| Shareholder Report | 12 Months Ended |
| Oct. 31, 2024 USD ($) Holding |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Federated Hermes Institutional Trust |
| Entity Central Index Key | 0000925723 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| C000240309 | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Institutional High Yield Bond Fund |
| Class Name | Class A Shares |
| Trading Symbol | FIHAX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Institutional High Yield Bond Fund (the "Fund") for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Material Fund Change Notice [Text Block] | This report describes planned changes made to the Fund since the beginning of the reporting period. |
| Additional Information Phone Number | 1-800-341-7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A Shares $79 0.74% |
| Expenses Paid, Amount | $ 79 |
| Expense Ratio, Percent | 0.74% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the Bloomberg US Corporate High Yield 2% Issuer Capped Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the Bloomberg US Aggregate Bond Index, which represents the overall U.S. fixed-income market. The Fund seeks high current income by investing primarily in lower-rated corporate fixed-income securities, including debt securities issued by U.S. or foreign businesses. Top Contributors to Performance ■ The Fund was positively impacted by security selection in the Building Materials, Consumer Cyclical Services, Healthcare, Cable & Satellite and Pharmaceutical industry sectors. ■ The Fund was positively impacted by its underweight position in the underperforming Metals and Mining sector. ■ Specific Fund holdings that positively impacted performance relative to the Index included: Clydesdale Acquisition, NFP Corp, Community Health Systems, SRS Distribution and Condor Merger Sub. Top Detractors from Performance ■ The Fund was negatively impacted by security selection overall, especially in the Media & Entertainment, Electric Utility, Automotive and Technology industry sectors. ■ The Fund was also negatively impacted by its industry allocation, especially its underweight allocations to the strong performing Wireline Telecommunications and Retail industry sectors. It was also negatively impacted by its overweight allocations to the underperforming Automotive and Packaging industry sectors. Given the strong absolute performance during the period, the Fund’s cash position was also a drag on relative performance. ■ Specific Fund holdings that negatively impacted performance relative to the Index included: Enviva Inc., iHeartCommunications, Ardagh Packaging, Terrier Media Buyer and Rackspace Technologies. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. |
| Line Graph [Table Text Block] | Class A Shares with sales load Bloomberg US Aggregate Bond Index Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) Lipper High Yield Funds Average 10/31/2014 $9,550 $10,000 $10,000 $10,000 10/31/2015 $9,594 $10,196 $9,809 $9,806 10/31/2016 $10,434 $10,641 $10,805 $10,541 10/31/2017 $11,308 $10,737 $11,768 $11,414 10/31/2018 $11,352 $10,517 $11,883 $11,453 10/31/2019 $12,328 $11,727 $12,879 $12,335 10/31/2020 $12,746 $12,453 $13,320 $12,587 10/31/2021 $13,885 $12,393 $14,722 $13,918 10/31/2022 $12,316 $10,450 $12,991 $12,368 10/31/2023 $12,976 $10,487 $13,800 $13,012 10/31/2024 $14,840 $11,593 $16,073 $15,008 |
| Average Annual Return [Table Text Block] | Fund/Index 1 Year 5 Years 10 Years Class A Shares with sales load 9.21% 2.83% 4.03% Class A Shares without sales load 14.36% 3.78% 4.51% Bloomberg US Aggregate Bond Index Footnote Reference 10.55% (0.23%) 1.49% Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) 16.47% 4.53% 4.86% Lipper High Yield Funds Average 15.34% 3.97% 4.03% |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Table Market Index Changed [Text Block] | The Fund has designated the Bloomberg US Aggregate Bond Index as its new broad-based securities market index in accordance with the SEC’s revised definition for such an index. |
| AssetsNet | $ 7,717,085,790 |
| Holdings Count | Holding | 576 |
| Advisory Fees Paid, Amount | $ 29,203,762 |
| InvestmentCompanyPortfolioTurnover | 24% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $7,717,085,790 Number of Investments 576 Portfolio Turnover 24% Total Advisory Fees Paid $29,203,762 |
