from Subsidiaries", "terseLabel": "Due from subsidiaries" } } }, "localname": "InterestIncomeOnAmountsDueFromSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestIncomeOnAssetsHeldForSale": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interest income from assets held for sale.", "label": "Interest Income on Assets Held for Sale", "terseLabel": "Assets held for sale" } } }, "localname": "InterestIncomeOnAssetsHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestIncomeOnCollateralPaid": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interest income on collateral paid.", "label": "Interest Income on Collateral Paid", "terseLabel": "Collateral paid" } } }, "localname": "InterestIncomeOnCollateralPaid", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestIncomeOnInvestmentSecurities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interest income on debt and equity investment securities.", "label": "Interest Income on Investment Securities", "terseLabel": "Investment securities" } } }, "localname": "InterestIncomeOnInvestmentSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestIncomeOnTradingSecuritiesAndFinancialAssetsDesignatedAtFairValue": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interest income on trading securities and financial assets designated at fair value through profit or loss.", "label": "Interest Income on Trading Securities and Financial Assets Designated at Fair Value", "terseLabel": "Trading securities and financial assets measured at FVIS and loans" } } }, "localname": "InterestIncomeOnTradingSecuritiesAndFinancialAssetsDesignatedAtFairValue", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InterestRateBenchmarkReformAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Interest Rate Benchmark Reform [Abstract]", "terseLabel": "Interest rate benchmark reform" } } }, "localname": "InterestRateBenchmarkReformAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "stringItemType" }, "wbk_InterestRateBenchmarksAxis": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table.", "label": "Interest rate benchmarks [axis]" } } }, "localname": "InterestRateBenchmarksAxis", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "stringItemType" }, "wbk_InterestRateBenchmarksMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for all interest rate benchmarks. It also represents the standard value for the 'Interest rate benchmarks' axis if no other member is used.", "label": "Interest Rate Benchmarks [Member]", "terseLabel": "Interest rate benchmarks [member]" } } }, "localname": "InterestRateBenchmarksMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestRateContractsSwapAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest rate swap agreements.", "label": "Interest Rate Contracts Swap Agreements [Member]", "terseLabel": "Swap agreements" } } }, "localname": "InterestRateContractsSwapAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestRateForwardAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest rate forward agreements.", "label": "Interest Rate Forward Agreements [Member]", "terseLabel": "Forward rate agreements" } } }, "localname": "InterestRateForwardAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_InterestRateOptionContractsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for interest rate option contracts.", "label": "Interest Rate Option Contracts [Member]", "terseLabel": "Interest rate options" } } }, "localname": "InterestRateOptionContractsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_InvestmentSecuritiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Investment Securities [Abstract]", "terseLabel": "Investment securities" } } }, "localname": "InvestmentSecuritiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "stringItemType" }, "wbk_InvestmentSecuritiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 5.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of debt and equity investment securities held by the entity, based on expected maturities.", "label": "Investment Securities, Based on Expected Maturities", "terseLabel": "Investment securities" } } }, "localname": "InvestmentSecuritiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InvestmentSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt and equity investment securities held by the entity.", "label": "Investment Securities [Member]", "terseLabel": "Investment securities" } } }, "localname": "InvestmentSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsImpactOfHedgeAccountingOnBalanceSheetAndReservesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_InvestmentsHeldDirectlyAndInUnitTrustsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for investments held directly and in unit trusts.", "label": "Investments Held Directly And In Unit Trusts [Member]", "terseLabel": "Investments held directly and in unit trusts" } } }, "localname": "InvestmentsHeldDirectlyAndInUnitTrustsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_InvestmentsInAssociatesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 11.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of investments in associates in an entity's separate financial statements, based on expected maturities.", "label": "Investments In Associates, Based on Expected Maturities", "terseLabel": "Investments in associates" } } }, "localname": "InvestmentsInAssociatesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_InvestmentsInSubsidiariesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 10.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of investments in subsidiaries in an entity's separate financial statements, based on expected maturities.", "label": "Investments In Subsidiaries, Based on Expected Maturities", "terseLabel": "Investment in subsidiaries" } } }, "localname": "InvestmentsInSubsidiariesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IssuancesOfDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 1.0, "parentTag": "wbk_IncreaseDecreaseThroughCashMovementsDebtSecurities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of debt instruments issued during the period.", "label": "Issuances of Debt Securities", "terseLabel": "Issuances" } } }, "localname": "IssuancesOfDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_IssuedCapitalNetOfTreasuryShares": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The nominal value of capital issued, net of entity's own equity instruments, held by the entity or other members of the consolidated group.", "label": "Issued Capital Net of Treasury Shares", "totalLabel": "Total share capital" } } }, "localname": "IssuedCapitalNetOfTreasuryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_JasonYettonMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Jason Yetton.", "label": "Jason Yetton [Member]", "terseLabel": "Jason Yetton" } } }, "localname": "JasonYettonMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_KeyManagementPersonnelCompensationOtherLongTermBenefitsAndOtherAdjustments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails": { "order": 3.0, "parentTag": "ifrs-full_KeyManagementPersonnelCompensation", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of compensation to key management personnel in the form of other long-term employee benefits and other adjustments.", "label": "Key Management Personnel Compensation, Other Long-Term Benefits And Other Adjustments", "terseLabel": "Other long-term benefits" } } }, "localname": "KeyManagementPersonnelCompensationOtherLongTermBenefitsAndOtherAdjustments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresRemunerationOfKmpDetails" ], "xbrltype": "monetaryItemType" }, "wbk_KeyParametersOfVarAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Key Parameters of VaR [Abstract]", "terseLabel": "Key parameters of VaR" } } }, "localname": "KeyParametersOfVarAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "stringItemType" }, "wbk_LaterThanFifteenYearsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of later than fifteen years.", "label": "Later Than Fifteen Years [Member]", "terseLabel": "Over 15 years" } } }, "localname": "LaterThanFifteenYearsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "wbk_LaterThanFiveYearsAndNotLaterThanFifteenYearsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of later than five years and not later than fifteen years.", "label": "Later Than Five Years And Not Later Than Fifteen Years [Member]", "terseLabel": "Over 5 years to 15 years" } } }, "localname": "LaterThanFiveYearsAndNotLaterThanFifteenYearsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails" ], "xbrltype": "domainItemType" }, "wbk_LeaseholdPremisesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a provision related to leasehold premises.", "label": "Leasehold Premises [Member]", "terseLabel": "Lease restoration obligations" } } }, "localname": "LeaseholdPremisesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "wbk_LegislativeLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Legislative Liabilities [Abstract]", "terseLabel": "Legislative liabilities" } } }, "localname": "LegislativeLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_LesVanceMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Les Vance.", "label": "Les Vance [Member]", "terseLabel": "Les Vance" } } }, "localname": "LesVanceMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_LettersOfCreditAndGuarantees": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails": { "order": 1.0, "parentTag": "wbk_UndrawnCreditCommitments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of letters of credit and guarantees.", "label": "Letters of Credit and Guarantees", "terseLabel": "Letters of credit and guarantees" } } }, "localname": "LettersOfCreditAndGuarantees", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LettersOfCreditAndGuaranteesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for letters of credit and guarantees.", "label": "Letters Of Credit And Guarantees [Member]", "terseLabel": "Letters of credit and guarantees" } } }, "localname": "LettersOfCreditAndGuaranteesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_LiabilitiesArisingFromInsuranceContractsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 6.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities under insurance contracts and reinsurance contracts issued, based on expected maturities.", "label": "Liabilities Arising From Insurance Contracts, Based on Expected Maturities", "terseLabel": "Life insurance liabilities" } } }, "localname": "LiabilitiesArisingFromInsuranceContractsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LiabilitiesClassifiedAsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for liabilities classified as held for sale.", "label": "Liabilities Classified As Held For Sale [Member]", "terseLabel": "Liabilities held for sale" } } }, "localname": "LiabilitiesClassifiedAsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_LiabilitiesExcludingLoanCapital": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 1.0, "parentTag": "ifrs-full_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities excluding loan capital.", "label": "Liabilities, excluding loan capital", "totalLabel": "Total liabilities excluding loan capital" } } }, "localname": "LiabilitiesExcludingLoanCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 2.0, "parentTag": "wbk_FinancialLiabilitiesBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities excluding loan capital, based on expected maturities.", "label": "Liabilities Excluding Loan Capital, Based on Expected Maturities", "totalLabel": "Total liabilities excluding loan capital" } } }, "localname": "LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LiabilitiesHeldForSaleBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 8.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities held for sale based on expected maturities.", "label": "Liabilities Held for Sale Based on Expected Maturities", "terseLabel": "Liabilities held for sale" } } }, "localname": "LiabilitiesHeldForSaleBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LiabilityAdequacyTestOnLifeInsuranceContractsAmountsRecognized": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amounts recognized as a result of the liability adequacy test on life insurance contracts.", "label": "Liability Adequacy Test on Life Insurance Contracts, Amounts Recognized", "terseLabel": "Amounts recognised as a result of the liability adequacy test on life insurance contracts" } } }, "localname": "LiabilityAdequacyTestOnLifeInsuranceContractsAmountsRecognized", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LifeBusinessAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Life Business [Abstract]", "terseLabel": "Life business:" } } }, "localname": "LifeBusinessAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "wbk_LifeInsuranceAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 9.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of life insurance assets, including investments managed by the Group.", "label": "Life Insurance Assets", "terseLabel": "Life insurance assets" } } }, "localname": "LifeInsuranceAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_LifeInsuranceAssetsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 8.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Assets held to meet life insurance policy liabilities, based on expected maturities.", "label": "Life Insurance Assets, Based on Expected Maturities", "terseLabel": "Life insurance assets" } } }, "localname": "LifeInsuranceAssetsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LifeInsuranceAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for life insurance assets.", "label": "Life Insurance Assets [Member]", "terseLabel": "Life insurance assets" } } }, "localname": "LifeInsuranceAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_LifeInsuranceLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for life insurance liabilities.", "label": "Life Insurance Liabilities [Member]", "terseLabel": "Life insurance liabilities" } } }, "localname": "LifeInsuranceLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails" ], "xbrltype": "domainItemType" }, "wbk_LifeInsuranceLiabilitiesNet": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of liabilities from life investment contracts, net of life insurance contracts.", "label": "Life Insurance Liabilities, Net", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "LifeInsuranceLiabilitiesNet", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LifeInsurancePremiumIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 1.0, "parentTag": "wbk_NetEarnedPremiumAndIncomeArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of life insurance premium income.", "label": "Life Insurance Premium Income", "terseLabel": "Life insurance premium income" } } }, "localname": "LifeInsurancePremiumIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LifeInvestmentContractsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for life investment contracts.", "label": "Life Investment Contracts [Member]", "terseLabel": "Life investment contracts" } } }, "localname": "LifeInvestmentContractsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_LineOfCreditAmountOfSupplementaryAllowanceDrawnDown": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the available funds from Supplementary Allowance portion of the credit facility that has been drawn down.", "label": "Line of Credit, Amount of Supplementary Allowance Drawn Down", "terseLabel": "Amount of drawn down from TFF" } } }, "localname": "LineOfCreditAmountOfSupplementaryAllowanceDrawnDown", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LineOfCreditTotalAmountDrawnDown": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The total amount of the available funds from the credit facility that has been drawn down.", "label": "Line of Credit, Total Amount Drawn Down", "terseLabel": "Total amount drawn down" } } }, "localname": "LineOfCreditTotalAmountDrawnDown", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LitigationAndNonLendingLossesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a provision for litigation and other non-lending losses.", "label": "Litigation And Non Lending Losses [Member]", "terseLabel": "Litigation and non-lending losses" } } }, "localname": "LitigationAndNonLendingLossesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "wbk_LoanAndCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans and credit commitments.", "label": "Loan And Credit Commitments [Member]", "terseLabel": "Loans and credit commitments" } } }, "localname": "LoanAndCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "domainItemType" }, "wbk_LoanCapital": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 2.0, "parentTag": "ifrs-full_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of instruments issued by the entity that qualify for inclusion as regulatory capital.", "label": "Loan Capital Amount", "periodEndLabel": "Balance at ending", "periodStartLabel": "Balance at beginning", "terseLabel": "Loan capital" } } }, "localname": "LoanCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 1.0, "parentTag": "wbk_FinancialLiabilitiesBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of instruments issued by the entity that qualify for inclusion as regulatory capital, based on expected maturities.", "label": "Loan Capital, Based on Expected Maturities", "terseLabel": "Loan capital" } } }, "localname": "LoanCapitalBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalFairValueHedgeAccountingAdjustments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": 2.0, "parentTag": "wbk_LoanCapitalTotalNonCashMovements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of fair value hedge accounting adjustments on loan capital.", "label": "Loan Capital, Fair Value Hedge Accounting Adjustments", "terseLabel": "Fair value hedge accounting adjustments" } } }, "localname": "LoanCapitalFairValueHedgeAccountingAdjustments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalForeignExchangeTranslationImpact": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": 1.0, "parentTag": "wbk_LoanCapitalTotalNonCashMovements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of foreign exchange translation impact on loan capital.", "label": "Loan Capital, Foreign Exchange Translation Impact", "terseLabel": "Fx translation impact" } } }, "localname": "LoanCapitalForeignExchangeTranslationImpact", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalIssuances": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": 1.0, "parentTag": "wbk_LoanCapitalTotalCashMovements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of loan capital issuances during the period.", "label": "Loan Capital, Issuances", "terseLabel": "Issuances" } } }, "localname": "LoanCapitalIssuances", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalMaturitiesRepaymentsBuyBacksAndReductions": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": 2.0, "parentTag": "wbk_LoanCapitalTotalCashMovements", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of Loan capital Maturities, repayments, buy backs and reductions during the period.", "label": "Loan Capital, Maturities, Repayments, Buy Backs and Reductions", "negatedLabel": "Maturities, repayments, buy backs and reductions" } } }, "localname": "LoanCapitalMaturitiesRepaymentsBuyBacksAndReductions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for instruments issued by the entity that qualify for inclusion as regulatory capital.", "label": "Loan Capital [Member]", "terseLabel": "Loan capital" } } }, "localname": "LoanCapitalMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails" ], "xbrltype": "domainItemType" }, "wbk_LoanCapitalOtherNonCashAdjustments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": 3.0, "parentTag": "wbk_LoanCapitalTotalNonCashMovements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of other non-cash adjustments to loan capital (amortisation of bond issue costs, etc.).", "label": "Loan Capital, Other Non Cash Adjustments", "terseLabel": "Other (amortisation of bond issue costs, etc.)" } } }, "localname": "LoanCapitalOtherNonCashAdjustments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalTotalCashMovements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of total cash movements in loan capital.", "label": "Loan Capital, Total Cash Movements", "totalLabel": "Total cash movements" } } }, "localname": "LoanCapitalTotalCashMovements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanCapitalTotalNonCashMovements": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of Total non-cash movements in loan capital.", "label": "Loan Capital, Total Non-Cash Movements", "totalLabel": "Total non-cash movements" } } }, "localname": "LoanCapitalTotalNonCashMovements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoanPortfolioDisaggregatedByLocationOfBookingOfficeAndProductTypeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Loan Portfolio Disaggregated by Location of Booking office and Product Type [Abstract]", "terseLabel": "Loan portfolio, disaggregated by location of booking office and product type" } } }, "localname": "LoanPortfolioDisaggregatedByLocationOfBookingOfficeAndProductTypeAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "stringItemType" }, "wbk_LoansAndCreditCommitments": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of loans and credit commitments.", "label": "Loans and Credit Commitments", "terseLabel": "Loans and credit commitments" } } }, "localname": "LoansAndCreditCommitments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoansAndCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans and credit commitments.", "label": "Loans And Credit Commitments [Member]", "terseLabel": "Loans and credit commitments" } } }, "localname": "LoansAndCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_LoansAndOtherAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans and other assets.", "label": "Loans And Other Assets [Member]", "terseLabel": "Loans and other assets" } } }, "localname": "LoansAndOtherAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_LoansAndOtherReceivablesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans and other receivables.", "label": "Loans And Other Receivables [Member]", "terseLabel": "Loans and other receivables" } } }, "localname": "LoansAndOtherReceivablesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "domainItemType" }, "wbk_LoansAndReceivablesBasedOnExpectedMaturitiesNetOfProvisions": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 6.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of non-derivative financial assets, based on expected maturities, with fixed or determinable payments that are not quoted in an active market, net of provisions.", "label": "Loans And Receivables, Based on Expected Maturities, Net of Provisions", "terseLabel": "Loans (net of provisions)" } } }, "localname": "LoansAndReceivablesBasedOnExpectedMaturitiesNetOfProvisions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LoansAndReceivablesCoverageFromCollateralAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Loans and Receivables, Coverage from Collateral [Abstract]", "terseLabel": "Collateral held" } } }, "localname": "LoansAndReceivablesCoverageFromCollateralAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "stringItemType" }, "wbk_LoansExcludingLoansIncludedInAssetsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans, excluding loans included in assets held for sale.", "label": "Loans Excluding Loans Included In Assets Held For Sale [Member]", "terseLabel": "Loans, excluding loans included in assets held for sale" } } }, "localname": "LoansExcludingLoansIncludedInAssetsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_LoansIncludedInAssetsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans included in assets held for sale.", "label": "Loans Included In Assets Held For Sale [Member]", "terseLabel": "Loans included in assets held for sale" } } }, "localname": "LoansIncludedInAssetsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_LondonInterbankOfferRateBritishPoundsSterlingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the interbank interest rate at which banks in London lend in British Pound Sterling.", "label": "London Interbank Offer Rate British Pounds Sterling [Member]", "terseLabel": "GBP LIBOR" } } }, "localname": "LondonInterbankOfferRateBritishPoundsSterlingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_LondonInterbankOfferRateUnitedStatesDollarMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the interbank interest rate at which banks in London lend in U.S. Dollars.", "label": "London Interbank Offer Rate United States Dollar [Member]", "terseLabel": "USD LIBOR" } } }, "localname": "LondonInterbankOfferRateUnitedStatesDollarMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_LongServiceLeaveMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a provision for employee long-term service leave.", "label": "Long Service Leave [Member]", "terseLabel": "Long service leave" } } }, "localname": "LongServiceLeaveMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "domainItemType" }, "wbk_LongTermWholesaleFundingRaised": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "New long-term wholesale funding raised by the entity during the period.", "label": "Long-term Wholesale Funding Raised", "terseLabel": "Long term wholesale funding raised" } } }, "localname": "LongTermWholesaleFundingRaised", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "monetaryItemType" }, "wbk_LossAllowanceOnDebtSecuritiesMeasuredAtFairValueThroughOtherComprehensiveIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome": { "order": 6.0, "parentTag": "ifrs-full_OtherComprehensiveIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of loss allowance on debt securities measured at fair value through other comprehensive income (FVOCI), net of tax.", "label": "Loss Allowance on Debt Securities Measured at Fair Value Through Other Comprehensive Income", "terseLabel": "Loss allowance on debt instruments measured at FVOCI" } } }, "localname": "LossAllowanceOnDebtSecuritiesMeasuredAtFairValueThroughOtherComprehensiveIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "wbk_MacroCashFlowHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for cash flows that are hedged against fluctuations caused by interest rate risks.", "label": "Macro Cash Flow Hedges [Member]", "terseLabel": "Macro cash flow hedges" } } }, "localname": "MacroCashFlowHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_MacroHedgeRelationshipsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to macro hedge relationships.", "label": "Macro Hedge Relationships [Member]", "terseLabel": "Macro hedge relationships" } } }, "localname": "MacroHedgeRelationshipsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_ManagingDirectorAndChiefExecutiveOfficerMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Managing Director and Chief Executive Officer.", "label": "Managing Director And Chief Executive Officer [Member]", "terseLabel": "Managing Director & Chief Executive Officer" } } }, "localname": "ManagingDirectorAndChiefExecutiveOfficerMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_ManufacturingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for manufacturing.", "label": "Manufacturing [Member]", "terseLabel": "Manufacturing" } } }, "localname": "ManufacturingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_MaterialReconcilingItemsAdjustmentsRelatingToPendalBtimMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for material adjustments used to reconcile items in the entity's financial statements, related to the sale of Pendal (BTIM).", "label": "Material Reconciling Items Adjustments Relating To Pendal Btim [Member]", "terseLabel": "Adjustments related to Pendal" } } }, "localname": "MaterialReconcilingItemsAdjustmentsRelatingToPendalBtimMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails" ], "xbrltype": "domainItemType" }, "wbk_MaterialReconcilingItemsFairValueGainOrLossOnEconomicHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for material adjustments used to reconcile items in the entity's financial statements, related to fair value gains or losses on economic hedges.", "label": "Material Reconciling Items Fair Value Gain Or Loss On Economic Hedges [Member]", "terseLabel": "Fair value gain/(loss) on economic hedges" } } }, "localname": "MaterialReconcilingItemsFairValueGainOrLossOnEconomicHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails" ], "xbrltype": "domainItemType" }, "wbk_MaterialReconcilingItemsIneffectiveHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for material adjustments used to reconcile items in the entity's financial statements, related to ineffective hedges.", "label": "Material Reconciling Items Ineffective Hedges [Member]", "terseLabel": "Ineffective hedges" } } }, "localname": "MaterialReconcilingItemsIneffectiveHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails" ], "xbrltype": "domainItemType" }, "wbk_MaterialReconcilingItemsTreasurySharesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for material adjustments used to reconcile items in the entity's financial statements, related to treasury share transactions.", "label": "Material Reconciling Items Treasury Shares [Member]", "terseLabel": "Treasury shares" } } }, "localname": "MaterialReconcilingItemsTreasurySharesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails" ], "xbrltype": "domainItemType" }, "wbk_MaximumExposureToCreditRiskFinancialInstrumentsExcludingLoans": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails": { "order": 2.0, "parentTag": "ifrs-full_MaximumExposureToCreditRisk", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that best represents the maximum exposure to credit risk associated with financial instruments excluding loans, without taking into account any collateral held or other credit enhancements.", "label": "Maximum Exposure To Credit Risk, Financial Instruments Excluding Loans", "terseLabel": "Total all other on balance sheet" } } }, "localname": "MaximumExposureToCreditRiskFinancialInstrumentsExcludingLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MaximumExposureToCreditRiskLoans": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails": { "order": 1.0, "parentTag": "ifrs-full_MaximumExposureToCreditRisk", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that best represents the maximum exposure to credit risk associated with loans, without taking into account any collateral held or other credit enhancements.", "label": "Maximum Exposure To Credit Risk, Loans", "terseLabel": "Loans" } } }, "localname": "MaximumExposureToCreditRiskLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MaximumExposureToCreditRiskOfFinancialAssetsMeasuredAtAmortisedCostOrAtFairValueThroughOtherComprehensiveIncome": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The maximum exposure to the credit risk of financial assets measured at amortised cost or at Fair Value through Other Comprehensive Income (FVOCI).", "label": "Maximum Exposure to Credit Risk of Financial Assets Measured at Amortised Cost or at Fair Value through Other Comprehensive Income", "terseLabel": "Credit quality exposure risk" } } }, "localname": "MaximumExposureToCreditRiskOfFinancialAssetsMeasuredAtAmortisedCostOrAtFairValueThroughOtherComprehensiveIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MaximumGuaranteesToCertainWhollyOwnedSubsidiaries": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Maximum guarantees to certain wholly owned subsidiaries which are Australian financial services or credit licensees to comply with legislative requirements.", "label": "Maximum Guarantees to Certain Wholly Owned Subsidiaries", "terseLabel": "Maximum amount of initial guarantee" } } }, "localname": "MaximumGuaranteesToCertainWhollyOwnedSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MaximumPercentageOfEarningsPayableUnderCovid19Restrictions": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The maximum percentage of earnings which may be paid as dividends under COVID-19 restrictions.", "label": "Maximum Percentage of Earnings Payable Under COVID19 Restrictions", "terseLabel": "Maximum percentage of earnings which may be paid as dividends under COVID-19 restrictions" } } }, "localname": "MaximumPercentageOfEarningsPayableUnderCovid19Restrictions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "percentItemType" }, "wbk_MaximumReinstatementGuaranteesToCertainWhollyOwnedSubsidiaries": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Maximum reinstatement guarantees to certain wholly owned subsidiaries which are Australian financial services or credit licensees to comply with legislative requirements.", "label": "Maximum Reinstatement Guarantees To Certain Wholly Owned Subsidiaries", "terseLabel": "Automatic reinstatement guarantee amount" } } }, "localname": "MaximumReinstatementGuaranteesToCertainWhollyOwnedSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MaximumRiskWeightedRatioEquityInvestmentsInSubsidiariesAsPercentageOfCommonEquityTierOneCapitalPerInvestment": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The maximum risk weighted ratio for equity investments in subsidiaries, as a percentage of Level 1 CET1 capital per investment", "label": "Maximum Risk Weighted Ratio, Equity Investments in Subsidiaries, As Percentage of Common Equity Tier One Capital Per Investment", "terseLabel": "Maximum risk weighted ratio, equity investments in subsidiaries, as a percentage of Level 1 CET1 capital per investment" } } }, "localname": "MaximumRiskWeightedRatioEquityInvestmentsInSubsidiariesAsPercentageOfCommonEquityTierOneCapitalPerInvestment", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_MichaelRowlandMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Michael Rowland.", "label": "Michael Rowland [Member]", "terseLabel": "Michael Rowland" } } }, "localname": "MichaelRowlandMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_MinimumCapitalBufferForDomesticSystemicallyImportantBanksPercentage": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of minimum capital buffer requirement for domestic systemically important banks (D-SIBs).", "label": "Minimum capital buffer for Domestic Systemically Important Banks, Percentage", "terseLabel": "Industry minimum CET1 ratio" } } }, "localname": "MinimumCapitalBufferForDomesticSystemicallyImportantBanksPercentage", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_MiningMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for mining.", "label": "Mining [Member]", "terseLabel": "Mining" } } }, "localname": "MiningMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_MiscellaneousOtherAssets": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 7.