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Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName Federated Hermes Municipal Bond Fund, Inc.
Prospectus Date rr_ProspectusDate May 31, 2024
Federated Hermes Municipal Bond Fund Inc.  
Risk Return Abstract rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading <span style="color:#000000;font-family:Times New Roman;font-size:14pt;">Fund Summary Information</span><span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Federated Hermes Municipal Bond Fund, Inc. (the “Fund”)</span>
Objective [Heading] rr_ObjectiveHeading <span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;text-transform:uppercase;">RISK/RETURN SUMMARY: INVESTMENT OBJECTIVE</span>
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The Fund’s investment objective is to provide for its shareholders a high level of current income which is exempt from federal regular income tax.
Expense [Heading] rr_ExpenseHeading <span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;text-transform:uppercase;">RISK/RETURN SUMMARY: FEES AND EXPENSES</span>
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock This table describes the fees and expenses that you may pay if you buy, hold and sell Class A Shares (A), Class C Shares (C), Class F Shares (F) or Institutional Shares (IS) of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000, or $1,000,000, in certain classes (e.g., A and F classes, respectively) of Federated Hermes funds. More information about these and other discounts is available from your financial professional, in the “What Do Shares Cost?” section of the Prospectus on page 19 and in “Appendix B” to this Prospectus.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Shareholder Fees (fees paid directly from your investment)</span>
Operating Expenses Caption [Text] rr_OperatingExpensesCaption <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination <span style="font-family:Arial Narrow;font-size:8pt;">June 1, 2025</span>
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Portfolio Turnover</span>
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 rate 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 19% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 19.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">100,000</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">, or $1,000,000, in certain classes (e.g., A and F classes, respectively) of Federated Hermes funds.</span>
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 100,000
Expense Example [Heading] rr_ExpenseExampleHeading <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Example</span>
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock This 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 for the time periods indicated and then redeem all of your Shares at the end of those periods. Expenses assuming no redemption are also shown. The Example also assumes that your investment has a 5% return each year and that operating expenses remain the same. The Example does not reflect sales charges (loads) on reinvested dividends. If these sales charges (loads) were included, your costs would be higher. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading <span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;text-transform:uppercase;">RISK/RETURN SUMMARY: INVESTMENTS, RISKS and PERFORMANCE</span><span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">What are the Fund’s Main Investment Strategies?</span>
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The Fund’s investment objective is to provide for its shareholders a high level of current income which is exempt from federal regular income tax. The Fund pursues its objective by investing its assets so that normally distributions of annual interest income are exempt from federal regular income tax. The Fund’s investment adviser (“Adviser”) may also invest the Fund’s assets in securities whose interest (while exempt from the federal regular income tax) may be subject to (or may be a specific preference item for purposes of) the federal alternative minimum income tax (AMT) for individuals.The Adviser may lengthen or shorten the duration of the Fund’s portfolio from time to time based on its interest rate outlook, but the Fund has no set duration parameters. Duration measures the price sensitivity of a fixed-income security to changes in interest rates.The Fund does not limit itself to securities of a particular maturity range.The Fund will invest at least a majority of its assets in securities rated investment grade (or unrated securities of comparable quality), and may purchase securities rated below investment grade (or unrated securities of comparable quality), which are also known as junk bonds, up to 49% of its assets. Investment-grade securities are securities that receive investment-grade ratings (i.e., generally ratings in the first, second, third or fourth highest rating category) by a nationally recognized statistical rating organization (NRSRO) or unrated securities of comparable quality. For example, securities rated AAA, AA, A or BBB (including modifiers, sub-categories or gradations) by S&P Global Ratings, an NRSRO, would be rated in the first, second, third or fourth ratings category, respectively. Securities rated below investment grade (or noninvestment-grade securities) are securities that do not receive investment-grade ratings (i.e., generally ratings below one of the four highest rating categories) by an NRSRO or unrated securities of comparable quality. For example, securities rated B or BB (including modifiers, sub-categories or gradations) by S&P Global Ratingswould be noninvestment-grade securities. The presence of a ratings modifier, sub-category, or gradation (for example, a (+) or (-)) is intended to show relative standing within the major rating categories and does not affect the security credit rating for purposes of the Fund’s investment parameters. The Fund does not have a specific minimum quality rating.The types of securities in which the Fund may principally invest include tax-exempt securities, such as the following types: general obligation bonds, special revenue bonds, private activity bonds, tax increment financing bonds, municipal leases, zero-coupon securities, inverse floaters, municipal mortgage-backed securities, planned amortization classes, variable rate demand instruments, municipal notes and municipal auction rate securities. Certain of the tax-exempt securities in which the Fund invests may be subject to credit enhancement. The Fund also may principally invest in derivative contracts (such as, for example, futures contracts, options contracts and swap contracts) and hybrid instruments to implement its investment strategies. For example, the Fund may use derivative contracts or hybrid instruments in an attempt to benefit from changes in the value of the underlying instrument(s), to gain exposure to the municipal bond sector, to increase or decrease the effective duration of the Fund’s portfolio or to hedge against potential losses. There can be no assurance that the Fund’s use of derivative contracts or hybrid instruments will work as intended. Derivative investments made by the Fund are included within the Fund’s 80% policy (as described below) and are calculated at market value. The Fund also may invest in certain securities or other investments as described herein (such as market discount bonds, credit default swaps and other derivative transactions) that will likely cause the Fund to realize a limited amount of ordinary income or short-term capital gains (which are treated as ordinary income for federal income tax purposes) and, as a result, may result in taxable distributions to shareholders.The Fund will normally invest its assets so that at least 80% of the income that it distributes will be exempt from federal regular income tax. This policy may not be changed without shareholder approval.
