v3.25.1
Label Element Value
Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName Federated Hermes Sustainable High Yield Bond Fund, Inc.
Prospectus Date rr_ProspectusDate May 31, 2025
Federated Hermes Sustainable High Yield 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 Sustainable High Yield 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 seek high current income.
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), Institutional Shares (IS) and Class R6 Shares (R6) 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 certain sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in certain classes (e.g., A class) 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 17 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, 2026</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 24% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 24.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">You may qualify for certain 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;"> in certain classes (e.g., A class) 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 pursues its investment objective by investing primarily in a diversified portfolio of sustainable, lower-rated fixed-income investments (i.e., BB or lower). These investments include lower-rated corporate bonds (also known as “junk bonds”) which include debt securities issued by U.S. or foreign businesses (including emerging market debt securities). The Fund’s investment adviser or sub-adviser (as applicable, the “Adviser”) does not target an average maturity for the Fund’s portfolio.The Adviser’s securities selection process includes a focus on sustainable investments and the avoidance of issuers with high environmental, social and governance (ESG) risk as determined in accordance with the Adviser’s sustainable investment methodology, which includes a proprietary analysis of a company’s creditworthiness, ESG risks and sustainability credentials. The Adviser assigns an ESG Rating to individual securities based on a proprietary assessment of material ESG risks. The Adviser determines these ratings based on research and due diligence, including a review of information that may be publicly available, company provided and/or from third party sources. The ESG Rating is determined by the Adviser’s view of risks including: environmental (e.g., temperature alignment, carbon intensity, water usage, waste reduction); social (e.g., human rights, employee rights, health/safety concerns, data privacy); and governance (e.g., management effectiveness and board composition). Additionally, issuers will be evaluated based on their approach to addressing greenhouse gas emissions based on the Adviser’s proprietary Climate Change Impact Score (CCI) methodology. These scores are determined by combining a review of data on greenhouse gas emissions, publicly available or company-disclosed information, third-party opinions and information derived from engagement with issuers. The Adviser may invest up to 15% of the Fund’s net assets in companies that have not been subject to sustainability analysis. The Fund will generally not purchase securities with ESG Ratings or CCI Scores below certain thresholds as determined by the Adviser. However, the Fund may purchase a “Green Bond,” “Social Bond” or “Sustainability-Linked Bond” (collectively, “GSS Bonds”) from certain issuers whose securities may otherwise be excluded based on ESG Ratings or CCI Scores. The Adviser will exclude companies that generate greater than 5% of their revenue from the manufacture of tobacco or controversial weapons, or that, in the Adviser’s view, are in violation of the UN Global Compact principles. For purposes of this strategy, examples of controversial weapons include cluster munitions, anti-personnel mines, biological weapons and chemical weapons. The Adviser also targets a lower weighted-average carbon intensity compared to that of the Bloomberg US Corporate High Yield 2% Issuer Capped Index. The Fund may invest in derivative contracts, in particular, futures contracts, option contracts and swap contracts, and/or hybrid instruments to implement elements of its investment strategy. For example, the Fund may use derivative contracts and/or hybrid instruments to increase or decrease the portfolio’s exposure to the investment(s) underlying the derivative contracts or hybrid instruments in an attempt to benefit from changes in the value of the underlying investment(s). 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 will invest at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in sustainable, lower-rated fixed-income investments. The Fund will notify shareholders at least 60 days in advance of any change in its investment policy to invest, under normal circumstances, less than 80% of its net assets (plus any borrowings for investment purposes) in sustainable, lower-rated fixed-income investments. For the purposes of this policy, the Adviser will consider “sustainable” investments as those that are selected in accordance with its sustainable investment methodology, which is based on a materiality assessment of a company’s carbon intensity and incorporates a proprietary scoring methodology focusing on the overall sustainability credentials of issuers.
