| Form N-CSR Cover | 12 Months Ended |
| Sep. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Vanguard Horizon Funds |
| Entity Central Index Key | 0000932471 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Sep. 30, 2024 |
| Shareholder Report | 12 Months Ended |
| Sep. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Vanguard Horizon Funds |
| Entity Central Index Key | 0000932471 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Sep. 30, 2024 |
| C000214947 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Vanguard International Core Stock Fund |
| Class Name | Investor Shares |
| Trading Symbol | VWICX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Vanguard International Core Stock Fund (the "Fund") for the period of October 1, 2023 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Investor Shares $ 0.48 % |
| Expenses Paid, Amount | $ 54 |
| Expense Ratio, Percent | 0.48% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended September 30, 2024, the Fund outperformed its benchmark, the MSCI All Country World Index ex USA. Global economic growth appeared relatively stable at around 3% during the period, quelling recession fears. With inflation continuing to moderate across much of the world, major central banks including the European Central Bank, the Bank of England, and the U.S. Federal Reserve began lowering policy rates. The FTSE Global All Cap Index of stocks returned about 31%. From a regional perspective, Pacific Rim stocks contributed by far the most to outperformance, followed by emerging markets, Europe, and North America. In each market, outperformance was driven by stock selection, as the Fund’s regional allocations essentially mirrored those of its benchmark. In terms of sectors, selection in consumer discretionary, industrials, communication services, and information technology was one of the largest sources of outperformance, while selection in financials, utilities, and materials was one of the largest sources of underperformance. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform since inception? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Cumulative Performance: October 16, 2019, Through September 30, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year Since Inception Investor Shares 27.08% 9.21 % MSCI All Country World Index ex USA 25.35% 7.33% |
| Performance Inception Date | Oct. 16, 2019 |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 1,982,000,000 |
| Holdings Count | Holding | 89 |
| Advisory Fees Paid, Amount | $ 3,403,000 |
| Investment Company Portfolio Turnover | 74% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 89 Portfolio Turnover Rate 74 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Asia 42.0 % Europe 45.9 % North America 5.6 % Oceania 4.0 % Other 0.6 % South America 1.3 % Other Assets and Liabilities—Net 0.6 % |
| C000214946 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Vanguard International Core Stock Fund |
| Class Name | Admiral™ Shares |
| Trading Symbol | VZICX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Vanguard International Core Stock Fund (the "Fund") for the period of October 1, 2023 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Admiral Shares $ 0.38 % |
| Expenses Paid, Amount | $ 43 |
| Expense Ratio, Percent | 0.38% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended September 30, 2024, the Fund outperformed its benchmark, the MSCI All Country World Index ex USA. Global economic growth appeared relatively stable at around 3% during the period, quelling recession fears. With inflation continuing to moderate across much of the world, major central banks including the European Central Bank, the Bank of England, and the U.S. Federal Reserve began lowering policy rates. The FTSE Global All Cap Index of stocks returned about 31%. From a regional perspective, Pacific Rim stocks contributed by far the most to outperformance, followed by emerging markets, Europe, and North America. In each market, outperformance was driven by stock selection, as the Fund’s regional allocations essentially mirrored those of its benchmark. In terms of sectors, selection in consumer discretionary, industrials, communication services, and information technology was one of the largest sources of outperformance, while selection in financials, utilities, and materials was one of the largest sources of underperformance. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform since inception? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Cumulative Performance: October 16, 2019, Through September 30, 2024 Initial Investment of $50,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year Since Inception Admiral Shares 27.18% 9.31 % MSCI All Country World Index ex USA 25.35% 7.33% |
| Performance Inception Date | Oct. 16, 2019 |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 1,982,000,000 |
| Holdings Count | Holding | 89 |
| Advisory Fees Paid, Amount | $ 3,403,000 |
| Investment Company Portfolio Turnover | 74% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 89 Portfolio Turnover Rate 74 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Asia 42.0 % Europe 45.9 % North America 5.6 % Oceania 4.0 % Other 0.6 % South America 1.3 % Other Assets and Liabilities—Net 0.6 % |
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | 60 Months Ended | |||||
| Sep. 30, 2024 | Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2020 | Oct. 16, 2019 | |
| C000214947 [Member] | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | Investor Shares | ||||||
| Account Value | $ 15,476 | $ 15,476 | $ 12,179 | $ 10,193 | $ 12,742 | $ 9,921 | $ 10,000 |
| Average Annual Return, Percent | 27.08% | 9.21% | |||||
| C000214946 [Member] | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | Admiral Shares | ||||||
| Account Value | $ 77,749 | $ 77,749 | 61,135 | 51,095 | 63,827 | 49,682 | 50,000 |
| Average Annual Return, Percent | 27.18% | 9.31% | |||||
| MSCI All Country World Index ex USA [Member] | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | MSCI All Country World Index ex USA | ||||||
| Account Value | $ 14,197 | $ 14,197 | $ 11,325 | $ 9,407 | $ 12,571 | $ 10,145 | $ 10,000 |
| Average Annual Return, Percent | 25.35% | 7.33% |
| Shareholder Report, Holdings (Details) | Sep. 30, 2024 |
| C000214947 [Member] | Other [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000214947 [Member] | Oceania [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000214947 [Member] | Asia [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 42% |
| C000214947 [Member] | Europe [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 45.90% |
| C000214947 [Member] | North America [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.60% |
| C000214947 [Member] | South America [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.30% |
| C000214947 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000214946 [Member] | Other [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000214946 [Member] | Oceania [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000214946 [Member] | Asia [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 42% |
| C000214946 [Member] | Europe [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 45.90% |
| C000214946 [Member] | North America [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.60% |
| C000214946 [Member] | South America [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.30% |
| C000214946 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
