| Label | Element | Value | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Document Type | dei_DocumentType | 485BPOS | ||||||||||||
| Document Period End Date | dei_DocumentPeriodEndDate | Dec. 31, 2024 | ||||||||||||
| Entity Registrant Name | dei_EntityRegistrantName | Putnam Investment Funds | ||||||||||||
| Entity Central Index Key | dei_EntityCentralIndexKey | 0000932101 | ||||||||||||
| Entity Inv Company Type | dei_EntityInvCompanyType | N-1A | ||||||||||||
| Amendment Flag | dei_AmendmentFlag | false | ||||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk/Return [Heading] | rr_RiskReturnHeading | Fund Summary | ||||||||||||
| Objective [Heading] | rr_ObjectiveHeading | Goal | ||||||||||||
| Objective, Primary [Text Block] | rr_ObjectivePrimaryTextBlock | The fund seeks as high a rate of current income as the Investment Manager (as defined below) believes is consistent with preservation of capital and maintenance of liquidity. |
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| Expense [Heading] | rr_ExpenseHeading | Fees and expenses | ||||||||||||
| Expense Narrative [Text Block] | rr_ExpenseNarrativeTextBlock | The following tables describe the fees and expenses you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. Information about sales charge discounts is available from your financial professional and in the Appendix to the fund’s prospectus. |
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| Shareholder Fees Caption [Text] | rr_ShareholderFeesCaption | Shareholder Fees (fees paid directly from your investment) | ||||||||||||
| Operating Expenses Caption [Text] | rr_OperatingExpensesCaption | Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment) | ||||||||||||
| Expense Example [Heading] | rr_ExpenseExampleHeading | Example | ||||||||||||
| Expense Example Narrative [Text Block] | rr_ExpenseExampleNarrativeTextBlock | The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then, except as indicated, redeem or hold all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Your actual costs may be higher or lower. |
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| Strategy [Heading] | rr_StrategyHeading | Investments, risks, and performance | ||||||||||||
| Strategy Narrative [Text Block] | rr_StrategyNarrativeTextBlock | Investments We invest at least 99.5 percent of the fund’s total assets in cash, U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities or cash. We invest mainly in debt securities that are obligations of the U.S. government, its agencies and instrumentalities and accordingly are backed by the full faith and credit of the United States (e.g., U.S. Treasury bills) or by the credit of a federal agency or government-sponsored entity (e.g.,securities issued by Fannie Mae and Freddie Mac). The U.S. government securities in which we invest may also include variable and floating rate instruments and when-issued and delayed delivery securities (i.e., payment or delivery of the securities occurs at a future date for a predetermined price). Under normal circumstances, we invest at least 80% of the fund’s net assets in U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities. This policy may be changed only after 60 days’ notice to shareholders. The securities purchased by the fund are subject to quality, maturity, diversification and other requirements pursuant to rules promulgated by the Securities and Exchange Commission. We may consider, among other factors, credit and interest rate risks and characteristics of the issuer or counterparty, as well as general market conditions, when deciding whether to buy or sell investments. |
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| Risk [Heading] | rr_RiskHeading | Risks | ||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | It is important to understand that you can lose money by investing in the fund. The value of investments in the fund’s portfolio may fall or fail to rise over extended periods of time for a variety of reasons, including general economic, political or financial market conditions, investor sentiment and market perceptions, government actions, geopolitical events or changes, outbreaks of infectious illnesses or other widespread public health issues, and factors related to a specific issuer, asset class, geography, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings, may negatively impact the fund’s performance, and may exacerbate other risks to which the fund is subject. The values of money market investments usually rise and fall in response to changes in interest rates. Interest rate risk is generally lowest for investments with short maturities (a significant part of the fund’s investments). Changes in the financial condition of an issuer or counterparty, changes in specific economic or political conditions that affect a particular type of issuer, and changes in general economic or political conditions can increase the risk of default by an issuer or counterparty, which can affect a security’s or instrument’s credit quality or value. Certain securities in which the fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States. There is no guarantee that the investment techniques, analyses, or judgments that we apply in making investment decisions for the fund will produce the intended outcome or that the investments we select for the fund will perform as well as other securities that were not selected for the fund. We, or the fund’s other service providers, may experience disruptions or operating errors that could negatively impact the fund. The fund may not achieve its goal, and it is not intended to be a complete investment program. 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 a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund’s sponsor is not required to reimburse the fund for losses, and you should not expect that the sponsor will provide financial support to the fund at any time, including during periods of market stress. |