Risk [Heading] rr_RiskHeading <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">What are the Main 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 Prior to May 26, 2023, the Fund was managed pursuant to a different investment strategy. As a result of the difference in investment strategy, the performance information presented for periods prior to May 26, 2023, reflects management of the Fund consistent with investment strategies in effect during those periods and might have differed materially if the Fund’s investments had been managed under its current strategies. 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 with a broad-based securities market index. The Fund’s performance is also compared to a secondary index to show how the Fund’s performance compares with the returns of an index with similar investments.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;font-weight:bold;margin-left:10pt;">Prior to May 26, 2023, the Fund was managed pursuant to a different investment strategy. As a result of the </span><span style="font-family:Times New Roman;font-size:10pt;font-weight:bold;">difference in investment strategy, the performance information presented for periods prior to May 26, 2023, reflects management of the Fund consistent with investment strategies in effect during those periods and might have differed materially if the Fund’s investments had been managed under its current strategies.</span><span style="font-family:Times New Roman;font-size:10pt;"> 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.</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.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>
Bar Chart [Heading] rr_BarChartHeading Federated Hermes Sustainable High Yield 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 sales 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 sales 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, 2025 to March 31, 2025, was 0.92%. Within the periods shown in the bar chart, the Fund’s A class highest quarterly return was 9.34% (quarter ended June 30, 2020). Its lowest quarterly return was (12.22)% (quarter ended March 31, 2020).
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 the A class, and after-tax returns for the C class, IS class and </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">R6 class will differ from those shown for the A class.</span>
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock The Fund’s IS and R6 classes commenced operations on January 27, 2017. For the periods prior to commencement of operations of the Fund’s IS and R6 classes, 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 and R6 classes since the IS and R6 classes have a lower expense ratio than the expense ratio of the A class. The performance of the A class has been adjusted to reflect the absence of sales charges. 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 the A class, and after-tax returns for the C class, IS class and R6 class will differ from those shown for the 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 Period Ended December 31, 2024)
Fee Waiver Or Reimbursement Over Assets, Later Of Termination Or Next Effective Prospectus federate_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, 2026</span><span style="font-family:Arial Narrow;font-size:8pt;">; or (b) the date of the Fund’s next effective Prospectus.</span>
Federated Hermes Sustainable High Yield 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 Sustainable High Yield 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 Sustainable High Yield 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 Sustainable High Yield Bond Fund Inc. | Counterparty Credit Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Counterparty Credit Risk. Credit risk includes the possibility that a party to a transaction involving the Fund will fail to meet its obligations. This could cause the Fund to lose the benefit of the transaction or prevent the Fund from selling or buying other securities to implement its investment strategy.
Federated Hermes Sustainable High Yield Bond Fund Inc. | Liquidity Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Liquidity Risk. Liquidity of individual corporate bonds varies considerably. Low-grade corporate bonds have less liquidity than investment-grade securities, which means that it may be more difficult to buy or sell a security at a favorable price or time.
Federated Hermes Sustainable High Yield 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 Sustainable High Yield 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, and/or other potentially adverse effects. Among other investments, lower-grade bonds and loans may be particularly sensitive to changes in the economy.
Federated Hermes Sustainable High Yield Bond Fund Inc. | Environmental Social and Governance Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Environmental, Social and Governance Risk. The Adviser considers environmental, social and governance (ESG) issues as part of its security selection process. ESG factors are not the only factors considered by the Adviser and there is no guarantee the companies in which the Fund invests will have favorable third party ESG profiles. Such considerations may fail to produce the intended result, and the Fund may underperform funds that do not have such a strategy.
Federated Hermes Sustainable High Yield 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 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 Sustainable High Yield Bond Fund Inc. | Call Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Call Risk. There is a possibility that an issuer of fixed-income securities in which the Fund may invest may redeem a security before maturity (a “call”) at a price below its current market price. An increase in the likelihood of a call may reduce the security’s price.
Federated Hermes Sustainable High Yield Bond Fund Inc. | Risk of Foreign Investing [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Risk of Foreign Investing. Because the Fund invests in securities issued by foreign companies, the Fund’s Share price may be more affected by foreign economic and political conditions, taxation policies and accounting and auditing standards than could otherwise be the case.
Federated Hermes Sustainable High Yield Bond Fund Inc. | Currency Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Currency Risk. Exchange rates for currencies fluctuate daily. Foreign securities are normally denominated and traded in foreign currencies. As a result, the value of the Fund’s foreign investments and the value of the shares may be affected favorably or unfavorably by changes in currency exchange rates relative to the U.S. dollar.