| Holdings [Text Block] | Top Index Classifications (% of Net Assets) Value Value Building Materials 3.6% Consumer Cyclical Services 4.1% Packaging 4.5% Health Care 4.5% Midstream 5.2% Gaming 5.3% Automotive 5.9% Cable Satellite 6.9% Insurance - P&C 7.6% Technology 11.7% |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| Summary of Change Legend [Text Block] | Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| C000240310 | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Institutional High Yield Bond Fund |
| Class Name | Class C Shares |
| Trading Symbol | FIHCX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Institutional High Yield Bond Fund (the "Fund") for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Material Fund Change Notice [Text Block] | This report describes planned changes made to the Fund since the beginning of the reporting period. |
| Additional Information Phone Number | 1-800-341-7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C Shares $163 1.53% |
| Expenses Paid, Amount | $ 163 |
| Expense Ratio, Percent | 1.53% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the Bloomberg US Corporate High Yield 2% Issuer Capped Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the Bloomberg US Aggregate Bond Index, which represents the overall U.S. fixed-income market. The Fund seeks high current income by investing primarily in lower-rated corporate fixed-income securities, including debt securities issued by U.S. or foreign businesses. Top Contributors to Performance ■ The Fund was positively impacted by security selection in the Building Materials, Consumer Cyclical Services, Healthcare, Cable & Satellite and Pharmaceutical industry sectors. ■ The Fund was positively impacted by its underweight position in the underperforming Metals and Mining sector. ■ Specific Fund holdings that positively impacted performance relative to the Index included: Clydesdale Acquisition, NFP Corp, Community Health Systems, SRS Distribution and Condor Merger Sub. Top Detractors from Performance ■ The Fund was negatively impacted by security selection overall, especially in the Media & Entertainment, Electric Utility, Automotive and Technology industry sectors. ■ The Fund was also negatively impacted by its industry allocation, especially its underweight allocations to the strong performing Wireline Telecommunications and Retail industry sectors. It was also negatively impacted by its overweight allocations to the underperforming Automotive and Packaging industry sectors. Given the strong absolute performance during the period, the Fund’s cash position was also a drag on relative performance. ■ Specific Fund holdings that negatively impacted performance relative to the Index included: Enviva Inc., iHeartCommunications, Ardagh Packaging, Terrier Media Buyer and Rackspace Technologies. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. |
| Line Graph [Table Text Block] | Class C Shares Bloomberg US Aggregate Bond Index Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) Lipper High Yield Funds Average 10/31/2014 $10,000 $10,000 $10,000 $10,000 10/31/2015 $10,047 $10,196 $9,809 $9,806 10/31/2016 $10,926 $10,641 $10,805 $10,541 10/31/2017 $11,841 $10,737 $11,768 $11,414 10/31/2018 $11,887 $10,517 $11,883 $11,453 10/31/2019 $12,909 $11,727 $12,879 $12,335 10/31/2020 $13,347 $12,453 $13,320 $12,587 10/31/2021 $14,540 $12,393 $14,722 $13,918 10/31/2022 $12,897 $10,450 $12,991 $12,368 10/31/2023 $13,450 $10,487 $13,800 $13,012 10/31/2024 $15,290 $11,593 $16,073 $15,008 |
| Average Annual Return [Table Text Block] | Fund/Index 1 Year 5 Years 10 Years Class C Shares with sales load 12.68% 3.44% 4.34% Class C Shares without sales load 13.68% 3.44% 4.34% Bloomberg US Aggregate Bond Index Footnote Reference 10.55% (0.23%) 1.49% Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) 16.47% 4.53% 4.86% Lipper High Yield Funds Average 15.34% 3.97% 4.03% |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Table Market Index Changed [Text Block] | The Fund has designated the Bloomberg US Aggregate Bond Index as its new broad-based securities market index in accordance with the SEC’s revised definition for such an index. |
| AssetsNet | $ 7,717,085,790 |
| Holdings Count | Holding | 576 |
| Advisory Fees Paid, Amount | $ 29,203,762 |
| InvestmentCompanyPortfolioTurnover | 24% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $7,717,085,790 Number of Investments 576 Portfolio Turnover 24% Total Advisory Fees Paid $29,203,762 |
| Holdings [Text Block] | Top Index Classifications (% of Net Assets) Value Value Building Materials 3.6% Consumer Cyclical Services 4.1% Packaging 4.5% Health Care 4.5% Midstream 5.2% Gaming 5.3% Automotive 5.9% Cable Satellite 6.9% Insurance - P&C 7.6% Technology 11.7% |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| Summary of Change Legend [Text Block] | Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| C000030278 | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Institutional High Yield Bond Fund |