Risk [Heading] rr_RiskHeading <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">What are the Main (or Principal) Risks of Investing in the Fund?</span>
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading <span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;text-transform:uppercase;">Performance: Bar Chart and Table</span><span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Risk/Return Bar Chart</span>
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The bar chart and performance table below reflect historical performance data for the Fund and are intended to help you analyze the Fund’s investment risks in light of its historical returns. The bar chart shows the variability of the Fund’s A class total returns on a calendar year-by-year basis. The Average Annual Total Return table shows returns for each class averaged over the stated periods, and includes comparative performance information. The Fund’s performance will fluctuate, and past performance (before and after taxes) is not necessarily an indication of future results. Updated performance information for the Fund is available under the “Products” section at FederatedHermes.com/us or by calling 1-800-341-7400.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns <span style="font-family:Times New Roman;font-size:10pt;margin-left:10pt;">The bar chart and performance table below reflect historical performance data for the Fund and are intended to help you </span><span style="font-family:Times New Roman;font-size:10pt;">analyze the Fund’s investment risks in light of its historical returns. The bar chart shows the variability of the Fund’s A class total returns on a calendar year-by-year basis.</span>
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone <span style="font-family:Times New Roman;font-size:10pt;">1-800-341-7400</span>
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress <span style="font-family:Times New Roman;font-size:10pt;">FederatedHermes</span><span style="font-family:Times New Roman;font-size:10pt;">.com/us</span>
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture <span style="font-family:Times New Roman;font-size:10pt;font-style:italic;">The Fund’s performance will fluctuate, and past performance (before and after taxes) is not necessarily an indication of future results</span><span style="font-family:Times New Roman;font-size:10pt;">.</span>
Bar Chart [Heading] rr_BarChartHeading Federated Hermes Municipal Bond Fund, Inc. – A Class
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads <span style="color:#000000;font-family:Arial Narrow;font-size:7.75pt;font-style:italic;">The total returns shown in the bar chart do not reflect the payment of any sale charges or recurring shareholder account fees. If these charges or fees had been included, the returns shown would have been lower.</span>
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock The total returns shown in the bar chart do not reflect the payment of any sale charges or recurring shareholder account fees. If these charges or fees had been included, the returns shown would have been lower.The Fund’s A class total return for the three-month period from January 1, 2024 to March 31, 2024, was (0.12)%.Within the periods shown in the bar chart, the Fund’s A class highest quarterly return was 8.41% (quarter ended December 31, 2023). Its lowest quarterly return was (6.11)% (quarter ended March 31, 2022).
