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BNY Mellon Inflation Adjusted Securities Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Fund Summary
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The fund seeks returns that exceed the rate of inflation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that 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 costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 67.49% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 67.49%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The Example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indicated and then hold or redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategy
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in inflation-indexed securities. These are fixed-income securities designed to protect investors from a loss of value due to inflation by periodically adjusting their principal and/or coupon according to the rate of inflation. The inflation-indexed securities issued by the U.S. Treasury and some foreign government issuers, for example, accrue inflation into the principal value of the bond. Other issuers may pay out the Consumer Price Index accruals as part of a semi-annual coupon.

The fund primarily invests in high quality, U.S. dollar-denominated, inflation-indexed securities. To a limited extent, the fund may invest in foreign currency-denominated, inflation-protected securities and other fixed-income securities not adjusted for inflation which are rated investment grade or the unrated equivalent as determined by BNY Mellon Investment Adviser, Inc. Such other fixed-income securities may include: U.S. government bonds and notes, corporate bonds, mortgage-related securities and asset-backed securities.

The fund seeks to keep the average effective duration of its portfolio at two to ten years. The fund may invest in individual fixed-income securities of any maturity or duration. The fund may adjust its portfolio holdings or average effective duration based on actual or anticipated changes in interest rates or credit quality. A bond's maturity is the length of time until the principal must be fully repaid with interest. Duration is an indication of an investment's "interest rate risk," or how sensitive a bond or the fund's portfolio may be to changes in interest rates.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. It is not a complete investment program. The fund's share price fluctuates, sometimes dramatically, which means you could lose money.

● Fixed-income market risk. The market value of a fixed-income security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. The fixed-income securities market can be susceptible to increases in volatility and decreases in liquidity. Liquidity can decline unpredictably in response to overall economic conditions or credit tightening. Increases in volatility and decreases in liquidity may be caused by a rise in interest rates (or the expectation of a rise in interest rates). An unexpected increase in fund redemption requests, including requests from shareholders who may own a significant percentage of the fund's shares, which may be triggered by market turmoil or an increase in interest rates, could cause the fund to sell its holdings at a loss or at undesirable prices and adversely affect the fund's share price and increase the fund's liquidity risk, fund expenses and/or taxable distributions. Federal Reserve policy in response to market conditions, including with respect to interest rates, may adversely affect the value, volatility and liquidity of dividend and interest paying securities. Policy and legislative changes worldwide are affecting many aspects of financial regulation. The impact of these changes on the markets and the practical implications for market participants may not be fully known for some time.

● Interest rate risk. Prices of bonds and other fixed rate fixed-income securities tend to move inversely with changes in interest rates. Typically, a rise in rates will adversely affect fixed-income securities and, accordingly, will cause the value of the fund's investments in these securities to decline. During periods of very low interest rates, which occur from time to time due to market forces or actions of governments and/or their central banks, including the Board of Governors of the Federal Reserve System in the U.S., the fund may be subject to a greater risk of principal decline from rising interest rates. When interest rates fall, the fund's investments in new securities may be at lower yields and may reduce the fund's income. Very low or negative interest rates may magnify interest rate risk. The magnitude of these fluctuations in the market price of fixed-income securities is generally greater for securities with longer effective maturities and durations because such instruments do not mature, reset interest rates or become callable for longer periods of time. The change in the value of a fixed-income security or portfolio can be approximated by multiplying its duration by a change in interest rates. For example, the market price of a fixed-income security with a duration of three years would be expected to decline 3% if interest rates rose 1%. Conversely, the market price of the same security would be expected to increase 3% if interest rates fell 1%. Interest rate changes may have different effects on the values of mortgage-related securities because of prepayment and extension risks. Interest rate changes may have different effects on the values of mortgage-related securities because of prepayment and extension risks. Interest rates in the United States currently are at or near historic lows due to market forces and actions of the Board of Governors of the Federal Reserve System in the U.S., primarily in response to the novel coronavirus (COVID-19) pandemic and resultant market disruptions. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from fund performance.

● Inflation-indexed security risk. Interest payments on inflation-indexed securities can be unpredictable and will vary as the principal and/or interest is periodically adjusted based on the rate of inflation. If the index measuring inflation falls, the interest payable on these securities will be reduced. The U.S. Treasury has guaranteed that in the event of a drop in prices, it would repay the par amount of its inflation-indexed securities. Inflation-indexed securities issued by corporations generally do not guarantee repayment of principal. Any increase in the principal amount of an inflation-indexed security will be considered taxable ordinary income, even though investors do not receive their principal until maturity. As a result, the fund may be required to make annual distributions to shareholders that exceed the cash the fund received, which may cause the fund to liquidate certain investments when it is not advantageous to do so. Also, if the principal value of an inflation-indexed security is adjusted downward due to deflation, amounts previously distributed may be characterized in some circumstances as a return of capital.

● Liquidity risk. When there is little or no active trading market for specific types of securities, it can become more difficult to sell the securities in a timely manner at or near their perceived value. In such a market, the value of such securities and the fund's share price may fall dramatically. Investments that are illiquid or that trade in lower volumes may be more difficult to value. Investments in foreign securities tend to have greater exposure to liquidity risk than

domestic securities. Liquidity risk also may refer to the risk that the fund will not be able to pay redemption proceeds within the allowable time period stated in this prospectus because of unusual market conditions, an unusually high volume of redemption requests, or other reasons. To meet redemption requests, the fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions, which may adversely affect the fund's share price.

