This annual shareholder report contains important information about DWS Money Market Prime Series (the "Fund") for the period August 1, 2024 to July 31, 2025.

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.

Additional Information Phone Number

(800) 728-3337

Additional Information Website

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Expenses [Text Block]

What were the Fund costs for the last year?

(Based on a hypothetical $10,000 investment)

Fund	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
DWS Cash Investment Trust Class A	$88	0.86%

Gross expense ratio as of the latest prospectus: 0.86%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount

$ 88

Expense Ratio, Percent

0.86%

AssetsNet

$ 570,614,217

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 1,821,253

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets ($)	570,614,217
Number of Portfolio Holdings	67
Total Net Advisory Fees Paid ($)	1,821,253
Weighted Average Maturity	36 days
7-Day Current Yield	3.59%

Weighted average maturity, also known as effective maturity, is the weighted average of the maturity date of bonds held by the Fund taking into consideration any available maturity shortening features.

Yields fluctuate and are not guaranteed. The 7-day current yield is the annualized net investment income per share as of July 31, 2025. The 7-Day Current Yield would have been 3.57% had certain expenses not been reduced.

Holdings [Text Block]

What did the Fund invest in?

Asset Allocation

Asset Type	% of Net Assets
Repurchase Agreements	41%
Variable Rate Demand Notes	18%
Certificates of Deposit and Bank Notes	16%
Commercial Paper	14%
Time Deposits	9%
Variable Rate Demand Preferred Shares	2%
Other Assets and Liabilities, Net	0%
Total	100%

Holdings-based data is subject to change.

C000035163

Shareholder Report [Line Items]

Fund Name

DWS Money Market Prime Series

Class Name

DWS Cash Investment Trust Class C

Trading Symbol

DOCXX

Annual or Semi-Annual Statement [Text Block]

This annual shareholder report contains important information about DWS Money Market Prime Series (the "Fund") for the period August 1, 2024 to July 31, 2025.

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.

Additional Information Phone Number

(800) 728-3337

Additional Information Website

Expenses [Text Block]

What were the Fund costs for the last year?

(Based on a hypothetical $10,000 investment)

Fund	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
DWS Cash Investment Trust Class C	$163	1.60%

Gross expense ratio as of the latest prospectus: 1.58%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount

$ 163

Expense Ratio, Percent

1.60%

AssetsNet

$ 570,614,217

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 1,821,253

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets ($)	570,614,217
Number of Portfolio Holdings	67
Total Net Advisory Fees Paid ($)	1,821,253
Weighted Average Maturity	36 days
7-Day Current Yield	2.88%

Yields fluctuate and are not guaranteed. The 7-day current yield is the annualized net investment income per share as of July 31, 2025.

Holdings [Text Block]

What did the Fund invest in?

Asset Allocation

Asset Type	% of Net Assets
Repurchase Agreements	41%
Variable Rate Demand Notes	18%
Certificates of Deposit and Bank Notes	16%
Commercial Paper	14%
Time Deposits	9%
Variable Rate Demand Preferred Shares	2%
Other Assets and Liabilities, Net	0%
Total	100%

Holdings-based data is subject to change.

C000035164

Shareholder Report [Line Items]

Fund Name

DWS Money Market Prime Series

Class Name

DWS Cash Investment Trust Class S

Trading Symbol

DOSXX

Annual or Semi-Annual Statement [Text Block]

This annual shareholder report contains important information about DWS Money Market Prime Series (the "Fund") for the period August 1, 2024 to July 31, 2025.

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.

Additional Information Phone Number

(800) 728-3337

Additional Information Website

Expenses [Text Block]

What were the Fund costs for the last year?

(Based on a hypothetical $10,000 investment)

Fund	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
DWS Cash Investment Trust Class S	$59	0.58%

Gross expense ratio as of the latest prospectus: 0.64%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount

$ 59

Expense Ratio, Percent

0.58%

AssetsNet

$ 570,614,217

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 1,821,253

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets ($)	570,614,217
Number of Portfolio Holdings	67
Total Net Advisory Fees Paid ($)	1,821,253
Weighted Average Maturity	36 days
7-Day Current Yield	3.88%

Yields fluctuate and are not guaranteed. The 7-day current yield is the annualized net investment income per share as of July 31, 2025. The 7-Day Current Yield would have been 3.79% had certain expenses not been reduced.

Holdings [Text Block]

What did the Fund invest in?

Asset Allocation

Asset Type	% of Net Assets
Repurchase Agreements	41%
Variable Rate Demand Notes	18%
Certificates of Deposit and Bank Notes	16%
Commercial Paper	14%
Time Deposits	9%
Variable Rate Demand Preferred Shares	2%
Other Assets and Liabilities, Net	0%
Total	100%

Holdings-based data is subject to change.

C000016691

Shareholder Report [Line Items]

Fund Name

DWS Money Market Prime Series

Class Name

DWS Money Market Fund

Trading Symbol

KMMXX

Annual or Semi-Annual Statement [Text Block]

This annual shareholder report contains important information about DWS Money Market Prime Series (the "Fund") for the period August 1, 2024 to July 31, 2025.

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.

Additional Information Phone Number

(800) 728-3337

Additional Information Website

Expenses [Text Block]

What were the Fund costs for the last year?

(Based on a hypothetical $10,000 investment)

Fund	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
DWS Money Market Fund	$59	0.58%

Gross expense ratio as of the latest prospectus: 0.60%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount

$ 59

Expense Ratio, Percent

0.58%

AssetsNet

$ 570,614,217

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 1,821,253

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets ($)	570,614,217
Number of Portfolio Holdings	67
Total Net Advisory Fees Paid ($)	1,821,253
Weighted Average Maturity	36 days
7-Day Current Yield	3.87%

Yields fluctuate and are not guaranteed. The 7-day current yield is the annualized net investment income per share as of July 31, 2025. The 7-Day Current Yield would have been 3.83% had certain expenses not been reduced.

Holdings [Text Block]

What did the Fund invest in?

Asset Allocation

Asset Type	% of Net Assets
Repurchase Agreements	41%
Variable Rate Demand Notes	18%
Certificates of Deposit and Bank Notes	16%
Commercial Paper	14%
Time Deposits	9%
Variable Rate Demand Preferred Shares	2%
Other Assets and Liabilities, Net	0%
Total	100%

Holdings-based data is subject to change.