Performance Table Heading rr_PerformanceTableHeading <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Average Annual Total Return Table</span>
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax returns are calculated using a standard set of assumptions. The stated returns assume the highest historical </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">federal</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> income and capital gains tax rates. These after-tax returns do </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">not </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">reflect the effect of any applicable </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">state</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> and</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;"> local</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> taxes.</span>
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax returns are not relevant to investors holding Shares through a 401(k) plan, an Individual Retirement Account or other tax-advantaged investment plan.</span>
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax returns are shown only for A class, and after-tax returns for C, F and IS classes will differ </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">from those shown below for A class.</span>
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock The Fund’s IS class commenced operations on July 27, 2017. For the periods prior to the commencement of operations of the Fund’s IS class, the performance information shown below is for the Fund’s A class. The performance of the A class has not been adjusted to reflect the expenses applicable to the IS class since the IS class has a lower expense ratio than the expense ratio of the A class. The performance of the A class has been adjusted to remove any voluntary waiver of the Fund expenses related to the A class that may have occurred during the periods prior to the commencement of operations of the IS class. The performance shown in the table has been adjusted to reflect differences between the sales loads and charges imposed on the purchase and redemption of the Fund’s IS class and A class.In addition to Return Before Taxes, Return After Taxes is shown for the Fund’s A class to illustrate the effect of federal taxes on Fund returns. After-tax returns are shown only for A class, and after-tax returns for C, F and IS classes will differ from those shown below for A class.Actual after-tax returns depend on each investor’s personal tax situation, and are likely to differ from those shown.After-tax returns are calculated using a standard set of assumptions. The stated returns assume the highest historical federal income and capital gains tax rates. These after-tax returns do not reflect the effect of any applicable state and local taxes.After-tax returns are not relevant to investors holding Shares through a 401(k) plan, an Individual Retirement Account or other tax-advantaged investment plan.(For the Periods Ended December 31, 2023)
Fee Waiver Or Reimbursement Over Assets, Later Of Termination Or Next Effective Prospectus fmbdf_FeeWaiverOrReimbursementOverAssetsLaterOfTerminationOrNextEffectiveProspectus <span style="font-family:Arial Narrow;font-size:8pt;"> up to but not including the later of (the “Termination Date”): (a) </span><span style="font-family:Arial Narrow;font-size:8pt;">June 1, 2025</span><span style="font-family:Arial Narrow;font-size:8pt;">; or (b) the date of the Fund’s next effective Prospectus.</span>
Federated Hermes Municipal Bond Fund Inc. | Risk Lose Money [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock All mutual funds take investment risks. Therefore, it is possible to lose money by investing in the Fund.
Federated Hermes Municipal Bond Fund Inc. | Risk Not Insured Depository Institution [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock The Shares offered by this Prospectus are not deposits or obligations of any bank, are not endorsed or guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.
Federated Hermes Municipal Bond Fund Inc. | Tax Exempt Securities Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Tax-Exempt Securities Risk. The amount of public information available about tax-exempt securities is generally less than for corporate equities or bonds. The secondary market for tax-exempt securities also tends to be less well-developed and less liquid than many other securities markets, which may limit the Fund’s ability to sell its tax-exempt securities at attractive prices. Special factors, such as legislative changes, and state and local economic and business developments, may adversely affect the yield and/or value of the Fund’s investments in tax-exempt securities. Tax-exempt issuers can and have defaulted on obligations, been downgraded or commenced insolvency proceedings. Like other issuers and securities, the likelihood that the credit risk associated with such issuers and such securities will increase is greater during times of economic stress and financial instability.
Federated Hermes Municipal Bond Fund Inc. | Call Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Call Risk. The Fund’s performance may be adversely affected by the possibility that an issuer of a security held by the Fund may redeem the security prior to maturity at a price below or above its current market value.
Federated Hermes Municipal Bond Fund Inc. | Credit Enhancement Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Credit Enhancement Risk. The securities in which the Fund invests may be subject to credit enhancement (for example, guarantees, letters of credit or bond insurance). If the credit quality of the credit enhancement provider (for example, a bank or bond insurer) is downgraded, the rating on a security credit enhanced by such credit enhancement provider also may be downgraded. Having multiple securities credit enhanced by the same enhancement provider will increase the adverse effects on the Fund that are likely to result from a downgrading of, or a default by, such an enhancement provider. Adverse developments in the banking or bond insurance industries also may negatively affect the Fund.
Federated Hermes Municipal Bond Fund Inc. | Leverage Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Leverage Risk. Leverage risk is created when an investment, which includes, for example, a derivative contract, exposes the Fund to a level of risk that exceeds the amount invested. Changes in the value of such an investment magnify the Fund’s risk of loss and potential for gain. Investments can have these same results if their returns are based on a multiple of a specified index, security or other benchmark.