● Government securities risk. Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities of a security held by the fund does not apply to the market value of such security or to shares of the fund itself.

● Foreign investment risk. To the extent the fund invests in foreign securities, the fund's performance will be influenced by political, social and economic factors affecting investments in foreign issuers. Special risks associated with investments in foreign issuers include exposure to currency fluctuations, less liquidity, less developed or less efficient trading markets, lack of comprehensive company information, political and economic instability and differing auditing and legal standards. Investments denominated in foreign currencies are subject to the risk that such currencies will decline in value relative to the U.S. dollar and affect the value of these investments held by the fund.

● Market risk. The value of the securities in which the fund invests may be affected by political, regulatory, economic and social developments, and developments that impact specific economic sectors, industries or segments of the market.  In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the fund.  Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.  These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies world-wide.  Recent examples include pandemic risks related to COVID-19 and aggressive measures taken world-wide in response by governments, including closing borders, restricting international and domestic travel, and the imposition of prolonged quarantines of large populations, and by businesses, including changes to operations and reducing staff. 

Risk Lose Money [Text] rr_RiskLoseMoney The fund's share price fluctuates, sometimes dramatically, which means you could lose money.
RIsk Not Insured [Text] rr_RiskNotInsured An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the performance of the fund's Class I shares from year to year. The table compares the average annual total returns of the fund's shares to those of a broad measure of market performance. The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. More recent performance information may be available at www.bnymellonim.com/us.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following bar chart and table provide some indication of the risks of investing in the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.bnymellonim.com/us
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Year-by-Year Total Returns as of 12/31 each year (%) Class I Shares
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Best Quarter
Q3, 2011: 4.77%

 

Worst Quarter
Q2, 2013: -6.90%

 

The year-to-date total return of the fund's Class I shares as of September 30, 2020 was 6.34%.
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date total return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2020
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 6.34%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2011
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.77%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2013
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.90%)
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes reflects no deductions for fees, expenses or taxes
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through U.S. tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax performance is shown only for Class I shares. After-tax performance of the fund's other share classes will vary.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

After-tax performance is shown only for Class I shares. After-tax performance of the fund's other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through U.S. tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

For the fund's Class Y shares, periods prior to the inception date reflect the performance of the fund's Class I shares. Such performance figures have not been adjusted to reflect applicable class fees and expenses. Each share class is invested in the same portfolio of securities, and the annual returns would have differed only to the extent that the classes have different expenses.
Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns (as of 12/31/19)
BNY Mellon Inflation Adjusted Securities Fund | Bloomberg Barclays U.S. TIPS 1-10 Year Index reflects no deductions for fees, expenses or taxes  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 6.86%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 2.36%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.57%
BNY Mellon Inflation Adjusted Securities Fund | Class I  
Risk/Return: rr_RiskReturnAbstract  
Management fees rr_ManagementFeesOverAssets 0.30%
Distribution (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Shareholder services fees rr_Component1OtherExpensesOverAssets none
Miscellaneous other expenses rr_Component3OtherExpensesOverAssets 0.36%
Total other expenses rr_OtherExpensesOverAssets 0.36%
Total annual fund operating expenses rr_ExpensesOverAssets 0.66%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 67
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 211
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 368
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 822
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 67
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 211
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 368
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 822
Annual Return 2010 rr_AnnualReturn2010 5.88%
Annual Return 2011 rr_AnnualReturn2011 13.20%
Annual Return 2012 rr_AnnualReturn2012 6.42%
Annual Return 2013 rr_AnnualReturn2013 (8.72%)
Annual Return 2014 rr_AnnualReturn2014 1.85%
Annual Return 2015 rr_AnnualReturn2015 (0.98%)
Annual Return 2016 rr_AnnualReturn2016 3.49%
Annual Return 2017 rr_AnnualReturn2017 1.64%
Annual Return 2018 rr_AnnualReturn2018 (0.77%)
Annual Return 2019 rr_AnnualReturn2019 6.25%
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 6.25%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.89%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.68%
BNY Mellon Inflation Adjusted Securities Fund | Class I | After Taxes on Distributions  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 5.58%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.28%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 1.79%
BNY Mellon Inflation Adjusted Securities Fund | Class I | After Taxes on Distributions and Sale of Fund Shares  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 3.69%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.17%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 1.76%
BNY Mellon Inflation Adjusted Securities Fund | Investor Shares  
Risk/Return: rr_RiskReturnAbstract  
Management fees rr_ManagementFeesOverAssets 0.30%
Distribution (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Shareholder services fees rr_Component1OtherExpensesOverAssets 0.25%
Miscellaneous other expenses rr_Component3OtherExpensesOverAssets 0.37%
Total other expenses rr_OtherExpensesOverAssets 0.62%
Total annual fund operating expenses rr_ExpensesOverAssets 0.92%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 94
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 293
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 509
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,131
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 94
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 293
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 509
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,131
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 5.91%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.63%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.37%
BNY Mellon Inflation Adjusted Securities Fund | Class Y  
Risk/Return: rr_RiskReturnAbstract  
Management fees rr_ManagementFeesOverAssets 0.30%
Distribution (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Shareholder services fees rr_Component1OtherExpensesOverAssets none
Miscellaneous other expenses rr_Component3OtherExpensesOverAssets 0.30%
Total other expenses rr_OtherExpensesOverAssets 0.30%
Total annual fund operating expenses rr_ExpensesOverAssets 0.60%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 61
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 192
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 335
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 750
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 61
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 192
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 335
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 750
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 6.32%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.96%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.72%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jul. 01, 2013