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DWS Treasury Portfolio Investment Risks - Investment Class Shares [Member] - DWS Treasury Portfolio
Mar. 31, 2025
Risk Money Market Fund [Member]  
Prospectus [Line Items]  
Risk [Text Block] Money market fund risk. You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.The Advisor has no legal obligation to provide financial support to the fund, and you should not expect that the Advisor will provide financial support to the fund at any time.
Risk Market [Member]  
Prospectus [Line Items]  
Risk [Text Block] Market risk. The market value of the securities in which the fund invests may be impacted by the prospects of individual issuers, particular sectors or governments and/or general economic conditions throughout the world due to increasingly interconnected global economies and financial markets.
Risk Market Disruption [Member]  
Prospectus [Line Items]  
Risk [Text Block] Market disruption risk. Economies and financial markets throughout the world have become increasingly interconnected, which has increased the likelihood that events or conditions in one country or region will adversely impact markets or issuers in other countries or regions. This includes reliance on global supply chains that are susceptible to disruptions resulting from, among other things, war and other armed conflicts, tariffs, extreme weather events, and natural disasters. Such supply chain disruptions can lead to, and have led to, economic and market disruptions that have far-reaching effects on financial markets worldwide. The value of the fund’s investments may be negatively affected by adverse changes in overall economic or market conditions, such as the level of economic activity and productivity, unemployment and labor force participation rates, inflation or deflation (and expectations for inflation or deflation), interest rates, demand and supply for particular products or resources including labor, debt levels and credit ratings, and trade policies, among other factors. Such adverse conditions may contribute to an overall economic contraction across entire economies or markets, which may negatively impact the profitability of issuers operating in those economies or markets. In addition, geopolitical and other globally interconnected occurrences, including war, terrorism, economic uncertainty or financial crises, contagion, tariffs and trade disputes, government debt crises (including defaults or downgrades) or uncertainty about government debt payments, government shutdowns, public health crises, natural disasters, supply chain disruptions, climate change and related events or conditions, have led, and in the future may lead, to disruptions in the US and world economies and markets, which may increase financial market volatility and have significant adverse direct or indirect effects on the fund and its investments. Adverse market conditions or disruptions could cause the fund to lose money, experience significant redemptions, and encounter operational difficulties. Although multiple asset classes may be affected by adverse market conditions or a particular market disruption, the duration and effects may not be the same for all types of assets.Current military and other armed conflicts in various geographic regions, including those in Europe and the Middle East, can lead to, and have led to, economic and market disruptions, which may not be limited to the geographic region in which the conflict is occurring. Such conflicts can also result, and have resulted in some cases, in sanctions being levied by the United States, the European Union and/or other countries against countries or other actors involved in the conflict. In addition, such conflicts and related sanctions can adversely affect regional and global energy, commodities, financial and other markets and thus could affect the value of the fund's investments. The extent and duration of any military conflict, related sanctions and resulting economic and market disruptions are impossible to predict, but could be substantial.Other market disruption events include pandemic spread of viruses, such as the novel coronavirus known as COVID-19, which have caused significant uncertainty, market volatility, decreased economic and other activity, increased government activity, including economic stimulus measures, and supply chain disruptions, and may adversely affect the fund and its investments.In addition, markets are becoming increasingly susceptible to disruption events resulting from the use of new and emerging technologies to engage in cyber-attacks or to take over the Web sites and/or social media accounts of companies, governmental entities or public officials, or to otherwise pose as or impersonate such, which then may be used to disseminate false or misleading information that can cause volatility in financial markets or for the securities of a particular company, group of companies, industry or other class of assets.Adverse market conditions or particular market disruptions, such as those discussed above, may magnify the impact of each of the other risks described in this “MAIN RISKS” section and may increase volatility in one or more markets in which the fund invests leading to the potential for greater losses for the fund.