| Class Name | Institutional Shares |
| Trading Symbol | FIHBX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Institutional High Yield Bond Fund (the "Fund") for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Material Fund Change Notice [Text Block] | This report describes planned changes made to the Fund since the beginning of the reporting period. |
| Additional Information Phone Number | 1-800-341-7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Shares $53 0.49% |
| Expenses Paid, Amount | $ 53 |
| Expense Ratio, Percent | 0.49% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the Bloomberg US Corporate High Yield 2% Issuer Capped Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the Bloomberg US Aggregate Bond Index, which represents the overall U.S. fixed-income market. The Fund seeks high current income by investing primarily in lower-rated corporate fixed-income securities, including debt securities issued by U.S. or foreign businesses. Top Contributors to Performance ■ The Fund was positively impacted by security selection in the Building Materials, Consumer Cyclical Services, Healthcare, Cable & Satellite and Pharmaceutical industry sectors. ■ The Fund was positively impacted by its underweight position in the underperforming Metals and Mining sector. ■ Specific Fund holdings that positively impacted performance relative to the Index included: Clydesdale Acquisition, NFP Corp, Community Health Systems, SRS Distribution and Condor Merger Sub. Top Detractors from Performance ■ The Fund was negatively impacted by security selection overall, especially in the Media & Entertainment, Electric Utility, Automotive and Technology industry sectors. ■ The Fund was also negatively impacted by its industry allocation, especially its underweight allocations to the strong performing Wireline Telecommunications and Retail industry sectors. It was also negatively impacted by its overweight allocations to the underperforming Automotive and Packaging industry sectors. Given the strong absolute performance during the period, the Fund’s cash position was also a drag on relative performance. ■ Specific Fund holdings that negatively impacted performance relative to the Index included: Enviva Inc., iHeartCommunications, Ardagh Packaging, Terrier Media Buyer and Rackspace Technologies. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. |
| Line Graph [Table Text Block] | Institutional Shares Bloomberg US Aggregate Bond Index Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) Lipper High Yield Funds Average 10/31/2014 $10,000 $10,000 $10,000 $10,000 10/31/2015 $10,047 $10,196 $9,809 $9,806 10/31/2016 $10,926 $10,641 $10,805 $10,541 10/31/2017 $11,841 $10,737 $11,768 $11,414 10/31/2018 $11,887 $10,517 $11,883 $11,453 10/31/2019 $12,909 $11,727 $12,879 $12,335 10/31/2020 $13,347 $12,453 $13,320 $12,587 10/31/2021 $14,540 $12,393 $14,722 $13,918 10/31/2022 $12,897 $10,450 $12,991 $12,368 10/31/2023 $13,596 $10,487 $13,800 $13,012 10/31/2024 $15,589 $11,593 $16,073 $15,008 |
| Average Annual Return [Table Text Block] | Fund/Index 1 Year 5 Years 10 Years Institutional Shares 14.66% 3.84% 4.54% Bloomberg US Aggregate Bond Index Footnote Reference 10.55% (0.23%) 1.49% Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) 16.47% 4.53% 4.86% Lipper High Yield Funds Average 15.34% 3.97% 4.03% |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Table Market Index Changed [Text Block] | The Fund has designated the Bloomberg US Aggregate Bond Index as its new broad-based securities market index in accordance with the SEC’s revised definition for such an index. |
| AssetsNet | $ 7,717,085,790 |
| Holdings Count | Holding | 576 |
| Advisory Fees Paid, Amount | $ 29,203,762 |
| InvestmentCompanyPortfolioTurnover | 24% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $7,717,085,790 Number of Investments 576 Portfolio Turnover 24% Total Advisory Fees Paid $29,203,762 |
| Holdings [Text Block] | Top Index Classifications (% of Net Assets) Value Value Building Materials 3.6% Consumer Cyclical Services 4.1% Packaging 4.5% Health Care 4.5% Midstream 5.2% Gaming 5.3% Automotive 5.9% Cable Satellite 6.9% Insurance - P&C 7.6% Technology 11.7% |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| Summary of Change Legend [Text Block] | Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| C000170849 | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Institutional High Yield Bond Fund |