Federated Hermes Municipal Bond Fund Inc. | Liquidity Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Liquidity Risk. Certain securities in which the Fund invests may be less readily marketable and may be subject to greater fluctuation in price than other securities. These features may make it more difficult to sell or buy a security at a favorable price or time. Noninvestment-grade securities generally have less liquidity than investment-grade securities. Liquidity risk also refers to the possibility that the Fund may not be able to sell a security or close out a derivative contract when it wants to. Over-the-counter derivative contracts generally carry greater liquidity risk than exchange-traded contracts.
Federated Hermes Municipal Bond Fund Inc. | Prepayment and Extension Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Prepayment and Extension Risk. When homeowners prepay their mortgages in response to lower interest rates, the Fund will be required to reinvest the proceeds at the lower interest rates available. Also, when interest rates fall, the price of municipal mortgage-backed securities may not rise to as great an extent as that of other fixed-income securities. When interest rates rise, homeowners are less likely to prepay their mortgages. A decreased rate of prepayments lengthens the expected maturity of a mortgage-backed security, and the price of mortgage-backed securities may decrease more than the price of other fixed-income securities when interest rates rise.
Federated Hermes Municipal Bond Fund Inc. | Risk of Investing in Derivative Contracts and Hybrid Instruments [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Risk of Investing in Derivative Contracts and Hybrid Instruments. Derivative contracts and hybrid instruments involve risks different from, or possibly greater than, risks associated with investing directly in securities and other traditional investments. Specific risk issues related to the use of such contracts and instruments include valuation and tax issues, increased potential for losses and/or costs to the Fund, and a potential reduction in gains to the Fund. Each of these issues is described in greater detail in this Prospectus. Derivative contracts and hybrid instruments may also involve other risks described in this Prospectus, such as interest rate, credit, liquidity and leverage risks.
Federated Hermes Municipal Bond Fund Inc. | Risk Associated with Noninvestment Grade Securities [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Risk Associated with Noninvestment-Grade Securities. Securities rated below investment grade may be subject to greater interest rate, credit and liquidity risks than investment-grade securities. These securities are considered speculative with respect to the issuer’s ability to pay interest and repay principal.
Federated Hermes Municipal Bond Fund Inc. | Risk Related to the Economy [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Risk Related to the Economy. The value of the Fund’s portfolio may decline in tandem with a drop in the overall value of the markets in which the Fund invests and/or other markets. Economic, political and financial conditions, industry or economic trends and developments or public health risks, such as epidemics or pandemics, may, from time to time, and for varying periods of time, cause the Fund to experience volatility, illiquidity, shareholder redemptions or other potentially adverse effects. Among other investments, lower-grade bonds may be particularly sensitive to changes in the economy.
Federated Hermes Municipal Bond Fund Inc. | Sector Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Sector Risk. A substantial part of the Fund’s portfolio may be comprised of securities issued or credit enhanced by companies in similar businesses, or with other similar characteristics. As a result, the Fund will be more susceptible to any economic, business, political or other developments which generally affect these issuers or entities.
Federated Hermes Municipal Bond Fund Inc. | Tax Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Tax Risk. In order to be tax-exempt, tax-exempt securities must meet certain legal requirements. Failure to meet such requirements may cause the interest received and distributed by the Fund to shareholders to be taxable. The federal income tax treatment of payments in respect of certain derivative contracts is unclear. The Fund also may invest in market discount bonds, enter into credit default swap arrangements and other derivative transactions, and engage in other permissible activities that will likely cause the Fund to realize a limited amount of ordinary income or short-term capital gains (which are treated as ordinary income for federal income tax purposes). Consequently, for each of these reasons, the Fund may receive payments, and make distributions, that are treated as ordinary income for federal income tax purposes. Income from the Fund also may be subject to AMT.
Federated Hermes Municipal Bond Fund Inc. | Issuer Credit Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Issuer Credit Risk. It is possible that interest or principal on securities will not be paid when due. Noninvestment-grade securities generally have a higher default risk than investment-grade securities. Such non-payment or default may reduce the value of the Fund’s portfolio holdings, its share price and its performance.
Federated Hermes Municipal Bond Fund Inc. | Counterparty Credit Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Counterparty Credit Risk. A party to a transaction involving the Fund may fail to meet its obligations. This could cause the Fund to lose money or to lose the benefit of the transaction or prevent the Fund from selling or buying other securities to implement its investment strategies.
