DWS Tax-Exempt Portfolio Performance Management - Tax Exempt Cash Managed Shares [Member] - DWS Tax-Exempt Portfolio |
Apr. 30, 2025 |
|---|---|
| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Past Performance</span> |
| Performance Narrative [Text Block] | How a fund's returns vary from year to year can give an idea of its risk. Past performance may not indicate future results. All performance figures below assume that dividends were reinvested. The 7-day yield, which is often referred to as the “current yield,” is the income generated by the fund over a seven-day period. This amount is then annualized, which means that we assume the fund generates the same income every week for a year. For more recent performance figures and the current yield, go to dws.com (the Web site does not form a part of this prospectus) or call the telephone number included in this prospectus. |
| Performance Past Does Not Indicate Future [Text] | <span style="color:#000000;font-family:Arial;font-size:10pt;"> Past performance may not indicate future </span><span style="color:#000000;font-family:Arial;font-size:10pt;">results.</span> |
| Performance Information Illustrates Variability of Returns [Text] | <span style="color:#000000;font-family:Arial;font-size:10pt;">How a fund's returns vary from year to year can give an idea of its risk.</span> |
| Bar Chart Narrative [Text Block] | Returns for other classes were different and are not shown here. |
| Bar Chart [Heading] | <span style="color:#000000;font-family:Arial;font-size:10pt;text-transform:uppercase;">CALENDAR YEAR TOTAL RETURNS </span><span style="color:#000000;font-family:Arial;font-size:8pt;">(%) (Tax-Exempt Cash Managed Shares)</span> |
| Bar Chart Closing [Text Block] | ReturnsPeriod endingBest Quarter0.82%December 31, 2023Worst Quarter0.00%March 31, 2015Year-to-Date1.18%June 30, 2025 |
| Performance Table Heading | <span style="font-family:Arial;font-size:10pt;text-transform:uppercase;">Average Annual Total Returns</span> <br/><span style="font-family:Arial;font-size:8pt;">(For periods ended 12/31/2024 expressed as a %) (Tax-Exempt Cash Managed Shares)</span> |
| Performance Table Closing [Text Block] | Total returns would have been lower if operating expenses had not been reduced.For more recent performance information, contact the financial services firm from which you obtained this prospectus. |
| Performance Availability Website Address [Text] | <span style="color:#000000;font-family:Arial;font-size:10pt;">dws.com</span> |
| Tax-Exempt Cash Managed Shares | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | <span style="font-family:Arial;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Year-to-Date</span> |
| Bar Chart, Year to Date Return | 1.18% |
| Bar Chart, Year to Date Return, Date | Jun. 30, 2025 |
| Highest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Best Quarter</span> |
| Highest Quarterly Return | 0.82% |
| Highest Quarterly Return, Date | Dec. 31, 2023 |
| Lowest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Worst Quarter</span> |
| Lowest Quarterly Return | none |
| Lowest Quarterly Return, Date | Mar. 31, 2015 |