| Class Name | Class R6 Shares |
| Trading Symbol | FIHLX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Institutional High Yield Bond Fund (the "Fund") for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Material Fund Change Notice [Text Block] | This report describes planned changes made to the Fund since the beginning of the reporting period. |
| Additional Information Phone Number | 1-800-341-7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R6 Shares $52 0.48% |
| Expenses Paid, Amount | $ 52 |
| Expense Ratio, Percent | 0.48% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the Bloomberg US Corporate High Yield 2% Issuer Capped Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the Bloomberg US Aggregate Bond Index, which represents the overall U.S. fixed-income market. The Fund seeks high current income by investing primarily in lower-rated corporate fixed-income securities, including debt securities issued by U.S. or foreign businesses. Top Contributors to Performance ■ The Fund was positively impacted by security selection in the Building Materials, Consumer Cyclical Services, Healthcare, Cable & Satellite and Pharmaceutical industry sectors. ■ The Fund was positively impacted by its underweight position in the underperforming Metals and Mining sector. ■ Specific Fund holdings that positively impacted performance relative to the Index included: Clydesdale Acquisition, NFP Corp, Community Health Systems, SRS Distribution and Condor Merger Sub. Top Detractors from Performance ■ The Fund was negatively impacted by security selection overall, especially in the Media & Entertainment, Electric Utility, Automotive and Technology industry sectors. ■ The Fund was also negatively impacted by its industry allocation, especially its underweight allocations to the strong performing Wireline Telecommunications and Retail industry sectors. It was also negatively impacted by its overweight allocations to the underperforming Automotive and Packaging industry sectors. Given the strong absolute performance during the period, the Fund’s cash position was also a drag on relative performance. ■ Specific Fund holdings that negatively impacted performance relative to the Index included: Enviva Inc., iHeartCommunications, Ardagh Packaging, Terrier Media Buyer and Rackspace Technologies. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. |
| Line Graph [Table Text Block] | Class R6 Shares Bloomberg US Aggregate Bond Index Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) Lipper High Yield Funds Average 10/31/2014 $10,000 $10,000 $10,000 $10,000 10/31/2015 $10,040 $10,196 $9,809 $9,806 10/31/2016 $10,916 $10,641 $10,805 $10,541 10/31/2017 $11,843 $10,737 $11,768 $11,414 10/31/2018 $11,878 $10,517 $11,883 $11,453 10/31/2019 $12,914 $11,727 $12,879 $12,335 10/31/2020 $13,340 $12,453 $13,320 $12,587 10/31/2021 $14,547 $12,393 $14,722 $13,918 10/31/2022 $12,892 $10,450 $12,991 $12,368 10/31/2023 $13,593 $10,487 $13,800 $13,012 10/31/2024 $15,604 $11,593 $16,073 $15,008 |
| Average Annual Return [Table Text Block] | Fund/Index 1 Year 5 Years 10 Years Class R6 Shares 14.80% 3.86% 4.55% Bloomberg US Aggregate Bond Index Footnote Reference 10.55% (0.23%) 1.49% Bloomberg US Corporate High Yield 2% Issuer Capped Index (BHY2%ICI) 16.47% 4.53% 4.86% Lipper High Yield Funds Average 15.34% 3.97% 4.03% |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Table Market Index Changed [Text Block] | The Fund has designated the Bloomberg US Aggregate Bond Index as its new broad-based securities market index in accordance with the SEC’s revised definition for such an index. |
| AssetsNet | $ 7,717,085,790 |
| Holdings Count | Holding | 576 |
| Advisory Fees Paid, Amount | $ 29,203,762 |
| InvestmentCompanyPortfolioTurnover | 24% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $7,717,085,790 Number of Investments 576 Portfolio Turnover 24% Total Advisory Fees Paid $29,203,762 |
| Holdings [Text Block] | Top Index Classifications (% of Net Assets) Value Value Building Materials 3.6% Consumer Cyclical Services 4.1% Packaging 4.5% Health Care 4.5% Midstream 5.2% Gaming 5.3% Automotive 5.9% Cable Satellite 6.9% Insurance - P&C 7.6% Technology 11.7% |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
| Summary of Change Legend [Text Block] | Following is a summary of material changes planned for the Fund since the beginning of the reporting period. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective December 27, 2024, Randal Stuckwish has been added to the Fund’s portfolio management team. |
