3.20.2 html 338 357 1 false 80 0 false 6 false false R1.htm 00090 - Document - Document and Entity Information Sheet http://www.janus.com/role/DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 00100 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS Sheet http://www.janus.com/role/StatementCondensedConsolidatedBalanceSheets CONDENSED CONSOLIDATED BALANCE SHEETS Statements 2 false false R3.htm 00105 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://www.janus.com/role/StatementCondensedConsolidatedBalanceSheetsParenthetical CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 3 false false R4.htm 00200 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) Sheet http://www.janus.com/role/StatementCondensedConsolidatedStatementsOfComprehensiveIncomeLoss CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) Statements 4 false false R5.htm 00300 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.janus.com/role/StatementCondensedConsolidatedStatementsOfCashFlows CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 5 false false R6.htm 00400 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY Sheet http://www.janus.com/role/StatementCondensedConsolidatedStatementsOfChangesInEquity CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY Statements 6 false false R7.htm 00405 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) Sheet http://www.janus.com/role/StatementCondensedConsolidatedStatementsOfChangesInEquityParenthetical CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) Statements 7 false false R8.htm 10101 - Disclosure - Basis of Presentation and Significant Accounting Policies Sheet http://www.janus.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies Basis of Presentation and Significant Accounting Policies Notes 8 false false R9.htm 10201 - Disclosure - Dispositions Sheet http://www.janus.com/role/DisclosureDispositions Dispositions Notes 9 false false R10.htm 10301 - Disclosure - Consolidation Sheet http://www.janus.com/role/DisclosureConsolidation Consolidation Notes 10 false false R11.htm 10401 - Disclosure - Investment Securities Sheet http://www.janus.com/role/DisclosureInvestmentSecurities Investment Securities Notes 11 false false R12.htm 10501 - Disclosure - Fair Value Measurements Sheet http://www.janus.com/role/DisclosureFairValueMeasurements Fair Value Measurements Notes 12 false false R13.htm 10601 - Disclosure - Goodwill and Intangible Assets Sheet http://www.janus.com/role/DisclosureGoodwillAndIntangibleAssets Goodwill and Intangible Assets Notes 13 false false R14.htm 10701 - Disclosure - Debt Sheet http://www.janus.com/role/DisclosureDebt Debt Notes 14 false false R15.htm 10801 - Disclosure - Income Taxes Sheet http://www.janus.com/role/DisclosureIncomeTaxes Income Taxes Notes 15 false false R16.htm 10901 - Disclosure - Noncontrolling Interests Sheet http://www.janus.com/role/DisclosureNoncontrollingInterests Noncontrolling Interests Notes 16 false false R17.htm 11001 - Disclosure - Long-Term Incentive Compensation Sheet http://www.janus.com/role/DisclosureLongTermIncentiveCompensation Long-Term Incentive Compensation Notes 17 false false R18.htm 11101 - Disclosure - Retirement Benefit Plans Sheet http://www.janus.com/role/DisclosureRetirementBenefitPlans Retirement Benefit Plans Notes 18 false false R19.htm 11201 - Disclosure - Accumulated Other Comprehensive Loss Sheet http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLoss Accumulated Other Comprehensive Loss Notes 19 false false R20.htm 11301 - Disclosure - Earnings (Loss) and Dividends Per Share Sheet http://www.janus.com/role/DisclosureEarningsLossAndDividendsPerShare Earnings (Loss) and Dividends Per Share Notes 20 false false R21.htm 11401 - Disclosure - Commitments and Contingencies Sheet http://www.janus.com/role/DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 21 false false R22.htm 20102 - Disclosure - Basis of Presentation and Significant Accounting Policies (Policies) Sheet http://www.janus.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies Basis of Presentation and Significant Accounting Policies (Policies) Policies http://www.janus.