Label	Element	Value
Prospectus [Line Items]	rr_ProspectusLineItems
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2018
Entity Registrant Name	dei_EntityRegistrantName	PUTNAM INVESTMENT FUNDS
Entity Central Index Key	dei_EntityCentralIndexKey	0000932101
Amendment Flag	dei_AmendmentFlag	false
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A
Trading Symbol	dei_TradingSymbol	PIF
Document Creation Date	dei_DocumentCreationDate	Dec. 26, 2019
Document Effective Date	dei_DocumentEffectiveDate	Dec. 30, 2019
Prospectus Date	rr_ProspectusDate	Dec. 30, 2019
Putnam International Capital Opportunities Fund
Prospectus [Line Items]	rr_ProspectusLineItems
Risk/Return [Heading]	rr_RiskReturnHeading	Fund summary
Objective [Heading]	rr_ObjectiveHeading	Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Putnam International Capital Opportunities Fund seeks long-term capital appreciation.
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 and hold shares of the fund. 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 advisor and in How do I buy fund shares? beginning on page 15 of the fund’s prospectus, in the Appendix to the fund’s prospectus, and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).
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 42%.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	42.00%
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. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 15 of the fund's prospectus, in the Appendix to the fund's prospectus, and in How to buy shares beginning on page II-1 of the fund's statement of additional information (SAI).
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.
Strategy [Heading]	rr_StrategyHeading	Investments, risks, and performance
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Investments We invest mainly in common stocks (growth or value stocks or both) of small and midsize companies outside the United States that we believe have favorable investment potential. For example, we may purchase stocks of companies with stock prices that reflect a value lower than that which we place on the company. We may also consider other factors that we believe will cause the stock price to rise. We invest mainly in developed countries, but may invest in emerging markets. We may consider, among other factors, a company’s valuation, financial strength, growth potential, competitive position in its industry, projected future earnings, cash flows and dividends when deciding whether to buy or sell investments. We may also use derivatives such as futures, options, certain foreign currency transactions, warrants and swap contracts, for both hedging and non-hedging purposes.
Risk [Heading]	rr_RiskHeading	Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	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, and factors related to a specific issuer, geography, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings. Growth stocks may be more susceptible to earnings disappointments, and value stocks may fail to rebound. These risks are generally greater for small and midsize companies. The value of international investments traded in foreign currencies may be adversely impacted by fluctuations in exchange rates. International investments, particularly investments in emerging markets, may carry risks associated with potentially less stable economies or governments (such as the risk of seizure by a foreign government, the imposition of currency or other restrictions, or high levels of inflation), and may be or become illiquid. Our use of derivatives may increase the risks of investing in the fund by increasing investment exposure (which may be considered leverage) or, in the case of many over-the-counter instruments, because of the potential inability to terminate or sell derivatives positions and the potential failure of the other party to the instrument to meet its obligations. 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	It is important to understand that you can lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	putnam.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Please remember that past performance is not necessarily an indication of future results.
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	The bar chart does not reflect the impact of sales charges. If it did, performance would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Year-to-date performance through 9/30/19    11.62% Best calendar quarter Q2 2009   36.85% Worst calendar quarter Q3 2011     –23.55%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-date performance through
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2019
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	11.62%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best calendar quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	36.85%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst calendar quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(23.55%)
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns after sales charges (for periods ended 12/31/18)
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 B share performance reflects conversion to class A shares after eight years.
Putnam International Capital Opportunities Fund | S&P Developed Ex-U.S. SmallCap Index (no deduction for fees, expenses or taxes)
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(18.41%)
5 Years	rr_AverageAnnualReturnYear05	2.78%
10 Years	rr_AverageAnnualReturnYear10	10.00%
Putnam International Capital Opportunities Fund | Class A
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.36%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.50%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 719
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,022
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,346
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,263
Annual Return 2009	rr_AnnualReturn2009	56.76%
Annual Return 2010	rr_AnnualReturn2010	18.70%
Annual Return 2011	rr_AnnualReturn2011	(21.25%)
Annual Return 2012	rr_AnnualReturn2012	22.19%
Annual Return 2013	rr_AnnualReturn2013	23.77%
Annual Return 2014	rr_AnnualReturn2014	(13.43%)
Annual Return 2015	rr_AnnualReturn2015	2.28%
Annual Return 2016	rr_AnnualReturn2016	(2.88%)
Annual Return 2017	rr_AnnualReturn2017	34.53%
Annual Return 2018	rr_AnnualReturn2018	(16.52%)
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(21.32%)
5 Years	rr_AverageAnnualReturnYear05	(1.86%)
10 Years	rr_AverageAnnualReturnYear10	7.27%
Putnam International Capital Opportunities Fund | Class A | after taxes on distributions
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(23.07%)
5 Years	rr_AverageAnnualReturnYear05	(2.60%)
10 Years	rr_AverageAnnualReturnYear10	6.81%
Putnam International Capital Opportunities Fund | Class A | after taxes on distributions and sale of fund shares
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(11.46%)
5 Years	rr_AverageAnnualReturnYear05	(1.29%)
10 Years	rr_AverageAnnualReturnYear10	6.07%
Putnam International Capital Opportunities Fund | Class B
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	5.00%	[3]
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.36%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.25%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 728
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,003
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,405
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	2,396
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	228
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	703
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,205
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,396
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(20.88%)
5 Years	rr_AverageAnnualReturnYear05	(1.77%)
10 Years	rr_AverageAnnualReturnYear10	7.25%
Putnam International Capital Opportunities Fund | Class C
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[4]