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| Bar Chart and Performance Table [Heading] | rr_BarChartAndPerformanceTableHeading | Performance | ||||||||||||
| Performance Narrative [Text Block] | rr_PerformanceNarrativeTextBlock | The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Class A shares. The table shows the average annual total returns of each class of the fund that has been in operation for at least one full calendar year. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated performance information, including its current net asset value, available at www.franklintempleton.com. The fund’s past performance is not necessarily an indication of how the fund will perform in the future. |
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| Performance Information Illustrates Variability of Returns [Text] | rr_PerformanceInformationIllustratesVariabilityOfReturns | The accompanying bar chart and table provide some indication of the risks of investing in the fund. | ||||||||||||
| Performance Availability Website Address [Text] | rr_PerformanceAvailabilityWebSiteAddress | www.franklintempleton.com | ||||||||||||
| Performance Past Does Not Indicate Future [Text] | rr_PerformancePastDoesNotIndicateFuture | The fund’s past performance is not necessarily an indication of how the fund will perform in the future | ||||||||||||
| Bar Chart [Heading] | rr_BarChartHeading | Annual total returns for class A shares before sales charges | ||||||||||||
| Highest Quarterly Return, Label | rr_HighestQuarterlyReturnLabel | Best calendar quarter | ||||||||||||
| Highest Quarterly Return, Date | rr_BarChartHighestQuarterlyReturnDate | Sep. 30, 2024 | ||||||||||||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 1.23% | ||||||||||||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | Worst calendar quarter | ||||||||||||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Mar. 31, 2022 | ||||||||||||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | none | ||||||||||||
| Performance Table Heading | rr_PerformanceTableHeading | Average annual total returns after sales charges For periods ended 12/31/24 | ||||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Class A | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | 1.00% | [1] | |||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | [2] | |||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.22% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.49% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 50 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 157 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 274 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 616 | ||||||||||||
| Annual Return 2017 | rr_AnnualReturn2017 | 0.30% | ||||||||||||
| Annual Return 2018 | rr_AnnualReturn2018 | 1.31% | ||||||||||||
| Annual Return 2019 | rr_AnnualReturn2019 | 1.65% | ||||||||||||
| Annual Return 2020 | rr_AnnualReturn2020 | 0.21% | ||||||||||||
| Annual Return 2021 | rr_AnnualReturn2021 | 0.01% | ||||||||||||
| Annual Return 2022 | rr_AnnualReturn2022 | 1.26% | ||||||||||||
| Annual Return 2023 | rr_AnnualReturn2023 | 4.65% | ||||||||||||
| Annual Return 2024 | rr_AnnualReturn2024 | 4.86% | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 4.86% | ||||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.17% | ||||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.62% | [3] | |||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Class C | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | 1.00% | [1] | |||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | [2] | |||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.22% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.49% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 150 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 157 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 274 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | 616 | ||||||||||||
| Expense Example, No Redemption, 1 Year | rr_ExpenseExampleNoRedemptionYear01 | 50 | ||||||||||||
| Expense Example, No Redemption, 3 Years | rr_ExpenseExampleNoRedemptionYear03 | 157 | ||||||||||||
| Expense Example, No Redemption, 5 Years | rr_ExpenseExampleNoRedemptionYear05 | 274 | ||||||||||||
| Expense Example, No Redemption, 10 Years | rr_ExpenseExampleNoRedemptionYear10 | $ 616 | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 3.86% | [4] | |||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.17% | [4] | |||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.62% | [3],[4] | |||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Class G | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | none | ||||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | [2] | |||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.09% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.36% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 37 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 116 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 202 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 456 | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 5.01% | [5] | |||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.26% | [5] | |||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.72% | [3],[5] | |||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Class P | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | none | ||||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | [2] | |||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.09% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.36% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 37 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 116 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 202 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 