3.20.2 html 21 154 1 false 21 0 false 2 false false R1.htm 000000 - Document - Document and Entity Information {Elements} Sheet http://www.deutschefunds.com/role/DocumentDocumentandEntityInformationElements Document and Entity Information 1 false true R2.htm 000011 - Document - Risk/Return Summary {Unlabeled} - DWS Government and Agency Securities Portfolio (DWS Gov and Agcy Money Fund) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSGovernmentandAgencySecuritiesPortfolioDWSGovandAgcyMoneyFund Risk/Return Summary- DWS Government and Agency Securities Portfolio (DWS Gov and Agcy Money Fund) 2 false false R8.htm 000019 - Disclosure - Risk/Return Detail Data {Elements} - DWS Government and Agency Securities Portfolio (DWS Gov and Agcy Money Fund) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSGovernmentandAgencySecuritiesPortfolioDWSGovandAgcyMoneyFund Risk/Return Detail Data- DWS Government and Agency Securities Portfolio (DWS Gov and Agcy Money Fund) 3 false true R9.htm 000021 - Document - Risk/Return Summary {Unlabeled} - DWS Government and Agency Securities Portfolio (DWS Gov Cash Inst Shares) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSGovernmentandAgencySecuritiesPortfolioDWSGovCashInstShares Risk/Return Summary- DWS Government and Agency Securities Portfolio (DWS Gov Cash Inst Shares) 4 false false R15.htm 000029 - Disclosure - Risk/Return Detail Data {Elements} - DWS Government and Agency Securities Portfolio (DWS Gov Cash Inst Shares) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSGovernmentandAgencySecuritiesPortfolioDWSGovCashInstShares Risk/Return Detail Data- DWS Government and Agency Securities Portfolio (DWS Gov Cash Inst Shares) 5 false true R16.htm 000031 - Document - Risk/Return Summary {Unlabeled} - DWS Government and Agency Securities Portfolio (Government Cash Managed Shares) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSGovernmentandAgencySecuritiesPortfolioGovernmentCashManagedShares Risk/Return Summary- DWS Government and Agency Securities Portfolio (Government Cash Managed Shares) 6 false false R22.htm 000039 - Disclosure - Risk/Return Detail Data {Elements} - DWS Government and Agency Securities Portfolio (Government Cash Managed Shares) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSGovernmentandAgencySecuritiesPortfolioGovernmentCashManagedShares Risk/Return Detail Data- DWS Government and Agency Securities Portfolio (Government Cash Managed Shares) 7 false true R23.htm 000041 - Document - Risk/Return Summary {Unlabeled} - DWS Government and Agency Securities Portfolio (Service Shares) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSGovernmentandAgencySecuritiesPortfolioServiceShares Risk/Return Summary- DWS Government and Agency Securities Portfolio (Service Shares) 8 false false R29.htm 000049 - Disclosure - Risk/Return Detail Data {Elements} - DWS Government and Agency Securities Portfolio (Service Shares) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSGovernmentandAgencySecuritiesPortfolioServiceShares Risk/Return Detail Data- DWS Government and Agency Securities Portfolio (Service Shares) 9 false true R30.htm 000051 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (Service Shares) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioServiceShares Risk/Return Summary- DWS Tax-Exempt Portfolio (Service Shares) 10 false false R36.htm 000059 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (Service Shares) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioServiceShares Risk/Return Detail Data- DWS Tax-Exempt Portfolio (Service Shares) 11 false true R37.htm 000061 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (DWS Tax Expt Cash Prmr Shrs) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioDWSTaxExptCashPrmrShrs Risk/Return Summary- DWS Tax-Exempt Portfolio (DWS Tax Expt Cash Prmr Shrs) 12 false false R43.htm 000069 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (DWS Tax Expt Cash Prmr Shrs) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioDWSTaxExptCashPrmrShrs Risk/Return Detail Data- DWS Tax-Exempt Portfolio (DWS Tax Expt Cash Prmr Shrs) 13 false true R44.htm 000071 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (DWS Tax Exempt Money Fund) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioDWSTaxExemptMoneyFund Risk/Return Summary- DWS Tax-Exempt Portfolio (DWS Tax Exempt Money Fund) 14 false false R50.htm 000079 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (DWS Tax Exempt Money Fund) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioDWSTaxExemptMoneyFund Risk/Return Detail Data- DWS Tax-Exempt Portfolio (DWS Tax Exempt Money Fund) 15 false true R51.htm 000081 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (DWS Tax Free Mony Fund Cl S) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioDWSTaxFreeMonyFundClS Risk/Return Summary- DWS Tax-Exempt Portfolio (DWS Tax Free Mony Fund Cl S) 16 false false R57.htm 000089 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (DWS Tax Free Mony Fund Cl S) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioDWSTaxFreeMonyFundClS Risk/Return Detail Data- DWS Tax-Exempt Portfolio (DWS Tax Free Mony Fund Cl S) 17 false true R58.htm 000091 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (Tax Exempt Cash Managed Shares) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioTaxExemptCashManagedShares Risk/Return Summary- DWS Tax-Exempt Portfolio (Tax Exempt Cash Managed Shares) 18 false false R64.htm 000099 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (Tax Exempt Cash Managed Shares) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioTaxExemptCashManagedShares Risk/Return Detail Data- DWS Tax-Exempt Portfolio (Tax Exempt Cash Managed Shares) 19 false true R65.htm 000101 - Document - Risk/Return Summary {Unlabeled} - DWS Tax-Exempt Portfolio (Tax Free Investment Class) Sheet http://www.deutschefunds.com/role/DocumentRiskReturnSummaryUnlabeledDWSTax-ExemptPortfolioTaxFreeInvestmentClass Risk/Return Summary- DWS Tax-Exempt Portfolio (Tax Free Investment Class) 20 false false R71.htm 000109 - Disclosure - Risk/Return Detail Data {Elements} - DWS Tax-Exempt Portfolio (Tax Free Investment Class) Sheet http://www.deutschefunds.com/role/DisclosureRiskReturnDetailDataElementsDWSTax-ExemptPortfolioTaxFreeInvestmentClass Risk/Return Detail Data- DWS Tax-Exempt Portfolio (Tax Free Investment Class) 21 false false R72.htm 040000 - Disclosure - Risk/Return Detail Data {Elements} Sheet http://xbrl.sec.gov/rr/role/RiskReturnDetailData Risk/Return Detail Data 22 false false All Reports Book All Reports cat-20200728.xml cat-20200728.xsd cat-20200728_cal.xml cat-20200728_def.xml cat-20200728_lab.xml cat-20200728_pre.xml BarChart1.png BarChart2.png BarChart3.png BarChart4.png BarChart5.png BarChart6.png BarChart7.png BarChart8.png BarChart9.png BarChart10.png http://xbrl.sec.gov/rr/2018-01-31 http://xbrl.sec.gov/dei/2018-01-31 true true