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.36%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.25%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 328
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	703
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,205
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	2,585
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	228
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	703
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,205
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,585
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(17.91%)
5 Years	rr_AverageAnnualReturnYear05	(1.44%)
10 Years	rr_AverageAnnualReturnYear10	7.10%
Putnam International Capital Opportunities Fund | Class R
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other expenses	rr_OtherExpensesOverAssets	0.36%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.75%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 178
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	551
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	949
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,062
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(16.72%)
5 Years	rr_AverageAnnualReturnYear05	(0.94%)
10 Years	rr_AverageAnnualReturnYear10	7.64%
Putnam International Capital Opportunities Fund | Class R6
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Other expenses	rr_OtherExpensesOverAssets	0.17%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.06%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 108
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	337
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	585
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,294
Label	rr_AverageAnnualReturnLabel	before taxes	[5]
1 Year	rr_AverageAnnualReturnYear01	(16.22%)	[5]
5 Years	rr_AverageAnnualReturnYear05	(0.43%)	[5]
10 Years	rr_AverageAnnualReturnYear10	8.19%	[5]
Putnam International Capital Opportunities Fund | Class Y
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.89%	[2]
Other expenses	rr_OtherExpensesOverAssets	0.36%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.25%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 127
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	397
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	686
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,511
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(16.31%)
5 Years	rr_AverageAnnualReturnYear05	(0.45%)
10 Years	rr_AverageAnnualReturnYear10	8.17%
Putnam PanAgora Managed Futures Strategy
Prospectus [Line Items]	rr_ProspectusLineItems
Risk/Return [Heading]	rr_RiskReturnHeading	Fund summary
Objective [Heading]	rr_ObjectiveHeading	Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Putnam PanAgora Managed Futures Strategy seeks absolute return (i.e. positive total return in diverse market environments over time).
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 and hold shares of the fund. 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 advisor and in How do I buy fund shares? beginning on page 25 of the fund’s prospectus, in the Appendix to the fund’s prospectus, and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).
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)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	12/30/2020
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 0%. However, the fund’s turnover rate is calculated without regard to transactions involving certain short-term instruments or derivatives. If such transactions were included in the calculation, the fund would have a higher turnover rate.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
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. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 25 of the fund's prospectus, in the Appendix to the fund's prospectus, and in How to buy shares beginning on page II-1 of the fund's statement of additional information (SAI).
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. Only the first year of each period in the example takes into account the expense reimbursement described above. Your actual costs may be higher or lower.
Strategy [Heading]	rr_StrategyHeading	Investments, risks, and performance
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Investments The fund pursues its goal by investing primarily in futures and forward contracts that provide exposure to equities, fixed income securities, commodities, and developed and emerging market currencies. These asset classes offer different return potential and exposure to different investment risks. In allocating the fund’s assets among these different asset classes, PanAgora Asset Management, Inc. (PanAgora), the subadviser to the fund, uses its proprietary trend following strategy, which relies on quantitative models and information and data inputs to those models to seek to identify and profit from price trends in global equity, fixed income, commodity and currency markets. Following the identification of a trend, the fund may take either a long or short position in an asset class. The size of the position taken is based on PanAgora’s systematic assessment of the trend and its likelihood of continuing, as well as PanAgora’s estimate of the risk of the instrument through which the position is implemented. Once a position has been added to the fund’s portfolio, PanAgora monitors for any indication of a reversal or loss of momentum in the price trend in order to determine when to exit the position. In constructing the fund’s portfolio, PanAgora uses a proprietary approach to balance the fund’s risk exposures in an effort to generate attractive returns, in diverse market conditions, that are generally uncorrelated with the returns of traditional asset classes. The fund expects to obtain exposure to developed market equity indexes, although it may have exposure to equity securities of any market capitalization throughout the world, including foreign and emerging markets. In the case of fixed income securities, the fund expects to seek exposure primarily to investment-grade securities, but may have exposure to fixed-income securities of any credit quality, duration or maturity. The fund may obtain exposure to any commodity and to both developed and emerging market currencies. The fund primarily gains long and short exposure to an asset class by investing in exchanged-traded futures and over-the-counter forward contracts, but may also invest in an asset class through other derivatives (such as options and swap contracts) or directly. The fund is “non-diversified,” which means that it may invest a greater percentage of its assets in fewer issuers than a “diversified” fund. A significant portion of the assets of the fund will be invested in short-term instruments, including cash and cash equivalents generally with one year or less term to maturity. These investments serve as collateral for the derivative positions the fund takes and also may earn income for the fund. Although the fund normally does not engage in borrowing, because the fund typically uses long and short futures and forwards to a significant extent (and may also take other short derivatives positions), the fund will operate with potentially significant investment leverage, which magnifies investment exposure. Instruments in the fund are generally liquid and exchange traded. The fund may invest directly or indirectly through its wholly-owned and controlled subsidiary, which like the fund, is sub-advised by PanAgora. The fund may invest no more than 25% of its assets in the subsidiary. The subsidiary will invest primarily in commodity futures but it may also invest in other commodity-related instruments (such as financial futures, option and swap contracts) or other asset classes (including through derivatives). Unlike the fund, the subsidiary may invest without limitation in commodity-related instruments. Unless indicated otherwise, references to the fund’s investments, investment exposures or risks include its indirect investments, investment exposures and risks through the subsidiary.