456 | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 5.01% | ||||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.26% | ||||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.72% | [3] | |||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Class R | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | none | ||||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | [2] | |||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.22% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.49% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 50 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 157 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 274 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 616 | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 4.86% | [4] | |||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.17% | [4] | |||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.62% | [3],[4] | |||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Risk Lose Money [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | It is important to understand that you can lose money by investing in the fund. | ||||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Risk Money Market Fund Price Fluctuates [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | The values of money market investments usually rise and fall in response to changes in interest rates. | ||||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Risk Not Insured Depository Institution [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | An investment in the fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | ||||||||||||
| Prospectus 1 [Member] | Putnam Government Money Market Fund | Risk Money Market Fund Sponsor May Not Provide Support [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | The fund’s sponsor is not required to reimburse the fund for losses, and you should not expect that the sponsor will provide financial support to the fund at any time, including during periods of market stress. | ||||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk/Return [Heading] | rr_RiskReturnHeading | Fund Summary | ||||||||||||
| Objective [Heading] | rr_ObjectiveHeading | Goal | ||||||||||||
| Objective, Primary [Text Block] | rr_ObjectivePrimaryTextBlock | The fund seeks as high a rate of current income as the Investment Manager (as defined below) believes is consistent with preservation of capital and maintenance of liquidity. |
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| Expense [Heading] | rr_ExpenseHeading | Fees and expenses | ||||||||||||
| Expense Narrative [Text Block] | rr_ExpenseNarrativeTextBlock | The following tables describe the fees and expenses you may pay if you buy, hold and sell Class I shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. |
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| Shareholder Fees Caption [Text] | rr_ShareholderFeesCaption | Shareholder fees (fees paid directly from your investment) | ||||||||||||
| Operating Expenses Caption [Text] | rr_OperatingExpensesCaption | Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment) | ||||||||||||
| Expense Example [Heading] | rr_ExpenseExampleHeading | Example | ||||||||||||
| Expense Example, No Redemption Narrative [Text Block] | rr_ExpenseExampleNoRedemptionNarrativeTextBlock | The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then redeem or hold all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Your actual costs may be higher or lower. |
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| Strategy [Heading] | rr_StrategyHeading | Investments, risks, and performance | ||||||||||||
| Strategy Narrative [Text Block] | rr_StrategyNarrativeTextBlock | Investments We invest at least 99.5 percent of the fund’s total assets in cash, U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities or cash. We invest mainly in debt securities that are obligations of the U.S. government, its agencies and instrumentalities and accordingly are backed by the full faith and credit of the United States (e.g., U.S. Treasury bills) or by the credit of a federal agency or government-sponsored entity (e.g.,securities issued by Fannie Mae and Freddie Mac). The U.S. government securities in which we invest may also include variable and floating rate instruments and when-issued and delayed delivery securities (i.e., payment or delivery of the securities occurs at a future date for a predetermined price). Under normal circumstances, we invest at least 80% of the fund’s net assets in U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities. This policy may be changed only after 60 days’ notice to shareholders. The securities purchased by the fund are subject to quality, maturity, diversification and other requirements pursuant to rules promulgated by the Securities and Exchange Commission. We may consider, among other factors, credit and interest rate risks and characteristics of the issuer or counterparty, as well as general market conditions, when deciding whether to buy or sell investments. |