Federated Hermes Municipal Bond Fund Inc. | Interest Rate Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Interest Rate Risk. Prices of fixed-income securities (including tax-exempt securities) generally fall when interest rates rise. The longer the duration of a fixed-income security, the more susceptible it is to interest rate risk. Recent and potential future changes in monetary policy made by central banks and/or their governments are likely to affect the level of interest rates.
Federated Hermes Municipal Bond Fund Inc. | Technology Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ◾ Technology Risk. The Adviser uses various technologies in managing the Fund, consistent with its investment objective(s) and strategy described in this Prospectus. For example, proprietary and third-party data and systems are utilized to support decision making for the Fund. Data imprecision, software or other technology malfunctions, programming inaccuracies and similar circumstances may impair the performance of these systems, which may negatively affect Fund performance.
Federated Hermes Municipal Bond Fund Inc. | A  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum Sales Charge (Load) rr_MaximumCumulativeSalesChargeOverOfferingPrice 4.50%
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.50%
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable) rr_MaximumDeferredSalesChargeOverOther none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price) rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption Fee (as a percentage of amount redeemed, if applicable) rr_RedemptionFeeOverRedemption none
Exchange Fee rr_ExchangeFeeOverRedemption none
Management Fee rr_ManagementFeesOverAssets 0.46%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.54%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.00%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.17%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.83%
1 Year rr_ExpenseExampleYear01 $ 547
3 Years rr_ExpenseExampleYear03 754
5 Years rr_ExpenseExampleYear05 978
10 Years rr_ExpenseExampleYear10 1,620
1 Year rr_ExpenseExampleNoRedemptionYear01 547
3 Years rr_ExpenseExampleNoRedemptionYear03 754
5 Years rr_ExpenseExampleNoRedemptionYear05 978
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,620
2014 rr_AnnualReturn2014 10.03%
2015 rr_AnnualReturn2015 2.66%
2016 rr_AnnualReturn2016 0.47%
2017 rr_AnnualReturn2017 5.07%
2018 rr_AnnualReturn2018 0.07%
2019 rr_AnnualReturn2019 7.96%
2020 rr_AnnualReturn2020 4.72%
2021 rr_AnnualReturn2021 2.06%
2022 rr_AnnualReturn2022 (10.78%)
2023 rr_AnnualReturn2023 6.84%
Year to Date Return, Label rr_YearToDateReturnLabel The Fund's A class total return for the three-month period
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Mar. 31, 2024
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (0.12%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2023
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 8.41%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2022
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.11%)
1 Year rr_AverageAnnualReturnYear01 2.04%
5 Years rr_AverageAnnualReturnYear05 0.99%
10 Years rr_AverageAnnualReturnYear10 2.28%
Federated Hermes Municipal Bond Fund Inc. | C  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum Sales Charge (Load) rr_MaximumCumulativeSalesChargeOverOfferingPrice 1.00%
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, as applicable) rr_MaximumDeferredSalesChargeOverOther 1.00%
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price) rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption Fee (as a percentage of amount redeemed, if applicable) rr_RedemptionFeeOverRedemption none
Exchange Fee rr_ExchangeFeeOverRedemption none
Management Fee rr_ManagementFeesOverAssets 0.46%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets 0.75%
Other Expenses rr_OtherExpensesOverAssets 0.54%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.75%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.17%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 1.58%
1 Year rr_ExpenseExampleYear01 $ 278
3 Years rr_ExpenseExampleYear03 551
5 Years rr_ExpenseExampleYear05 949
10 Years rr_ExpenseExampleYear10 1,864
1 Year rr_ExpenseExampleNoRedemptionYear01 178
3 Years rr_ExpenseExampleNoRedemptionYear03 551
5 Years rr_ExpenseExampleNoRedemptionYear05 949
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,864
1 Year rr_AverageAnnualReturnYear01 5.04%
5 Years rr_AverageAnnualReturnYear05 1.16%
10 Years rr_AverageAnnualReturnYear10 2.11%
Federated Hermes Municipal Bond Fund Inc. | F  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum Sales Charge (Load) rr_MaximumCumulativeSalesChargeOverOfferingPrice 2.00%
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 1.00%
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable) rr_MaximumDeferredSalesChargeOverOther 1.00%