Federated Hermes Sustainable High Yield Bond Fund Inc. | European Union and Eurozone Related Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock European Union and Eurozone Related Risk. A number of countries in the European Union (EU), including certain countries within the EU that have adopted the euro (Eurozone), have experienced, and may continue to experience, severe economic and financial difficulties. Additional countries within the EU may also fall subject to such difficulties. These events could negatively affect the value and liquidity of the Fund’s investments in euro-denominated securities and derivative contracts, securities of issuers located in the EU or with significant exposure to EU issuers or countries.
Federated Hermes Sustainable High Yield Bond Fund Inc. | Risk of Investing in Emerging Market Countries [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Risk of Investing in Emerging Market Countries. Securities issued or traded in emerging markets generally entail greater risks than securities issued or traded in developed markets. Securities markets within emerging market countries may experience low or non-existent trading volume, resulting in a lack of liquidity and increased volatility in prices for such securities. Political and economic structures in emerging market countries generally lack the social, political and economic stability of developed countries, which may affect the value of the Fund’s investments in these countries. There may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards comparable to those to which U.S. companies are subject.
Federated Hermes Sustainable High Yield 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, currency, liquidity and leverage risks.
Federated Hermes Sustainable High Yield 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 exposes the Fund to a level of risk that exceeds the amount invested.
Federated Hermes Sustainable High Yield 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 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 Sustainable High Yield Bond Fund Inc. | A  
Risk Return Abstract rr_RiskReturnAbstract  
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 0.50%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.54%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.04%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.14%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.90%
1 Year rr_ExpenseExampleYear01 $ 551
3 Years rr_ExpenseExampleYear03 766
5 Years rr_ExpenseExampleYear05 998
10 Years rr_ExpenseExampleYear10 1,664
1 Year rr_ExpenseExampleNoRedemptionYear01 551
3 Years rr_ExpenseExampleNoRedemptionYear03 766
5 Years rr_ExpenseExampleNoRedemptionYear05 998
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,664
2015 rr_AnnualReturn2015 (3.28%)
2016 rr_AnnualReturn2016 14.31%
2017 rr_AnnualReturn2017 6.53%
2018 rr_AnnualReturn2018 (3.06%)
2019 rr_AnnualReturn2019 14.35%
2020 rr_AnnualReturn2020 5.89%
2021 rr_AnnualReturn2021 4.69%
2022 rr_AnnualReturn2022 (11.73%)
2023 rr_AnnualReturn2023 12.42%
2024 rr_AnnualReturn2024 6.16%
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, 2025
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 0.92%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 9.34%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (12.22%)
1 Year rr_AverageAnnualReturnYear01 1.35%
5 Years rr_AverageAnnualReturnYear05 2.19%
10 Years rr_AverageAnnualReturnYear10 3.82%
Federated Hermes Sustainable High Yield Bond Fund Inc. | C  
Risk Return Abstract rr_RiskReturnAbstract  
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 0.50%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets 0.75%
Other Expenses rr_OtherExpensesOverAssets 0.54%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.79%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.05%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 1.74%
1 Year rr_ExpenseExampleYear01 $ 282
3 Years rr_ExpenseExampleYear03 563
5 Years rr_ExpenseExampleYear05 970
10 Years rr_ExpenseExampleYear10 1,908
1 Year rr_ExpenseExampleNoRedemptionYear01 182
3 Years rr_ExpenseExampleNoRedemptionYear03 563
5 Years rr_ExpenseExampleNoRedemptionYear05 970
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,908
1 Year rr_AverageAnnualReturnYear01 4.32%
5 Years rr_AverageAnnualReturnYear05 2.35%
10 Years rr_AverageAnnualReturnYear10 3.65%
Federated Hermes Sustainable High Yield Bond Fund Inc. | IS  