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of miscellaneous other assets.", "label": "Miscellaneous Other Assets", "terseLabel": "Other" } } }, "localname": "MiscellaneousOtherAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MiscellaneousOtherLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 3.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of miscellaneous other liabilities.", "label": "Miscellaneous Other liabilities", "terseLabel": "Other" } } }, "localname": "MiscellaneousOtherLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MiscellaneousOtherOperatingIncomeExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 12.0, "parentTag": "ifrs-full_OtherIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The net amount of miscellaneous other operating income (expense).", "label": "Miscellaneous Other Operating Income (Expense)", "terseLabel": "Other" } } }, "localname": "MiscellaneousOtherOperatingIncomeExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_MiscellaneousOtherReservesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition is available.", "label": "Miscellaneous Other Reserves [Abstract]", "terseLabel": "Other reserves" } } }, "localname": "MiscellaneousOtherReservesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "wbk_MotorVehicleDealerFinanceAndNovatedLeasingBusinessesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Motor Vehicle Dealer Finance and Novated Leasing Businesses.", "label": "Motor Vehicle Dealer Finance And Novated Leasing Businesses [Member]", "terseLabel": "Westpac Motor Vehicle Dealer Finance and Novated Leasing business" } } }, "localname": "MotorVehicleDealerFinanceAndNovatedLeasingBusinessesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_MovementsInGroupsFundingCompositionAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Movements in the Group's funding composition [Abstract]", "terseLabel": "Movements in the Group's funding composition" } } }, "localname": "MovementsInGroupsFundingCompositionAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "stringItemType" }, "wbk_NetCashEarningsAdjustments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails": { "order": 2.0, "parentTag": "ifrs-full_ProfitLossAttributableToOwnersOfParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The adjustment to profit (loss) from operations for non-cash flow items which do not affect cash distributions available to shareholders.", "label": "Net Cash Earnings Adjustments", "terseLabel": "Net cash earnings adjustments", "verboseLabel": "Total cash earnings adjustment (post-tax)" } } }, "localname": "NetCashEarningsAdjustments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NetEarnedPremiumAndIncomeArisingFromInsuranceContracts": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "wbk_NetWealthManagementAndInsuranceIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of premium ad income arising from insurance contracts", "label": "Net Earned Premium and Income Arising from Insurance Contracts", "totalLabel": "Total insurance premium, investment and other income" } } }, "localname": "NetEarnedPremiumAndIncomeArisingFromInsuranceContracts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NetEarnedPremiumGeneralInsuranceAndLendersMortgageInsurance": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "wbk_NetEarnedPremiumAndIncomeArisingFromInsuranceContracts", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of premiums earned on general insurance and lenders mortgage insurance (LMI) contracts net of reinsurance premiums.", "label": "Net Earned Premium, General Insurance and Lenders Mortgage Insurance", "terseLabel": "General insurance and lenders mortgage insurance (LMI) net premium earned" } } }, "localname": "NetEarnedPremiumGeneralInsuranceAndLendersMortgageInsurance", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NetIncreaseDecreaseInAssetsOperatingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Net (Increase) Decrease in Assets, Operating Activities [Abstract]", "terseLabel": "Net (increase)/decrease in:" } } }, "localname": "NetIncreaseDecreaseInAssetsOperatingActivitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "wbk_NetIncreaseDecreaseInExposureToCreditRiskFromLoansDueToTransfersBetweenStages": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in exposure to credit risk from loans due to transfers between stages.", "label": "Net Increase (decrease) in exposure to Credit Risk from Loans Due to Transfers Between Stages", "terseLabel": "Net increase (decrease) in exposure to credit risk from loans due to transfers between stages" } } }, "localname": "NetIncreaseDecreaseInExposureToCreditRiskFromLoansDueToTransfersBetweenStages", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NetIncreaseDecreaseInLiabilitiesOperatingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Net Increase (Decrease) in Liabilities, Operating Activities [Abstract]", "terseLabel": "Net increase/(decrease) in:", "verboseLabel": "(Decrease)/increase in other operating liabilities:" } } }, "localname": "NetIncreaseDecreaseInLiabilitiesOperatingActivitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfNetCashProvidedByUsedInOperatingActivitiesToNetProfitDetails", "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "stringItemType" }, "wbk_NetInterestIncomeAtRiskAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Net Interest Income-at-Risk [Abstract]", "terseLabel": "Net interest income-at-risk (NaR)" } } }, "localname": "NetInterestIncomeAtRiskAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "stringItemType" }, "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 1.0, "parentTag": "ifrs-full_ProfitLossBeforeTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of net operating income before operating expenses and impairment charges, calculated as interest income and non-interest income less interest expense.", "label": "Net Operating Income Before Operating Expense and Impairment Charges", "totalLabel": "Net operating income before operating expenses and impairment (charges)/benefits" } } }, "localname": "NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "wbk_NetWealthManagementAndInsuranceIncome": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 2.0, "parentTag": "wbk_NonInterestIncomeExpense", "weight": 1.0 }, "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 3.0, "parentTag": "wbk_NetOperatingIncomeBeforeOperatingExpenseAndImpairmentCharges", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The aggregate amount of net wealth management and insurance income.", "label": "Net Wealth Management and Insurance Income", "totalLabel": "Net wealth management and insurance income", "verboseLabel": "Net wealth management and insurance income" } } }, "localname": "NetWealthManagementAndInsuranceIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "wbk_NewSouthWalesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of New South Wales.", "label": "New South Wales [Member]", "terseLabel": "New South Wales" } } }, "localname": "NewSouthWalesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_NewZealandBankingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Westpac New Zealand reportable segment.", "label": "New Zealand Banking [Member]", "terseLabel": "New Zealand" } } }, "localname": "NewZealandBankingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "wbk_NewZealandFiveYearSwapRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for New Zealand 5 year swap rate.", "label": "New Zealand Five Year Swap Rate [Member]", "terseLabel": "New Zealand 5 year swap rate" } } }, "localname": "NewZealandFiveYearSwapRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_NinetyDayBankBillRateMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for 90 day bank bill rate.", "label": "Ninety Day Bank Bill Rate [Member]", "terseLabel": "90 day bank bill rate" } } }, "localname": "NinetyDayBankBillRateMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_NoSpecificMaturityMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for an unspecified maturity time band.", "label": "No Specific Maturity [Member]", "terseLabel": "No Specific Maturity" } } }, "localname": "NoSpecificMaturityMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_NonCashFinancingActivitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Non-cash Financing Activities [Abstract]", "terseLabel": "Non-cash financing activities" } } }, "localname": "NonCashFinancingActivitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "stringItemType" }, "wbk_NonDerivativeExposureToInterestRateReformFinancialAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of exposure of non-derivative financial assets to interest rate reform.", "label": "Non-Derivative Exposure to Interest Rate Reform, Financial Assets", "terseLabel": "Financial assets (carrying amount)" } } }, "localname": "NonDerivativeExposureToInterestRateReformFinancialAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NonDerivativeExposureToInterestRateReformFinancialLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of exposure of non-derivative financial liabilities to interest rate reform.", "label": "Non-Derivative Exposure to Interest Rate Reform, Financial Liabilities", "terseLabel": "Financial liabilities (carrying amount)" } } }, "localname": "NonDerivativeExposureToInterestRateReformFinancialLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NonDerivativeFinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to non-derivative financial liabilities, excluding loan capital.", "label": "Non-Derivative Financial Liabilities, Excluding Loan Capital, Undiscounted Cash Flows", "terseLabel": "Non-derivative financial liabilities, excluding loan capital" } } }, "localname": "NonDerivativeFinancialLiabilitiesExcludingLoanCapitalUndiscountedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NonDerivativeFinancialLiabilitiesLoanCapitalUndiscountedCashFlows": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of contractual undiscounted cash flows in relation to non-derivative financial liabilities classified as loan capital.", "label": "Non-Derivative Financial Liabilities, Loan Capital, Undiscounted Cash Flows", "terseLabel": "Loan capital" } } }, "localname": "NonDerivativeFinancialLiabilitiesLoanCapitalUndiscountedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NonInterestBearingLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Non-Interest Bearing Liabilities [Abstract]", "terseLabel": "Non-interest bearing liabilities" } } }, "localname": "NonInterestBearingLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_NonInterestBearingRepayableAtCallMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for non-interest bearing deposits or other borrowings, repayable at call.", "label": "Non Interest Bearing Repayable At Call [Member]", "terseLabel": "Non-interest bearing, repayable at call" } } }, "localname": "NonInterestBearingRepayableAtCallMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_NonInterestEarningAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Non-Interest Earning Assets", "terseLabel": "Non-interest earning assets" } } }, "localname": "NonInterestEarningAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_NonInterestIncomeExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The net amount of non-interest income (expense), which may be derived from: (1) fees and commissions; (2) wealth management and insurance; (3) trading; and (4) other.", "label": "Non-interest Income (Expense)", "totalLabel": "Total non-interest income" } } }, "localname": "NonInterestIncomeExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NonPerformingLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for non-performing loans.", "label": "Non Performing Loans [Member]", "terseLabel": "Non-performing loans" } } }, "localname": "NonPerformingLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "domainItemType" }, "wbk_NonPerformingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Non-performing.", "label": "Non Performing [Member]", "terseLabel": "Non-performing" } } }, "localname": "NonPerformingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_NonTradedMarketRiskAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Non-traded Market Risk [Abstract]", "terseLabel": "Non-traded market risk" } } }, "localname": "NonTradedMarketRiskAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "stringItemType" }, "wbk_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Noncurrent Assets Or Disposal Groups Classified As Held For Sale [Line Items]", "terseLabel": "Assets and liabilities held for sale" } } }, "localname": "NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "stringItemType" }, "wbk_NoncurrentAssetsOrdisposalGroupsClassifiedAsHeldForSaleTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing information related to non-current assets or disposal groups classified as held for sale.", "label": "Noncurrent Assets OrDisposal Groups Classified As Held For Sale [Table]" } } }, "localname": "NoncurrentAssetsOrdisposalGroupsClassifiedAsHeldForSaleTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "stringItemType" }, "wbk_NorthernTerritoryMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the location of Northern Territory.", "label": "Northern Territory [Member]", "terseLabel": "Northern Territory" } } }, "localname": "NorthernTerritoryMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_NotesToCashFlowStatementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Notes To The Cash Flow Statement [Abstract]" } } }, "localname": "NotesToCashFlowStatementAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_NotesToCashFlowStatementsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Notes to the cash flow statements" } } }, "localname": "NotesToCashFlowStatementsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_NotionalAmountOfNotesNotSubjectToApprovalForRedemption": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Principal amount of subordinated notes not subject to prior written APRA's approval for redemption.", "label": "Notional Amount of Notes Not Subject to Approval for Redemption", "terseLabel": "Principal amount of subordinated notes not subject to APRA's approval for redemption" } } }, "localname": "NotionalAmountOfNotesNotSubjectToApprovalForRedemption", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NotionalAmountsOfOffBalanceSheetExposureToLossFromInterestsInStructuredEntities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The amount that best represents the entity's notional amounts of off-balance sheet exposure to loss from its interests in structured entities.", "label": "Notional Amounts of Off-balance Sheet Exposure to Loss from Interests in Structured Entities", "terseLabel": "Total notional amounts of off-balance sheet exposures" } } }, "localname": "NotionalAmountsOfOffBalanceSheetExposureToLossFromInterestsInStructuredEntities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_NumberOfAssociates": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of associates material to the entity.", "label": "Number of Associates", "terseLabel": "Number of associates material to the Group" } } }, "localname": "NumberOfAssociates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "integerItemType" }, "wbk_NumberOfBusinessDaysForImmediateAndIrrevocableTerminationOfRightsAfterNonViabilityTriggerEventIfConversionNotOccur": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of business days for immediate and irrevocable termination of rights after non-viability trigger event if conversion not occur.", "label": "Number of Business Days for Immediate and Irrevocable Termination of Rights After Non-viability Trigger Event If Conversion Not Occur", "terseLabel": "Number of business days for immediate and irrevocable termination of rights after non-viability trigger event if conversion not occur" } } }, "localname": "NumberOfBusinessDaysForImmediateAndIrrevocableTerminationOfRightsAfterNonViabilityTriggerEventIfConversionNotOccur", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "durationItemType" }, "wbk_NumberOfBusinessDaysForPaymentOfDividendDistributionOrInterest": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of business days for payment of dividend, distribution or interest.", "label": "Number of Business Days for Payment of Dividend Distribution or Interest", "terseLabel": "Number of business days for payment of dividend, distribution or interest" } } }, "localname": "NumberOfBusinessDaysForPaymentOfDividendDistributionOrInterest", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "durationItemType" }, "wbk_NumberOfBusinessDaysPriorToCapitalTriggerEventDateOrNonViabilityTriggerEventDateToDetermineSharePriceForConversion": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of business days prior to capital trigger event date or non-viability trigger event date to determine share price for conversion.", "label": "Number of Business Days Prior to Capital Trigger Event Date or Non-viability Trigger Event Date to Determine Share Price for Conversion", "terseLabel": "Number of business days prior to capital trigger event date or non-viability trigger event date to determine share price for conversion" } } }, "localname": "NumberOfBusinessDaysPriorToCapitalTriggerEventDateOrNonViabilityTriggerEventDateToDetermineSharePriceForConversion", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "durationItemType" }, "wbk_NumberOfBusinessDaysPriorToScheduledConversionDateToDetermineSharePrice": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of business days prior to scheduled conversion date to determine share price.", "label": "Number of Business Days Prior to Scheduled Conversion Date to Determine Share Price", "terseLabel": "Number of business days prior to scheduled conversion date to determine share price" } } }, "localname": "NumberOfBusinessDaysPriorToScheduledConversionDateToDetermineSharePrice", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "durationItemType" }, "wbk_NumberOfBusinessesSoldDuringYear": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of businesses sold during the year.", "label": "Number of Businesses Sold During the Year", "terseLabel": "Number of businesses sold during the year" } } }, "localname": "NumberOfBusinessesSoldDuringYear", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "integerItemType" }, "wbk_NumberOfCoveredBondPrograms": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of covered bond programs.", "label": "Number of Covered Bond Programs", "terseLabel": "Number of covered bond programs" } } }, "localname": "NumberOfCoveredBondPrograms", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "integerItemType" }, "wbk_NumberOfKeyManagementPersonnelWithLoans": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Number of key management personnel with loans provided by the entity.", "label": "Number of Key Management Personnel With Loans", "terseLabel": "Number of KMP with loans" } } }, "localname": "NumberOfKeyManagementPersonnelWithLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "integerItemType" }, "wbk_NumberOfOrdinarySharesPurchasedSoldOnMarket": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The net number of ordinary shares purchased or sold on market.", "label": "Number of Ordinary Shares Purchased (sold) on Market", "verboseLabel": "Net number of ordinary shares purchased/(sold) on market" } } }, "localname": "NumberOfOrdinarySharesPurchasedSoldOnMarket", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_NumberOfOtherEquityInstrumentsReleasedInShareBasedPaymentArrangement": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of other equity instruments (i.e. other than share options) released in a share-based payment arrangement.", "label": "Number Of Other Equity Instruments Released In Share based Payment Arrangement", "terseLabel": "Released" } } }, "localname": "NumberOfOtherEquityInstrumentsReleasedInShareBasedPaymentArrangement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "decimalItemType" }, "wbk_NumberOfSharesInEntityHeldByEntityOrByItsSubsidiariesOrAssociatesOther": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of shares in the entity held by the entity or by its subsidiaries or associates, excluding unvested shares related to a restricted share plan.", "label": "Number of shares in entity held by entity or by its subsidiaries or associates, other", "terseLabel": "Number of other treasury shares held" } } }, "localname": "NumberOfSharesInEntityHeldByEntityOrByItsSubsidiariesOrAssociatesOther", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_NumberOfSharesInEntityHeldByEntityUnvestedRestrictedShares": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of unvested shares in the entity held by the entity in relation to a restricted share plan.", "label": "Number of shares in entity held by entity, unvested restricted shares", "terseLabel": "Number of unvested RSP treasury shares held" } } }, "localname": "NumberOfSharesInEntityHeldByEntityUnvestedRestrictedShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_NumberOfSharesIssuedDuringPeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of shares issued during the period.", "label": "Number of Shares Issued During the Period", "terseLabel": "Share issuances" } } }, "localname": "NumberOfSharesIssuedDuringPeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "sharesItemType" }, "wbk_NumberOfVotesPerOrdinaryShares": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The number of votes per ordinary shares.", "label": "Number of Votes per Ordinary Shares", "terseLabel": "Number of votes per ordinary shares" } } }, "localname": "NumberOfVotesPerOrdinaryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "integerItemType" }, "wbk_OccupancyExpensesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Occupancy Expenses [Abstract]", "terseLabel": "Occupancy expenses" } } }, "localname": "OccupancyExpensesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "wbk_OccupancyExpensesOther": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 3.0, "parentTag": "ifrs-full_OccupancyExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of other occupancy expenses.", "label": "Occupancy Expenses, Other", "terseLabel": "Other" } } }, "localname": "OccupancyExpensesOther", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OffMarketBuyBackOfSharesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for an off-market buy back of shares.", "label": "Off Market Buy Back Of Shares [Member]", "terseLabel": "Off-market buy back of shares" } } }, "localname": "OffMarketBuyBackOfSharesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "domainItemType" }, "wbk_OneToOneHedgeRelationshipsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to one to one hedge relationships.", "label": "One To One Hedge Relationships [Member]", "terseLabel": "One-to-one hedge relationships" } } }, "localname": "OneToOneHedgeRelationshipsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails", "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsWeightedAverageFxRateRelatedToSignificantHedgingInstrumentsInOneToOneHedgeRelationshipsDetails" ], "xbrltype": "domainItemType" }, "wbk_OneYearVestingPeriodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to one year vesting period.", "label": "One Year Vesting Period [Member]", "terseLabel": "One-year vesting period" } } }, "localname": "OneYearVestingPeriodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_OperatingExpensesWriteDownOfAssetsHeldForSaleToFairValueNetOfCostsToSellAndOtherRelatedCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount recognized in operating expenses for the write down of assets held for sale to the estimated fair value, net of costs to sell and other related costs.", "label": "Operating Expenses, Write Down Of Assets Held for Sale to Fair Value, Net of Costs to Sell and Other Related Costs", "terseLabel": "Writedown of assets held for sale to their estimated fair value less costs to sell and recognition of related separation and transaction costs" } } }, "localname": "OperatingExpensesWriteDownOfAssetsHeldForSaleToFairValueNetOfCostsToSellAndOtherRelatedCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OperatingExpensesWriteDownOfGoodwillAndRecognitionOfRelatedSeparationAndTransactionCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount recognised in operating expenses during the period for the write down of goodwill and recognition of related separation and transaction costs.", "label": "Operating Expenses, Write Down of Goodwill, and Recognition of Related Separation and Transaction Costs", "terseLabel": "Write down of goodwill, and recognition of related separation and transaction costs" } } }, "localname": "OperatingExpensesWriteDownOfGoodwillAndRecognitionOfRelatedSeparationAndTransactionCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OrdinarySharesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Ordinary Shares [Abstract]", "terseLabel": "Ordinary Shares" } } }, "localname": "OrdinarySharesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "wbk_OrdinarySharesPurchasedAndSoldOnMarketAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Ordinary Shares Purchased and Sold on Market [Abstract]", "terseLabel": "Ordinary shares purchased and sold on market" } } }, "localname": "OrdinarySharesPurchasedAndSoldOnMarketAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "stringItemType" }, "wbk_OtherAssetsPrepaymentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other assets - prepayments.", "label": "Other Assets Prepayments [Member]", "terseLabel": "Other assets - prepayments" } } }, "localname": "OtherAssetsPrepaymentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherCommitments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails": { "order": 3.0, "parentTag": "wbk_UndrawnCreditCommitments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of other commitments.", "label": "Other Commitments", "terseLabel": "Other" } } }, "localname": "OtherCommitments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other commitments.", "label": "Other Commitments [Member]", "terseLabel": "Other commitments" } } }, "localname": "OtherCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstrumentsExcludingExchangeDifferences": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of other comprehensive income, before tax, related to gains (losses) from changes in the fair value of investments in equity instruments that the entity has designated at fair value through other comprehensive income, excluding exchange differences.", "label": "Other comprehensive income, before tax, gains (losses) from investments in equity instruments excluding exchange differences", "terseLabel": "Net gains/(losses) from changes in fair value" } } }, "localname": "OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstrumentsExcludingExchangeDifferences", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherComprehensiveIncomeGainsLossesFromInvestmentsInEquityInstrumentsTax": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The income tax effect of gains (losses) from changes in the fair value of investments in equity instruments that the entity has designated at fair value through other comprehensive income.", "label": "Other comprehensive income, gains (losses) from investments in equity instruments, tax", "negatedLabel": "Income tax effect" } } }, "localname": "OtherComprehensiveIncomeGainsLossesFromInvestmentsInEquityInstrumentsTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherCurrencyMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents all other currencies not specifically defined.", "label": "Other Currency [Member]", "terseLabel": "Other" } } }, "localname": "OtherCurrencyMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherCurrencyPairsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other currency pairs not separately disclosed.", "label": "Other Currency Pairs [Member]", "terseLabel": "Other currency pairs" } } }, "localname": "OtherCurrencyPairsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherEquityMovementsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Other Equity Movements [Abstract]", "terseLabel": "Other equity movements" } } }, "localname": "OtherEquityMovementsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "stringItemType" }, "wbk_OtherFeeAndCommissionIncomeExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails": { "order": 3.0, "parentTag": "ifrs-full_FeeAndCommissionIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of fee and commission income (expense) that the entity does not separately disclose in the same statement or note.", "label": "Other Fee And Commission Income (Expense)", "terseLabel": "Other non-risk fee income" } } }, "localname": "OtherFeeAndCommissionIncomeExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherFinancialAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Other financial assets" } } }, "localname": "OtherFinancialAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_OtherFinancialAssetsBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 7.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of financial assets based on expected maturities that the entity does not separately disclose in the same statement or note.", "label": "Other Financial Assets, Based On Expected Maturities", "terseLabel": "Other financial assets" } } }, "localname": "OtherFinancialAssetsBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherFinancialAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other financial assets.", "label": "Other Financial Assets [Member]", "terseLabel": "Other financial assets" } } }, "localname": "OtherFinancialAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherFinancialLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Other financial liabilities" } } }, "localname": "OtherFinancialLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_OtherFinancialLiabilitiesAtFairValueThroughProfitOrLossMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other financial liabilities at fair value through profit or loss.", "label": "Other Financial Liabilities At Fair Value Through Profit Or Loss [Member]", "terseLabel": "Other financial liabilities" } } }, "localname": "OtherFinancialLiabilitiesAtFairValueThroughProfitOrLossMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherFinancialLiabilitiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 3.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of financial liabilities based on expected maturities that the entity does not separately disclose in the same statement or note.", "label": "Other Financial Liabilities, Based On Expected Maturities", "terseLabel": "Other financial liabilities" } } }, "localname": "OtherFinancialLiabilitiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherFinancialLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other financial liabilities.", "label": "Other Financial Liabilities [Member]", "terseLabel": "Other financial liabilities" } } }, "localname": "OtherFinancialLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesNotMeasuredAtFairValueDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskContractualMaturityOfFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherIncomeNet": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of other income, net.", "label": "Other Income, Net", "terseLabel": "Other income" } } }, "localname": "OtherIncomeNet", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherIndustryMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other industries.", "label": "Other Industry [Member]", "terseLabel": "Other" } } }, "localname": "OtherIndustryMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherIntangibleAssetsAndGoodwillMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other intangible assets and goodwill.", "label": "Other Intangible Assets And Goodwill [Member]", "terseLabel": "Goodwill and other intangibles" } } }, "localname": "OtherIntangibleAssetsAndGoodwillMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherInterestBearingAtCallMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other interest bearing deposits or other borrowings, at call.", "label": "Other Interest Bearing At Call [Member]", "terseLabel": "Other interest bearing at call" } } }, "localname": "OtherInterestBearingAtCallMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherInterestBearingLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other interest bearing liabilities not separately identified.", "label": "Other Interest Bearing Liabilities [Member]", "terseLabel": "Other interest bearing liabilities" } } }, "localname": "OtherInterestBearingLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherInterestBearingTermMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other interest bearing term deposits or other borrowings.", "label": "Other Interest Bearing Term [Member]", "terseLabel": "Other interest bearing term" } } }, "localname": "OtherInterestBearingTermMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsAverageBalancesAndAverageRatesForMajorCategoriesOfDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherInterestExpense": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of interest expense not separately disclosed.", "label": "Other Interest Expense", "negatedLabel": "Other interest expense" } } }, "localname": "OtherInterestExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherInterestRatesNotSeparatelyDisclosedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other interest rates not separately disclosed.", "label": "Other Interest Rates Not Separately Disclosed [Member]", "terseLabel": "Other" } } }, "localname": "OtherInterestRatesNotSeparatelyDisclosedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformDerivativesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherMarketRisksMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Other market risks.", "label": "Other Market Risks [Member]", "terseLabel": "Other market risks" } } }, "localname": "OtherMarketRisksMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other securities.", "label": "Other Securities [Member]", "terseLabel": "Other" } } }, "localname": "OtherSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "domainItemType" }, "wbk_OtherTreasuryShares": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails": { "order": 2.0, "parentTag": "ifrs-full_TreasuryShares", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "An entity's other own equity instruments, held by the entity or other members of the consolidated group.", "label": "Other Treasury Shares", "negatedTerseLabel": "Other treasury shares" } } }, "localname": "OtherTreasuryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_OtherUnusualOrInfrequentEventsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for other unusual or infrequent events.", "label": "Other Unusual Or Infrequent Events [Member]", "terseLabel": "Other risks" } } }, "localname": "OtherUnusualOrInfrequentEventsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesPortfolioOverlaysDetails" ], "xbrltype": "domainItemType" }, "wbk_OwnIssuancesInstrumentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the entity's own issuance of short-term debt instruments.", "label": "Own Issuances Instruments [Member]", "terseLabel": "Own issuances" } } }, "localname": "OwnIssuancesInstrumentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails", "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "domainItemType" }, "wbk_OwnIssuancesSeniorMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the entity's own issuance of senior short-term debt instruments.", "label": "Own Issuances Senior [Member]", "terseLabel": "Senior debt" } } }, "localname": "OwnIssuancesSeniorMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "wbk_PacificIslandsAsiaAmericasAndEuropeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Pacific Islands, Asia, the Americas and Europe.", "label": "Pacific Islands Asia Americas And Europe [Member]", "terseLabel": "Other overseas" } } }, "localname": "PacificIslandsAsiaAmericasAndEuropeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails", "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsSummaryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_PartiallySecuredLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans for which the secured loan to collateral value ratio is greater than 100% but not more than 150%.", "label": "Partially Secured Loans [Member]", "terseLabel": "Partially secured" } } }, "localname": "PartiallySecuredLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "domainItemType" }, "wbk_PaymentsToAcquireOrRedeemEntitysSharesForExerciseOfOptionsAndRights": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 8.