Risk Interest Rate [Member]  
Prospectus [Line Items]  
Risk [Text Block] Interest rate risk. Rising interest rates could cause the value of the fund’s investments — and therefore its share price as well — to decline. A rising interest rate environment may cause investors to move out of fixed-income securities and related markets on a large scale, which could adversely affect the price and liquidity of such securities and could also result in increased redemptions from the fund. Increased redemptions from the fund may force the fund to sell investments at a time when it is not advantageous to do so, which could result in losses. A sharp rise in interest rates could cause the value of the fund’s investments to decline and impair the fund’s ability to maintain a stable $1.00 share price. Conversely, any decline in interest rates is likely to cause the fund’s yield to decline, and during periods of unusually low or negative interest rates, the fund’s yield may approach or fall below zero. A low or negative interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of current income and, at times, could impair the fund’s ability to maintain a stable $1.00 share price. Over time, the total return of a money market fund may not keep pace with inflation, which could result in a net loss of purchasing power for long-term investors. Interest rates can change in response to the supply and demand for credit, government and/or central bank monetary policy and action, inflation rates, and other factors. Recent and potential future changes in monetary policy made by central banks or governments are likely to affect the level of interest rates. Changing interest rates may have unpredictable effects on markets, may result in heightened market volatility and potential illiquidity and may detract from fund performance to the extent the fund is exposed to such interest rates and/or volatility. Money market funds try to minimize interest rate risk by purchasing short-term securities. If there is an insufficient supply of US government securities to meet investor demand, it could result in lower yields on such securities and increase interest rate risk for the fund.
Risk Security Selection [Member]  
Prospectus [Line Items]  
Risk [Text Block] Security selection risk. Although short-term securities are relatively stable investments, it is possible that the securities in which the fund invests will not perform as expected. This could cause the fund's returns to lag behind those of similar money market funds and could result in a decline in share price.
Risk Repurchase [Member]  
Prospectus [Line Items]  
Risk [Text Block] Repurchase agreement risk. If the party that sells the securities to the fund defaults on its obligation to repurchase them at the agreed-upon time and price, the fund could lose money.
Risk Counterparty [Member]  
Prospectus [Line Items]  
Risk [Text Block] Counterparty risk. A financial institution or other counterparty with whom the fund does business, or that underwrites, distributes or guarantees any investments or contracts that the fund owns or is otherwise exposed to, may decline in financial health and become unable to honor its commitments. This could cause losses for the fund or could delay the return or delivery of collateral or other assets to the fund.
Risk Credit [Member]  
Prospectus [Line Items]  
Risk [Text Block] Credit risk. The fund's performance could be hurt and the fund's share price could fall below $1.00 if an issuer of a debt security suffers an adverse change in financial condition that results in the issuer not making timely payments of interest or principal, a security downgrade or an inability to meet a financial obligation.
Risk US Government Default [Member]  
Prospectus [Line Items]  
Risk [Text Block] US government default risk. Due to the rising US government debt burden and potential limitations caused by the statutory debt ceiling, it is possible that the US government may not be able to meet its financial obligations or that securities issued by the US government may experience credit downgrades. In the past, US sovereign credit has experienced downgrades and there can be no guarantee that it will not experience further downgrades in the future by rating agencies. Such a credit event may adversely impact the financial markets and the fund. From time to time, uncertainty regarding the status of negotiations in the US government to increase the statutory debt ceiling and/or failure to increase the statutory debt ceiling could increase the risk that the US government may default on payments on certain US government securities, cause the credit rating of the US government to be downgraded or increase volatility in financial markets, result in higher interest rates, reduce prices of US Treasury securities and/or increase the costs of certain kinds of debt.
