DWS Tax-Exempt Portfolio Investment Strategy - DWS Tax Free Mony Fund Cl S [Member] - DWS Tax-Exempt Portfolio	Apr. 30, 2025
Prospectus [Line Items]
Strategy [Heading]	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	Main investments. The fund normally invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in municipal securities, the income from which is free from regular federal income tax and alternative minimum tax (AMT). This policy is fundamental and may not be changed without shareholder approval.Due to regulatory changes, effective June 11, 2026, the fund will replace the 80% investment policy and related disclosures set forth in this prospectus. Specifically, effective June 11, 2026, under normal circumstances, the fund will invest at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in municipal securities, the income from which is free from regular federal income tax and alternative minimum tax (AMT).The fund is a money market fund that is managed in accordance with federal regulations, which govern the quality, maturity, diversity and liquidity of instruments in which a money market fund may invest.The fund follows policies designed to maintain a stable $1.00 share price.The fund may invest in municipal trust receipts (MTRs), general obligation and revenue notes and bonds, municipal obligations backed by third parties, obligations of the territories or Commonwealths of the US and other municipal instruments paying a fixed, variable or floating interest rate.The fund is designed for investors in a moderate to high tax bracket who are interested in federal tax-exempt income along with the liquidity and stability that a money market fund is designed to offer.Management process. Working in consultation with portfolio management, a credit team screens potential securities and develops a list of those that the fund may buy. Portfolio management, looking for attractive yield and weighing considerations such as credit quality, economic outlooks and possible interest rate movements, then decides which securities on this list to buy.

DWS Tax-Exempt Portfolio Investment Strategy - DWS Tax Free Mony Fund Cl S [Member] - DWS Tax-Exempt Portfolio

Apr. 30, 2025

<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Principal Investment Strategies</span>

Strategy Narrative [Text Block]

Main investments. The fund normally invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in municipal securities, the income from which is free from regular federal income tax and alternative minimum tax (AMT). This policy is fundamental and may not be changed without shareholder approval.Due to regulatory changes, effective June 11, 2026, the fund will replace the 80% investment policy and related disclosures set forth in this prospectus. Specifically, effective June 11, 2026, under normal circumstances, the fund will invest at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in municipal securities, the income from which is free from regular federal income tax and alternative minimum tax (AMT).The fund is a money market fund that is managed in accordance with federal regulations, which govern the quality, maturity, diversity and liquidity of instruments in which a money market fund may invest.The fund follows policies designed to maintain a stable $1.00 share price.The fund may invest in municipal trust receipts (MTRs), general obligation and revenue notes and bonds, municipal obligations backed by third parties, obligations of the territories or Commonwealths of the US and other municipal instruments paying a fixed, variable or floating interest rate.The fund is designed for investors in a moderate to high tax bracket who are interested in federal tax-exempt income along with the liquidity and stability that a money market fund is designed to offer.Management process. Working in consultation with portfolio management, a credit team screens potential securities and develops a list of those that the fund may buy. Portfolio management, looking for attractive yield and weighing considerations such as credit quality, economic outlooks and possible interest rate movements, then decides which securities on this list to buy.