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow to acquire or redeem entity's shares for issuance upon exercise of employee options and rights.", "label": "Payments to acquire or redeem entity's shares for exercise of options and rights", "negatedLabel": "Purchase of shares relating to share-based payment arrangements" } } }, "localname": "PaymentsToAcquireOrRedeemEntitysSharesForExerciseOfOptionsAndRights", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_PaymentsToAcquireOrRedeemEntitysSharesForRestrictedSharePlan": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 9.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow to acquire or redeem entity's shares to be held as treasury shares until vesting under a restricted share plan.", "label": "Payments to acquire or redeem entity's shares for restricted share plan", "negatedLabel": "Purchase of RSP treasury shares" } } }, "localname": "PaymentsToAcquireOrRedeemEntitysSharesForRestrictedSharePlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_PaymentsToAcquireOrRedeemProceedsFromReissuanceOfOtherTreasuryShares": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 10.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow (inflow) from the acquisition of the entity's shares as treasury shares or the reissuance of such shares, excluding transactions related to a restricted share plan.", "label": "Payments to acquire or redeem (proceeds from reissuance of) other treasury shares", "negatedLabel": "Net sale/(purchase) of other treasury shares" } } }, "localname": "PaymentsToAcquireOrRedeemProceedsFromReissuanceOfOtherTreasuryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_PercentageOfConditionalSupplementalAllocation": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Additional percentage of eligible loans, as a percentage of total eligible loans, that is available subject to specified conditions.", "label": "Percentage of Conditional Supplemental Allocation", "terseLabel": "Percentage of conditional additional allocation" } } }, "localname": "PercentageOfConditionalSupplementalAllocation", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfContributionOnMembersSalary": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of contribution on members' salary.", "label": "Percentage Of Contribution On Members Salary", "terseLabel": "Percentage of contribution on member's salary" } } }, "localname": "PercentageOfContributionOnMembersSalary", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfCreditConcentrationsFinancialAssetsHeldInAustralia": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of credit concentration of financial assets held in Australia.", "label": "Percentage of Credit Concentrations, Financial Assets Held in Australia", "terseLabel": "Financial assets held in Australia (as a percent)" } } }, "localname": "PercentageOfCreditConcentrationsFinancialAssetsHeldInAustralia", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfCreditConcentrationsFinancialAssetsIssuedByFinancialInstitutions": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of credit concentration of financial assets issued by financial institutions.", "label": "Percentage of Credit Concentrations, Financial Assets Issued by Financial Institutions", "terseLabel": "Financial assets issued by financial institutions (as a percent)" } } }, "localname": "PercentageOfCreditConcentrationsFinancialAssetsIssuedByFinancialInstitutions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfCreditConcentrationsFinancialAssetsIssuedByGovernmentOrSemiGovernmentAuthorities": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of credit concentration of financial assets issued by government and semi-government authorities.", "label": "Percentage of Credit Concentrations, Financial Assets Issued by Government or Semi Government Authorities", "terseLabel": "Financial assets issued by government or semi-government authorities (as a percent)" } } }, "localname": "PercentageOfCreditConcentrationsFinancialAssetsIssuedByGovernmentOrSemiGovernmentAuthorities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfCustomerDepositsToTotalLoans": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of customer deposits to total loans.", "label": "Percentage of Customer Deposits to Total Loans", "terseLabel": "Customer deposits to loan ratio" } } }, "localname": "PercentageOfCustomerDepositsToTotalLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfFundingThroughCustomerDeposits": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": 1.0, "parentTag": "wbk_PercentageOfTotalFunding", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The percentage of the entity's funding that is provided through customer deposits.", "label": "Percentage of Funding Through Customer Deposits", "terseLabel": "Customer deposits" } } }, "localname": "PercentageOfFundingThroughCustomerDeposits", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfFundingThroughEquity": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": 5.0, "parentTag": "wbk_PercentageOfTotalFunding", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The percentage of the entity's funding that is provided through equity.", "label": "Percentage of Funding Through Equity", "terseLabel": "Equity" } } }, "localname": "PercentageOfFundingThroughEquity", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfFundingThroughSecuritisation": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": 4.0, "parentTag": "wbk_PercentageOfTotalFunding", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The percentage of the entity's funding that is provided through securitisation.", "label": "Percentage of Funding Through Securitisation", "terseLabel": "Securitisation" } } }, "localname": "PercentageOfFundingThroughSecuritisation", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfFundingThroughWholesaleFundingWithResidualMaturityLessThan12Months": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": 3.0, "parentTag": "wbk_PercentageOfTotalFunding", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The percentage of the entity's funding that is provided through wholesale funding with residual maturity less than 12 months.", "label": "Percentage Of Funding Through Wholesale Funding With Residual Maturity Less Than 12 Months", "terseLabel": "Wholesale funding with a residual maturity less than 12 months" } } }, "localname": "PercentageOfFundingThroughWholesaleFundingWithResidualMaturityLessThan12Months", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfFundingThroughWholesaleTermFundingWithResidualMaturityGreaterThan12Months": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": 2.0, "parentTag": "wbk_PercentageOfTotalFunding", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The percentage of the entity's funding that is provided through wholesale term funding with residual maturity greater than 12 months.", "label": "Percentage Of Funding Through Wholesale Term Funding With Residual Maturity Greater Than 12 Months", "terseLabel": "Wholesale term funding with residual maturity greater than 12 months" } } }, "localname": "PercentageOfFundingThroughWholesaleTermFundingWithResidualMaturityGreaterThan12Months", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfIncreaseDecreaseInRateOfGrowthInCommercialPropertyPrices": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the percent of increase decrease in the rate of growth in commercial property prices.", "label": "Percentage of Increase Decrease in Rate of Growth in Commercial Property Prices", "terseLabel": "Commercial property index, percentage of forecast growth (contraction)" } } }, "localname": "PercentageOfIncreaseDecreaseInRateOfGrowthInCommercialPropertyPrices", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfIncreaseDecreaseInReturnToGrowthInResidentialPropertyPrices": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the percent of increase or decrease in the rate of growth in residential property prices.", "label": "Percentage of Increase Decrease in Return To Growth in Residential Property Prices", "terseLabel": "Residential property prices, percentage of forecast appreciation (contraction)" } } }, "localname": "PercentageOfIncreaseDecreaseInReturnToGrowthInResidentialPropertyPrices", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfInitialAllocationOfLoans": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Initial allocation of eligible loans, as a percentage of total eligible loans.", "label": "Percentage of Initial Allocation of Loans", "terseLabel": "Total percentage of initial allocation of eligible loans" } } }, "localname": "PercentageOfInitialAllocationOfLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfInitialAllocationOfLoansExcludingConditionalAdditionalAllocation": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Initial allocation of eligible loans, as a percentage of total eligible loans, excluding additional conditional allocation.", "label": "Percentage of Initial Allocation of Loans, Excluding Conditional Additional Allocation", "terseLabel": "Percentage of initial allocation of eligible loans" } } }, "localname": "PercentageOfInitialAllocationOfLoansExcludingConditionalAdditionalAllocation", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfNetInterestIncomeAtRiskOverReportedNetIncome": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of Net interest income-at-risk (NaR) over the reported net interest income.", "label": "Percentage of Net Interest Income at Risk over the Reported Net Income", "terseLabel": "Net interest income-at-risk (as a percent)" } } }, "localname": "PercentageOfNetInterestIncomeAtRiskOverReportedNetIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfSegmentNonCurrentAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of segment non-current assets to total non-current assets.", "label": "Percentage of Segment Non Current Assets", "terseLabel": "Non-current assets (as a percent)" } } }, "localname": "PercentageOfSegmentNonCurrentAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfSegmentRevenues": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of segment revenues to total revenues.", "label": "Percentage Of Segment Revenues", "terseLabel": "Revenues (as a percent)" } } }, "localname": "PercentageOfSegmentRevenues", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingGeographicSegmentsDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfSharePriceToDetermineMaximumConversionNumber": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of share price to determine maximum conversion number.", "label": "Percentage of Share Price to Determine Maximum Conversion Number", "terseLabel": "Percentage of share price to determine maximum conversion number" } } }, "localname": "PercentageOfSharePriceToDetermineMaximumConversionNumber", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfTotalFunding": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en-us": { "role": { "documentation": "The total percentage of the entity's funding that is provided through specified sources.", "label": "Percentage of Total Funding", "totalLabel": "Group's total funding" } } }, "localname": "PercentageOfTotalFunding", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "percentItemType" }, "wbk_PercentageOfWeightingAssignedToScenario": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of weighting assigned to a scenario.", "label": "Percentage of Weighting Assigned to Scenario", "terseLabel": "Percentage of weight assigned to scenario" } } }, "localname": "PercentageOfWeightingAssignedToScenario", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails" ], "xbrltype": "percentItemType" }, "wbk_PerformingLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for non-performing loans.", "label": "Performing Loans [Member]", "terseLabel": "Performing loans" } } }, "localname": "PerformingLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "domainItemType" }, "wbk_PerformingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for performing.", "label": "Performing [Member]", "terseLabel": "Performing" } } }, "localname": "PerformingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_PeriodOfHistoricalDataUsedForVar": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The period of historical data used for Value at Risk.", "label": "Period of Historical Data Used for VaR", "terseLabel": "Period of historical data used" } } }, "localname": "PeriodOfHistoricalDataUsedForVar", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskValueAtRiskDetails" ], "xbrltype": "durationItemType" }, "wbk_PeriodOfProjectionForNar": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The future period over which Net interest income-at-risk is modelled.", "label": "Period of Projection for NaR", "terseLabel": "Time horizon for modelling of interest rate scenarios" } } }, "localname": "PeriodOfProjectionForNar", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "durationItemType" }, "wbk_PeriodOverWhichManagementHasProjectedCashFlows": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Period over which management has projected cash flows based on financial budgets/forecasts approved by management including, when a period greater than five years is used for a cash-generating unit (group of units).", "label": "Period Over Which Management Has Projected Cash Flows", "terseLabel": "Forecast period" } } }, "localname": "PeriodOverWhichManagementHasProjectedCashFlows", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "durationItemType" }, "wbk_PeriodPriorToPaymentOfDividendOnShareForPaymentOfInterest": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The period prior to payment of dividend on share for payment of interest.", "label": "Period Prior to Payment of Dividend on Share for Payment of Interest", "terseLabel": "Period prior to payment of dividend on share for payment of interest" } } }, "localname": "PeriodPriorToPaymentOfDividendOnShareForPaymentOfInterest", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "durationItemType" }, "wbk_PersonalLoansAndCardsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for personal loans and credit cards.", "label": "Personal Loans And Cards [Member]", "terseLabel": "Personal" } } }, "localname": "PersonalLoansAndCardsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureLoansContractualMaturitiesAndInterestRateSegmentationDetails", "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "domainItemType" }, "wbk_PeterKingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Peter King.", "label": "Peter King [Member]", "terseLabel": "Peter King" } } }, "localname": "PeterKingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_PortfolioFairValueHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a portion hedged may be designated in terms of an amount of currency (eg dollars, euro, pounds) rather than as individual assets (or liabilities) in fair value hedges.", "label": "Portfolio Fair Value Hedges [Member]", "terseLabel": "Portfolio fair value hedges" } } }, "localname": "PortfolioFairValueHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsHedgingInstrumentsDetails" ], "xbrltype": "domainItemType" }, "wbk_PostEmploymentBenefitExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 2.0, "parentTag": "ifrs-full_EmployeeBenefitsExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of post-employment benefit expense, relating both to defined benefit plans and to defined contribution plans.", "label": "Post-employment benefit expense", "terseLabel": "Superannuation expense" } } }, "localname": "PostEmploymentBenefitExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PostageAndStationeryExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 3.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from postage and purchases of stationery.", "label": "Postage and Stationery Expense", "terseLabel": "Postage and stationery" } } }, "localname": "PostageAndStationeryExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PreTaxImpactToReserveOfCashFlowHedges": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The aggregate pre-tax impact to the cash flow hedging reserve.", "label": "Pre-Tax Impact to Reserve Of Cash Flow Hedges", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "PreTaxImpactToReserveOfCashFlowHedges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PreTaxImpactToReserveOfCashFlowHedgesAttributableBalancesTransferredToInterestIncome": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The pre-tax impact to the cash flow hedging reserve attributable balances transferred to interest income.", "label": "Pre-Tax Impact to Reserve Of Cash Flow Hedges Attributable Balances Transferred to Interest Income", "terseLabel": "Transferred to interest income" } } }, "localname": "PreTaxImpactToReserveOfCashFlowHedgesAttributableBalancesTransferredToInterestIncome", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PreTaxImpactToReserveOfCashFlowHedgesAttributableToGainsLossesOnCashFlowHedges": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The pre-tax impact to the cash flow hedging reserve attributable to gains (losses) on cash flow hedges.", "label": "Pre-Tax Impact to Reserve Of Cash Flow Hedges Attributable to Gains (Losses) On Cash Flow Hedges", "terseLabel": "Net gains/(losses) from changes in fair value" } } }, "localname": "PreTaxImpactToReserveOfCashFlowHedgesAttributableToGainsLossesOnCashFlowHedges", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsPreTaxImpactOfCashFlowAndNetInvestmentHedgesOnReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PricePerShareInRelationToFinalDividendReinvestmentPlan": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Price of a single share for the prior year final dividend in relation to the dividend reinvestment plan.", "label": "Price per Share in Relation to Final Dividend Reinvestment Plan", "terseLabel": "DRP - price per share for final dividend" } } }, "localname": "PricePerShareInRelationToFinalDividendReinvestmentPlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "wbk_PricePerShareInRelationToFinalDividendReinvestmentPlanUnderwrite": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Price of a single share for the prior year final dividend in relation to the dividend investment plan underwrite.", "label": "Price Per Share in Relation to Final Dividend Reinvestment Plan Underwrite", "terseLabel": "DRP underwrite - price per share" } } }, "localname": "PricePerShareInRelationToFinalDividendReinvestmentPlanUnderwrite", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "wbk_PricePerShareInRelationToInterimDividendReinvestmentPlan": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Price of a single share for the current year interim dividend in relation to the dividend reinvestment plan.", "label": "Price per Share in Relation to Interim Dividend Reinvestment Plan", "terseLabel": "DRP - price per share for interim dividend" } } }, "localname": "PricePerShareInRelationToInterimDividendReinvestmentPlan", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "perShareItemType" }, "wbk_PricewaterhouseCoopersAustraliaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the auditor, PricewaterhouseCoopers (PwC) Australia.", "label": "Pricewaterhouse Coopers Australia [Member]", "terseLabel": "PwC Australia" } } }, "localname": "PricewaterhouseCoopersAustraliaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "domainItemType" }, "wbk_PricewaterhouseCoopersOverseasMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for PricewaterhouseCoopers (PwC) network firms outside of Australia.", "label": "Pricewaterhouse Coopers Overseas [Member]", "terseLabel": "Overseas PwC network firms" } } }, "localname": "PricewaterhouseCoopersOverseasMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAuditorSRemunerationDetails" ], "xbrltype": "domainItemType" }, "wbk_PriorYearAdjustmentImpactToBalanceSheetMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for prior year adjustment impact to the balance sheet.", "label": "Prior Year Adjustment Impact To Balance Sheet [Member]", "terseLabel": "Prior year impact on opening balance sheet" } } }, "localname": "PriorYearAdjustmentImpactToBalanceSheetMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails" ], "xbrltype": "domainItemType" }, "wbk_ProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperationsNetOfCashDeconsolidated": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from the disposal of non-current assets or disposal groups classified as held for sale and discontinued operations, net of cash that was deconsolidated.", "label": "Proceeds from disposal of non-current assets or disposal groups classified as held for sale and discontinued operations, net of cash deconsolidated", "totalLabel": "Cash consideration (paid)/received (net of transaction costs and cash held)" } } }, "localname": "ProceedsFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperationsNetOfCashDeconsolidated", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ProceedsFromIssueOfLoanCapitalNetOfIssueCosts": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 4.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from the issuing of loan capital, net of issue costs.", "label": "Proceeds from issue of loan capital, net of issue costs", "terseLabel": "Issue of loan capital (net of issue costs)" } } }, "localname": "ProceedsFromIssueOfLoanCapitalNetOfIssueCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ProceedsFromIssuingSharesToUnderwriters": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 7.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from issuing shares to underwriters.", "label": "Proceeds From Issuing Shares to Underwriters", "terseLabel": "Proceeds from dividend reinvestment plan underwrite" } } }, "localname": "ProceedsFromIssuingSharesToUnderwriters", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ProceedsPaymentsFromChangesInOwnershipInterestsInSubsidiariesThatDoNotResultInLossOfControl": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 4.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow (outflow) due to changes in ownership interests in subsidiaries that do not result in a loss of control.", "label": "Proceeds (payments) from changes in ownership interests in subsidiaries that do not result in loss of control", "terseLabel": "Net (increase)/decrease in investments in controlled entities" } } }, "localname": "ProceedsPaymentsFromChangesInOwnershipInterestsInSubsidiariesThatDoNotResultInLossOfControl", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ProceedsPaymentsFromChangesInReceivablesDueFromAndPayablesDueToRelatedParties": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 3.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow (outflow) due to changes in the amount of receivables due from and payables due to related parties.", "label": "Proceeds (payments) from changes in receivables due from and payables due to related parties", "terseLabel": "Net movement in amounts due to/from controlled entities" } } }, "localname": "ProceedsPaymentsFromChangesInReceivablesDueFromAndPayablesDueToRelatedParties", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ProceedsPaymentsFromDisposalOfControlledEntitiesNetOfCashDisposed": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 5.0, "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of proceeds (payments) from disposal of controlled entities, net of cash disposed.", "label": "Proceeds/(Payments) from disposal of controlled entities, net of cash disposed", "terseLabel": "Proceeds from disposal of controlled entities, net of cash disposed" } } }, "localname": "ProceedsPaymentsFromDisposalOfControlledEntitiesNetOfCashDisposed", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ProfessionalAndProcessingServicesExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 1.0, "parentTag": "ifrs-full_OtherExpenseByNature", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from professional and processing services.", "label": "Professional and Processing Services Expense", "terseLabel": "Professional and processing services" } } }, "localname": "ProfessionalAndProcessingServicesExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ProfitLossFromOperationsBeforeCashEarningsAdjustment": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails": { "order": 1.0, "parentTag": "ifrs-full_ProfitLossAttributableToOwnersOfParent", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of profit (loss) from operations before cash earnings adjustment.", "label": "Profit (Loss) From Operations Before Cash Earnings Adjustment", "terseLabel": "Cash earnings", "totalLabel": "Cash earnings" } } }, "localname": "ProfitLossFromOperationsBeforeCashEarningsAdjustment", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingReconciliationOfCashEarningsToNetProfitAttributableToOwnersOfWbcDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_PropertyAndEquipmentExcludingNetworkEquipmentMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for property and equipment, excluding network equipment.", "label": "Property And Equipment Excluding Network Equipment [Member]", "terseLabel": "Property and equipment" } } }, "localname": "PropertyAndEquipmentExcludingNetworkEquipmentMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "domainItemType" }, "wbk_PropertyMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for property.", "label": "Property [Member]", "terseLabel": "Property" } } }, "localname": "PropertyMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "wbk_PropertyServicesAndBusinessServicesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for property services and business services.", "label": "Property Services And Business Services [Member]", "terseLabel": "Property services and business services" } } }, "localname": "PropertyServicesAndBusinessServicesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_ProposedDividendMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for proposed dividends.", "label": "Proposed Dividend [Member]", "terseLabel": "Proposed dividend" } } }, "localname": "ProposedDividendMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionForEmployeeBenefitsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions for long service leave, annual leave and other employee benefits.", "label": "Provision For Employee Benefits [Member]", "terseLabel": "Provision for long service leave, annual leave and other employee benefits" } } }, "localname": "ProvisionForEmployeeBenefitsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionForExpectedCreditLossesOnDebtSecuritiesAtAmortisedCostMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions for expected credit losses on debt securities at amortised cost.", "label": "Provision For Expected Credit Losses On Debt Securities At Amortised Cost [Member]", "terseLabel": "Provision for ECL on debt securities at amortised cost" } } }, "localname": "ProvisionForExpectedCreditLossesOnDebtSecuritiesAtAmortisedCostMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionForPotentialPenalty": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of provision for potential penalties.", "label": "Provision for Potential Penalty", "terseLabel": "Provision for a potential penalty" } } }, "localname": "ProvisionForPotentialPenalty", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ProvisionInRelationToAustracCivilProceedingsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provision in relation to the AUSTRAC civil proceedings.", "label": "Provision In Relation To Austrac Civil Proceedings [Member]", "terseLabel": "Provision in relation to the AUSTRAC civil proceedings" } } }, "localname": "ProvisionInRelationToAustracCivilProceedingsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionsForExpectedCreditLossesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Provisions for expected credit losses" } } }, "localname": "ProvisionsForExpectedCreditLossesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_ProvisionsForExpectedCreditLossesOnCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions for expected credit losses on credit commitments.", "label": "Provisions For Expected Credit Losses On Credit Commitments [Member]", "terseLabel": "Provision for ECL on credit commitments" } } }, "localname": "ProvisionsForExpectedCreditLossesOnCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions for expected credit losses on loans and credit commitments.", "label": "Provisions For Expected Credit Losses On Loans And Credit Commitments [Member]", "terseLabel": "Provisions for ECL on loans and credit commitments" } } }, "localname": "ProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesReconciliationOfImpairmentChargesDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionsForExpectedCreditLossesOnLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions for expected credit losses on loans.", "label": "Provisions For Expected Credit Losses On Loans [Member]", "terseLabel": "Provision for ECL on loans" } } }, "localname": "ProvisionsForExpectedCreditLossesOnLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_ProvisionsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for provisions.", "label": "Provisions [Member]", "terseLabel": "Provisions" } } }, "localname": "ProvisionsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBalanceSheetPresentationDetails" ], "xbrltype": "domainItemType" }, "wbk_QueenslandMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of Queensland.", "label": "Queensland [Member]", "terseLabel": "Queensland" } } }, "localname": "QueenslandMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_RateOfDividendDistributionTax": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The tax rate applicable on distributions of dividends.", "label": "Rate of Dividend Distribution Tax", "terseLabel": "Dividend tax rate (as a percent)" } } }, "localname": "RateOfDividendDistributionTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails", "http://www.westpac.com.au/role/StatementStatementOfChangesInEquityParenthetical" ], "xbrltype": "percentItemType" }, "wbk_ReceiptsFromInterestAndSimilarItemsRelatedToLifeBusiness": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 8.0, "parentTag": "ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cash inflow from interest and other similar items, related to life insurance business.", "label": "Receipts from interest and similar items related to life business", "terseLabel": "Interest and other items of similar nature" } } }, "localname": "ReceiptsFromInterestAndSimilarItemsRelatedToLifeBusiness", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_ReclassificationAdjustmentsOnCashFlowHedgesTax": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of reclassification adjustments related to cash flow hedges, tax.", "label": "Reclassification Adjustments on Cash Flow Hedges Tax", "terseLabel": "Income tax effect" } } }, "localname": "ReclassificationAdjustmentsOnCashFlowHedgesTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeTax": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The income tax effect of reclassification adjustments related to financial assets measured at fair value through other comprehensive