| 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 Convertible Securities Fund | ||||||||
| Entity Central Index Key | dei_EntityCentralIndexKey | 0000081247 | ||||||||
| Entity Inv Company Type | dei_EntityInvCompanyType | N-1A | ||||||||
| Amendment Flag | dei_AmendmentFlag | false | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities 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, with equal emphasis, current income and capital appreciation. Its secondary objective is conservation of capital. |
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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. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Putnam funds. More information about these and other discounts is available from your financial professional and in How do I buy fund shares? beginning on page 18 of the fund’s prospectus, in the Appendix to the fund’s prospectus, and in How to buy shares beginning on page 17 of the fund’s statement of additional information (“SAI”). |
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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) | ||||||||
| Portfolio Turnover [Heading] | rr_PortfolioTurnoverHeading | Portfolio turnover | ||||||||
| Portfolio Turnover [Text Block] | rr_PortfolioTurnoverTextBlock | The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 61%. |
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| Portfolio Turnover, Rate | rr_PortfolioTurnoverRate | 61.00% | ||||||||
| Expense Breakpoint Discounts [Text] | rr_ExpenseBreakpointDiscounts | You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Putnam funds. | ||||||||
| Expense Breakpoint, Minimum Investment Required [Amount] | rr_ExpenseBreakpointMinimumInvestmentRequiredAmount | $ 50,000 | ||||||||
| 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 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 mainly in convertible securities of U.S. companies. Under normal circumstances, we invest at least 80% of the fund’s net assets in convertible securities. This policy may be changed only after 60 days’ notice to shareholders. Convertible securities combine the investment characteristics of bonds and common stocks. Convertible securities include bonds, preferred stocks and other instruments that can be converted into or exchanged for common stock or equivalent value. A significant portion of the convertible securities we buy are below-investment-grade (sometimes referred to as “junk bonds”). The convertible bonds we buy usually have intermediate-to long-term stated maturities (i.e., three years or longer), but often contain “put” features, which allow bondholders to sell the bond back to the company under specified circumstances, that result in shorter effective maturities. When deciding whether to buy or sell investments, we may consider, among other factors: (i) a security’s structural features, such as its position in a company’s capital structure and “put” and “call” features (a company’s right to repurchase the security under specified circumstances is a “call” feature); (ii) credit and prepayment risks; and (iii) with respect to a company’s common stock underlying a convertible security, the stock’s valuation and the company’s financial strength, growth potential, competitive position in its industry, projected future earnings, cash flows and dividends. |
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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. These risks are generally greater for convertible securities issued by small and midsize companies (which may constitute a significant portion of the fund’s investments from time to time). The value of convertible securities may be adversely affected by changes in the prices of underlying common stocks. Convertible securities tend to provide higher yields than common stocks. However, a higher yield may not protect investors against the risk of loss or adequately mitigate any loss associated with a decline in the price of a convertible security. Convertible securities are subject to credit risk, which is the risk that an issuer of the fund’s investments may default on payment of interest or principal. Credit risk is generally greater for below-investment-grade convertible securities (a significant part of the fund’s investments), which can be more sensitive to changes in markets, credit conditions, and interest rates, and may be considered speculative. Generally, convertible securities may be less sensitive to interest rate changes than non-convertible bonds as a result of convertible securities’ convertibility and “put” features. Interest rate risk is generally greater for longer-term bonds and convertible securities whose underlying stock price has fallen significantly below the conversion price. Bond investments may be more susceptible to downgrades or defaults during economic downturns or other periods of economic stress. The fund may be an investment option for mutual funds that are managed by the Investment Manager and its affiliates as “funds of funds.” Additionally, other investors from time to time may make substantial investments in the fund. Such shareholders may at times be considered to control the fund. Dispositions of a large number of shares by these shareholders may adversely affect the fund’s liquidity and net assets. These redemptions may also force the fund to sell securities, which may increase the fund’s brokerage costs. 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. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. |
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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 and also compares the fund’s performance with the average annual total returns of a broad measure of market performance and an additional index with characteristics relevant to the fund. 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 per share, available at www.franklintempleton.com. The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. Sales charges are not reflected in the accompanying bar chart, and if those charges were included, returns would be less than those shown. |