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies 22 false false R23.htm 30203 - Disclosure - Dispositions (Tables) Sheet http://www.janus.com/role/DisclosureDispositionsTables Dispositions (Tables) Tables http://www.janus.com/role/DisclosureDispositions 23 false false R24.htm 30303 - Disclosure - Consolidation (Tables) Sheet http://www.janus.com/role/DisclosureConsolidationTables Consolidation (Tables) Tables http://www.janus.com/role/DisclosureConsolidation 24 false false R25.htm 30403 - Disclosure - Investment Securities (Tables) Sheet http://www.janus.com/role/DisclosureInvestmentSecuritiesTables Investment Securities (Tables) Tables http://www.janus.com/role/DisclosureInvestmentSecurities 25 false false R26.htm 30503 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.janus.com/role/DisclosureFairValueMeasurements 26 false false R27.htm 30603 - Disclosure - Goodwill and Intangible Assets (Tables) Sheet http://www.janus.com/role/DisclosureGoodwillAndIntangibleAssetsTables Goodwill and Intangible Assets (Tables) Tables http://www.janus.com/role/DisclosureGoodwillAndIntangibleAssets 27 false false R28.htm 30703 - Disclosure - Debt (Tables) Sheet http://www.janus.com/role/DisclosureDebtTables Debt (Tables) Tables http://www.janus.com/role/DisclosureDebt 28 false false R29.htm 30803 - Disclosure - Income Taxes (Tables) Sheet http://www.janus.com/role/DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://www.janus.com/role/DisclosureIncomeTaxes 29 false false R30.htm 30903 - Disclosure - Noncontrolling Interests (Tables) Sheet http://www.janus.com/role/DisclosureNoncontrollingInterestsTables Noncontrolling Interests (Tables) Tables http://www.janus.com/role/DisclosureNoncontrollingInterests 30 false false R31.htm 31103 - Disclosure - Retirement Benefit Plans (Tables) Sheet http://www.janus.com/role/DisclosureRetirementBenefitPlansTables Retirement Benefit Plans (Tables) Tables http://www.janus.com/role/DisclosureRetirementBenefitPlans 31 false false R32.htm 31203 - Disclosure - Accumulated Other Comprehensive Loss (Tables) Sheet http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLossTables Accumulated Other Comprehensive Loss (Tables) Tables http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLoss 32 false false R33.htm 31303 - Disclosure - Earnings (Loss) and Dividends Per Share (Tables) Sheet http://www.janus.com/role/DisclosureEarningsLossAndDividendsPerShareTables Earnings (Loss) and Dividends Per Share (Tables) Tables http://www.janus.com/role/DisclosureEarningsLossAndDividendsPerShare 33 false false R34.htm 40101 - Disclosure - Basis of Presentation and Significant Accounting Policies (Details) Sheet http://www.janus.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesDetails Basis of Presentation and Significant Accounting Policies (Details) Details http://www.janus.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies 34 false false R35.htm 40201 - Disclosure - Dispositions (Details) Sheet http://www.janus.com/role/DisclosureDispositionsDetails Dispositions (Details) Details http://www.janus.com/role/DisclosureDispositionsTables 35 false false R36.htm 40202 - Disclosure - Dispositions - Gain on Sale (Details) Sheet http://www.janus.com/role/DisclosureDispositionsGainOnSaleDetails Dispositions - Gain on Sale (Details) Details 36 false false R37.htm 40301 - Disclosure - Consolidation - VIEs (Details) Sheet http://www.janus.com/role/DisclosureConsolidationViesDetails Consolidation - VIEs (Details) Details 37 false false R38.htm 40302 - Disclosure - Consolidation - VREs (Details) Sheet http://www.janus.com/role/DisclosureConsolidationVresDetails Consolidation - VREs (Details) Details 38 false false R39.htm 40401 - Disclosure - Investment Securities - General Disclosure (Details) Sheet http://www.janus.com/role/DisclosureInvestmentSecuritiesGeneralDisclosureDetails Investment Securities - General Disclosure (Details) Details 39 false false R40.htm 40402 - Disclosure - Investment Securities - Offsetting Derivatives (Details) Sheet http://www.janus.com/role/DisclosureInvestmentSecuritiesOffsettingDerivativesDetails Investment Securities - Offsetting Derivatives (Details) Details 40 false false R41.htm 40501 - Disclosure - Fair Value Measurements - Level of Fair Value (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsLevelOfFairValueDetails Fair Value Measurements - Level of Fair Value (Details) Details 41 false false R42.htm 40502 - Disclosure - Fair Value Measurements - Valuation techniques and significant unobservable inputs (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsValuationTechniquesAndSignificantUnobservableInputsDetails Fair Value Measurements - Valuation