income.", "label": "Reclassification adjustments on financial assets measured at fair value through other comprehensive income, tax", "terseLabel": "Income tax effect" } } }, "localname": "ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeTax", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RecognisedInEquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Recognised in Equity [Abstract]", "terseLabel": "Gains/(losses) recognised in equity on:" } } }, "localname": "RecognisedInEquityAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "wbk_ReconciliationOfCashProceedsFromDisposalAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Reconciliation Of Cash Proceeds From Disposal [Abstract]", "terseLabel": "Reconciliation of cash proceeds from disposal" } } }, "localname": "ReconciliationOfCashProceedsFromDisposalAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsReconciliationOfCashProceedsFromDisposalDetails" ], "xbrltype": "stringItemType" }, "wbk_ReconciliationOfChangesInDebtSecuritiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition is available.", "label": "Movement reconciliation" } } }, "localname": "ReconciliationOfChangesInDebtSecuritiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "stringItemType" }, "wbk_ReconciliationOfChangesInDeferredTaxAssetAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Reconciliation of Changes in Deferred Tax Asset [Abstract]", "terseLabel": "Movements" } } }, "localname": "ReconciliationOfChangesInDeferredTaxAssetAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_ReconciliationOfChangesInDeferredTaxLiabilityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Reconciliation of Changes in Deferred Tax Liability [Abstract]", "terseLabel": "Movements" } } }, "localname": "ReconciliationOfChangesInDeferredTaxLiabilityAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "wbk_ReconciliationOfImpairmentChargesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the reconciliation of impairment charges.", "label": "Reconciliation of Impairment Charges [Table Text Block]", "terseLabel": "Reconciliation of impairment charges" } } }, "localname": "ReconciliationOfImpairmentChargesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_ReconciliationOfProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Reconciliation of Provisions for Expected Credit Losses on Loans and Credit Commitments [Abstract]", "terseLabel": "Reconciliation of provisions for ECL on loans and credit commitments" } } }, "localname": "ReconciliationOfProvisionsForExpectedCreditLossesOnLoansAndCreditCommitmentsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "wbk_RedemptionOfDebtSecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails": { "order": 2.0, "parentTag": "wbk_IncreaseDecreaseThroughCashMovementsDebtSecurities", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of debt instruments redeemed during the period.", "label": "Redemption of Debt Securities", "negatedLabel": "Maturities, repayments, buy backs and reductions" } } }, "localname": "RedemptionOfDebtSecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesMovementReconciliationDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RedemptionOfLoanCapital": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementCashFlowStatements": { "order": 5.0, "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The cash outflow for redemption of loan capital.", "label": "Redemption of loan capital", "negatedLabel": "Redemption of loan capital" } } }, "localname": "RedemptionOfLoanCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementCashFlowStatements" ], "xbrltype": "monetaryItemType" }, "wbk_RegulatoryDepositsWithCentralBanks": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails": { "order": 3.0, "parentTag": "ifrs-full_CashAndBankBalancesAtCentralBanks", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of cash classified as regulatory deposits with central banks.", "label": "Regulatory Deposits with Central Banks", "terseLabel": "Regulatory deposits with central banks" } } }, "localname": "RegulatoryDepositsWithCentralBanks", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ReinventureFundIncorporatedLimitedPartnershipMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Reinventure Fund, I.L.P.", "label": "Reinventure Fund Incorporated Limited Partnership [Member]", "terseLabel": "Reinventure Fund, I.L.P." } } }, "localname": "ReinventureFundIncorporatedLimitedPartnershipMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_ReportedProbabilityWeightedEclMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to reported probability of weighted expected credit losses.", "label": "Reported Probability Weighted Ecl [Member]", "terseLabel": "Reported probability-weighted ECL" } } }, "localname": "ReportedProbabilityWeightedEclMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "domainItemType" }, "wbk_ReserveForMiscellaneousOtherReserves": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails": { "order": 4.0, "parentTag": "ifrs-full_OtherReserves", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of reserve for miscellaneous other reserves.", "label": "Reserve for Miscellaneous Other Reserves", "periodEndLabel": "Balance as at end of year", "periodStartLabel": "Balance as at beginning of year" } } }, "localname": "ReserveForMiscellaneousOtherReserves", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ReservesReclassifiedToProfitOrLossOnDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of reserves reclassified to profit or loss on disposal of non-current assets or disposal groups classified as held for sale and discontinued operations.", "label": "Reserves reclassified to profit or loss on disposal of non-current assets or disposal groups classified as held for sale and discontinued operations", "terseLabel": "Reserves reclassified to income statement" } } }, "localname": "ReservesReclassifiedToProfitOrLossOnDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RestatedOpeningBalanceOfNetDeferredTaxAssetsDueToAdoptionOfNewAccountingPolicies": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of restated opening balance of net deferred tax assets due to adoption of new accounting policies.", "label": "Restated Opening Balance Of Net Deferred Tax Assets Due To Adoption Of New Accounting Policies", "terseLabel": "Restated opening balance" } } }, "localname": "RestatedOpeningBalanceOfNetDeferredTaxAssetsDueToAdoptionOfNewAccountingPolicies", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RestatedOpeningBalanceOfNetDeferredTaxLiabilitiesDueToAdoptionOfNewAccountingPolicies": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of restated opening balance of net deferred tax liabilities due to adoption of new accounting policies.", "label": "Restated Opening Balance Of Net Deferred Tax Liabilities Due To Adoption Of New Accounting Policies", "terseLabel": "Restated opening balance" } } }, "localname": "RestatedOpeningBalanceOfNetDeferredTaxLiabilitiesDueToAdoptionOfNewAccountingPolicies", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxMovementsInDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RestrictedSharePlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to restricted share plan.", "label": "Restricted Share Plan [Member]", "terseLabel": "Restricted Share Plan (RSP)" } } }, "localname": "RestrictedSharePlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_RestrictedSharePlanTreasuryShares": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails": { "order": 1.0, "parentTag": "ifrs-full_TreasuryShares", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "An entity's restricted share, held by the entity or other members of the consolidated group.", "label": "RSP treasury shares held", "negatedTerseLabel": "RSP treasury shares" } } }, "localname": "RestrictedSharePlanTreasuryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RestructuredLoansAndCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for restructured loans and credit commitments.", "label": "Restructured Loans And Credit Commitments [Member]", "terseLabel": "Restructured loans and credit commitments" } } }, "localname": "RestructuredLoansAndCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_RetailLendingMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for retail lending.", "label": "Retail Lending [Member]", "terseLabel": "Retail lending" } } }, "localname": "RetailLendingMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_RevenueFromInterestAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Revenue From Interest [Abstract]", "terseLabel": "Interest income:" } } }, "localname": "RevenueFromInterestAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "stringItemType" }, "wbk_RevenueFromInterestExcludingInterestCalculatedUsingEffectiveInterestRateMethod": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementIncomeStatements": { "order": 2.0, "parentTag": "ifrs-full_RevenueFromInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of income from interest excluding interest calculated using the effective interest rate method.", "label": "Revenue From Interest Excluding Interest Calculated Using The Effective Interest Rate Method", "terseLabel": "Other", "verboseLabel": "Total other interest income" } } }, "localname": "RevenueFromInterestExcludingInterestCalculatedUsingEffectiveInterestRateMethod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNetInterestIncomeDetails", "http://www.westpac.com.au/role/StatementIncomeStatements" ], "xbrltype": "monetaryItemType" }, "wbk_RevenueFromInterestRelatedPartyTransactions": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of revenue arising from the charging of interest on loans in related party transactions.", "label": "Revenue from interest, related party transactions", "terseLabel": "Interest payable for the year" } } }, "localname": "RevenueFromInterestRelatedPartyTransactions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOtherTransactionsWithKmpDetails" ], "xbrltype": "monetaryItemType" }, "wbk_RichardBurtonMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to group executive Richard Burton.", "label": "Richard Burton [Member]", "terseLabel": "Richard Burton" } } }, "localname": "RichardBurtonMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_RiskWeightedRatioEquityInvestmentsInSubsidiaries": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The risk weighted ratio for equity investments in subsidiaries.", "label": "Risk Weighted Ratio, Equity Investments in Subsidiaries", "terseLabel": "Risk weighted ratio, equity investments in subsidiaries" } } }, "localname": "RiskWeightedRatioEquityInvestmentsInSubsidiaries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_ScheduleOfAdjustmentsToProvisionForExpectedCreditLossesForCovid19TableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of adjustments to the provision for expected credit losses (ECL) related to impacts of COVID-19.", "label": "Schedule of Adjustments to Provision for Expected Credit Losses for COVID19 [Table Text Block]", "terseLabel": "Schedule of impact of overlays on the provision for ECL" } } }, "localname": "ScheduleOfAdjustmentsToProvisionForExpectedCreditLossesForCovid19TableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfDividendsNotRecognisedAtYearEndTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of dividends not recognised at year end.", "label": "Schedule of Dividends Not Recognised at Year End [Table Text Block]", "terseLabel": "Schedule of dividends not recognised at year end" } } }, "localname": "ScheduleOfDividendsNotRecognisedAtYearEndTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfLoansReceivableTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the loans receivable including gross carrying value, allowance, and net carrying value as of the balance sheet date.", "label": "Schedule of Loans Receivable [Table Text Block]", "terseLabel": "Schedule of loan portfolio disaggregated by location of booking office and product type" } } }, "localname": "ScheduleOfLoansReceivableTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfMaturitiesAndWeightedAverageYieldOfAvailableForSaleSecuritiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of maturities and weighted-average yield of available-for-sale securities.", "label": "Schedule of Maturities and Weighted Average Yield of Available-for-sale Securities [Table Text Block]", "terseLabel": "Schedule of maturities of the available-for-sale securities and their weighted-average yield" } } }, "localname": "ScheduleOfMaturitiesAndWeightedAverageYieldOfAvailableForSaleSecuritiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfNonCashFinancingActivitiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of non-cash financing activities.", "label": "Schedule Of Non Cash Financing Activities [Table Text Block]", "terseLabel": "Schedule of non-cash financing activities" } } }, "localname": "ScheduleOfNonCashFinancingActivitiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToConsolidatedCashFlowStatementTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of information pertaining to the offsetting of financial assets and financial liabilities.", "label": "Schedule Of Offsetting Of Financial Assets And Financial Liabilities [Table Text Block]", "terseLabel": "Schedule of offsetting financial assets and financial liabilities" } } }, "localname": "ScheduleOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfRelatedPartyPerformanceOptionsAndShareRightsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of performance share options, performance share rights and unhurdled share rights held by key management personnel and their related parties.", "label": "Schedule of related party performance options and share rights [Table Text Block]", "terseLabel": "Schedule of options and share rights held by key management personnel, including their related parties" } } }, "localname": "ScheduleOfRelatedPartyPerformanceOptionsAndShareRightsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfSensitivityOfProvisionForEclTableTextblock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure pertaining the information sensitivity of the provision for ECL.", "label": "Schedule Of Sensitivity Of The Provision for ECL [Table Text Block]", "terseLabel": "Summary of the the probability weighted scenarios" } } }, "localname": "ScheduleOfSensitivityOfProvisionForEclTableTextblock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScheduleOfWeightedAverageInterestRatesOfSignificantHedgingInstrumentsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of weighted average interest rates of significant hedging instruments.", "label": "Schedule of Weighted average Interest Rates of Significant Hedging Instruments [Table Text Block]", "terseLabel": "Schedule of weighted average FX rate related to significant hedging instruments in one-to-one hedge relationships" } } }, "localname": "ScheduleOfWeightedAverageInterestRatesOfSignificantHedgingInstrumentsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "wbk_ScottCollaryMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Scott Collary.", "label": "Scott Collary [Member]", "terseLabel": "Scott Collary" } } }, "localname": "ScottCollaryMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritiesForReverseRepurchaseAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for securities purchased to be resold in reverse repurchase transactions.", "label": "Securities For Reverse Repurchase Agreements [Member]", "terseLabel": "Reverse repurchase agreements" } } }, "localname": "SecuritiesForReverseRepurchaseAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritiesIncludingCertificatesOfDepositMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Securities (including certificates of deposit).", "label": "Securities Including Certificates Of Deposit [Member]", "terseLabel": "Securities (including certificates of deposit)" } } }, "localname": "SecuritiesIncludingCertificatesOfDepositMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritiesPledgedUnderRepurchaseAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Securities pledged under repurchase agreements.", "label": "Securities Pledged Under Repurchase Agreements [Member]", "terseLabel": "Securities pledged under repurchase agreements" } } }, "localname": "SecuritiesPledgedUnderRepurchaseAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskAssetsPledgedAsCollateralDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritiesPurchasedNotDelivered": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 4.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of the liability for securities purchased but not yet delivered.", "label": "Securities Purchased not Delivered", "terseLabel": "Securities purchased not delivered" } } }, "localname": "SecuritiesPurchasedNotDelivered", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritiesSoldNotDelivered": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails": { "order": 2.0, "parentTag": "ifrs-full_OtherFinancialAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of securities sold but not yet delivered.", "label": "Securities Sold not Delivered", "terseLabel": "Securities sold not delivered" } } }, "localname": "SecuritiesSoldNotDelivered", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritiesSoldNotYetPurchased": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 6.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of obligation to deliver securities to a buyer for the sale of securities that the entity does not own at the time of sale but that are promised to be delivered to the buyer.", "label": "Securities Sold, Not Yet Purchased", "terseLabel": "Securities sold short" } } }, "localname": "SecuritiesSoldNotYetPurchased", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritiesSoldUnderAgreementsToRepurchaseRepurchaseLiabilityInTradingPortfolio": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 5.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount due for securities sold under agreements to repurchase, managed as part of a trading portfolio.", "label": "Securities Sold under Agreements to Repurchase, Repurchase Liability in Trading Portfolio", "terseLabel": "Repurchase agreements" } } }, "localname": "SecuritiesSoldUnderAgreementsToRepurchaseRepurchaseLiabilityInTradingPortfolio", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritiesUnderDerivativesAndStockBorrowingOtherCollateral": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails": { "order": 3.0, "parentTag": "wbk_CollateralHeldAgainstFinancialAssetsOtherThanLoansTotal", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of securities held as collateral under derivatives and stock borrowing.", "label": "Securities Under Derivatives and Stock Borrowing, Other Collateral", "terseLabel": "Securities under derivatives and stock borrowing" } } }, "localname": "SecuritiesUnderDerivativesAndStockBorrowingOtherCollateral", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritiesUnderReverseRepurchaseAgreementOtherCollateral": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails": { "order": 2.0, "parentTag": "wbk_CollateralHeldAgainstFinancialAssetsOtherThanLoansTotal", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of securities held as collateral under reverse repurchase agreements.", "label": "Securities Under Reverse Repurchase Agreement, Other Collateral", "terseLabel": "Securities under reverse repurchase agreement" } } }, "localname": "SecuritiesUnderReverseRepurchaseAgreementOtherCollateral", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldAgainstFinancialAssetsOtherThanLoansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecuritisationMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for funding obtained through securitisation.", "label": "Securitisation [Member]", "terseLabel": "Securitisation" } } }, "localname": "SecuritisationMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritisationOwnAssetsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to securitisation-own assets.", "label": "Securitisation Own Assets [Member]", "terseLabel": "Securitisation" } } }, "localname": "SecuritisationOwnAssetsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_SecuritisedLoans": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of securitised loans included in loans and receivables.", "label": "Securitised Loans", "terseLabel": "Securitised loans" } } }, "localname": "SecuritisedLoans", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoansLoanPortfolioDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SecurityRepurchaseAgreementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to security repurchase agreements.", "label": "Security Repurchase Agreements [Member]", "terseLabel": "Repurchase agreements" } } }, "localname": "SecurityRepurchaseAgreementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_SegmentGroupBusinessesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a segment designated as Group Businesses.", "label": "Segment Group Businesses [Member]", "terseLabel": "Group Businesses" } } }, "localname": "SegmentGroupBusinessesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_SegmentResultsOnCashEarningsBasisAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Segment Results on Cash Earnings Basis [Abstract]", "terseLabel": "Income Statement" } } }, "localname": "SegmentResultsOnCashEarningsBasisAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "stringItemType" }, "wbk_SeniorInstrumentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for senior debt issued by the entity.", "label": "Senior Instruments [Member]", "terseLabel": "Senior" } } }, "localname": "SeniorInstrumentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "domainItemType" }, "wbk_SensitivityAnalysisAmountOfIncreaseInProvisionForExpectedCreditLoss": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of increase in provision for expected credit loss if 1% of stage 1 gross exposure from loans and credit commitments was reflected in stage 2.", "label": "Sensitivity Analysis, Amount of Increase in Provision for Expected Credit Loss", "terseLabel": "Amount of increase in provision for ECL" } } }, "localname": "SensitivityAnalysisAmountOfIncreaseInProvisionForExpectedCreditLoss", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SensitivityAnalysisIncreaseDecreaseInExpectedCreditLossDueToChangesInAssumptions": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The increase (decrease) in expected credit loss due to changes in assumptions.", "label": "Sensitivity Analysis, Increase (Decrease) in Expected Credit Loss Due to Changes in Assumptions", "terseLabel": "Adjustment to ECL based on probability weighted scenario" } } }, "localname": "SensitivityAnalysisIncreaseDecreaseInExpectedCreditLossDueToChangesInAssumptions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesSensitivityAnalysisDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ServicesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for services.", "label": "Services [Member]", "terseLabel": "Services" } } }, "localname": "ServicesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_SetoffOfDeferredTaxAssetsAndDeferredTaxLiabilities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails": { "order": 2.0, "parentTag": "ifrs-full_NetDeferredTaxAssets", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails": { "order": 2.0, "parentTag": "ifrs-full_NetDeferredTaxLiabilities", "weight": -1.0 } }, "lang": { "en-us": { "role": { "documentation": "The amount of set-off of deferred tax assets and deferred tax liabilities.", "label": "Setoff of Deferred Tax Assets and Deferred Tax Liabilities", "negatedLabel": "Set-off of deferred tax assets and deferred tax liabilities" } } }, "localname": "SetoffOfDeferredTaxAssetsAndDeferredTaxLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SettlementAndClearingBalances": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails": { "order": 7.0, "parentTag": "ifrs-full_OtherFinancialLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of settlement and clearing balances.", "label": "Settlement and Clearing Balances", "terseLabel": "Settlement and clearing balances" } } }, "localname": "SettlementAndClearingBalances", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOtherFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ShareBasedPaymentArrangementAverageCashReturnOnEquityPerformancePeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the average cash return on equity performance period under the share-based payment arrangement.", "label": "Share Based Payment Arrangement, Average Cash Return on Equity, Performance Period", "terseLabel": "Performance period, average cash Return on Equity" } } }, "localname": "ShareBasedPaymentArrangementAverageCashReturnOnEquityPerformancePeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "durationItemType" }, "wbk_ShareBasedPaymentsReserveAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition is available.", "label": "Share-based Payments Reserve [Abstract]", "terseLabel": "Share-based payment reserve" } } }, "localname": "ShareBasedPaymentsReserveAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareholdersEquityReconciliationOfMovementInReservesDetails" ], "xbrltype": "stringItemType" }, "wbk_ShareCapitalAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Share Capital [Abstract]", "terseLabel": "Share capital:" } } }, "localname": "ShareCapitalAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "stringItemType" }, "wbk_ShareOptionsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Share Options [Abstract]", "terseLabel": "Share options" } } }, "localname": "ShareOptionsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "stringItemType" }, "wbk_ShareOptionsAndShareRightsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to share options and share rights.", "label": "Share Options And Share Rights [Member]", "terseLabel": "Share options and share rights" } } }, "localname": "ShareOptionsAndShareRightsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails" ], "xbrltype": "domainItemType" }, "wbk_ShareRightsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for share rights, an equity-settled share-based payment arrangement as defined in the plan agreement.", "label": "Share Rights [Member]", "terseLabel": "Share rights" } } }, "localname": "ShareRightsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_SharebasedPaymentArrangementAverageNumberOfSharesAllocatedPerParticipant": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the average number of shares allocated per participant under the sharebased payment arrangement.", "label": "Sharebased Payment Arrangement, Average Number Of Shares Allocated Per Participant", "terseLabel": "Average number of shares allocated per participant" } } }, "localname": "SharebasedPaymentArrangementAverageNumberOfSharesAllocatedPerParticipant", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails" ], "xbrltype": "sharesItemType" }, "wbk_SharebasedPaymentArrangementCostOfSharesAllocated": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The cost of shares allocated.", "label": "Share-Based Payment Arrangement, Cost of Shares Allocated", "terseLabel": "Cost of shares allocated" } } }, "localname": "SharebasedPaymentArrangementCostOfSharesAllocated", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SharebasedPaymentArrangementFairValueAssumptionsDividendYield": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of an expected dividend used to calculate the fair value of share options granted.", "label": "Sharebased Payment Arrangement, Fair Value Assumptions, Dividend Yield", "terseLabel": "Dividend yield" } } }, "localname": "SharebasedPaymentArrangementFairValueAssumptionsDividendYield", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsFairValueAssumptionsDetails" ], "xbrltype": "percentItemType" }, "wbk_SharebasedPaymentArrangementHoldingLockPeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the holding lock period under the sharebased payment arrangement.", "label": "Share-Based Payment Arrangement, Holding Lock Period", "terseLabel": "Holding lock period" } } }, "localname": "SharebasedPaymentArrangementHoldingLockPeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "durationItemType" }, "wbk_SharebasedPaymentArrangementMarketPricePerShare": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The market price per share under the sharebased payment arrangement.", "label": "Sharebased Payment Arrangement, Market Price Per Share", "terseLabel": "Market price per share" } } }, "localname": "SharebasedPaymentArrangementMarketPricePerShare", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails" ], "xbrltype": "perShareItemType" }, "wbk_SharebasedPaymentArrangementNumberOfParticipants": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the number of participants under the sharebased payment arrangement.", "label": "Sharebased Payment Arrangement, Number Of Participants", "terseLabel": "Number of participants" } } }, "localname": "SharebasedPaymentArrangementNumberOfParticipants", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails" ], "xbrltype": "integerItemType" }, "wbk_SharebasedPaymentArrangementPerformancePeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the performance period under the sharebased payment arrangement.", "label": "Share-Based Payment Arrangement, Performance Period", "terseLabel": "Performance period" } } }, "localname": "SharebasedPaymentArrangementPerformancePeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "durationItemType" }, "wbk_SharebasedPaymentArrangementServiceConditionShareRetentionPeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the share retention period under the sharebased payment arrangement.", "label": "Share-Based Payment Arrangement, Service Condition Share Retention Period", "terseLabel": "Service conditions" } } }, "localname": "SharebasedPaymentArrangementServiceConditionShareRetentionPeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "durationItemType" }, "wbk_SharebasedPaymentArrangementTotalFairValueOfSharesGranted": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of fair value of shares allocated under the sharebased payment arrangement.", "label": "Sharebased Payment Arrangement, Total Fair Value Of Shares Granted", "terseLabel": "Total fair value" } } }, "localname": "SharebasedPaymentArrangementTotalFairValueOfSharesGranted", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsEmployeeSharePlanDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SharebasedPaymentArrangementVestingPeriod": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Share-Based Payment Arrangement, Vesting Period", "terseLabel": "Vesting period" } } }, "localname": "SharebasedPaymentArrangementVestingPeriod", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "durationItemType" }, "wbk_ShareholdersEquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Shareholders' equity [Abstract]", "terseLabel": "Shareholders' equity" } } }, "localname": "ShareholdersEquityAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_SharesIssuedToSatisfy2021DividendReinvestmentPlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for shares issued to satisfy Dividend Reinvestment Plan for the 2021 final ordinary dividend.", "label": "Shares Issued To Satisfy2021 Dividend Reinvestment Plan [Member]", "terseLabel": "Shares Issued to satisfy DRP for 2021 final ordinary dividend" } } }, "localname": "SharesIssuedToSatisfy2021DividendReinvestmentPlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSubsequentEventsDetails" ], "xbrltype": "domainItemType" }, "wbk_SharesIssuedToSatisfyDividendReinvestmentPlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for shares issued to satisfy the Dividend Reinvestment Plan (DRP) for the 2020 final ordinary dividend.", "label": "Shares Issued To Satisfy Dividend Reinvestment Plan [Member]", "terseLabel": "Shares Issued to satisfy DRP for 2020 final ordinary dividend" } } }, "localname": "SharesIssuedToSatisfyDividendReinvestmentPlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDividendsDetails" ], "xbrltype": "domainItemType" }, "wbk_SignificantAssumptionsUsedInRecoverableAmountForGoodwillAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Significant Assumptions Used in Recoverable Amount for Goodwill [Abstract]", "terseLabel": "Significant assumptions used in recoverable amount for goodwill" } } }, "localname": "SignificantAssumptionsUsedInRecoverableAmountForGoodwillAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "stringItemType" }, "wbk_SimonPowerMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Simon Power.", "label": "Simon Power [Member]", "terseLabel": "Simon Power" } } }, "localname": "SimonPowerMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureRelatedPartyDisclosuresOptionsAndShareRightsHoldingsDetails" ], "xbrltype": "domainItemType" }, "wbk_SixMonthUsLiborMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for 6 month US$ LIBOR.", "label": "Six Month Us Libor [Member]", "terseLabel": "6 month US$ LIBOR" } } }, "localname": "SixMonthUsLiborMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_SizeOfStructuredEntities": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Represented either by the total assets or market capitalisation of the entity, or if not available, the Group's total committed exposure (for lending arrangements and external debt and equity holdings), funds under management (for Group managed funds) or the total value of notes on issue (for investments in third-party asset-backed securities).", "label": "Size of Structured Entities", "terseLabel": "Size of structured entities" } } }, "localname": "SizeOfStructuredEntities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SoftwareMaintenanceAndLicencesExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 4.