Risk [Heading]	rr_RiskHeading	Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	It is important to understand that you can lose money by investing in the fund. There can be no assurance that employing a trend following strategy will achieve any particular level of return. The fund’s allocation of assets among and within asset classes may hurt performance, and efforts to balance risk exposures across and within asset classes may not be successful. If the quantitative models or data that are used in managing the fund prove to be incorrect or incomplete, investment decisions made in reliance on the models or data may not produce the desired results and the fund may realize losses. Investments made based on quantitative models may perform differently from the market as a whole. 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, 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. These risks are generally greater for small and midsize companies. The fixed income securities in which the fund invests (whether directly or indirectly through derivatives) are subject to interest rate risk, which means the value of those investments is likely to fall if interest rates rise. The fund’s investments in fixed income securities also are subject to credit risk, which is the risk that the issuer of the fixed income security may default on payment of interest or principal. Interest rate risk is generally greater for the fund’s investments in longer-term fixed income securities. Exposure to the commodities markets may subject the fund to greater volatility than investments in traditional securities. The value of commodity-linked derivative investments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. Future regulatory developments may impact the fund’s ability to invest in commodity-linked derivatives. The fund’s investments in forward contracts and futures and other derivatives are subject to losses caused by unanticipated market movements, and there may be imperfect correlation between price movements of a derivative and price movements of the security or other asset for which the derivative is intended as a substitute. Derivatives may be difficult to value and may increase the fund’s transaction costs. Derivatives also involve the risk of the potential inability to terminate or sell the derivatives positions. Derivatives can significantly increase the fund’s exposure to credit and counterparty risks. Derivatives, particularly forward contracts and other over-the-counter instruments, involve the potential failure of the other party to the derivative to meet its obligations. Derivatives also are subject to the risk that the fund is delayed or prevented from recovering margin or other amounts deposited with a futures commission merchant or futures clearinghouse. If the fund has insufficient cash, it may have to sell its investments to meet daily variation margin requirements at a time when it may be disadvantageous to do so. The fund’s use of derivatives also increases its risks by increasing investment exposure (which may be considered leverage). Leveraging may cause the fund’s performance to be more volatile, may expose the fund to losses in excess of the amounts invested, and may require the fund to liquidate portfolio securities when it may not be advantageous to do so, to satisfy its obligations or to meet segregation requirements. The fund’s use of “short” derivatives positions may have the effect of economic leverage, which magnifies investment exposure, and may result in losses if the underlying assets appreciate in value. The value of international investments traded in foreign currencies may be adversely impacted by fluctuations in exchange rates. International investments, particularly investments in emerging markets, may carry risks associated with potentially less stable economies or governments (such as the risk of seizure by a foreign government, the imposition of currency or other restrictions, or high levels of inflation), and may be or become illiquid. A fund that invests in (or provides exposure to) fewer issuers or that makes large investments in (or provides large amounts of exposure to) a small number of issuers is more vulnerable than a more broadly diversified fund to fluctuations in the values of the securities to which it has exposure. By investing in the subsidiary, the fund is indirectly exposed to the risks associated with the subsidiary’s investments. The subsidiary is not registered under the Investment Company Act of 1940, as amended (the “1940 Act”), and is not subject to all the investor protections of the 1940 Act. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the fund and/or the subsidiary to operate as described in this prospectus and could adversely affect 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	It is important to understand that you can lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	The fund is “non-diversified,” which means that it may invest a greater percentage of its assets in fewer issuers than a “diversified” fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	putnam.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Please remember that past performance is not necessarily an indication of future results.
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	The bar chart does not reflect the impact of sales charges. If it did, performance would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Year-to-date performance through 9/30/19  3.37% Best calendar quarter Q3 2018   1.83% Worst calendar quarter Q4 2018 −5.78%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-date performance
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2019
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	3.37%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best calendar quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.83%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst calendar quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.78%)
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns after sales charges (for periods ended 12/31/18)
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	ICE BofAML Indexes: ICE Data Indices, LLC (“ICE BofAML”), used with permission. ICE BofAML permits use of the ICE BofAML indices and related data on an “as is” basis; makes no warranties regarding same; does not guarantee the suitability, quality, accuracy, timeliness, and/or completeness of the ICE BofAML indices or any data included in, related to, or derived therefrom; assumes no liability in connection with the use of the foregoing; and does not sponsor, endorse, or recommend Putnam Investments, or any of its products or services. 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.