techniques and significant unobservable inputs (Details) Details 42 false false R43.htm 40503 - Disclosure - Fair Value Measurements - Contingent Consideration (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsContingentConsiderationDetails Fair Value Measurements - Contingent Consideration (Details) Details 43 false false R44.htm 40504 - Disclosure - Fair Value Measurements - Disposal of Geneva (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsDisposalOfGenevaDetails Fair Value Measurements - Disposal of Geneva (Details) Details 44 false false R45.htm 40505 - Disclosure - Fair Value Measurements - Acquisition of Kapstream (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsAcquisitionOfKapstreamDetails Fair Value Measurements - Acquisition of Kapstream (Details) Details 45 false false R46.htm 40506 - Disclosure - Fair Value Measurements - Disposal of Volantis (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsDisposalOfVolantisDetails Fair Value Measurements - Disposal of Volantis (Details) Details 46 false false R47.htm 40507 - Disclosure - Fair Value Measurements - Level 3 Rollforward (Details) Sheet http://www.janus.com/role/DisclosureFairValueMeasurementsLevel3RollforwardDetails Fair Value Measurements - Level 3 Rollforward (Details) Details 47 false false R48.htm 40601 - Disclosure - Goodwill and Intangible Assets (Details) Sheet http://www.janus.com/role/DisclosureGoodwillAndIntangibleAssetsDetails Goodwill and Intangible Assets (Details) Details http://www.janus.com/role/DisclosureGoodwillAndIntangibleAssetsTables 48 false false R49.htm 40701 - Disclosure - Debt (Details) Sheet http://www.janus.com/role/DisclosureDebtDetails Debt (Details) Details http://www.janus.com/role/DisclosureDebtTables 49 false false R50.htm 40801 - Disclosure - Income Taxes (Details) Sheet http://www.janus.com/role/DisclosureIncomeTaxesDetails Income Taxes (Details) Details http://www.janus.com/role/DisclosureIncomeTaxesTables 50 false false R51.htm 40901 - Disclosure - Noncontrolling Interests - Redeemable (Details) Sheet http://www.janus.com/role/DisclosureNoncontrollingInterestsRedeemableDetails Noncontrolling Interests - Redeemable (Details) Details 51 false false R52.htm 40902 - Disclosure - Noncontrolling Interests - Nonredeemable (Details) Sheet http://www.janus.com/role/DisclosureNoncontrollingInterestsNonredeemableDetails Noncontrolling Interests - Nonredeemable (Details) Details 52 false false R53.htm 41001 - Disclosure - Long-Term Incentive and Employee Compensation (Details) Sheet http://www.janus.com/role/DisclosureLongTermIncentiveAndEmployeeCompensationDetails Long-Term Incentive and Employee Compensation (Details) Details 53 false false R54.htm 41101 - Disclosure - Retirement benefit plans - Actuarial gains(losses), benefit cost, cash flows (Details) Sheet http://www.janus.com/role/DisclosureRetirementBenefitPlansActuarialGainsLossesBenefitCostCashFlowsDetails Retirement benefit plans - Actuarial gains(losses), benefit cost, cash flows (Details) Details 54 false false R55.htm 41201 - Disclosure - Accumulated Other Comprehensive Loss (Details) Sheet http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLossDetails Accumulated Other Comprehensive Loss (Details) Details http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLossTables 55 false false R56.htm 41202 - Disclosure - Accumulated Other Comprehensive Loss - OCI (Details) Sheet http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLossOciDetails Accumulated Other Comprehensive Loss - OCI (Details) Details http://www.janus.com/role/DisclosureAccumulatedOtherComprehensiveLossTables 56 false false R57.htm 41301 - Disclosure - Earnings (Loss) and Dividends Per Share (Details) Sheet http://www.janus.com/role/DisclosureEarningsLossAndDividendsPerShareDetails Earnings (Loss) and Dividends Per Share (Details) Details http://www.janus.com/role/DisclosureEarningsLossAndDividendsPerShareTables 57 false false All Reports Book All Reports jhg-20200630x10q.htm jhg-20200630.xsd jhg-20200630_cal.xml jhg-20200630_def.xml jhg-20200630_lab.xml jhg-20200630_pre.xml jhg-20200630xex15d1.htm jhg-20200630xex31d1.htm jhg-20200630xex31d2.htm jhg-20200630xex32d1.htm jhg-20200630xex32d2.htm jhg-20200630x10q001.gif jhg-20200630x10q003.jpg http://fasb.org/us-gaap/2019-01-31 http://xbrl.sec.gov/dei/2019-01-31 http://xbrl.sec.gov/country/2017-01-31 http://fasb.org/srt/2019-01-31 true true