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from software maintenance and licences.", "label": "Software Maintenance and Licences Expense", "terseLabel": "Software maintenance and licences" } } }, "localname": "SoftwareMaintenanceAndLicencesExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_SoftwareServiceArrangementsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Software-as-a-Service (SaaS) arrangements.", "label": "Software Service Arrangements [Member]", "terseLabel": "Software-as-a-Service (SaaS) arrangements" } } }, "localname": "SoftwareServiceArrangementsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationChangesInAccountingPolicyDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "domainItemType" }, "wbk_SouthAustraliaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of South Australia.", "label": "South Australia [Member]", "terseLabel": "South Australia" } } }, "localname": "SouthAustraliaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_SpecialistBusinessesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to operating segment \"Specialist Businesses\" which includes Wealth Platforms, Superannuation and Retirement Products, Investments, Insurance, Auto Finance and Westpac Pacific.", "label": "Specialist Businesses [Member]", "terseLabel": "Specialist Businesses" } } }, "localname": "SpecialistBusinessesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_StageOneMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The member represents the stage one status in analysis of credit impairment, for financial assets where there has been no significant increase in credit risk since origination.", "label": "Stage One [Member]", "terseLabel": "Performing - Stage 1" } } }, "localname": "StageOneMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_StageThreeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The member represents the stage three status in analysis of credit impairment, for financial assets that are non-performing.", "label": "Stage Three [Member]", "terseLabel": "Non-performing - Stage 3" } } }, "localname": "StageThreeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_StageTwoMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The member represents the stage two status in analysis of credit impairment, for financial assets where there has been a significant increase in credit risk since origination but where the asset is still performing.", "label": "Stage Two [Member]", "terseLabel": "Performing - Stage 2" } } }, "localname": "StageTwoMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesImpactOfChangesInCreditExposuresOnProvisionForEclDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesLoansAndCreditCommitmentsDetails", "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMovementInProvisionForEclOnLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_StockBorrowingArrangements": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of expense related to stock borrowing arrangements.", "label": "Stock Borrowing Arrangements", "terseLabel": "Stock borrowing arrangements" } } }, "localname": "StockBorrowingArrangements", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOffsettingFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_StockIssuedDuringPeriodValueDividendReinvestmentPlanUnderwritersOption": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity": { "order": 4.0, "parentTag": "ifrs-full_ChangesInEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Value of stock issued during the period from a dividend reinvestment plan (DRIP) to underwriters.", "label": "Stock Issued During Period, Value, Dividend Reinvestment Plan, Underwriters Option", "terseLabel": "Dividend reinvestment plan underwrite" } } }, "localname": "StockIssuedDuringPeriodValueDividendReinvestmentPlanUnderwritersOption", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "monetaryItemType" }, "wbk_StrongCreditGradeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for strong credit grade.", "label": "Strong Credit Grade [Member]", "terseLabel": "Strong" } } }, "localname": "StrongCreditGradeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_StructuredNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for structured notes, which are debt securities issued by financial institutions with return is based on equity indexes, a single equity, a basket of equities, interest rates, commodities or foreign currencies.", "label": "Structured Notes [Member]", "terseLabel": "Structured notes" } } }, "localname": "StructuredNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesSummaryOfBalancesDetails" ], "xbrltype": "domainItemType" }, "wbk_SubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for subordinated notes.", "label": "Subordinated Notes [Member]", "terseLabel": "Subordinated notes" } } }, "localname": "SubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_SubordinatedPerpetualNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for subordinated perpetual notes.", "label": "Subordinated Perpetual Notes [Member]", "terseLabel": "Subordinated perpetual notes" } } }, "localname": "SubordinatedPerpetualNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_SummaryOfChangeInNetInterestIncomeTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the change in net interest income from year to year.", "label": "Summary Of Change In Net Interest Income [Table Text Block]", "terseLabel": "Summary of change in net interest income" } } }, "localname": "SummaryOfChangeInNetInterestIncomeTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesTables" ], "xbrltype": "textBlockItemType" }, "wbk_SummaryOfKeyMacroeconomicAssumptionsTableTextBlock": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Tabular disclosure of the key macroeconomic assumptions used in scenario forecasting.", "label": "Summary of Key Macroeconomic Assumptions [Table Text Block]", "terseLabel": "Summary of key macroeconomic assumptions for base case scenario" } } }, "localname": "SummaryOfKeyMacroeconomicAssumptionsTableTextBlock", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesTables" ], "xbrltype": "textBlockItemType" }, "wbk_SupplementalCashFlowStatementDisclosuresLineItems": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.", "label": "Supplemental Cash Flow Statement Disclosures [Line Items]", "terseLabel": "Notes to the consolidated cash flow statement" } } }, "localname": "SupplementalCashFlowStatementDisclosuresLineItems", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "stringItemType" }, "wbk_SupplementalCashFlowStatementDisclosuresTable": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Schedule disclosing supplemental cash flow statement information.", "label": "Supplemental Cash Flow Statement Disclosures [Table]" } } }, "localname": "SupplementalCashFlowStatementDisclosuresTable", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsCashAndBalancesWithCentralBanksAndRestrictedCashDetails", "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsNonCashFinancingActivitiesAndRestrictedCashDetails" ], "xbrltype": "stringItemType" }, "wbk_TargetCommonEquityTierOneRiskBasedCapitalForCapitalAdequacyToRiskWeightedAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The target Tier one Capital ratio requirement for minimum reserves.", "label": "Target Common Equity Tier One Risk Based Capital For Capital Adequacy To Risk Weighted Assets", "terseLabel": "Target Common Equity Tier 1 (CET1)" } } }, "localname": "TargetCommonEquityTierOneRiskBasedCapitalForCapitalAdequacyToRiskWeightedAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_TasmaniaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of Tasmania.", "label": "Tasmania [Member]", "terseLabel": "Tasmania" } } }, "localname": "TasmaniaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_TaxEffectAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Tax Effect [Abstract]", "terseLabel": "The effect of amounts which are not deductible/(assessable) in calculating taxable income" } } }, "localname": "TaxEffectAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "stringItemType" }, "wbk_TaxEffectOfAdjustmentForLifeBusinessTaxRates": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 4.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to adjustment for life insurance business tax rates.", "label": "Tax Effect of Adjustment for Life Business Tax Rates", "terseLabel": "Life insurance: Adjustment for life business tax rates" } } }, "localname": "TaxEffectOfAdjustmentForLifeBusinessTaxRates", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TaxEffectOfDividendAdjustments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 5.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to dividend adjustments.", "label": "Tax Effect of Dividend Adjustments", "negatedLabel": "Dividend adjustments" } } }, "localname": "TaxEffectOfDividendAdjustments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TaxEffectOfHybridCapitalDistributions": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 2.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to hybrid capital distributions.", "label": "Tax Effect of Hybrid Capital Distributions", "terseLabel": "Hybrid capital distributions" } } }, "localname": "TaxEffectOfHybridCapitalDistributions", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TaxEffectOfTaxAdjustmentOnPolicyholderEarnings": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails": { "order": 3.0, "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to tax adjustment on life insurance policyholder earnings.", "label": "Tax Effect of Tax Adjustment on Policyholder Earnings", "terseLabel": "Life insurance: Tax adjustment on policyholder earnings" } } }, "localname": "TaxEffectOfTaxAdjustmentOnPolicyholderEarnings", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxExpenseDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TechnologyExpenses": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 3.0, "parentTag": "ifrs-full_OperatingExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The aggregate amount of technology-related expense.", "label": "Technology Expenses", "totalLabel": "Total technology expenses" } } }, "localname": "TechnologyExpenses", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TechnologyExpensesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Technology Expenses [Abstract]", "terseLabel": "Technology expenses" } } }, "localname": "TechnologyExpensesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "stringItemType" }, "wbk_TechnologyServicesExpense": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails": { "order": 3.0, "parentTag": "wbk_TechnologyExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of expense arising from technology services.", "label": "Technology Services Expense", "terseLabel": "Technology services" } } }, "localname": "TechnologyServicesExpense", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureOperatingExpensesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TemporaryDifferencesCashFlowHedgesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for differences between the carrying amount of cash flow hedges in the statement of financial position and its tax base.", "label": "Temporary Differences Cash Flow Hedges [Member]", "terseLabel": "Cash-flow hedges" } } }, "localname": "TemporaryDifferencesCashFlowHedgesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_TemporaryDifferencesDefinedBenefitMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for differences between the carrying amount of defined benefit in the statement of financial position and its tax base.", "label": "Temporary Differences Defined Benefit [Member]", "terseLabel": "Defined benefit" } } }, "localname": "TemporaryDifferencesDefinedBenefitMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_TemporaryDifferencesInvestmentSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for differences between the carrying amount of investment securities in the statement of financial position and its tax base.", "label": "Temporary Differences Investment Securities [Member]", "terseLabel": "Investment securities" } } }, "localname": "TemporaryDifferencesInvestmentSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_TemporaryDifferencesLeaseLiabilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for temporary tax differences related to lease liabilities.", "label": "Temporary Differences Lease Liabilities [Member]", "terseLabel": "Lease liabilities" } } }, "localname": "TemporaryDifferencesLeaseLiabilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_TemporaryDifferencesOtherProvisionsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for differences between the carrying amount of other provisions in the statement of financial position and its tax base.", "label": "Temporary Differences Other Provisions [Member]", "terseLabel": "Other provisions" } } }, "localname": "TemporaryDifferencesOtherProvisionsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_TemporaryDifferencesPropertyAndEquipmentMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for differences between the carrying amount of property and equipment in the statement of financial position and its tax base.", "label": "Temporary Differences Property And Equipment [Member]", "terseLabel": "Property and equipment" } } }, "localname": "TemporaryDifferencesPropertyAndEquipmentMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxAssetsDetails", "http://www.westpac.com.au/role/DisclosureIncomeTaxDeferredTaxLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_TermDepositsMoreThanUs100000": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "Amount of term deposit liabilities, in denominations of more than US$100,000.", "label": "Term Deposits, More than US$100,000", "terseLabel": "Term deposits in excess of insured amounts" } } }, "localname": "TermDepositsMoreThanUs100000", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TermFundingFacilityMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Term Funding Facility (TFF) issued by the Reserve Bank of Australia.", "label": "Term Funding Facility [Member]", "terseLabel": "Term Funding Facility (TFF)" } } }, "localname": "TermFundingFacilityMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "domainItemType" }, "wbk_TermLendingFacilityMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Term Lending Facility (TLF) issued by the Reserve Bank of New Zealand.", "label": "Term Lending Facility [Member]", "terseLabel": "Term Lending Facility (TLF)" } } }, "localname": "TermLendingFacilityMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "domainItemType" }, "wbk_TermOfAgreement": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The period of time for which an agreement is in effect.", "label": "Term of Agreement", "terseLabel": "Term of exclusive agreement" } } }, "localname": "TermOfAgreement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "durationItemType" }, "wbk_ThreeYearVestingPeriodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to three year vesting period.", "label": "Three Year Vesting Period [Member]", "terseLabel": "Three-year vesting period" } } }, "localname": "ThreeYearVestingPeriodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_ThresholdForCapitalisationForSoftwareDevelopmentCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The threshold amount for capitalisation for software development costs.", "label": "Threshold for Capitalisation for Software Development Costs", "terseLabel": "Threshold amount for capitalisation for software development costs" } } }, "localname": "ThresholdForCapitalisationForSoftwareDevelopmentCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialStatementsPreparationCriticalAccountingAssumptionsAndEstimatesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ThresholdPriceOfSharesAllocatedToEmployees": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Represents the threshold amount up to which shares are allocated free of cost per employee.", "label": "Threshold Price Of Shares Allocated to Employees", "terseLabel": "Threshold amount of shares allocated at free of cost per employee" } } }, "localname": "ThresholdPriceOfSharesAllocatedToEmployees", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TierOneCapitalSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Tier One capital securities.", "label": "Tier One Capital Securities [Member]", "terseLabel": "Tier 1 capital securities" } } }, "localname": "TierOneCapitalSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "domainItemType" }, "wbk_TierOneRiskBasedCapitalForMinimumReservesToRiskWeightedAssets": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The minimum Tier one Capital ratio required for minimum reserves purposes under the regulatory framework.", "label": "Tier One Risk Based Capital for Minimum Reserves to Risk Weighted Assets", "terseLabel": "Minimum requirement of Tier 1 capital ratio" } } }, "localname": "TierOneRiskBasedCapitalForMinimumReservesToRiskWeightedAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureCapitalAdequacyDetails" ], "xbrltype": "percentItemType" }, "wbk_TierTwoCapitalSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Tier 2 capital securities.", "label": "Tier Two Capital Securities [Member]", "terseLabel": "Tier 2 capital securities" } } }, "localname": "TierTwoCapitalSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "domainItemType" }, "wbk_TierTwoLoanCapitalMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Tier 2 loan capital.", "label": "Tier Two Loan Capital [Member]", "terseLabel": "Tier 2 loan capital" } } }, "localname": "TierTwoLoanCapitalMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalTables" ], "xbrltype": "domainItemType" }, "wbk_TimeBandCalendarYear2021Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of calendar year 2021.", "label": "Time Band Calendar Year2021 [Member]", "terseLabel": "Calendar year 2021" } } }, "localname": "TimeBandCalendarYear2021Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandCalendarYear2022Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of calendar year 2022.", "label": "Time Band Calendar Year2022 [Member]", "terseLabel": "Calendar year 2022" } } }, "localname": "TimeBandCalendarYear2022Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandCalendarYears2021And2022Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of calendar years 2021 and 2022.", "label": "Time Band Calendar Years2021 And2022 [Member]", "terseLabel": "Calendar years 2021 and 2022" } } }, "localname": "TimeBandCalendarYears2021And2022Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandDecember2021Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of December 2021.", "label": "Time Band December2021 [Member]", "terseLabel": "December 2021" } } }, "localname": "TimeBandDecember2021Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandDecember2022Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of December 2022.", "label": "Time Band December2022 [Member]", "terseLabel": "December 2022" } } }, "localname": "TimeBandDecember2022Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandFebruary2021Member": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of February 2021.", "label": "Time Band February2021 [Member]", "terseLabel": "February 2021" } } }, "localname": "TimeBandFebruary2021Member", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TimeBandRemainderOfCalendarYearMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for a time band of the remainder of the calendar year.", "label": "Time Band Remainder Of Calendar Year [Member]", "terseLabel": "December 2020" } } }, "localname": "TimeBandRemainderOfCalendarYearMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "domainItemType" }, "wbk_TotalAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Assets [Abstract]", "terseLabel": "Total assets" } } }, "localname": "TotalAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalConsiderationFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The total consideration received from the disposal of non-current assets or disposal groups classified as held for sale and discontinued operations, including cash proceeds and retained interest.", "label": "Total consideration from disposal of non-current assets or disposal groups classified as held for sale and discontinued operations", "totalLabel": "Total consideration" } } }, "localname": "TotalConsiderationFromDisposalOfNonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleAndDiscontinuedOperations", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsOtherDisclosuresForEntitiesOverWhichControlCeasedDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TotalDerivativesCarryingValueAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Derivatives Carrying Value, Assets [Abstract]", "terseLabel": "Total derivatives carrying value, Assets" } } }, "localname": "TotalDerivativesCarryingValueAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalDerivativesCarryingValueLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Derivatives Carrying Value, Liabilities [Abstract]", "terseLabel": "Total derivatives carrying value, Liabilities" } } }, "localname": "TotalDerivativesCarryingValueLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDerivativeFinancialInstrumentsCarryingValueOfDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalEquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Equity [Abstract]", "terseLabel": "Total equity" } } }, "localname": "TotalEquityAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalFundingAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Funding [Abstract]", "terseLabel": "Group's total funding" } } }, "localname": "TotalFundingAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalIntangibleAssetsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Intangible Assets [Abstract]", "terseLabel": "Total intangible assets" } } }, "localname": "TotalIntangibleAssetsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Liabilities [Abstract]", "terseLabel": "Total liabilities" } } }, "localname": "TotalLiabilitiesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalLiabilitiesAndEquityAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Total Liabilities and Equity [Abstract]", "terseLabel": "Total liabilities and equity" } } }, "localname": "TotalLiabilitiesAndEquityAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesLiabilitiesAndEquityDetails" ], "xbrltype": "stringItemType" }, "wbk_TotalPercentageOfLoanPortfolio": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of the loan portfolio covered by collateral held.", "label": "Total Percentage of Loan Portfolio", "terseLabel": "Secured loan to collateral value ratio (as a percent)" } } }, "localname": "TotalPercentageOfLoanPortfolio", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "percentItemType" }, "wbk_TradeAndOtherPayablesToRelatedPartiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 7.0, "parentTag": "wbk_LiabilitiesExcludingLoanCapitalBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of payables based on expected maturities due to related parties.", "label": "Trade And Other Payables To Related Parties, Based on Expected Maturities", "terseLabel": "Due to subsidiaries" } } }, "localname": "TradeAndOtherPayablesToRelatedPartiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TradeAndOtherReceivablesDueFromRelatedPartiesBasedOnExpectedMaturities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 9.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of receivables based on expected maturities due from related parties.", "label": "Trade And Other Receivables, Due From Related Parties, Based On Expected Maturities", "terseLabel": "Due from subsidiaries" } } }, "localname": "TradeAndOtherReceivablesDueFromRelatedPartiesBasedOnExpectedMaturities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TradeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for trade.", "label": "Trade [Member]", "terseLabel": "Trade" } } }, "localname": "TradeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_TradedMarketRiskAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Traded Market Risk [Abstract]", "terseLabel": "Traded market risk" } } }, "localname": "TradedMarketRiskAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskTradedMarketRiskDetails" ], "xbrltype": "stringItemType" }, "wbk_TradingOtherDebtSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for debt securities other than government and semi-government securities, held by the entity and classified as trading.", "label": "Trading Other Debt Securities [Member]", "terseLabel": "Other debt securities" } } }, "localname": "TradingOtherDebtSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesBalancesRecognisedDetails", "http://www.westpac.com.au/role/DisclosureInvestmentSecuritiesMaturitiesDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "domainItemType" }, "wbk_TradingSecuritiesAndFinancialAssetsBasedOnExpectedMaturitiesMeasuredAtFairValueThroughIncomeStatement": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails": { "order": 3.0, "parentTag": "wbk_FinancialAssetsBasedOnExpectedMaturities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Trading securities and financial assets based on expected maturities, measured at fair value through income statement (FVIS).", "label": "Trading Securities And Financial Assets, Based On Expected Maturities, Measured At Fair Value Through Income Statement", "terseLabel": "Trading securities and financial assets measured at FVIS" } } }, "localname": "TradingSecuritiesAndFinancialAssetsBasedOnExpectedMaturitiesMeasuredAtFairValueThroughIncomeStatement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskExpectedMaturityOfFinancialAssetsAndFinancialLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TradingSecuritiesAndFinancialAssetsDesignatedAtFairValueMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for trading securities and other financial assets designated at fair value through profit or loss.", "label": "Trading Securities And Financial Assets Designated At Fair Value [Member]", "terseLabel": "Trading securities and financial assets measured at FVIS" } } }, "localname": "TradingSecuritiesAndFinancialAssetsDesignatedAtFairValueMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesAssetsDetails", "http://www.westpac.com.au/role/DisclosureAverageBalanceSheetAndInterestRatesVariancesDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesHierarchyDetails", "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditConcentrationsForEachSignificantClassOfFinancialAssetDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskLiquidAssetsDetails", "http://www.westpac.com.au/role/DisclosureStructuredEntitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatement": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://www.westpac.com.au/role/StatementBalanceSheets": { "order": 3.0, "parentTag": "ifrs-full_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Trading securities and financial assets measured at fair value through income statement (FVIS).", "label": "Trading Securities And Financial Assets Measured At Fair Value Through Income Statement", "terseLabel": "Trading securities and financial assets measured at fair value through income statement (FVIS)", "totalLabel": "Total trading securities and financial assets measured at FVIS", "verboseLabel": "Trading securities and other financial assets measured at FVIS" } } }, "localname": "TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatement", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNotesToCashFlowStatementsAssetsAndLiabilitiesOverWhichControlCeasedDetails", "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails", "http://www.westpac.com.au/role/StatementBalanceSheets" ], "xbrltype": "monetaryItemType" }, "wbk_TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Trading securities and financial assets measured at FVIS" } } }, "localname": "TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatementAbstract", "nsuri": "http://www.westpac.com.au/20210930", "xbrltype": "stringItemType" }, "wbk_TradingSecuritiesClassifiedAsOtherMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for trading securities classified as other", "label": "Trading Securities Classified As Other [Member]", "terseLabel": "Other" } } }, "localname": "TradingSecuritiesClassifiedAsOtherMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "domainItemType" }, "wbk_TradingSecuritiesDebtAndEquitySecurities": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails": { "order": 1.0, "parentTag": "wbk_TradingSecuritiesAndFinancialAssetsMeasuredAtFairValueThroughIncomeStatement", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "Actively traded debt (government and other) and equity instruments and those acquired for sale in the near term.", "label": "Trading Securities, Debt And Equity Securities", "terseLabel": "Trading securities" } } }, "localname": "TradingSecuritiesDebtAndEquitySecurities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureTradingSecuritiesAndFinancialAssetsMeasuredAtFvisDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TransactionsInCapacityAsEquityholdersAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Transactions in Capacity as Equityholders [Abstract]", "terseLabel": "Transactions in capacity as equity holders" } } }, "localname": "TransactionsInCapacityAsEquityholdersAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfChangesInEquity" ], "xbrltype": "stringItemType" }, "wbk_TransferredToIncomeStatementAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Transferred to income statements:" } } }, "localname": "TransferredToIncomeStatementAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/StatementStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "wbk_TransferredToPurchaserOnSettlementOfAssetsAndLiabilitiesHeldForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The decrease in provisions due to transfers to purchaser on settlement of assets and liabilities held for sale.", "label": "Transferred to Purchaser on Settlement of Assets and Liabilities Held for Sale", "negatedLabel": "Transferred to purchaser on settlement of assets and liabilities held for sale" } } }, "localname": "TransferredToPurchaserOnSettlementOfAssetsAndLiabilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsMovementsInProvisionsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TransfersIntoAndOutOfLevel3OfFairValueHierarchyAssets": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of transfers of assets into and out of Level 3 of the fair value hierarchy.", "label": "Transfers Into And Out Of Level 3 Of Fair Value Hierarchy, Assets", "terseLabel": "Transfer into or out of non-market observables" } } }, "localname": "TransfersIntoAndOutOfLevel3OfFairValueHierarchyAssets", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TransfersIntoAndOutOfLevel3OfFairValueHierarchyLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of transfers of liabilities into and out of Level 3 of the fair value hierarchy.", "label": "Transfers Into And Out Of Level 3 Of Fair Value Hierarchy, Liabilities", "terseLabel": "Transfer into or out of non-market observables" } } }, "localname": "TransfersIntoAndOutOfLevel3OfFairValueHierarchyLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFairValuesOfFinancialAssetsAndFinancialLiabilitiesReconciliationOfNonMarketObservablesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_TransportAndStorageMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for transport and storage.", "label": "Transport And Storage [Member]", "terseLabel": "Transport and storage" } } }, "localname": "TransportAndStorageMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_TwoYearVestingPeriodMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to two year vesting period.", "label": "Two Year Vesting Period [Member]", "terseLabel": "Two-year vesting period" } } }, "localname": "TwoYearVestingPeriodMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_UndrawnCreditCommitments": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails": { "order": 3.0, "parentTag": "ifrs-full_MaximumExposureToCreditRisk", "weight": 1.0 }, "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of undrawn credit commitments.", "label": "Undrawn Credit Commitments", "terseLabel": "Undrawn credit commitments", "totalLabel": "Total undrawn credit commitments" } } }, "localname": "UndrawnCreditCommitments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails", "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_UndrawnCreditCommitmentsAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Undrawn Credit Commitments [Abstract]", "terseLabel": "Undrawn credit commitments" } } }, "localname": "UndrawnCreditCommitmentsAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "stringItemType" }, "wbk_UndrawnCreditCommitmentsClassifiedAsHeldForSaleMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for undrawn credit commitments classified as held for sale.", "label": "Undrawn Credit Commitments Classified As Held For Sale [Member]", "terseLabel": "Undrawn credit commitments classified as held for sale" } } }, "localname": "UndrawnCreditCommitmentsClassifiedAsHeldForSaleMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_UndrawnCreditCommitmentsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for undrawn credit commitments.", "label": "Undrawn Credit Commitments [Member]", "terseLabel": "Undrawn credit commitments" } } }, "localname": "UndrawnCreditCommitmentsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails", "http://www.westpac.com.au/role/DisclosureFinancialRiskNonPerformingLoansAndCreditCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_UndrawnCreditCommitmentsNotionalAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The notional amount of undrawn credit commitments.", "label": "Undrawn Credit Commitments, Notional Amount", "terseLabel": "Undrawn credit commitments (Notional contractual amount)" } } }, "localname": "UndrawnCreditCommitmentsNotionalAmount", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskInterestRateBenchmarkReformNonDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "wbk_UndrawnCreditCommitmentsRelatedToFacilitiesHeldForSale": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of undrawn credit commitments related to facilities held for sale.", "label": "Undrawn Credit Commitments Related to Facilities Held for Sale", "terseLabel": "Undrawn credit commitments related to facilities held for sale" } } }, "localname": "UndrawnCreditCommitmentsRelatedToFacilitiesHeldForSale", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsUndrawnCreditCommitmentsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_UndrawnFundingAndLiquidityFacilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of