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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 (before and after taxes) 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 | ||||||||
| Bar Chart Does Not Reflect Sales Loads [Text] | rr_BarChartDoesNotReflectSalesLoads | Sales charges are not reflected in the accompanying bar chart, and if those charges were included, returns would be less than those shown. | ||||||||
| Highest Quarterly Return, Label | rr_HighestQuarterlyReturnLabel | Best calendar quarter | ||||||||
| Highest Quarterly Return, Date | rr_BarChartHighestQuarterlyReturnDate | Jun. 30, 2020 | ||||||||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 25.30% | ||||||||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | Worst calendar quarter | ||||||||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Jun. 30, 2022 | ||||||||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | (15.22%) | ||||||||
| Performance Table Heading | rr_PerformanceTableHeading | Average annual total returns after sales charges For periods ended 12/31/24 | ||||||||
| Performance Table Uses Highest Federal Rate | rr_PerformanceTableUsesHighestFederalRate | After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect state and local taxes. | ||||||||
| Performance Table Not Relevant to Tax Deferred | rr_PerformanceTableNotRelevantToTaxDeferred | Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. | ||||||||
| Performance Table One Class of after Tax Shown [Text] | rr_PerformanceTableOneClassOfAfterTaxShown | After-tax returns are shown for class A shares only and will vary for other classes. | ||||||||
| Performance Table Closing [Text Block] | rr_PerformanceTableClosingTextBlock | After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are shown for class A shares only and will vary for other classes. These after-tax returns do not apply if you hold your fund shares through a 401(k) plan, an IRA, or another tax-advantaged arrangement. Class C share performance reflects conversion to class A shares after eight years. Important data provider notices and terms are available at www.franklintempletondatasources.com. All data is subject to change. |
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| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Bloomberg U.S. Aggregate Index (no deduction for fees, expenses or taxes) | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 1.25% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | (0.33%) | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 1.35% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | ICE BofA U.S. Convertible Index (no deduction for fees, expenses or taxes) | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 11.14% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 9.66% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 9.07% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Class A | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 5.75% | ||||||||
| Maximum Deferred Sales Charge (as a percentage) | rr_MaximumDeferredSalesChargeOverOther | 1.00% | [1] | |||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | 0.25% | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.17% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 1.03% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 674 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 884 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 1,111 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 1,762 | ||||||||
| Annual Return 2015 | rr_AnnualReturn2015 | (7.03%) | ||||||||
| Annual Return 2016 | rr_AnnualReturn2016 | 9.51% | ||||||||
| Annual Return 2017 | rr_AnnualReturn2017 | 14.93% | ||||||||
| Annual Return 2018 | rr_AnnualReturn2018 | (3.26%) | ||||||||
| Annual Return 2019 | rr_AnnualReturn2019 | 24.31% | ||||||||
| Annual Return 2020 | rr_AnnualReturn2020 | 44.97% | ||||||||
| Annual Return 2021 | rr_AnnualReturn2021 | 4.01% | ||||||||
| Annual Return 2022 | rr_AnnualReturn2022 | (18.57%) | ||||||||
| Annual Return 2023 | rr_AnnualReturn2023 | 10.13% | ||||||||
| Annual Return 2024 | rr_AnnualReturn2024 | 12.60% | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 6.12% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 7.49% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 7.28% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Class A | After Taxes on Distributions | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 5.57% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 5.22% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 5.19% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Class A | After Taxes on Distributions and Sales | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 3.72% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 5.43% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 5.22% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities 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% | [2] | |||||||
| Management Fees (as a percentage of Assets) | rr_ManagementFeesOverAssets | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | 1.00% | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.17% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 1.78% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 281 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 560 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 964 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | 1,897 | ||||||||
| Expense Example, No Redemption, 1 Year | rr_ExpenseExampleNoRedemptionYear01 | 181 | ||||||||
| Expense Example, No Redemption, 3 Years | rr_ExpenseExampleNoRedemptionYear03 | 560 | ||||||||
| Expense Example, No Redemption, 5 Years | rr_ExpenseExampleNoRedemptionYear05 | 964 | ||||||||