Putnam PanAgora Managed Futures Strategy | ICE BofAML U.S. Treasury Bill Index (no deduction for fees. expenses or taxes)
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	1.88%
Since Inception	rr_AverageAnnualReturnSinceInception	1.69%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class A
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Management fees	rr_ManagementFeesOverAssets	1.00%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.93%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.55%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 724
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,307
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,914
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,547
Annual Return 2018	rr_AnnualReturn2018	(6.62%)
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(11.99%)
Since Inception	rr_AverageAnnualReturnSinceInception	(8.45%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class A | after taxes on distributions
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(12.88%)
Since Inception	rr_AverageAnnualReturnSinceInception	(9.27%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class A | after taxes on distributions and sale of fund shares
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(7.10%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.71%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class B
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	5.00%	[9]
Management fees	rr_ManagementFeesOverAssets	1.00%	[6],[10]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%	[10]
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7],[10]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%	[10]
Total annual fund operating expenses	rr_ExpensesOverAssets	3.68%	[10]
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8],[10]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.30%	[10]
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 733
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,299
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,985
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	3,677
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	233
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	999
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,785
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 3,677
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(11.82%)
Since Inception	rr_AverageAnnualReturnSinceInception	(7.70%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class C
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[4]
Management fees	rr_ManagementFeesOverAssets	1.00%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.68%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.30%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 333
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	999
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,785
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	3,843
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	233
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	999
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,785
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 3,843
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(8.24%)
Since Inception	rr_AverageAnnualReturnSinceInception	(4.83%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class R
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.00%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.18%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.80%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 183
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	851
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,544
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,390
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(6.86%)
Since Inception	rr_AverageAnnualReturnSinceInception	(4.30%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class R6
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.00%	[6]
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.68%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.30%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 132
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	701
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,297
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,911
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(6.38%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.84%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Managed Futures Strategy | Class Y
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.00%	[6]
Other expenses	rr_OtherExpensesOverAssets	1.63%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.68%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.38%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.30%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 132
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	701
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,297
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,911
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(6.38%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.84%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund
Prospectus [Line Items]	rr_ProspectusLineItems
Risk/Return [Heading]	rr_RiskReturnHeading	Fund summary
Objective [Heading]	rr_ObjectiveHeading	Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Putnam PanAgora Market Neutral Fund seeks absolute return (i.e. positive total return in diverse market environments over time).
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 and hold shares of the fund. 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 advisor and in How do I buy fund shares? beginning on page 21 of the fund’s prospectus, in the Appendix to the fund’s prospectus, and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).
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)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	12/30/2020
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 0%. However, the fund’s turnover rate is calculated without regard to transactions involving certain short-term instruments or derivatives. If such transactions were included in the calculation, the fund would have a higher turnover rate.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
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. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 21 of the fund's prospectus, in the Appendix to the fund's prospectus, and in How to buy shares beginning on page II-1 of the fund's statement of additional information (SAI).
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. Only the first year of each period in the example takes into account the expense reimbursement described above. Your actual costs may be higher or lower.
Strategy [Heading]	rr_StrategyHeading	Investments, risks, and performance
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Investments The fund pursues its goal by investing through a diversified set of long/short equity strategies that seek to identify and exploit multiple price inefficiencies that exist in global equity markets. PanAgora Asset Management, Inc. (“PanAgora”), the subadviser to the fund, believes that these inefficiencies create investment opportunities in different market segments, at different times, and for different reasons, before they are ultimately arbitraged away. By using a diversified set of strategies that PanAgora believes have low correlation to one another, the fund seeks to generate returns under different market conditions and over different time horizons that are more stable over time than the returns of any individual strategy. The fund’s strategies rely on quantitative models and information and data inputs to those models in an effort to capitalize on investment opportunities that exist when the prospects of a company’s likely success or failure are not fully recognized by market participants. The fund’s strategies are managed within three distinct sleeves of the fund designed to capitalize on long-term, intermediate-term, and short-term price inefficiencies. PanAgora strategically allocates the fund’s investments among the various strategies, varying the allocations from time to time based upon its assessment of the attractiveness of the available opportunity set, to seek to increase the potential for higher returns. Although the fund may have net long or short exposure to the stock market at any time, PanAgora expects that, over time, the fund’s returns will not closely correlate with stock market movements. PanAgora may adjust the fund’s portfolio from time to time, and may use derivatives, to minimize exposure to stock market movements. The fund’s portfolio is also adjusted on a regular basis in an effort to manage risk from systematic factors (such as market or interest rate movements), risk from sector, country and region exposure, as well as excessive risk from any one security, by using derivatives, exchange traded funds (ETFs) and other risk management and portfolio construction techniques. PanAgora expects to implement the fund’s strategies primarily through investing in total return swap contracts, although it may also use other derivatives (such as futures contracts, options, currency swaps and other swap contracts), to take long or short positions in equity securities (principally common stocks, American Depositary Receipts (ADRs), and real estate investment trusts (REITs)), fixed income securities, and other investment companies. The fund may have exposure to U.S. and non-U.S. (including both developed and emerging market) companies, to companies of any market capitalization and to fixed income securities of any credit quality, duration or maturity (principally government-issued instruments, money market instruments, and investment-grade corporate instruments). At times, the fund may also hold these instruments directly. The fund may take “short” derivatives positions and may use derivatives to hedge and for speculative purposes. In addition, the fund may invest up to 25% of its net assets in stock, rights, warrants, and other securities of special purpose acquisition companies (“SPACs”). A significant portion of the assets of the fund will be invested in short-term instruments, including cash and cash equivalents generally with one year or less term to maturity. These investments serve as collateral for the derivative positions the fund takes and also may earn income for the fund.