Risk Return Abstract rr_RiskReturnAbstract  
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 0.50%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.29%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.79%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.14%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.65%
1 Year rr_ExpenseExampleYear01 $ 81
3 Years rr_ExpenseExampleYear03 252
5 Years rr_ExpenseExampleYear05 439
10 Years rr_ExpenseExampleYear10 978
1 Year rr_ExpenseExampleNoRedemptionYear01 81
3 Years rr_ExpenseExampleNoRedemptionYear03 252
5 Years rr_ExpenseExampleNoRedemptionYear05 439
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 978
1 Year rr_AverageAnnualReturnYear01 6.60%
5 Years rr_AverageAnnualReturnYear05 3.44%
10 Years rr_AverageAnnualReturnYear10 4.52%
Federated Hermes Sustainable High Yield Bond Fund Inc. | R6  
Risk Return Abstract rr_RiskReturnAbstract  
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 0.50%
Distribution (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.21%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.71%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.07%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.64%
1 Year rr_ExpenseExampleYear01 $ 73
3 Years rr_ExpenseExampleYear03 227
5 Years rr_ExpenseExampleYear05 395
10 Years rr_ExpenseExampleYear10 883
1 Year rr_ExpenseExampleNoRedemptionYear01 73
3 Years rr_ExpenseExampleNoRedemptionYear03 227
5 Years rr_ExpenseExampleNoRedemptionYear05 395
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 883
1 Year rr_AverageAnnualReturnYear01 6.45%
5 Years rr_AverageAnnualReturnYear05 3.45%
10 Years rr_AverageAnnualReturnYear10 4.52%
Federated Hermes Sustainable High Yield Bond Fund Inc. | Return After Taxes on Distributions | A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (0.86%)
5 Years rr_AverageAnnualReturnYear05 0.03%
10 Years rr_AverageAnnualReturnYear10 1.55%
Federated Hermes Sustainable High Yield Bond Fund Inc. | Return After Taxes on Distributions and Sale of Fund Shares | A  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.76%
5 Years rr_AverageAnnualReturnYear05 0.71%
10 Years rr_AverageAnnualReturnYear10 1.88%
Federated Hermes Sustainable High Yield Bond Fund Inc. | Bloomberg US Aggregate Bond Index(reflects no deduction for fees, expenses, or taxes)  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 1.25% [2]
5 Years rr_AverageAnnualReturnYear05 (0.33%) [2]
10 Years rr_AverageAnnualReturnYear10 1.35% [2]
Federated Hermes Sustainable High Yield Bond Fund Inc. | Bloomberg US Corporate High Yield 2% Issuer Capped Index(reflects no deduction for fees, expenses or taxes)  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 8.19% [3]
5 Years rr_AverageAnnualReturnYear05 4.20% [3]
10 Years rr_AverageAnnualReturnYear10 5.16% [3]
Federated Hermes Sustainable High Yield Bond Fund Inc. | Lipper High Yield Funds Average  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 7.67% [4]
5 Years rr_AverageAnnualReturnYear05 3.63% [4]
10 Years rr_AverageAnnualReturnYear10 4.35% [4]
[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, IS and R6 classes (after the voluntary waivers and/or reimbursements) will not exceed 0.89%, 1.73%, 0.64% and 0.63% (the “Fee Limit”), respectively, up to but not including the later of (the “Termination Date”): (a) June 1, 2026; 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 Trustees.
[2] The Fund has designated the Bloomberg US Aggregate Bond Index as the new broad-based securities market index in accordance with the SEC’s revised requirements for such an index. The Bloomberg US Aggregate Bond Index is a broad-based benchmark that measures the investment-grade, U.S. dollar-denominated, fixed-rate taxable bond market.
[3] The Bloomberg US Corporate High Yield 2% Issuer Capped Index is an issuer-constrained version of the Bloomberg US Corporate High Yield Index that measures the market of USD-denominated, noninvestment-grade, fixed-rate, taxable corporate bonds. The index follows the same rules as the uncapped index but limits the exposure of each issuer to 2% of the total market value and redistributes any excess market value index-wide on a pro rata basis.
[4] Lipper figures represent the average of the total returns reported by all mutual funds designated by Lipper, Inc., as falling into the respective category and is not adjusted to reflect any sales charges.