undrawn funding and liquidity facilities.", "label": "Undrawn Funding and Liquidity Facilities", "terseLabel": "Undrawn funding and liquidity facilities" } } }, "localname": "UndrawnFundingAndLiquidityFacilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSecuritisationCoveredBondsAndOtherTransferredAssetsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_UninsuredInterbankDepositsIncludedInOtherFinancialLiabilities": { "auth_ref": [], "crdr": "credit", "lang": { "en-us": { "role": { "documentation": "The amount of interbank deposits in excess of the insured amount that are included in other financial liabilities.", "label": "Uninsured Interbank Deposits Included in Other Financial Liabilities", "terseLabel": "Interbank term deposits in excess of insured amounts" } } }, "localname": "UninsuredInterbankDepositsIncludedInOtherFinancialLiabilities", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDepositsAndOtherBorrowingsCertificatesOfDepositAndTermDepositsDetails" ], "xbrltype": "monetaryItemType" }, "wbk_UnitTrustsMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for unit trusts.", "label": "Unit Trusts [Member]", "terseLabel": "Unit Trusts" } } }, "localname": "UnitTrustsMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLifeInsuranceAssetsAndLifeInsuranceLiabilitiesAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_UnrecognisedDeferredTaxBalancesAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "n/a", "label": "Unrecognised Deferred Tax Balances [Abstract]", "terseLabel": "Unrecognised deferred tax balances" } } }, "localname": "UnrecognisedDeferredTaxBalancesAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIncomeTaxUnrecognisedDeferredTaxBalancesDetails" ], "xbrltype": "stringItemType" }, "wbk_UnsecuredLoansMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for loans for which the secured loan to collateral value ratio is greater than 150%, or no security held (e.g. can include credit cards, personal loans, and exposure to highly rated corporate entities).", "label": "Unsecured Loans [Member]", "terseLabel": "Unsecured" } } }, "localname": "UnsecuredLoansMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCollateralHeldDetails" ], "xbrltype": "domainItemType" }, "wbk_UpsideScenarioMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the upside scenario.", "label": "Upside Scenario [Member]", "terseLabel": "Upside scenario" } } }, "localname": "UpsideScenarioMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesMacroeconomicScenarioWeightingsDetails" ], "xbrltype": "domainItemType" }, "wbk_Us1250MillionAdditionalTierOneSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$1,250 million additional tier one securities.", "label": "Us1250 Million Additional Tier One Securities [Member]", "terseLabel": "USD 1,250 million securities" } } }, "localname": "Us1250MillionAdditionalTierOneSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_UsCommercialPaperMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the entity's own issuances of US commercial paper.", "label": "Us Commercial Paper [Member]", "terseLabel": "US commercial paper" } } }, "localname": "UsCommercialPaperMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureDebtIssuesByCurrencyDetails" ], "xbrltype": "domainItemType" }, "wbk_UsdAdditionalTierOneSecuritiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for USD additional tier one securities.", "label": "Usd Additional Tier One Securities [Member]", "terseLabel": "USD AT1 securities" } } }, "localname": "UsdAdditionalTierOneSecuritiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_UtilitiesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for utilities.", "label": "Utilities [Member]", "terseLabel": "Utilities" } } }, "localname": "UtilitiesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditRiskByIndustryDetails" ], "xbrltype": "domainItemType" }, "wbk_ValuationAssumptionEconomicForecastCaseRateInBasisPoints": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The case rate basis points used as a valuation assumption in an economic forecast.", "label": "Valuation Assumption, Economic Forecast, Case Rate, In Basis Points", "terseLabel": "Cash rate, basis points" } } }, "localname": "ValuationAssumptionEconomicForecastCaseRateInBasisPoints", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "integerItemType" }, "wbk_ValuationAssumptionEconomicForecastPercentageOfGdpGrowthContraction": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of GDP growth (contraction) used as a valuation assumption in an economic forecast.", "label": "Valuation Assumption, Economic Forecast, Percentage of GDP Growth (Contraction)", "terseLabel": "Annual GDP, percentage of forecast growth (contraction)" } } }, "localname": "ValuationAssumptionEconomicForecastPercentageOfGdpGrowthContraction", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesModelledProvisionForEclDetails" ], "xbrltype": "percentItemType" }, "wbk_ValueAtRiskForInterestRateRiskInBankingBooks": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The measure of a potential loss exposure as a result of future market movements, based on a specified confidence interval and measurement horizon.", "label": "Value at Risk for Interest Rate Risk in Banking Books", "terseLabel": "Value at Risk - IRBBB" } } }, "localname": "ValueAtRiskForInterestRateRiskInBankingBooks", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "monetaryItemType" }, "wbk_ValueAtRiskIrrbbAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Value at Risk - IRRBB [Abstract]", "terseLabel": "Value at Risk - IRRBB" } } }, "localname": "ValueAtRiskIrrbbAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "stringItemType" }, "wbk_VarianceFromCurrentMarketYieldForNar": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of increase or decrease from current market yield curves used in modelling interest rate scenarios for Net interest income-at-risk.", "label": "Variance from Current Market Yield for NaR", "terseLabel": "Variance from current market yield used in modelling interest rate scenarios" } } }, "localname": "VarianceFromCurrentMarketYieldForNar", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskNonTradedMarketRiskDetails" ], "xbrltype": "decimalItemType" }, "wbk_VictoriaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of Victoria.", "label": "Victoria [Member]", "terseLabel": "Victoria" } } }, "localname": "VictoriaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_WeakCreditGradeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for weak credit grade.", "label": "Weak Credit Grade [Member]", "terseLabel": "Weak" } } }, "localname": "WeakCreditGradeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskCreditQualityOfFinancialAssetsDetails" ], "xbrltype": "domainItemType" }, "wbk_WealthManagementAndInsuranceIncomeAbstract": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "No definition available.", "label": "Wealth Management and Insurance Income [Abstract]", "verboseLabel": "Net wealth management and insurance income" } } }, "localname": "WealthManagementAndInsuranceIncomeAbstract", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "stringItemType" }, "wbk_WeighedAverageTreasuryShares": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 2.0, "parentTag": "ifrs-full_WeightedAverageShares", "weight": -1.0 } }, "lang": { "en-us": { "role": { "documentation": "The number of treasury shares held as of the beginning of the period, adjusted by the number of treasury shares acquired or re-issued during the period multiplied by a time-weighting factor.", "label": "Weighed Average Treasury Shares", "negatedLabel": "Treasury shares (including RSP share rights)" } } }, "localname": "WeighedAverageTreasuryShares", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "wbk_WeightedAverageCostOfCapital": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of weighted average cost of capital.", "label": "Weighted Average Cost of Capital", "terseLabel": "Group's equity rate" } } }, "localname": "WeightedAverageCostOfCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "percentItemType" }, "wbk_WeightedAverageMaturityPeriodForShortTermFundingPortfolio": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The weighted average period until maturity for the short-term funding portfolio.", "label": "Weighted Average Maturity Period for Short Term Funding Portfolio", "terseLabel": "Weighted average maturity period for short term funding portfolio" } } }, "localname": "WeightedAverageMaturityPeriodForShortTermFundingPortfolio", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureFinancialRiskFundingCompositionAndTermFundingFacilityDetails" ], "xbrltype": "durationItemType" }, "wbk_WeightedAveragePreTaxCostOfCapital": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of weighted average pre-tax cost of capital.", "label": "Weighted Average Pre Tax Cost of Capital", "terseLabel": "Group's adjusted pre-tax equity rate" } } }, "localname": "WeightedAveragePreTaxCostOfCapital", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "percentItemType" }, "wbk_WeightedAverageRemainingContractualLifeOfOtherEquityInstruments": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The weighted average remaining contractual life of other equity instruments.", "label": "Weighted Average Remaining Contractual Life Of Other Equity Instruments", "terseLabel": "Weighted average remaining contractual life" } } }, "localname": "WeightedAverageRemainingContractualLifeOfOtherEquityInstruments", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "durationItemType" }, "wbk_WeightedAverageSharesIssued": { "auth_ref": [], "calculation": { "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails": { "order": 1.0, "parentTag": "ifrs-full_WeightedAverageShares", "weight": 1.0 } }, "lang": { "en-us": { "role": { "documentation": "The number of ordinary shares issued as of the beginning of the period, adjusted by the number of ordinary shares cancelled or issued during the period multiplied by a time-weighting factor.", "label": "Weighted Average Shares Issued", "terseLabel": "Weighted average number of ordinary shares on issue" } } }, "localname": "WeightedAverageSharesIssued", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureEarningsPerShareDetails" ], "xbrltype": "sharesItemType" }, "wbk_WesternAustraliaMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to location of Western Australia.", "label": "Western Australia [Member]", "terseLabel": "Western Australia" } } }, "localname": "WesternAustraliaMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsContingentLiabilitiesContingentAssetsAndCreditCommitmentsProvisionsAndContingentLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "wbk_Westpac130MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$130 million subordinated notes.", "label": "Westpac130 Million Subordinated Notes [Member]", "terseLabel": "AUD 130 million subordinated notes" } } }, "localname": "Westpac130MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_Westpac185MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$185 million subordinated notes.", "label": "Westpac185 Million Subordinated Notes [Member]", "terseLabel": "AUD 185 million subordinated notes" } } }, "localname": "Westpac185MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_Westpac250MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$250 million subordinated notes.", "label": "Westpac250 Million Subordinated Notes [Member]", "terseLabel": "AUD 250 million subordinated notes" } } }, "localname": "Westpac250MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_Westpac725MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$725 million subordinated notes.", "label": "Westpac725 Million Subordinated Notes [Member]", "terseLabel": "AUD 725 million subordinated notes" } } }, "localname": "Westpac725MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacA175MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$175 million subordinated notes.", "label": "Westpac A175 Million Subordinated Notes [Member]", "terseLabel": "AUD 175 million subordinated notes" } } }, "localname": "WestpacA175MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacA350Million4.334PercentSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$350 million 4.334% subordinated notes.", "label": "Westpac A350 Million4.334 Percent Subordinated Notes [Member]", "terseLabel": "AUD 350 million 4.334% subordinated notes" } } }, "localname": "WestpacA350Million4.334PercentSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacA350Million4.5PercentSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$350 million 4.5% subordinated notes.", "label": "Westpac A350 Million4.5 Percent Subordinated Notes [Member]", "terseLabel": "AUD 350 million 4.50% subordinated notes" } } }, "localname": "WestpacA350Million4.5PercentSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacA700MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for A$700 million subordinated notes.", "label": "Westpac A700 Million Subordinated Notes [Member]", "terseLabel": "AUD 700 million subordinated notes" } } }, "localname": "WestpacA700MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacAud1000MillionSubordinatedFloatingRateNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for AUD$1,000 million Floating 90 day bank bill rate + 1.98% p.a. subordinated notes.", "label": "Westpac Aud1000 Million Subordinated Floating Rate Notes [Member]", "terseLabel": "AUD 1,000 million subordinated notes" } } }, "localname": "WestpacAud1000MillionSubordinatedFloatingRateNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacAud1250MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for AUD 1,250 million subordinated notes.", "label": "Westpac Aud1250 Million Subordinated Notes [Member]", "terseLabel": "AUD 1,250 million subordinated notes" } } }, "localname": "WestpacAud1250MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacAustralianLifeInsuranceBusinessMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Australian Life Insurance business.", "label": "Westpac Australian Life Insurance Business [Member]", "terseLabel": "Westpac Australian Life Insurance business" } } }, "localname": "WestpacAustralianLifeInsuranceBusinessMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacBankPNGLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Bank-PNG-Limited.", "label": "Westpac Bank P N G Limited [Member]", "terseLabel": "Westpac Bank-PNG-Limited" } } }, "localname": "WestpacBankPNGLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesEightMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Capital Notes 8.", "label": "Westpac Capital Notes Eight [Member]", "terseLabel": "AUD 1,750 million WCN8" } } }, "localname": "WestpacCapitalNotesEightMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesFiveMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac capital notes five.", "label": "Westpac Capital Notes Five [Member]", "terseLabel": "AUD 1,690 million WCN5" } } }, "localname": "WestpacCapitalNotesFiveMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesFourMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac capital notes four.", "label": "Westpac Capital Notes Four [Member]", "terseLabel": "AUD 1,702 million WCN4" } } }, "localname": "WestpacCapitalNotesFourMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Capital Notes.", "label": "Westpac Capital Notes [Member]", "terseLabel": "Westpac capital notes (WCN)" } } }, "localname": "WestpacCapitalNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails", "http://www.westpac.com.au/role/DisclosureLoanCapitalSummaryDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesSevenMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Capital Notes 7.", "label": "Westpac Capital Notes Seven [Member]", "terseLabel": "AUD 1,723 million WCN7" } } }, "localname": "WestpacCapitalNotesSevenMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesSixMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac capital notes six.", "label": "Westpac Capital Notes Six [Member]", "terseLabel": "AUD 1,423 million WCN6" } } }, "localname": "WestpacCapitalNotesSixMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesThreeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac capital notes three.", "label": "Westpac Capital Notes Three [Member]", "terseLabel": "AUD 1,324 million WCN3" } } }, "localname": "WestpacCapitalNotesThreeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacCapitalNotesTwoMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac capital notes two.", "label": "Westpac Capital Notes Two [Member]", "terseLabel": "AUD 1,311 million WCN2" } } }, "localname": "WestpacCapitalNotesTwoMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalAdditionalTier1LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacEur1000MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for EUR 1,000 million subordinated notes.", "label": "Westpac Eur1000 Million Subordinated Notes [Member]", "terseLabel": "EUR 1,000 million subordinated notes" } } }, "localname": "WestpacEur1000MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacGeneralInsuranceLimitedAndWestpacGeneralInsuranceServicesLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac General Insurance Limited and Westpac General Insurance Services Limited.", "label": "Westpac General Insurance Limited And Westpac General Insurance Services Limited [Member]", "terseLabel": "Westpac General Insurance Limited and Westpac General Insurance Services Limited" } } }, "localname": "WestpacGeneralInsuranceLimitedAndWestpacGeneralInsuranceServicesLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacGroupPlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to Westpac Group plan.", "label": "Westpac Group Plan [Member]", "terseLabel": "Westpac Group Plan" } } }, "localname": "WestpacGroupPlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacInstitutionalBankMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Westpac Institutional Bank reportable segment.", "label": "Westpac Institutional Bank [Member]", "terseLabel": "Westpac Institutional Bank" } } }, "localname": "WestpacInstitutionalBankMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsBalancesDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsGoodwillAllocationToCgusDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails", "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJkd600MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for HKD600 million subordinated notes.", "label": "Westpac Jkd600 Million Subordinated Notes [Member]", "terseLabel": "HKD 600 million subordinated notes" } } }, "localname": "WestpacJkd600MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy10000MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY10,000 million subordinated notes.", "label": "Westpac Jpy10000 Million Subordinated Notes [Member]", "terseLabel": "JPY 10,000 million subordinated notes" } } }, "localname": "WestpacJpy10000MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy10200MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY10,200 million subordinated notes.", "label": "Westpac Jpy10200 Million Subordinated Notes [Member]", "terseLabel": "JPY 10,200 million subordinated notes" } } }, "localname": "WestpacJpy10200MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy12000MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY12,000 million subordinated notes.", "label": "Westpac Jpy12000 Million Subordinated Notes [Member]", "terseLabel": "JPY 12,000 million subordinated notes" } } }, "localname": "WestpacJpy12000MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy13500MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY13,500 million subordinated notes.", "label": "Westpac Jpy13500 Million Subordinated Notes [Member]", "terseLabel": "JPY 13,500 million subordinated notes" } } }, "localname": "WestpacJpy13500MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy20000MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY20,000 million subordinated notes.", "label": "Westpac Jpy20000 Million Subordinated Notes [Member]", "terseLabel": "JPY 20,000 million subordinated notes" } } }, "localname": "WestpacJpy20000MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacJpy8000MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for JPY8,000 million subordinated notes.", "label": "Westpac Jpy8000 Million Subordinated Notes [Member]", "terseLabel": "JPY 8,000 million subordinated notes" } } }, "localname": "WestpacJpy8000MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacLendersMortgageInsuranceLimitedAndWestpacInstitutionalBankMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Lenders Mortgage Insurance Limited and Westpac Institutional Bank.", "label": "Westpac Lenders Mortgage Insurance Limited And Westpac Institutional Bank [Member]", "terseLabel": "Westpac Lenders Mortgage Insurance Limited and Westpac Institutional Bank" } } }, "localname": "WestpacLendersMortgageInsuranceLimitedAndWestpacInstitutionalBankMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacLendersMortgageInsuranceLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Lenders Mortgage Insurance Limited.", "label": "Westpac Lenders Mortgage Insurance Limited [Member]", "terseLabel": "Westpac Lenders Mortgage Insurance Limited" } } }, "localname": "WestpacLendersMortgageInsuranceLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails", "http://www.westpac.com.au/role/DisclosureIntangibleAssetsImpairmentTestingDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacLongTermIncentivePlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to Westpac long term incentive plan.", "label": "Westpac Long Term Incentive Plan [Member]", "terseLabel": "Westpac Long Term Variable Reward Plan (LTVR)" } } }, "localname": "WestpacLongTermIncentivePlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNZCoveredBondLimitedAndWestpacNZSecuritisationLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac NZ Covered Bond Limited (WNZCBL) and Westpac NZ Securitisation Limited (WNZSL).", "label": "Westpac N Z Covered Bond Limited And Westpac N Z Securitisation Limited [Member]", "terseLabel": "Westpac NZ Covered Bond Limited (WNZCBL) and Westpac NZ Securitisation Limited (WNZSL)" } } }, "localname": "WestpacNZCoveredBondLimitedAndWestpacNZSecuritisationLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNZCoveredBondLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac NZ Covered Bond Limited.", "label": "Westpac N Z Covered Bond Limited [Member]", "terseLabel": "Westpac NZ Covered Bond Limited" } } }, "localname": "WestpacNZCoveredBondLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNZSecuritisationLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac NZ Securitisation Limited.", "label": "Westpac N Z Securitisation Limited [Member]", "terseLabel": "Westpac NZ Securitisation Limited" } } }, "localname": "WestpacNZSecuritisationLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNewZealandLifeInsuranceBusinessMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac New Zealand Life Insurance business.", "label": "Westpac New Zealand Life Insurance Business [Member]", "terseLabel": "Westpac New Zealand Life Insurance business" } } }, "localname": "WestpacNewZealandLifeInsuranceBusinessMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNewZealandLimitedMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac New Zealand Limited (WNZL).", "label": "Westpac New Zealand Limited [Member]", "terseLabel": "WNZL" } } }, "localname": "WestpacNewZealandLimitedMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureInvestmentsInSubsidiariesAndAssociatesDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNewZealandMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for the Westpac New Zealand reportable segment.", "label": "Westpac New Zealand [Member]", "terseLabel": "Westpac New Zealand" } } }, "localname": "WestpacNewZealandMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSegmentReportingSegmentResultsDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNewZealandSuperannuationSchemeMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents information pertaining to Westpac New Zealand Superannuation Scheme.", "label": "Westpac New Zealand Superannuation Scheme [Member]", "terseLabel": "Westpac New Zealand Superannuation Scheme" } } }, "localname": "WestpacNewZealandSuperannuationSchemeMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureSuperannuationCommitmentsDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacNz400MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for NZ$400 million subordinated notes.", "label": "Westpac Nz400 Million Subordinated Notes [Member]", "terseLabel": "NZD 400 million subordinated notes" } } }, "localname": "WestpacNz400MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacPacificMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Pacific.", "label": "Westpac Pacific [Member]", "terseLabel": "Westpac Pacific" } } }, "localname": "WestpacPacificMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacPerformancePlanMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "Represents the information pertaining to Westpac performance plan.", "label": "Westpac Performance Plan [Member]", "terseLabel": "Westpac Performance Plan (WPP)" } } }, "localname": "WestpacPerformancePlanMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsSummaryOfPlansDetails", "http://www.westpac.com.au/role/DisclosureShareBasedPaymentsWestpacLongTermIncentivePlanWestpacPerformancePlanWppRestrictedSharePlanRspDetails", "http://www.westpac.com.au/role/DisclosureShareholdersEquityShareCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacS325MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for S$325 million subordinated notes.", "label": "Westpac S325 Million Subordinated Notes [Member]", "terseLabel": "SGD 325 million subordinated notes" } } }, "localname": "WestpacS325MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUS1000MillionSubordinatedFixed4.421PercentNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$1,000 million Fixed 4.421% p.a. subordinated notes.", "label": "Westpac U S1000 Million Subordinated Fixed4.421 Percent Notes [Member]", "terseLabel": "USD 1,000 million 4.421% fixed rate subordinated notes" } } }, "localname": "WestpacUS1000MillionSubordinatedFixed4.421PercentNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUS1250MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$1,250 million subordinated notes.", "label": "Westpac U S1250 Million Subordinated Notes [Member]", "terseLabel": "USD 1,250 million subordinated notes" } } }, "localname": "WestpacUS1250MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUS1500Million2.894PercentSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$1,500 million 2.894% subordinated notes.", "label": "Westpac U S1500 Million2.894 Percent Subordinated Notes [Member]", "terseLabel": "USD 1500 million 2.894% subordinated notes" } } }, "localname": "WestpacUS1500Million2.894PercentSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUS1500Million4.322PercentSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$1,500 million 4.322% subordinated notes.", "label": "Westpac U S1500 Million4.322 Percent Subordinated Notes [Member]", "terseLabel": "USD 1500 million 4.322% subordinated notes" } } }, "localname": "WestpacUS1500Million4.322PercentSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUs100MillionSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for US$100 million subordinated notes.", "label": "Westpac Us100 Million Subordinated Notes [Member]", "terseLabel": "USD 100 million subordinated notes" } } }, "localname": "WestpacUs100MillionSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUsd1000MillionSubordinatedNotesFixedRate2.963PercentMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for USD 1,000 million subordinated notes at fixed rate of 2.963%.", "label": "Westpac Usd1000 Million Subordinated Notes Fixed Rate2.963 Percent [Member]", "terseLabel": "USD 1,000 million 2.963% fixed rate subordinated notes" } } }, "localname": "WestpacUsd1000MillionSubordinatedNotesFixedRate2.963PercentMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacUsd1500Million2.668PercentSubordinatedNotesMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for USD 1,500 million 2.668% subordinated notes.", "label": "Westpac Usd1500 Million2.668 Percent Subordinated Notes [Member]", "terseLabel": "USD 1500 million 2.668% subordinated notes" } } }, "localname": "WestpacUsd1500Million2.668PercentSubordinatedNotesMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureLoanCapitalTier2LoanCapitalDetails" ], "xbrltype": "domainItemType" }, "wbk_WestpacVendorFinanceMember": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "This member stands for Westpac Vendor Finance.", "label": "Westpac Vendor Finance [Member]", "terseLabel": "Westpac Vendor Finance" } } }, "localname": "WestpacVendorFinanceMember", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureAssetsAndLiabilitiesHeldForSaleBusinessesNoLongerHeldForSaleDetails" ], "xbrltype": "domainItemType" }, "wbk_WriteOffOfDeferredAcquisitionCosts": { "auth_ref": [], "crdr": "debit", "lang": { "en-us": { "role": { "documentation": "The amount of deferred acquisition costs written off during the period.", "label": "Write-Off of Deferred Acquisition Costs", "terseLabel": "Write-off of deferred acquisition costs" } } }, "localname": "WriteOffOfDeferredAcquisitionCosts", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureNonInterestIncomeDetails" ], "xbrltype": "monetaryItemType" }, "wbk_WriteOffsToAverageLoansNetOfRecoveries": { "auth_ref": [], "lang": { "en-us": { "role": { "documentation": "The percentage of write-offs net of recoveries to average loans.", "label": "Write-Offs to Average Loans, Net of Recoveries", "terseLabel": "Total write-offs net of recoveries to average loans" } } }, "localname": "WriteOffsToAverageLoansNetOfRecoveries", "nsuri": "http://www.westpac.com.au/20210930", "presentation": [ "http://www.westpac.com.au/role/DisclosureProvisionsForExpectedCreditLossesImpairmentChargesTotalWriteOffsNetOfRecoveriesToAverageLoansDetails" ], "xbrltype": "percentItemType" } }, "unitCount": 15 } }, "std_ref": { "r0": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "10", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_10_e&doctype=Standard", "URIDate": "2020-01-01" }, "r1": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "102", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_102&doctype=Standard", "URIDate": "2020-01-01" }, "r10": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "107", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_107&doctype=Standard", "URIDate": "2020-01-01" }, "r100": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "21", "Paragraph": "52", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=21&code=ifrs-tx-2020-en-r&anchor=para_52_b&doctype=Standard", "URIDate": "2020-01-01" }, "r101": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "17", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_17_a&doctype=Standard", "URIDate": "2020-01-01" }, "r102": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "17", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_17_b&doctype=Standard", "URIDate": "2020-01-01" }, "r103": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "17", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_17_d&doctype=Standard", "URIDate": "2020-01-01" }, "r104": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "17", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_17_e&doctype=Standard", "URIDate": "2020-01-01" }, "r105": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "17", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_17&doctype=Standard", "URIDate": "2020-01-01" }, "r106": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "18", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_18_b&doctype=Standard", "URIDate": "2020-01-01" }, "r107": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "18", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_18&doctype=Standard", "URIDate": "2020-01-01" }, "r108": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "19", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_19_f&doctype=Standard", "URIDate": "2020-01-01" }, "r109": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "19", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_19&doctype=Standard", "URIDate": "2020-01-01" }, "r11": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "108", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_108&doctype=Standard", "URIDate": "2020-01-01" }, "r110": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Paragraph": "20", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard", "URIDate": "2020-01-01" }, "r111": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "24", "Section": "Disclosures", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS24_g13-24_TI", "URIDate": "2020-01-01" }, "r112": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "26", "Paragraph": "35", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2020-en-r&anchor=para_35_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r113": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "26", "Paragraph": "35", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2020-en-r&anchor=para_35_b_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r114": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "26", "Paragraph": "35", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2020-en-r&anchor=para_35_b_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r115": { "Clause": "viii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "26", "Paragraph": "35", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2020-en-r&anchor=para_35_b_viii&doctype=Standard", "URIDate": "2020-01-01" }, "r116": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "27", "Paragraph": "10", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_10&doctype=Standard", "URIDate": "2020-01-01" }, "r117": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "27", "Paragraph": "16", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_16_b_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r118": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "27", "Paragraph": "16", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_16_b&doctype=Standard", "URIDate": "2020-01-01" }, "r119": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "27", "Paragraph": "17", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_17_b_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r12": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "112", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard", "URIDate": "2020-01-01" }, "r120": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "27", "Paragraph": "17", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_17_b&doctype=Standard", "URIDate": "2020-01-01" }, "r121": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "32", "Paragraph": "34", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=32&code=ifrs-tx-2020-en-r&anchor=para_34&doctype=Standard", "URIDate": "2020-01-01" }, "r122": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "33", "Paragraph": "66", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2020-en-r&anchor=para_66&doctype=Standard", "URIDate": "2020-01-01" }, "r123": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "33", "Paragraph": "70", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2020-en-r&anchor=para_70_a&doctype=Standard", "URIDate": "2020-01-01" }, "r124": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "33", "Paragraph": "70", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2020-en-r&anchor=para_70_b&doctype=Standard", "URIDate": "2020-01-01" }, "r125": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "33", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS33_g70-73A_TI", "URIDate": "2020-01-01" }, "r126": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "126", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_126_a&doctype=Standard", "URIDate": "2020-01-01" }, "r127": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "126", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_126&doctype=Standard", "URIDate": "2020-01-01" }, "r128": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "127", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_127&doctype=Standard", "URIDate": "2020-01-01" }, "r129": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "129", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_129_a&doctype=Standard", "URIDate": "2020-01-01" }, "r13": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "117", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_117_b&doctype=Standard", "URIDate": "2020-01-01" }, "r130": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "130", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_130_b&doctype=Standard", "URIDate": "2020-01-01" }, "r131": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "130", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_130_d_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r132": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "130", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_130&doctype=Standard", "URIDate": "2020-01-01" }, "r133": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "134", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_134_a&doctype=Standard", "URIDate": "2020-01-01" }, "r134": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "134", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_134_d_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r135": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "134", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_134_e_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r136": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Paragraph": "135", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&anchor=para_135_a&doctype=Standard", "URIDate": "2020-01-01" }, "r137": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "36", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS36_g126-137_TI", "URIDate": "2020-01-01" }, "r138": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "70", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_70&doctype=Standard", "URIDate": "2020-01-01" }, "r139": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "84", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_84_a&doctype=Standard", "URIDate": "2020-01-01" }, "r14": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "134", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_134&doctype=Standard", "URIDate": "2020-01-01" }, "r140": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "84", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_84_b&doctype=Standard", "URIDate": "2020-01-01" }, "r141": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "84", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_84_c&doctype=Standard", "URIDate": "2020-01-01" }, "r142": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "84", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_84_d&doctype=Standard", "URIDate": "2020-01-01" }, "r143": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "84", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_84&doctype=Standard", "URIDate": "2020-01-01" }, "r144": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "86", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_86&doctype=Standard", "URIDate": "2020-01-01" }, "r145": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "87", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_87&doctype=Standard", "URIDate": "2020-01-01" }, "r146": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "88", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_88&doctype=Standard", "URIDate": "2020-01-01" }, "r147": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Paragraph": "89", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&anchor=para_89&doctype=Standard", "URIDate": "2020-01-01" }, "r148": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "37", "Section": "Example 10 A court case", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2020-en-r&doctype=Illustrative%20Examples&dita_xref=IAS37_IE_C_ex10_TI", "URIDate": "2020-01-01" }, "r149": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_a&doctype=Standard", "URIDate": "2020-01-01" }, "r15": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "137", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_137_a&doctype=Standard", "URIDate": "2020-01-01" }, "r150": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_c&doctype=Standard", "URIDate": "2020-01-01" }, "r151": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_i&doctype=Standard", "URIDate": "2020-01-01" }, "r152": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r153": { "Clause": "vi", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_vi&doctype=Standard", "URIDate": "2020-01-01" }, "r154": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e&doctype=Standard", "URIDate": "2020-01-01" }, "r155": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "118", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118&doctype=Standard", "URIDate": "2020-01-01" }, "r156": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "119", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_119_a&doctype=Standard", "URIDate": "2020-01-01" }, "r157": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "38", "Paragraph": "119", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_119_c&doctype=Standard", "URIDate": "2020-01-01" }, "r158": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "39", "Paragraph": "102", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=39&code=ifrs-tx-2020-en-r&anchor=para_102_a&doctype=Standard", "URIDate": "2020-01-01" }, "r159": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "39", "Paragraph": "86", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=39&code=ifrs-tx-2020-en-r&anchor=para_86_a&doctype=Standard", "URIDate": "2020-01-01" }, "r16": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "41", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_41_b&doctype=Standard", "URIDate": "2020-01-01" }, "r160": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "39", "Paragraph": "86", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=39&code=ifrs-tx-2020-en-r&anchor=para_86_b&doctype=Standard", "URIDate": "2020-01-01" }, "r161": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "39", "Paragraph": "86", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=39&code=ifrs-tx-2020-en-r&anchor=para_86_c&doctype=Standard", "URIDate": "2020-01-01" }, "r162": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "40", "Paragraph": "32A", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2020-en-r&anchor=para_32A&doctype=Standard", "URIDate": "2020-01-01" }, "r163": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "40", "Paragraph": "76", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2020-en-r&anchor=para_76&doctype=Standard", "URIDate": "2020-01-01" }, "r164": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "40", "Paragraph": "79", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2020-en-r&anchor=para_79_c&doctype=Standard", "URIDate": "2020-01-01" }, "r165": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "40", "Paragraph": "79", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2020-en-r&anchor=para_79_d&doctype=Standard", "URIDate": "2020-01-01" }, "r166": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "41", "Paragraph": "50", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=41&code=ifrs-tx-2020-en-r&anchor=para_50&doctype=Standard", "URIDate": "2020-01-01" }, "r167": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "41", "Paragraph": "54", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=41&code=ifrs-tx-2020-en-r&anchor=para_54_f&doctype=Standard", "URIDate": "2020-01-01" }, "r168": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "10", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_10&doctype=Standard", "URIDate": "2020-01-01" }, "r169": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "14", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_14_b&doctype=Standard", "URIDate": "2020-01-01" }, "r17": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_a&doctype=Standard", "URIDate": "2020-01-01" }, "r170": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "14", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_14&doctype=Standard", "URIDate": "2020-01-01" }, "r171": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "16", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_16_a&doctype=Standard", "URIDate": "2020-01-01" }, "r172": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "16", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_16_b&doctype=Standard", "URIDate": "2020-01-01" }, "r173": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "16", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_16&doctype=Standard", "URIDate": "2020-01-01" }, "r174": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "17", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_a&doctype=Standard", "URIDate": "2020-01-01" }, "r175": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "17", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_c&doctype=Standard", "URIDate": "2020-01-01" }, "r176": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "17", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_d&doctype=Standard", "URIDate": "2020-01-01" }, "r177": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "17", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_e&doctype=Standard", "URIDate": "2020-01-01" }, "r178": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "17", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17&doctype=Standard", "URIDate": "2020-01-01" }, "r179": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "18", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_18_b&doctype=Standard", "URIDate": "2020-01-01" }, "r18": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_c&doctype=Standard", "URIDate": "2020-01-01" }, "r180": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "20", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_b&doctype=Standard", "URIDate": "2020-01-01" }, "r181": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "20", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard", "URIDate": "2020-01-01" }, "r182": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "25", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_25&doctype=Standard", "URIDate": "2020-01-01" }, "r183": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "28", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_28&doctype=Standard", "URIDate": "2020-01-01" }, "r184": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "31", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_31&doctype=Standard", "URIDate": "2020-01-01" }, "r185": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "35", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35&doctype=Standard", "URIDate": "2020-01-01" }, "r186": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "45", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_45&doctype=Standard", "URIDate": "2020-01-01" }, "r187": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Paragraph": "50", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_50_d&doctype=Standard", "URIDate": "2020-01-01" }, "r188": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Section": "A Statement of cash flows for an entity other than a financial institution", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&doctype=Illustrative%20Examples&dita_xref=IAS07_IE_A_TI", "URIDate": "2020-01-01" }, "r189": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "7", "Section": "Presentation of a statement of cash flows", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS07_g10-17_TI", "URIDate": "2020-01-01" }, "r19": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_d&doctype=Standard", "URIDate": "2020-01-01" }, "r190": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "8", "Paragraph": "28", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28&doctype=Standard", "URIDate": "2020-01-01" }, "r191": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "8", "Paragraph": "29", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=8&code=ifrs-tx-2020-en-r&anchor=para_29&doctype=Standard", "URIDate": "2020-01-01" }, "r192": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "8", "Paragraph": "30", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=8&code=ifrs-tx-2020-en-r&anchor=para_30_b&doctype=Standard", "URIDate": "2020-01-01" }, "r193": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "8", "Paragraph": "39", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=8&code=ifrs-tx-2020-en-r&anchor=para_39&doctype=Standard", "URIDate": "2020-01-01" }, "r194": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "1", "Paragraph": "24", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_24_a&doctype=Standard", "URIDate": "2020-01-01" }, "r195": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "1", "Paragraph": "24", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_24_b&doctype=Standard", "URIDate": "2020-01-01" }, "r196": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "1", "Paragraph": "32", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_32_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r197": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "1", "Paragraph": "32", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_32_a_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r198": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "1", "Paragraph": "IG63", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_IG63&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r199": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "10", "Paragraph": "22", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=10&code=ifrs-tx-2020-en-r&anchor=para_22&doctype=Standard", "URIDate": "2020-01-01" }, "r2": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "103", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard", "URIDate": "2020-01-01" }, "r20": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "i", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_i&doctype=Standard", "URIDate": "2020-01-01" }, "r200": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "1", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_1&doctype=Standard", "URIDate": "2020-01-01" }, "r201": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "12", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_12_e&doctype=Standard", "URIDate": "2020-01-01" }, "r202": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "12", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_12_f&doctype=Standard", "URIDate": "2020-01-01" }, "r203": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "19", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_19&doctype=Standard", "URIDate": "2020-01-01" }, "r204": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "19B", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_19B_c&doctype=Standard", "URIDate": "2020-01-01" }, "r205": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "19B", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_19B&doctype=Standard", "URIDate": "2020-01-01" }, "r206": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "2", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_2_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r207": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "26", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_26&doctype=Standard", "URIDate": "2020-01-01" }, "r208": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "29", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_29_c&doctype=Standard", "URIDate": "2020-01-01" }, "r209": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B10", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r21": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "j", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_j&doctype=Standard", "URIDate": "2020-01-01" }, "r210": { "Clause": "ix", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B12", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_ix&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r211": { "Clause": "v", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B12", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r212": { "Clause": "viii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B12", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_viii&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r213": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B13", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B13_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r214": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B13", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B13_e&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r215": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B13", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B13_f&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r216": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B13", "Subparagraph": "g", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B13_g&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r217": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B16", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B16_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r218": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B23", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B23_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r219": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B23", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B23_b&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r22": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "k", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_k&doctype=Standard", "URIDate": "2020-01-01" }, "r220": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B23", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B23_c&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r221": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B4", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B4_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r222": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Paragraph": "B4", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B4_e&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r223": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "12", "Section": "Nature of the risks associated with an entity's interests in consolidated structured entities", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS12_g14-17_TI", "URIDate": "2020-01-01" }, "r224": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_a&doctype=Standard", "URIDate": "2020-01-01" }, "r225": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_b&doctype=Standard", "URIDate": "2020-01-01" }, "r226": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_d&doctype=Standard", "URIDate": "2020-01-01" }, "r227": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_e_i&doctype=Standard", "URIDate": "2020-01-01" }, "r228": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_e_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r229": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_e&doctype=Standard", "URIDate": "2020-01-01" }, "r23": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "l", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_l&doctype=Standard", "URIDate": "2020-01-01" }, "r230": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_f&doctype=Standard", "URIDate": "2020-01-01" }, "r231": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "Subparagraph": "h", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_h&doctype=Standard", "URIDate": "2020-01-01" }, "r232": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "93", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93&doctype=Standard", "URIDate": "2020-01-01" }, "r233": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "94", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_94&doctype=Standard", "URIDate": "2020-01-01" }, "r234": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "97", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_97&doctype=Standard", "URIDate": "2020-01-01" }, "r235": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "B36", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_B36_d&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r236": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "B6", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_B6&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r237": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "IE60", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_IE60&doctype=Illustrative%20Examples", "URIDate": "2020-01-01" }, "r238": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Paragraph": "IE63", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_IE63&doctype=Illustrative%20Examples", "URIDate": "2020-01-01" }, "r239": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "13", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS13_g91-99_TI", "URIDate": "2020-01-01" }, "r24": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "m", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_m&doctype=Standard", "URIDate": "2020-01-01" }, "r240": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "14", "Paragraph": "33", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=14&code=ifrs-tx-2020-en-r&anchor=para_33_b&doctype=Standard", "URIDate": "2020-01-01" }, "r241": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "115", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_115&doctype=Standard", "URIDate": "2020-01-01" }, "r242": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "120", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_120_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r243": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "B89", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_B89_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r244": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "B89", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_B89_b&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r245": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "B89", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_B89_c&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r246": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "15", "Paragraph": "B89", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_B89_d&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r247": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "16", "Paragraph": "53", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53&doctype=Standard", "URIDate": "2020-01-01" }, "r248": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "16", "Paragraph": "90", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_90_b&doctype=Standard", "URIDate": "2020-01-01" }, "r249": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "16", "Paragraph": "94", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_94&doctype=Standard", "URIDate": "2020-01-01" }, "r25": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "n", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_n&doctype=Standard", "URIDate": "2020-01-01" }, "r250": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "16", "Paragraph": "97", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_97&doctype=Standard", "URIDate": "2020-01-01" }, "r251": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "44", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_44&doctype=Standard", "URIDate": "2020-01-01" }, "r252": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "45", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r253": { "Clause": "vi", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "45", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_vi&doctype=Standard", "URIDate": "2020-01-01" }, "r254": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "45", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_c&doctype=Standard", "URIDate": "2020-01-01" }, "r255": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "45", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_d&doctype=Standard", "URIDate": "2020-01-01" }, "r256": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "45", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45&doctype=Standard", "URIDate": "2020-01-01" }, "r257": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "47", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_47_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r258": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "2", "Paragraph": "47", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_47_b&doctype=Standard", "URIDate": "2020-01-01" }, "r259": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "3", "Paragraph": "B67", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B67_c&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r26": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "o", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_o&doctype=Standard", "URIDate": "2020-01-01" }, "r260": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "3", "Paragraph": "B67", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B67_d_iv&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r261": { "Clause": "v", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "3", "Paragraph": "B67", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B67_d_v&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r262": { "Clause": "vii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "3", "Paragraph": "B67", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B67_d_vii&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r263": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "3", "Paragraph": "B67", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B67_d&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r264": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "5", "Paragraph": "33", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r265": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "5", "Paragraph": "33", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_b&doctype=Standard", "URIDate": "2020-01-01" }, "r266": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "5", "Paragraph": "38", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_38&doctype=Standard", "URIDate": "2020-01-01" }, "r267": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "5", "Section": "Presentation and disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS05_g30-42_TI", "URIDate": "2020-01-01" }, "r268": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_a&doctype=Standard", "URIDate": "2020-01-01" }, "r269": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_b&doctype=Standard", "URIDate": "2020-01-01" }, "r27": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "p", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_p&doctype=Standard", "URIDate": "2020-01-01" }, "r270": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_c&doctype=Standard", "URIDate": "2020-01-01" }, "r271": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_d_i&doctype=Standard", "URIDate": "2020-01-01" }, "r272": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_d_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r273": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "13C", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_13C_e&doctype=Standard", "URIDate": "2020-01-01" }, "r274": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "14", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_14_a&doctype=Standard", "URIDate": "2020-01-01" }, "r275": { "Clause": "viii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "20", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a_viii&doctype=Standard", "URIDate": "2020-01-01" }, "r276": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "21C", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_21C&doctype=Standard", "URIDate": "2020-01-01" }, "r277": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "23A", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_23A&doctype=Standard", "URIDate": "2020-01-01" }, "r278": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "23B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_23B_a&doctype=Standard", "URIDate": "2020-01-01" }, "r279": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24A", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_a&doctype=Standard", "URIDate": "2020-01-01" }, "r28": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "q", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_q&doctype=Standard", "URIDate": "2020-01-01" }, "r280": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24A", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_c&doctype=Standard", "URIDate": "2020-01-01" }, "r281": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24A", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_d&doctype=Standard", "URIDate": "2020-01-01" }, "r282": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24A", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A&doctype=Standard", "URIDate": "2020-01-01" }, "r283": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r284": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_a_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r285": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_a_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r286": { "Clause": "v", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_a_v&doctype=Standard", "URIDate": "2020-01-01" }, "r287": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r288": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B_b_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r289": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24B", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24B&doctype=Standard", "URIDate": "2020-01-01" }, "r29": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "54", "Subparagraph": "r", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_r&doctype=Standard", "URIDate": "2020-01-01" }, "r290": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24C", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24C_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r291": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24C", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24C_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r292": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24C", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24C_b_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r293": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24C", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24C&doctype=Standard", "URIDate": "2020-01-01" }, "r294": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "24E", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24E_a&doctype=Standard", "URIDate": "2020-01-01" }, "r295": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "25", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_25&doctype=Standard", "URIDate": "2020-01-01" }, "r296": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "31", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_31&doctype=Standard", "URIDate": "2020-01-01" }, "r297": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "32", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_32&doctype=Standard", "URIDate": "2020-01-01" }, "r298": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "33", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_33&doctype=Standard", "URIDate": "2020-01-01" }, "r299": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "34", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_34&doctype=Standard", "URIDate": "2020-01-01" }, "r3": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "104", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_104