Risk [Heading]	rr_RiskHeading	Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	It is important to understand that you can lose money by investing in the fund. There can be no assurance that the fund’s strategies will achieve any particular level of return. The fund’s allocation of assets among strategies and asset classes may hurt performance, and efforts to generate returns under different market conditions and over different time horizons through the use of strategies and allocation decisions may not be successful. If the quantitative models or data that are used in managing the fund prove to be incorrect or incomplete, investment decisions made in reliance on the models or data may not produce the desired results and the fund may realize losses. Investments made based on quantitative models may perform differently from the market as a whole. 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, 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. These risks are generally greater for small and midsize companies. The fixed income securities in which the fund invests (whether directly or indirectly through derivatives) are subject to interest rate risk, which means the value of those investments is likely to fall if interest rates rise. The fund’s investments in fixed income securities also are subject to credit risk, which is the risk that the issuer of the fixed income security may default on payment of interest or principal. Interest rate risk is generally greater for the fund’s investments in longer-term fixed income securities. The fund’s investments in total return swap contracts and other derivatives are subject to losses caused by unanticipated market movements, and there may be imperfect correlation between price movements of a derivative and price movements of the security or other asset for which the derivative is intended as a substitute. Derivatives may be difficult to value and may increase the fund’s transaction costs. Derivatives also involve the risk of the potential inability to terminate or sell derivatives positions. Derivatives can significantly increase the fund’s exposure to credit and counterparty risks. Derivatives, particularly over-the-counter instruments, involve the risk of the potential failure of the other party to the instrument to meet its obligations. Derivatives are subject to the risk that the fund may be delayed or prevented from recovering margin or other amounts deposited with a clearinghouse, futures commission merchant or other counterparty. If the fund has insufficient cash, it may have to sell its investments to meet daily variation margin requirements at a time when it may be disadvantageous to do so. The fund’s use of derivatives also increases its risks by increasing investment exposure (which may be considered leverage). Leveraging may cause the fund’s performance to be more volatile, may expose the fund to losses in excess of the amounts invested, and may require the fund to liquidate portfolio securities when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. The fund’s use of “short” derivatives positions may have the effect of economic leverage, which magnifies investment exposure, and may result in losses if the underlying assets appreciate in value. Because SPACs and similar entities are in essence blank check companies without an operating history or ongoing business other than seeking acquisitions, the value of their securities is particularly dependent on the ability of the entity’s management to identify and complete a profitable acquisition. In addition, the securities issued by SPACs may be considered illiquid and/or be subject to restrictions on resale. The value of international investments traded in foreign currencies may be adversely impacted by fluctuations in exchange rates. International investments, particularly investments in emerging markets, may carry risks associated with potentially less stable economies or governments (such as the risk of seizure by a foreign government, the imposition of currency or other restrictions, or high levels of inflation), and may be illiquid. Exposure to REITs subjects the fund to the risks associated with direct ownership in real estate, including economic downturns that have an adverse effect on real estate markets. Exposure to open-end or closed-end investment companies and ETFs subjects the fund to substantially the same risks as those associated with direct ownership of the securities comprising the index on which an index ETF is based or the other holdings of an active or index ETF or other investment company. The fund may have some direct or indirect exposure to illiquid securities. PanAgora may not be able to sell the fund’s illiquid investments when it considers it desirable to do so, or PanAgora may be able to sell them only at less than their value. The fund expects to engage in frequent trading. Funds with high turnover may be more likely to realize capital gains that must be distributed to shareholders as taxable ordinary income. High turnover may also cause a fund to pay more brokerage commissions and to incur other transaction costs (including imputed transaction costs), which may detract from performance. 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	It is important to understand that you can lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	putnam.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Please remember that past performance is not necessarily an indication of future results.
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	The bar chart does not reflect the impact of sales charges. If it did, performance would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Year-to-date performance through 9/30/19  −5.87% Best calendar quarter Q3 2018   −0.75% Worst calendar quarter Q2 2018  −3.50%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-date performance
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2019
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(5.87%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best calendar quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	(0.75%)
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst calendar quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.50%)
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns after sales charges (for periods ended 12/31/18)
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	ICE BofAML Indexes: ICE Data Indices, LLC (“ICE BofAML”), used with permission. ICE BofAML permits use of the ICE BofAML indices and related data on an “as is” basis; makes no warranties regarding same; does not guarantee the suitability, quality, accuracy, timeliness, and/or completeness of the ICE BofAML indices or any data included in, related to, or derived therefrom; assumes no liability in connection with the use of the foregoing; and does not sponsor, endorse, or recommend Putnam Investments, or any of its products or services. 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.