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price) rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption Fee (as a percentage of amount redeemed, if applicable) rr_RedemptionFeeOverRedemption none
Exchange Fee rr_ExchangeFeeOverRedemption none
Management Fee rr_ManagementFeesOverAssets 0.46%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.54%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.00%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.17%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.83%
1 Year rr_ExpenseExampleYear01 $ 301
3 Years rr_ExpenseExampleYear03 515
5 Years rr_ExpenseExampleYear05 647
10 Years rr_ExpenseExampleYear10 1,312
1 Year rr_ExpenseExampleNoRedemptionYear01 201
3 Years rr_ExpenseExampleNoRedemptionYear03 415
5 Years rr_ExpenseExampleNoRedemptionYear05 647
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,312
1 Year rr_AverageAnnualReturnYear01 4.83%
5 Years rr_AverageAnnualReturnYear05 1.70%
10 Years rr_AverageAnnualReturnYear10 2.64%
Federated Hermes Municipal Bond Fund Inc. | IS  
Risk Return Abstract rr_RiskReturnAbstract  
Maximum Sales Charge (Load) rr_MaximumCumulativeSalesChargeOverOfferingPrice none
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, as applicable) rr_MaximumDeferredSalesChargeOverOther none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price) rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption Fee (as a percentage of amount redeemed, if applicable) rr_RedemptionFeeOverRedemption none
Exchange Fee rr_ExchangeFeeOverRedemption none
Management Fee rr_ManagementFeesOverAssets 0.47%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.28%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.75%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.17%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.58%
1 Year rr_ExpenseExampleYear01 $ 77
3 Years rr_ExpenseExampleYear03 240
5 Years rr_ExpenseExampleYear05 417
10 Years rr_ExpenseExampleYear10 930
1 Year rr_ExpenseExampleNoRedemptionYear01 77
3 Years rr_ExpenseExampleNoRedemptionYear03 240
5 Years rr_ExpenseExampleNoRedemptionYear05 417
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 930
1 Year rr_AverageAnnualReturnYear01 7.13%
5 Years rr_AverageAnnualReturnYear05 2.12%
10 Years rr_AverageAnnualReturnYear10 2.85%
Federated Hermes Municipal Bond Fund Inc. | Return After Taxes on Distributions | A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 2.04%
5 Years rr_AverageAnnualReturnYear05 0.87%
10 Years rr_AverageAnnualReturnYear10 2.21%
Federated Hermes Municipal Bond Fund Inc. | Return After Taxes on Distributions and Sale of Fund Shares | A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 2.30%
5 Years rr_AverageAnnualReturnYear05 1.31%
10 Years rr_AverageAnnualReturnYear10 2.39%
Federated Hermes Municipal Bond Fund Inc. | S&P Municipal Bond Index1(reflects no deduction for fees, expenses or taxes)  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 6.03% [2]
5 Years rr_AverageAnnualReturnYear05 2.24% [2]
10 Years rr_AverageAnnualReturnYear10 3.06% [2]
Federated Hermes Municipal Bond Fund Inc. | Morningstar Municipal National Long Funds Average2  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 6.97% [3]
5 Years rr_AverageAnnualReturnYear05 1.96% [3]
10 Years rr_AverageAnnualReturnYear10 3.03% [3]
[1] The Adviser and certain of its affiliates, on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (excluding acquired fund fees and expenses, interest expense, extraordinary expenses and proxy-related expenses, if any) paid by the Fund’s A, C, F and IS classes (after the voluntary waivers and/or reimbursements) will not exceed 0.83%, 1.58%, 0.83% and 0.58% (the “Fee Limit”), respectively, up to but not including the later of (the “Termination Date”): (a) June 1, 2025; or (b) the date of the Fund’s next effective Prospectus.While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Fund’s Board of Directors.
[2] The S&P Municipal Bond Index (“Main Index”) is a broad, comprehensive, market value-weighted index composed of approximately 55,000 bond issues that are exempt from U.S. federal income taxes or subject to the alternative minimum tax (AMT). Eligibility criteria for inclusion in the Main Index include, but are not limited to: the bond issuer must be a state (including the Commonwealth of Puerto Rico and U.S. territories) or a local government or a state or local government entity where interest on the bond is exempt from U.S. federal income taxes or subject to the AMT; the bond must be held by a mutual fund for which Standard & Poor’s Securities Evaluations, Inc. provides prices; it must be denominated in U.S. dollars and have a minimum par amount of $2 million; and the bond must have a minimum term to maturity and/or call date greater than or equal to one calendar month. The Main Index is rebalanced monthly.
[3] Morningstar figures represent the average of the total returns reported by all the mutual funds designated by Morningstar as falling into the respective category indicated.