&doctype=Standard", "URIDate": "2020-01-01" }, "r30": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "55", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard", "URIDate": "2020-01-01" }, "r300": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35H", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35H&doctype=Standard", "URIDate": "2020-01-01" }, "r301": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35I", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35I_c&doctype=Standard", "URIDate": "2020-01-01" }, "r302": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35I", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35I&doctype=Standard", "URIDate": "2020-01-01" }, "r303": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35K", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35K_a&doctype=Standard", "URIDate": "2020-01-01" }, "r304": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35K", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35K&doctype=Standard", "URIDate": "2020-01-01" }, "r305": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35M", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35M&doctype=Standard", "URIDate": "2020-01-01" }, "r306": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "35N", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35N&doctype=Standard", "URIDate": "2020-01-01" }, "r307": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "36", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_36&doctype=Standard", "URIDate": "2020-01-01" }, "r308": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "39", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_39_a&doctype=Standard", "URIDate": "2020-01-01" }, "r309": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "39", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_39_b&doctype=Standard", "URIDate": "2020-01-01" }, "r31": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "56", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_56&doctype=Standard", "URIDate": "2020-01-01" }, "r310": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "39", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_39_c&doctype=Standard", "URIDate": "2020-01-01" }, "r311": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "39", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_39&doctype=Standard", "URIDate": "2020-01-01" }, "r312": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "40", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_40_a&doctype=Standard", "URIDate": "2020-01-01" }, "r313": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "41", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_41&doctype=Standard", "URIDate": "2020-01-01" }, "r314": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "42D", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_42D_d&doctype=Standard", "URIDate": "2020-01-01" }, "r315": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "42D", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_42D_e&doctype=Standard", "URIDate": "2020-01-01" }, "r316": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "42D", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_42D&doctype=Standard", "URIDate": "2020-01-01" }, "r317": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "42E", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_42E_e&doctype=Standard", "URIDate": "2020-01-01" }, "r318": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "42I", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_42I&doctype=Standard", "URIDate": "2020-01-01" }, "r319": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "6", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_6&doctype=Standard", "URIDate": "2020-01-01" }, "r32": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "61", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_61_a&doctype=Standard", "URIDate": "2020-01-01" }, "r320": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "7", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_7&doctype=Standard", "URIDate": "2020-01-01" }, "r321": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "8", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8_a&doctype=Standard", "URIDate": "2020-01-01" }, "r322": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "8", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8_f&doctype=Standard", "URIDate": "2020-01-01" }, "r323": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "8", "Subparagraph": "h", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8_h&doctype=Standard", "URIDate": "2020-01-01" }, "r324": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "8", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8&doctype=Standard", "URIDate": "2020-01-01" }, "r325": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r326": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11_b&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r327": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11_c&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r328": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11_d&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r329": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r33": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "61", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_61_b&doctype=Standard", "URIDate": "2020-01-01" }, "r330": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B11E", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B11E&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r331": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35_a&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r332": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35_b&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r333": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35_c&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r334": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35_d&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r335": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "Subparagraph": "g", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35_g&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r336": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B35", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B35&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r337": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B51", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B51&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r338": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "B52", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_B52&doctype=Appendix&subtype=B", "URIDate": "2020-01-01" }, "r339": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG20B", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG20B&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r34": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "61", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_61&doctype=Standard", "URIDate": "2020-01-01" }, "r340": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG20C", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG20C&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r341": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG31A", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG31A&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r342": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG32", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG32&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r343": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG40B", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG40B&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r344": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Paragraph": "IG40D", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_IG40D&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r345": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Section": "Credit risk", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS07_g35A-38_TI", "URIDate": "2020-01-01" }, "r346": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Section": "Defined terms", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&doctype=Appendix&subtype=A&dita_xref=IFRS07_APPA_TI", "URIDate": "2020-01-01" }, "r347": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Section": "Offsetting financial assets and financial liabilities", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS07_g13A-13F_TI", "URIDate": "2020-01-01" }, "r348": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Section": "Scope", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS07_g3-5A_TI", "URIDate": "2020-01-01" }, "r349": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "7", "Section": "Transfers of financial assets", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS07_g42A-42S_TI", "URIDate": "2020-01-01" }, "r35": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "7", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_7&doctype=Standard", "URIDate": "2020-01-01" }, "r350": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "16", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_16&doctype=Standard", "URIDate": "2020-01-01" }, "r351": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "23", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_a&doctype=Standard", "URIDate": "2020-01-01" }, "r352": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "23", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_c&doctype=Standard", "URIDate": "2020-01-01" }, "r353": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "23", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_d&doctype=Standard", "URIDate": "2020-01-01" }, "r354": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "23", "Subparagraph": "h", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_h&doctype=Standard", "URIDate": "2020-01-01" }, "r355": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "23", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard", "URIDate": "2020-01-01" }, "r356": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_a&doctype=Standard", "URIDate": "2020-01-01" }, "r357": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard", "URIDate": "2020-01-01" }, "r358": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_c&doctype=Standard", "URIDate": "2020-01-01" }, "r359": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_d&doctype=Standard", "URIDate": "2020-01-01" }, "r36": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "78", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_b&doctype=Standard", "URIDate": "2020-01-01" }, "r360": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_e&doctype=Standard", "URIDate": "2020-01-01" }, "r361": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "28", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28&doctype=Standard", "URIDate": "2020-01-01" }, "r362": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "32", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_32&doctype=Standard", "URIDate": "2020-01-01" }, "r363": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "33", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_33_a&doctype=Standard", "URIDate": "2020-01-01" }, "r364": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "33", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_33_b&doctype=Standard", "URIDate": "2020-01-01" }, "r365": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "33", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_33&doctype=Standard", "URIDate": "2020-01-01" }, "r366": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Paragraph": "34", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_34&doctype=Standard", "URIDate": "2020-01-01" }, "r367": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "8", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS08_g20-24_TI", "URIDate": "2020-01-01" }, "r368": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "9", "Paragraph": "6.5.11", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2020-en-r&anchor=para_6.5.11&doctype=Standard", "URIDate": "2020-01-01" }, "r369": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "9", "Paragraph": "6.5.13", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2020-en-r&anchor=para_6.5.13_a&doctype=Standard", "URIDate": "2020-01-01" }, "r37": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "78", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_d&doctype=Standard", "URIDate": "2020-01-01" }, "r370": { "IssueDate": "2020-01-01", "Name": "IFRS", "Number": "9", "Paragraph": "7.2.34", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2020-en-r&anchor=para_7.2.34&doctype=Standard", "URIDate": "2020-01-01" }, "r371": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Note": "Effective 2021-01-01", "Number": "1", "Paragraph": "82", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r372": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "109", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_109&doctype=Standard", "URIDate": "2020-01-01" }, "r373": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "113", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_113_b&doctype=Standard", "URIDate": "2020-01-01" }, "r374": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "120", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_120&doctype=Standard", "URIDate": "2020-01-01" }, "r375": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "124", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_124&doctype=Standard", "URIDate": "2020-01-01" }, "r376": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "125", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_125&doctype=Standard", "URIDate": "2020-01-01" }, "r377": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "127", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_127&doctype=Standard", "URIDate": "2020-01-01" }, "r378": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "128", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_128_a_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r379": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "128", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_128_a&doctype=Standard", "URIDate": "2020-01-01" }, "r38": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "78", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_e&doctype=Standard", "URIDate": "2020-01-01" }, "r380": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "132", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_132_b&doctype=Standard", "URIDate": "2020-01-01" }, "r381": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "96", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_96_a&doctype=Standard", "URIDate": "2020-01-01" }, "r382": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "96", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_96_b&doctype=Standard", "URIDate": "2020-01-01" }, "r383": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "96", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_96_c&doctype=Standard", "URIDate": "2020-01-01" }, "r384": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Paragraph": "C32", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_C32&doctype=Appendix&subtype=C", "URIDate": "2020-01-01" }, "r385": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective 2021-01-01", "Number": "17", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IFRS17_g93-132_TI", "URIDate": "2020-01-01" }, "r386": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective on first application of IFRS 9", "Number": "4", "Paragraph": "39L", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39L_b&doctype=Standard", "URIDate": "2020-01-01" }, "r387": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Effective on first application of IFRS 9", "Number": "4", "Paragraph": "39L", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39L_e&doctype=Standard", "URIDate": "2020-01-01" }, "r388": { "IssueDate": "2020-01-01", "Name": "IAS", "Note": "Expiry date 2021-01-01", "Number": "1", "Paragraph": "112", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2017-en-b&anchor=para_112_c&doctype=Standard&forcepdf=true", "URIDate": "2020-01-01" }, "r389": { "IssueDate": "2020-01-01", "Name": "IAS", "Note": "Expiry date 2021-01-01", "Number": "1", "Paragraph": "117", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2017-en-b&anchor=para_117_b&doctype=Standard&forcepdf=true", "URIDate": "2020-01-01" }, "r39": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "78", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78&doctype=Standard", "URIDate": "2020-01-01" }, "r390": { "IssueDate": "2020-01-01", "Name": "IAS", "Note": "Expiry date 2021-01-01", "Number": "1", "Paragraph": "55", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-b&anchor=para_55&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r391": { "IssueDate": "2020-01-01", "Name": "IAS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "14", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-b&anchor=para_14_e&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r392": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "36", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_36&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r393": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "37", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_37_a&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r394": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "37", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_37_b&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r395": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "37", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_37_e&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r396": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "39G", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39G_a&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r397": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "IG20", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_IG20_a&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r398": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "IG37", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_IG37_a&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r399": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "IG37", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_IG37_b&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r4": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_a&doctype=Standard", "URIDate": "2020-01-01" }, "r40": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "79", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79_a_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r400": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "IG37", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_IG37_c&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r401": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Paragraph": "IG37", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_IG37_d&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r402": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "4", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&doctype=Standard&book=b&dita_xref=IFRS04_g36-39M_TI", "URIDate": "2020-01-01" }, "r403": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "22", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_22&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r404": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "23", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_23_c&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r405": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "23", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_23_d&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r406": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "36", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_36_a&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r407": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "36", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_36_c&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r408": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "37", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_37_a&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r409": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "37", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_37_b&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r41": { "Clause": "iv", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "79", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79_a_iv&doctype=Standard", "URIDate": "2020-01-01" }, "r410": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "37", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_37&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r411": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "8", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_8_c&doctype=Standard&book=b", "URIDate": "2020-01-01" }, "r412": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG25", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG25_b&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r413": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG28", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG28_a&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r414": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG28", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG28_b&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r415": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG28", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG28_c&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r416": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG28", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG28_d&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r417": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG29", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG29_a&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r418": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG29", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG29_b&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r419": { "IssueDate": "2020-01-01", "Name": "IFRS", "Note": "Expiry date 2021-01-01", "Number": "7", "Paragraph": "IG29", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG29&doctype=Implementation%20Guidance&book=b", "URIDate": "2020-01-01" }, "r42": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "79", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79_a&doctype=Standard", "URIDate": "2020-01-01" }, "r420": { "Name": "Exchange Act", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "b" }, "r421": { "Name": "Exchange Act", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "d1-1" }, "r422": { "Name": "Exchange Act", "Number": "240", "Publisher": "SEC", "Section": "15", "Subsection": "d-3" }, "r423": { "Name": "Form 10-K", "Number": "249", "Publisher": "SEC", "Section": "310" }, "r424": { "Name": "Form 20-F", "Number": "249", "Publisher": "SEC", "Section": "220", "Subsection": "f" }, "r425": { "Name": "Form 40-F", "Number": "249", "Publisher": "SEC", "Section": "240", "Subsection": "f" }, "r426": { "Name": "Forms 10-K, 10-Q, 20-F", "Number": "240", "Publisher": "SEC", "Section": "13", "Subsection": "a-1" }, "r427": { "Name": "Regulation 12B", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "b-2" }, "r428": { "Name": "Regulation S-T", "Number": "232", "Publisher": "SEC", "Section": "405" }, "r429": { "Name": "Securities Act", "Number": "Section", "Publisher": "SEC", "Section": "12" }, "r43": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "79", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79_b&doctype=Standard", "URIDate": "2020-01-01" }, "r44": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "79", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_79&doctype=Standard", "URIDate": "2020-01-01" }, "r45": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81A", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_a&doctype=Standard", "URIDate": "2020-01-01" }, "r46": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81A", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_b&doctype=Standard", "URIDate": "2020-01-01" }, "r47": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81A", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_c&doctype=Standard", "URIDate": "2020-01-01" }, "r48": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_a_i&doctype=Standard", "URIDate": "2020-01-01" }, "r49": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81B", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_a_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r5": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_i&doctype=Standard", "URIDate": "2020-01-01" }, "r50": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81B", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_b_i&doctype=Standard", "URIDate": "2020-01-01" }, "r51": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "81B", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_b_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r52": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "82", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_a&doctype=Standard", "URIDate": "2020-01-01" }, "r53": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "82", "Subparagraph": "ba", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_ba&doctype=Standard", "URIDate": "2020-01-01" }, "r54": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "82", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_d&doctype=Standard", "URIDate": "2020-01-01" }, "r55": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "85", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard", "URIDate": "2020-01-01" }, "r56": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "90", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_90&doctype=Standard", "URIDate": "2020-01-01" }, "r57": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "91", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_91_a&doctype=Standard", "URIDate": "2020-01-01" }, "r58": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "91", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_91_b&doctype=Standard", "URIDate": "2020-01-01" }, "r59": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "92", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_92&doctype=Standard", "URIDate": "2020-01-01" }, "r6": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r60": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "98", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_98_b&doctype=Standard", "URIDate": "2020-01-01" }, "r61": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "98", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_98_c&doctype=Standard", "URIDate": "2020-01-01" }, "r62": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "99", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_99&doctype=Standard", "URIDate": "2020-01-01" }, "r63": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "IG6", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_IG6&doctype=Implementation%20Guidance", "URIDate": "2020-01-01" }, "r64": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "10", "Paragraph": "13", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=10&code=ifrs-tx-2020-en-r&anchor=para_13&doctype=Standard", "URIDate": "2020-01-01" }, "r65": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "10", "Paragraph": "21", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=10&code=ifrs-tx-2020-en-r&anchor=para_21&doctype=Standard", "URIDate": "2020-01-01" }, "r66": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "10", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=10&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS10_g17-22_TI", "URIDate": "2020-01-01" }, "r67": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "79", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_79&doctype=Standard", "URIDate": "2020-01-01" }, "r68": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "80", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_80&doctype=Standard", "URIDate": "2020-01-01" }, "r69": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "ab", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_ab&doctype=Standard", "URIDate": "2020-01-01" }, "r7": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r70": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_c_i&doctype=Standard", "URIDate": "2020-01-01" }, "r71": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_c_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r72": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_e&doctype=Standard", "URIDate": "2020-01-01" }, "r73": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_f&doctype=Standard", "URIDate": "2020-01-01" }, "r74": { "Clause": "i", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "g", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_g_i&doctype=Standard", "URIDate": "2020-01-01" }, "r75": { "Clause": "ii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "g", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_g_ii&doctype=Standard", "URIDate": "2020-01-01" }, "r76": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Paragraph": "81", "Subparagraph": "g", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_g&doctype=Standard", "URIDate": "2020-01-01" }, "r77": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "12", "Section": "Disclosure", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS12_g79-88_TI", "URIDate": "2020-01-01" }, "r78": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "16", "Paragraph": "37", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_37&doctype=Standard", "URIDate": "2020-01-01" }, "r79": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "16", "Paragraph": "73", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_73_d&doctype=Standard", "URIDate": "2020-01-01" }, "r8": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d&doctype=Standard", "URIDate": "2020-01-01" }, "r80": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "16", "Paragraph": "73", "Subparagraph": "e", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_73_e&doctype=Standard", "URIDate": "2020-01-01" }, "r81": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "16", "Paragraph": "73", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_73&doctype=Standard", "URIDate": "2020-01-01" }, "r82": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "16", "Paragraph": "75", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_75_b&doctype=Standard", "URIDate": "2020-01-01" }, "r83": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "138", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_138_a&doctype=Standard", "URIDate": "2020-01-01" }, "r84": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "138", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_138_d&doctype=Standard", "URIDate": "2020-01-01" }, "r85": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "138", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_138&doctype=Standard", "URIDate": "2020-01-01" }, "r86": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "140", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_140_a&doctype=Standard", "URIDate": "2020-01-01" }, "r87": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "141", "Subparagraph": "f", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_141_f&doctype=Standard", "URIDate": "2020-01-01" }, "r88": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "142", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_142&doctype=Standard", "URIDate": "2020-01-01" }, "r89": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "144", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_144&doctype=Standard", "URIDate": "2020-01-01" }, "r9": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "1", "Paragraph": "106", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106&doctype=Standard", "URIDate": "2020-01-01" }, "r90": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "145", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145_a&doctype=Standard", "URIDate": "2020-01-01" }, "r91": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "145", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145&doctype=Standard", "URIDate": "2020-01-01" }, "r92": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "147", "Subparagraph": "b", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_147_b&doctype=Standard", "URIDate": "2020-01-01" }, "r93": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "147", "Subparagraph": "c", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_147_c&doctype=Standard", "URIDate": "2020-01-01" }, "r94": { "Clause": "iii", "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "148", "Subparagraph": "d", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_148_d_iii&doctype=Standard", "URIDate": "2020-01-01" }, "r95": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "158", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_158&doctype=Standard", "URIDate": "2020-01-01" }, "r96": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "5", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_5&doctype=Standard", "URIDate": "2020-01-01" }, "r97": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Paragraph": "57", "Subparagraph": "a", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_57_a&doctype=Standard", "URIDate": "2020-01-01" }, "r98": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "19", "Section": "Scope", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&doctype=Standard&dita_xref=IAS19_g2-7_TI", "URIDate": "2020-01-01" }, "r99": { "IssueDate": "2020-01-01", "Name": "IAS", "Number": "21", "Paragraph": "48", "URI": "http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=21&code=ifrs-tx-2020-en-r&anchor=para_48&doctype=Standard", "URIDate": "2020-01-01" } }, "version": "2.1" }