Putnam PanAgora Market Neutral Fund | ICE BofAML U.S. Treasury Bill Index (no deduction for fees. expenses or taxes)
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	1.88%
Since Inception	rr_AverageAnnualReturnSinceInception	1.69%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class A
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Management fees	rr_ManagementFeesOverAssets	1.30%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	1.74%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.31%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.81%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 748
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,403
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	2,080
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,876
Annual Return 2018	rr_AnnualReturn2018	(6.79%)
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(12.15%)
Since Inception	rr_AverageAnnualReturnSinceInception	(10.55%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class A | after taxes on distributions
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(12.15%)
Since Inception	rr_AverageAnnualReturnSinceInception	(10.55%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class A | after taxes on distributions and sale of fund shares
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(7.19%)
Since Inception	rr_AverageAnnualReturnSinceInception	(8.01%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class B
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	5.00%	[9]
Management fees	rr_ManagementFeesOverAssets	1.30%	[10]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%	[10]
Other expenses	rr_OtherExpensesOverAssets	1.74%	[7],[10]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%	[10]
Total annual fund operating expenses	rr_ExpensesOverAssets	4.06%	[10]
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8],[10]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.56%	[10]
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 759
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,399
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	2,154
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	4,004
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	259
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	1,099
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,954
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 4,004
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(12.04%)
Since Inception	rr_AverageAnnualReturnSinceInception	(9.87%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class C
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[4]
Management fees	rr_ManagementFeesOverAssets	1.30%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	1.74%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total annual fund operating expenses	rr_ExpensesOverAssets	4.06%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.56%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 359
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,099
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,954
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	4,164
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	259
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	1,099
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,954
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 4,164
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(8.34%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.95%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class R
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.30%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other expenses	rr_OtherExpensesOverAssets	1.74%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.56%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.06%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 209
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	953
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,718
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,729
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(6.90%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.47%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class R6
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.30%
Other expenses	rr_OtherExpensesOverAssets	1.75%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.07%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.57%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 160
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	807
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,480
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,278
Label	rr_AverageAnnualReturnLabel	before taxes
1 Year	rr_AverageAnnualReturnYear01	(6.58%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.07%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 21, 2017
Putnam PanAgora Market Neutral Fund | Class Y
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	1.30%
Other expenses	rr_OtherExpensesOverAssets	1.74%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total annual fund operating expenses	rr_ExpensesOverAssets	3.06%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.50%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.56%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 159
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	804
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,475
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 3,269
Putnam PanAgora Risk Parity Fund
Prospectus [Line Items]	rr_ProspectusLineItems
Risk/Return [Heading]	rr_RiskReturnHeading	Fund summary
Objective [Heading]	rr_ObjectiveHeading	Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Putnam PanAgora Risk Parity Fund seeks total return. Total return is composed of capital appreciation and income.
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 and hold shares of the fund. 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 advisor and in How do I buy fund shares? beginning on page 25 of the fund’s prospectus, in the Appendix to the fund’s prospectus, and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).
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 0%. However, the fund’s turnover rate is calculated without regard to transactions involving certain short-term instruments or derivatives. If such transactions were included in the calculation, the fund would have a higher turnover rate.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
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. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 25 of the fund's prospectus, in the Appendix to the fund's prospectus, and in How to buy shares beginning on page II-1 of the fund's statement of additional information (SAI).
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. Only the first year of each period in the example takes into account the expense reimbursement described above. Your actual costs may be higher or lower.
Strategy [Heading]	rr_StrategyHeading	Investments, risks, and performance
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Investments The fund pursues an investment strategy designed to generate returns from investing in a combination of asset classes with diversified risk characteristics. The fund strategically allocates its investments among equities, fixed-income instruments and commodities in an effort to participate in periods of economic growth, preserve capital during periods of economic contraction, and preserve real rates of return during periods of heightened inflation. In allocating the fund’s assets among the different asset classes, PanAgora Asset Management, Inc. (“PanAgora”), the subadviser to the fund, employs a proprietary “risk parity” approach, which relies on quantitative models and information and data inputs to those models to seek to diversify the fund’s portfolio risks across and within asset classes. When allocating investments across asset classes, the fund generally allocates a greater portion of its assets to asset classes PanAgora views as having lower risk, such as developed market bonds, than to asset classes PanAgora views as having higher risk, such as global equities. In its “neutral” position, the fund’s assets are generally strategically allocated among the different asset classes so that the anticipated contribution of each asset class to the overall risk of the fund will be approximately as follows: 40% from equity risk; 40% from fixed income risk; and 20% from inflation risk. However, PanAgora may seek different risk contributions from time to time, including in response to market conditions. When allocating investments within each asset class, PanAgora’s risk parity approach seeks to diversify the fund’s risk exposures across a variety of factors, including industry sectors, geographies, companies and commodity types. The fund will gain exposure to different areas of risk either through direct investment or through derivative instruments, primarily including forwards, futures, and swaps, but which may also include, but are not limited to, options. The fund may invest without limit in equity securities, including, but not limited to, global developed markets large-cap equities, emerging markets equities, and U.S. small and mid-cap equities. The fund may additionally invest in fixed-income securities of any credit quality, duration or maturity (including, but not limited to, U.S. and non-U.S. sovereign bonds, global inflation-linked government bonds (including Treasury Inflation Protected Securities), and investment-grade corporate bonds), commodities (including through, but not limited to, commodity-linked notes and commodity-related derivative instruments (primarily commodity futures and swaps on commodity futures)), exchange-traded funds (“ETFs”), exchange-traded notes, and emerging markets and other currencies (including through cash bonds and currency forwards). These asset classes offer different return potential and exposure to different investment risks. While the fund normally does not engage in borrowing, the fund typically uses derivatives to a significant extent and may take “short” derivatives positions. A significant portion of the assets of the fund will be invested in short-term instruments, including cash and cash equivalents generally with one year or less term to maturity. These investments serve as collateral for the derivative positions the fund takes and also may earn income for the fund. The fund is “non-diversified,” which means that it may invest a greater percentage of its assets in fewer issuers than a “diversified” fund. The fund may invest directly or indirectly through its wholly-owned and controlled subsidiary, which, like the fund, is sub-advised by PanAgora. The fund may invest no more than 25% of its assets in the subsidiary. Generally, the subsidiary will invest primarily in commodity futures and swaps on commodity futures but it may also invest in other commodity-related instruments (such as financial futures, option and swap contracts) or other asset classes (including through derivatives). Unlike the fund, the subsidiary may invest without limitation in commodity-related instruments. Unless indicated otherwise, references to the fund’s investments, investment exposures or risks include its indirect investments, investment exposures and risks through the subsidiary.