| Expense Example, No Redemption, 10 Years | rr_ExpenseExampleNoRedemptionYear10 | $ 1,897 | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 10.79% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 7.96% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 7.27% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities 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 | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | 0.50% | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.17% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 1.28% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 130 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 406 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 702 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 1,545 | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 12.32% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 8.50% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 7.65% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Class R6 | ||||||||||
| 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 | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.11% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.72% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 74 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 230 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 401 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 894 | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 13.00% | [3] | |||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 9.11% | [3] | |||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 8.25% | [3] | |||||||
| Prospectus 1 [Member] | Putnam Convertible Securities Fund | Class Y | ||||||||||
| 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 | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.17% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.78% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 80 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 249 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 433 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 966 | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 12.89% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 9.05% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 8.19% | ||||||||
| Prospectus 1 [Member] | Putnam Convertible Securities 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 Convertible Securities Fund | Risk Not Insured Depository Institution [Member] | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| Risk [Text Block] | rr_RiskTextBlock | An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | ||||||||
| Prospectus 2 [Member] | Putnam Convertible Securities 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, with equal emphasis, current income and capital appreciation. Its secondary objective is conservation of capital. |
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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) | ||||||||
| Portfolio Turnover [Heading] | rr_PortfolioTurnoverHeading | Portfolio turnover | ||||||||
| Portfolio Turnover [Text Block] | rr_PortfolioTurnoverTextBlock | The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 61%. |
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| Portfolio Turnover, Rate | rr_PortfolioTurnoverRate | 61.00% | ||||||||
| 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 redeem 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 mainly in convertible securities of U.S. companies. Under normal circumstances, we invest at least 80% of the fund’s net assets in convertible securities. This policy may be changed only after 60 days’ notice to shareholders. Convertible securities combine the investment characteristics of bonds and common stocks. Convertible securities include bonds, preferred stocks and other instruments that can be converted into or exchanged for common stock or equivalent value. A significant portion of the convertible securities we buy are below-investment-grade (sometimes referred to as “junk bonds”). The convertible bonds we buy usually have intermediate-to long-term stated maturities (i.e., three years or longer), but often contain “put” features, which allow bondholders to sell the bond back to the company under specified circumstances, that result in shorter effective maturities. When deciding whether to buy or sell investments, we may consider, among other factors: (i) a security’s structural features, such as its position in a company’s capital structure and “put” and “call” features (a company’s right to repurchase the security under specified circumstances is a “call” feature); (ii) credit and prepayment risks; and (iii) with respect to a company’s common stock underlying a convertible security, the stock’s valuation and the company’s financial strength, growth potential, competitive position in its industry, projected future earnings, cash flows and dividends. |
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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. These risks are generally greater for convertible securities issued by small and midsize companies (which may constitute a significant portion of the fund’s investments from time to time). The value of convertible securities may be adversely affected by changes in the prices of underlying common stocks. Convertible securities tend to provide higher yields than common stocks. However, a higher yield may not protect investors against the risk of loss or adequately mitigate any loss associated with a decline in the price of a convertible security. Convertible securities are subject to credit risk, which is the risk that an issuer of the fund’s investments may default on payment of interest or principal. Credit risk is generally greater for below-investment-grade convertible securities (a significant part of the fund’s investments), which can be more sensitive to changes in markets, credit conditions, and interest rates, and may be considered