Risk Liquidity [Member]  
Prospectus [Line Items]  
Risk [Text Block] Liquidity and transaction risk. The liquidity of portfolio securities can deteriorate rapidly due to credit events affecting issuers or due to general market conditions and a lack of willing buyers. When there are no willing buyers and an instrument cannot be readily sold at a desired time or price, the fund may have to accept a lower price or may not be able to sell the instrument at all. The potential for liquidity risk may be magnified by a rising interest rate environment or other circumstances where investor redemptions from money market funds may be higher than normal, potentially causing increased supply in the market due to selling activity. If dealer capacity in debt instruments is insufficient for market conditions, it may further inhibit liquidity and increase volatility in the debt markets. Additionally, market participants other than the fund may attempt to sell debt holdings at the same time as the fund, which could cause downward pricing pressure and contribute to illiquidity. An inability to sell one or more portfolio securities can adversely affect the fund’s ability to maintain a $1.00 share price or prevent the fund from being able to take advantage of other investment opportunities.Unusual market conditions, an unusually high volume of redemption requests or other similar conditions could cause the fund to be unable to pay redemption proceeds within a short period of time. If the fund is forced to sell securities at an unfavorable time and/or under unfavorable conditions, such sales may adversely affect the fund’s ability to maintain a $1.00 share price.
Risk Holding Cash [Member]  
Prospectus [Line Items]  
Risk [Text Block] Risks of holding cash. The fund will at times hold cash positions, which may hurt the fund’s performance. Cash positions may also subject the fund to additional risks and costs, including any fees imposed by the fund’s custodian for large cash balances.
Risk Inflation [Member]  
Prospectus [Line Items]  
Risk [Text Block] Inflation risk. Inflation risk is the risk that the real value of certain assets or real income from investments (the value of such assets or income after accounting for inflation) will be less in the future as inflation decreases the value of money. Inflation, and investors’ expectation of future inflation, can impact the current value of the fund's portfolio, resulting in lower asset values and losses to shareholders. This risk may be elevated compared to historical market conditions and could be impacted by monetary policy measures and the current interest rate environment.
Risk Operational And Technology [Member]  
Prospectus [Line Items]  
Risk [Text Block] Operational and technology risk. Cyber-attacks, disruptions or failures that affect the fund’s service providers or counterparties, issuers of securities held by the fund, or other market participants may adversely affect the fund and its shareholders, including by causing losses for the fund or impairing fund operations. For example, the fund’s or its service providers’ assets or sensitive or confidential information may be misappropriated, data may be corrupted and operations may be disrupted (e.g., cyber-attacks, operational failures or broader disruptions may cause the release of private shareholder information or confidential fund information, interfere with the processing of shareholder transactions, impact the ability to calculate the fund’s net asset value and impede trading). Market events and disruptions also may trigger a volume of transactions that overloads current information technology and communication systems and processes, impacting the ability to conduct the fund’s operations.While the fund and its service providers may establish business continuity and other plans and processes that seek to address the possibility of and fallout from cyber-attacks, disruptions or failures, there are inherent limitations in such plans and systems, including that they do not apply to third parties, such as fund counterparties, issuers of securities held by the fund or other market participants, as well as the possibility that certain risks have not been identified or that unknown threats may emerge in the future and there is no assurance that such plans and processes will be effective. Among other situations, disruptions (for example, pandemics or health crises) that cause prolonged periods of remote work or significant employee absences at the fund’s service providers could impact the ability to conduct the fund’s operations. In addition, the fund cannot directly control any cybersecurity plans and systems put in place by its service providers, fund counterparties, issuers of securities held by the fund or other market participants.
Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] There are several risk factors that could reduce the yield you get from the fund, cause the fund’s performance to trail that of other investments, or cause you to lose money.
Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Money Market Fund May Not Preserve Dollar [Member]  
Prospectus [Line Items]  
Risk [Text Block] Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so.
Risk Money Market Fund Sponsor May Not Provide Support [Member]  
Prospectus [Line Items]  
Risk [Text Block] The Advisor has no legal obligation to provide financial support to the fund, and you should not expect that the Advisor will provide financial support to the fund at any time.