Risk [Heading]	rr_RiskHeading	Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	It is important to understand that you can lose money by investing in the fund. There can be no assurance that employing a “risk parity” approach will achieve any particular level of return or will, in fact, reduce volatility or potential loss. The fund’s efforts to strategically allocate its investments among and within asset classes may be unsuccessful and may hurt performance, and efforts to diversify risk through the use of leverage may not be successful. If the quantitative models or data that are used in managing the fund prove to be incorrect or incomplete, investment decisions made in reliance on the models or data may not produce the desired results and the fund may realize losses. Additionally, market movements are likely to change the risk levels and risk allocations of the fund. Investments made based on quantitative models may perform differently from the market as a whole. 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, 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. These risks are generally greater for small and midsize companies. The fixed income securities in which the fund invests (whether directly or indirectly through derivatives) are subject to interest rate risk, which means the value of those investments is likely to fall if interest rates rise. The fund’s investments in fixed income securities also are subject to credit risk, which is the risk that the issuer of the fixed income security may default on payment of interest or principal. Interest rate risk is generally greater for the fund’s investments in longer-term fixed income securities, and credit risk is generally greater for below-investment-grade bonds, which may be considered speculative. The value of the inflation-protected securities to which the fund is exposed generally declines during periods of rising real interest rates (i.e., nominal interest rate minus inflation) and increases during periods of declining real interest rates. When real interest rates are rising faster than nominal interest rates, inflation-indexed bonds, including Treasury Inflation Protected Securities, may experience greater losses than other fixed income securities with similar durations. Exposure to the commodities markets may subject the fund to greater volatility than investments in traditional securities. The value of commodity-linked instruments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. Future regulatory developments may impact the fund’s ability to invest in commodity-linked instruments. The fund’s investments in forwards, futures, swaps, and other derivatives are subject to losses caused by unanticipated market movements, and there may be imperfect correlation between price movements of a derivative and price movements of the security or other asset for which the derivative is intended as a substitute. Derivatives may be difficult to value and may increase the fund’s transaction costs. Derivatives also involve the risk of the potential inability to terminate or sell the derivatives positions. Derivatives can significantly increase the fund’s exposure to credit and counterparty risks. Derivatives, particularly over-the-counter instruments, involve the risk of the potential failure of the other party to the derivative to meet its obligations. Derivatives are subject to the risk that the fund may be delayed or prevented from recovering margin or other amounts deposited with a clearinghouse, futures commission merchant or other counterparty. If the fund has insufficient cash, it may have to sell its investments to meet daily variation margin requirements at a time when it may be disadvantageous to do so. The fund’s use of derivatives also increases its risks by increasing investment exposure (which may be considered leverage). Leveraging may cause the fund’s performance to be more volatile, may expose the fund to losses in excess of the amounts invested, and may require the fund to liquidate portfolio securities when it may not be advantageous to do so, to satisfy its obligations or to meet segregation requirements. The fund’s use of “short” derivatives positions may have the effect of economic leverage, which magnifies investment exposure, and may result in losses if the underlying assets appreciate in value. The value of international investments traded in foreign currencies may be adversely impacted by fluctuations in exchange rates. International investments, particularly investments in emerging markets, may carry risks associated with potentially less stable economies or governments (such as the risk of seizure by a foreign government, the imposition of currency or other restrictions, or high levels of inflation), and may be or become illiquid. A fund that invests in (or provides exposure to) fewer issuers or that makes large investments in (or provides large amounts of exposure to) a small number of issuers is more vulnerable than a more broadly diversified fund to fluctuations in the values of the securities to which it has exposure. An investment in an investment company or ETF involves substantially the same risks as investing directly in the underlying securities. An investment company or ETF may not achieve its investment objective or execute its investment strategy effectively, which may adversely affect the fund’s performance. The fund must pay its pro rata portion of an investment company’s or ETF’s fees and expenses. Shares of a closed-end investment company or ETF may trade at a premium or discount to the net asset value of its portfolio securities. By investing in the subsidiary, the fund is indirectly exposed to the risks associated with the subsidiary’s investments. The subsidiary is not registered under the Investment Company Act of 1940, as amended (the “1940 Act”), and is not subject to all the investor protections of the 1940 Act. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the fund and/or the subsidiary to operate as described in this prospectus and could adversely affect 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	It is important to understand that you can lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	The fund is “non-diversified,” which means that it may invest a greater percentage of its assets in fewer issuers than a “diversified” fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	putnam.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Please remember that past performance is not necessarily an indication of future results.