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| Risk [Heading] | rr_RiskHeading | Risks | ||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | It is important to understand that you can lose money by investing in the fund. The value of investments in the fund’s portfolio may fall or fail to rise over extended periods of time for a variety of reasons, including general economic, political or financial market conditions, investor sentiment and market perceptions, government actions, geopolitical events or changes, outbreaks of infectious illnesses or other widespread public health issues, and factors related to a specific issuer, asset class, geography, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings, may negatively impact the fund’s performance, and may exacerbate other risks to which the fund is subject. The values of money market investments usually rise and fall in response to changes in interest rates. Interest rate risk is generally lowest for investments with short maturities (a significant part of the fund’s investments). Changes in the financial condition of an issuer or counterparty, changes in specific economic or political conditions that affect a particular type of issuer, and changes in general economic or political conditions can increase the risk of default by an issuer or counterparty, which can affect a security’s or instrument’s credit quality or value. Certain securities in which the fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States. There is no guarantee that the investment techniques, analyses, or judgments that we apply in making investment decisions for the fund will produce the intended outcome or that the investments we select for the fund will perform as well as other securities that were not selected for the fund. We, or the fund’s other service providers, may experience disruptions or operating errors that could negatively impact the fund. The fund may not achieve its goal, and it is not intended to be a complete investment program. 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 a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund’s sponsor is not required to reimburse the fund for losses, and you should not expect that the sponsor will provide financial support to the fund at any time, including during periods of market stress. |
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| Bar Chart and Performance Table [Heading] | rr_BarChartAndPerformanceTableHeading | Performance | ||||||||||||
| Performance Narrative [Text Block] | rr_PerformanceNarrativeTextBlock | The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Class I shares. The table shows the average annual total returns of Class I shares. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund’s past performance is not necessarily an indication of how the fund will perform in the future. |
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| Performance Information Illustrates Variability of Returns [Text] | rr_PerformanceInformationIllustratesVariabilityOfReturns | The accompanying bar chart and table provide some indication of the risks of investing in the fund | ||||||||||||
| Performance Past Does Not Indicate Future [Text] | rr_PerformancePastDoesNotIndicateFuture | The fund’s past performance is not necessarily an indication of how the fund will perform in the future. | ||||||||||||
| Bar Chart [Heading] | rr_BarChartHeading | Annual total returns for class I shares before sales charges | ||||||||||||
| Highest Quarterly Return, Label | rr_HighestQuarterlyReturnLabel | Best calendar quarter | ||||||||||||
| Highest Quarterly Return, Date | rr_BarChartHighestQuarterlyReturnDate | Dec. 31, 2023 | ||||||||||||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 1.27% | ||||||||||||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | Worst calendar quarter | ||||||||||||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Mar. 31, 2022 | ||||||||||||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | none | ||||||||||||
| Performance Table Heading | rr_PerformanceTableHeading | Average annual total returns after sales charges For periods ended 12/31/24 | ||||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | Class I | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.27% | ||||||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | ||||||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.09% | ||||||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.36% | ||||||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 37 | ||||||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 116 | ||||||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 202 | ||||||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 456 | ||||||||||||
| Annual Return 2017 | rr_AnnualReturn2017 | 0.43% | ||||||||||||
| Annual Return 2018 | rr_AnnualReturn2018 | 1.47% | ||||||||||||
| Annual Return 2019 | rr_AnnualReturn2019 | 1.82% | ||||||||||||
| Annual Return 2020 | rr_AnnualReturn2020 | 0.25% | ||||||||||||
| Annual Return 2021 | rr_AnnualReturn2021 | 0.01% | ||||||||||||
| Annual Return 2022 | rr_AnnualReturn2022 | 1.35% | ||||||||||||
| Annual Return 2023 | rr_AnnualReturn2023 | 4.79% | ||||||||||||
| Annual Return 2024 | rr_AnnualReturn2024 | 5.01% | ||||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 5.01% | ||||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.26% | ||||||||||||
| Since Inception | rr_AverageAnnualReturnSinceInception | 1.72% | [6] | |||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | Risk Lose Money [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | It is important to understand that you can lose money by investing in the fund. | ||||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | Risk Money Market Fund Price Fluctuates [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | The values of money market investments usually rise and fall in response to changes in interest rates | ||||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | Risk Not Insured Depository Institution [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | An investment in the fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | ||||||||||||
| Prospectus 2 [Member] | Putnam Government Money Market Fund | Risk Money Market Fund Sponsor May Not Provide Support [Member] | ||||||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||||||
| Risk [Text Block] | rr_RiskTextBlock | The fund’s sponsor is not required to reimburse the fund for losses, and you should not expect that the sponsor will provide financial support to the fund at any time, including during periods of market stress. | ||||||||||||
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