speculative. Generally, convertible securities may be less sensitive to interest rate changes than non-convertible bonds as a result of convertible securities’ convertibility and “put” features. Interest rate risk is generally greater for longer-term bonds and convertible securities whose underlying stock price has fallen significantly below the conversion price. Bond investments may be more susceptible to downgrades or defaults during economic downturns or other periods of economic stress. The fund may be an investment option for mutual funds that are managed by the Investment Manager and its affiliates as “funds of funds.” Additionally, other investors from time to time may make substantial investments in the fund. Such shareholders may at times be considered to control the fund. Dispositions of a large number of shares by these shareholders may adversely affect the fund’s liquidity and net assets. These redemptions may also force the fund to sell securities, which may increase the fund’s brokerage costs. 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. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. |
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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 and also compares the fund’s performance with the average annual total returns of a broad measure of market performance and an additional index with characteristics relevant to the fund. 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 (before and after taxes) 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 (before and after taxes) 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 | Jun. 30, 2020 | ||||||||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 25.39% | ||||||||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | Worst calendar quarter | ||||||||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Jun. 30, 2022 | ||||||||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | (15.16%) | ||||||||
| Performance Table Heading | rr_PerformanceTableHeading | Average annual total returns after sales charges For periods ended 12/31/24 | ||||||||
| Performance Table Uses Highest Federal Rate | rr_PerformanceTableUsesHighestFederalRate | After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect state and local taxes. | ||||||||
| Performance Table Not Relevant to Tax Deferred | rr_PerformanceTableNotRelevantToTaxDeferred | Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. | ||||||||
| Performance Table Closing [Text Block] | rr_PerformanceTableClosingTextBlock | After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. Important data provider notices and terms are available at www.franklintempletondatasources.com. All data is subject to change. |
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| Prospectus 2 [Member] | Putnam Convertible Securities Fund | Bloomberg U.S. Aggregate Index (no deduction for fees, expenses or taxes) | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 1.25% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | (0.33%) | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 1.35% | ||||||||
| Prospectus 2 [Member] | Putnam Convertible Securities Fund | ICE BofA U.S. Convertible Index (no deduction for fees, expenses or taxes) | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 11.14% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 9.66% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 9.07% | ||||||||
| Prospectus 2 [Member] | Putnam Convertible Securities Fund | Class I | ||||||||||
| 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 | 0.61% | ||||||||
| Distribution and Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | ||||||||
| Other Expenses (as a percentage of Assets): | rr_OtherExpensesOverAssets | 0.07% | ||||||||
| Expenses (as a percentage of Assets) | rr_ExpensesOverAssets | 0.68% | ||||||||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 69 | ||||||||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 218 | ||||||||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 379 | ||||||||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 847 | ||||||||
| Annual Return 2015 | rr_AnnualReturn2015 | (6.69%) | ||||||||
| Annual Return 2016 | rr_AnnualReturn2016 | 9.95% | ||||||||
| Annual Return 2017 | rr_AnnualReturn2017 | 15.42% | ||||||||
| Annual Return 2018 | rr_AnnualReturn2018 | (2.90%) | ||||||||
| Annual Return 2019 | rr_AnnualReturn2019 | 24.74% | ||||||||
| Annual Return 2020 | rr_AnnualReturn2020 | 45.55% | ||||||||
| Annual Return 2021 | rr_AnnualReturn2021 | 4.40% | ||||||||
| Annual Return 2022 | rr_AnnualReturn2022 | (18.28%) | ||||||||
| Annual Return 2023 | rr_AnnualReturn2023 | 10.52% | ||||||||
| Annual Return 2024 | rr_AnnualReturn2024 | 13.01% | ||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 13.01% | [4] | |||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 9.17% | [4] | |||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 8.32% | [4] | |||||||
| Prospectus 2 [Member] | Putnam Convertible Securities Fund | Class I | After Taxes on Distributions | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 12.30% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 6.67% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 5.99% | ||||||||
| Prospectus 2 [Member] | Putnam Convertible Securities Fund | Class I | After Taxes on Distributions and Sales | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 7.82% | ||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 6.65% | ||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 5.93% | ||||||||
| Prospectus 2 [Member] | Putnam Convertible Securities 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 Convertible Securities Fund | Risk Not Insured Depository Institution [Member] | ||||||||||
| Prospectus [Line Items] | rr_ProspectusLineItems | |||||||||
| Risk [Text Block] | rr_RiskTextBlock | An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | ||||||||
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