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	The bar chart does not reflect the impact of sales charges. If it did, performance would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Year-to-date performance through 9/30/19  18.84% Best calendar quarter Q2 2018   −0.50% Worst calendar quarter Q4 2018 −3.43%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-date performance
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2019
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	18.84%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best calendar quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	(0.50%)
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst calendar quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.43%)
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns after sales charges (for periods ended 12/31/18)
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	Putnam PanAgora Risk Parity Blended Benchmark is an unmanaged index administered by Putnam Management, 35% of which is the MSCI ACWI (ND), 50% of which is the Bloomberg Barclays Long U.S. Treasury Index, and 15% of which is the S&P GSCI. 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.
Putnam PanAgora Risk Parity Fund | Putnam PanAgora Risk Parity Blended Benchmark (no deduction for fees, expenses or taxes)
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(5.88%)
Since Inception	rr_AverageAnnualReturnSinceInception	(1.28%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class A
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Management fees	rr_ManagementFeesOverAssets	0.75%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.66%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.71%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.29%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 699
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,044
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,413
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,445
Annual Return 2018	rr_AnnualReturn2018	(6.65%)
1 Year	rr_AverageAnnualReturnYear01	(12.02%)
Since Inception	rr_AverageAnnualReturnSinceInception	(7.58%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class A | after taxes on distributions
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(12.29%)
Since Inception	rr_AverageAnnualReturnSinceInception	(7.97%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class A | after taxes on distributions and sale of fund shares
Prospectus [Line Items]	rr_ProspectusLineItems
1 Year	rr_AverageAnnualReturnYear01	(7.12%)
Since Inception	rr_AverageAnnualReturnSinceInception	(5.89%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class B
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	5.00%	[9]
Management fees	rr_ManagementFeesOverAssets	0.75%	[6],[10]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%	[10]
Other expenses	rr_OtherExpensesOverAssets	0.66%	[7],[10]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%	[10]
Total annual fund operating expenses	rr_ExpensesOverAssets	2.46%	[10]
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8],[10]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.04%	[10]
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 707
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	1,027
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,473
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	2,579
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	207
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	727
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,273
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,579
1 Year	rr_AverageAnnualReturnYear01	(12.00%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.93%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class C
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[4]
Management fees	rr_ManagementFeesOverAssets	0.75%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.66%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.46%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	2.04%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 307
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	727
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,273
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	2,764
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	207
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	727
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,273
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,764
1 Year	rr_AverageAnnualReturnYear01	(8.20%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.87%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class R
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.75%	[6]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other expenses	rr_OtherExpensesOverAssets	0.66%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.96%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.54%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 157
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	575
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	1,018
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 2,251
1 Year	rr_AverageAnnualReturnYear01	(6.80%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.41%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class R6
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.75%	[6]
Other expenses	rr_OtherExpensesOverAssets	0.67%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.47%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.05%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 107
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	424
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	763
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,721
1 Year	rr_AverageAnnualReturnYear01	(6.31%)
Since Inception	rr_AverageAnnualReturnSinceInception	(2.94%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017
Putnam PanAgora Risk Parity Fund | Class Y
Prospectus [Line Items]	rr_ProspectusLineItems
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.75%	[6]
Other expenses	rr_OtherExpensesOverAssets	0.66%	[7]
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.46%
Expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.42%)	[8]
Total annual fund operating expenses after expense reimbursement	rr_NetExpensesOverAssets	1.04%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 106
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	420
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	758
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,710
1 Year	rr_AverageAnnualReturnYear01	(6.31%)
Since Inception	rr_AverageAnnualReturnSinceInception	(2.94%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 20, 2017

[1] Applies only to certain redemptions of shares bought with no initial sales charge.

[2] Management fees are subject to a performance adjustment. The fund's base management fee is subject to adjustment, up or down, based on the fund's performance relative to the performance of the S&P Developed Ex-U.S. SmallCap Index. For the most recent fiscal year, the fund's base management fee prior to any performance adjustment was 0.921%.

[3] This charge is phased out over six years.

[4] This charge is eliminated after one year.

[5] Performance for class R6 shares prior to their inception (5/22/18) is derived from the historical performance of class Y shares and has not been adjusted for the lower investor servicing fees applicable to class R6 shares; had it, returns would have been higher.

[6] Includes management fee payable to Putnam Management by the fund's wholly-owned subsidiary. The management fee paid by the fund to Putnam Management is reduced by an amount equal to the management fee Putnam Management receives from the subsidiary under the management contract between Putnam Management and the subsidiary.

[7] Restated to reflect current fees.

[8] Reflects Putnam Investment Management, LLC's contractual obligation to limit certain fund expenses through 12/30/2020. This obligation may be modified or discontinued only with approval of the Board of Trustees.

[9] A deferred sales charge on class B shares may apply to certain redemptions of shares purchased by exchange from another fund.

[10] Purchases of class B shares are closed to new and existing investors except by exchange from class B shares of another Putnam fund or through dividend and/or capital gains reinvestment.