| Shareholder Report | 12 Months Ended |
| Nov. 30, 2024 USD ($) Holding |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Vanguard New Jersey Tax-Free Funds |
| Entity Central Index Key | 0000821404 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Nov. 30, 2024 |
| C000007965 | |
| Shareholder Report [Line Items] | |
| Fund Name | New Jersey Long-Term Tax-Exempt Fund |
| Class Name | Admiral™ Shares |
| Trading Symbol | VNJUX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Vanguard New Jersey Long-Term Tax-Exempt Fund (the "Fund") for the period of December 1, 2023, to November 30, 2024. |
| 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 $9 0.09% |
| Expenses Paid, Amount | $ 9 |
| Expense Ratio, Percent | 0.09% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended November 30, 2024, the Fund outperformed its benchmark, the Bloomberg NJ Municipal Bond Index. At the national level, economic growth hovered around 3% on a year-over-year basis for the period, quelling recession fears. Consumer price inflation trended lower, falling below 3% in July, and the Federal Reserve began to cut short-term interest rates in September. The pivot in monetary policy contributed to strong gains for U.S. investment-grade bonds. New Jersey remains on a good credit trend, with revenue growth normalizing since the COVID-19 pandemic. After upgrades by credit rating agencies, reflecting the fiscal progress the state has made, state general obligation (GO) bond ratings have likely stabilized. An above-benchmark level of interest rate sensitivity helped the Fund outperform its benchmark as the Fed began its easing cycle. An overweight to lower-rated bonds also helped as their yield advantage versus higher-rated issues narrowed. The most value was added through security selection, particularly within GO bonds, school districts, transportation, and hospitals. |
| Line Graph [Table Text Block] | Admiral Shares Bloomberg NJ Municipal Bond Index Bloomberg Municipal Bond Index 2014 $50,000 $50,000 $50,000 2015 $50,620 $50,486 $50,615 2015 $49,784 $49,396 $50,356 2015 $50,081 $49,352 $50,774 2015 $51,127 $50,671 $51,549 2016 $52,496 $52,081 $52,613 2016 $53,620 $53,135 $53,312 2016 $55,067 $54,780 $54,266 2016 $51,720 $51,375 $51,436 2017 $52,815 $52,573 $52,747 2017 $54,442 $53,960 $54,090 2017 $55,716 $55,163 $54,745 2017 $55,932 $55,370 $54,308 2018 $55,572 $55,151 $54,067 2018 $56,508 $55,897 $54,692 2018 $56,972 $56,604 $55,013 2018 $56,812 $56,385 $54,921 2019 $58,322 $57,998 $56,299 2019 $60,851 $60,399 $58,195 2019 $62,844 $62,448 $59,809 2019 $62,542 $62,124 $59,585 2020 $65,171 $64,579 $61,625 2020 $61,662 $60,318 $60,510 2020 $64,448 $63,977 $61,745 2020 $65,767 $65,011 $62,501 2021 $66,284 $65,800 $62,277 2021 $68,017 $67,193 $63,376 2021 $68,636 $68,049 $63,841 2021 $68,625 $67,768 $63,733 2022 $66,315 $65,501 $61,866 2022 $62,866 $62,331 $59,070 2022 $61,586 $61,876 $58,330 2022 $61,770 $61,757 $58,227 2023 $62,285 $62,533 $58,713 2023 $63,433 $63,456 $59,359 2023 $63,406 $63,617 $59,325 2023 $64,791 $65,092 $60,720 2024 $66,626 $66,477 $61,894 2024 $65,624 $65,439 $60,946 2024 $67,977 $67,654 $62,937 2024 $69,108 $68,518 $63,714 |
| Average Annual Return [Table Text Block] | 1 Year 5 Years 10 Years Admiral Shares 6.66% 2.02% 3.29% Bloomberg NJ Municipal Bond Index 5.26% 1.98% 3.20% Bloomberg Municipal Bond Index 4.93% 1.35% 2.45% |
| AssetsNet | $ 2,602,000,000 |
| Holdings Count | Holding | 913 |
| Advisory Fees Paid, Amount | $ 258,000 |
| InvestmentCompanyPortfolioTurnover | 41% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of November 30, 2024 Fund Net Assets (in millions) $2,602 Number of Portfolio Holdings 913 Portfolio Turnover Rate 41% Total Investment Advisory Fees (in thousands) $258 |
| Holdings [Text Block] | This table reflects the Fund's investments, including short-term investments, derivatives and other assets and liabilities. Distribution by Stated Maturity % of Net Assets (as of November 30, 2024) Less than 1 Year 5.5% 1 to 3 Years 4.2% 3 to 5 Years 3.0% 5 to 10 Years 14.0% 10 to 20 Years 39.7% 20 to 30 Years 29.0% Greater than 30 Years 3.2% Other Assets and Liabilities—Net 1.4% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000007964 | |
| Shareholder Report [Line Items] | |
| Fund Name | New Jersey Long-Term Tax-Exempt Fund |
| Class Name | Investor Shares |
| Trading Symbol | VNJTX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Vanguard New Jersey Long-Term Tax-Exempt Fund (the "Fund") for the period of December 1, 2023, to November 30, 2024. |
| 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 $18 0.17% |
| Expenses Paid, Amount | $ 18 |
| Expense Ratio, Percent | 0.17% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended November 30, 2024, the Fund outperformed its benchmark, the Bloomberg NJ Municipal Bond Index. At the national level, economic growth hovered around 3% on a year-over-year basis for the period, quelling recession fears. Consumer price inflation trended lower, falling below 3% in July, and the Federal Reserve began to cut short-term interest rates in September. The pivot in monetary policy contributed to strong gains for U.S. investment-grade bonds. New Jersey remains on a good credit trend, with revenue growth normalizing since the COVID-19 pandemic. After upgrades by credit rating agencies, reflecting the fiscal progress the state has made, state general obligation (GO) bond ratings have likely stabilized. An above-benchmark level of interest rate sensitivity helped the Fund outperform its benchmark as the Fed began its easing cycle. An overweight to lower-rated bonds also helped as their yield advantage versus higher-rated issues narrowed. The most value was added through security selection, particularly within GO bonds, school districts, transportation, and hospitals. |
| Line Graph [Table Text Block] | Investor Shares Bloomberg NJ Municipal Bond Index Bloomberg Municipal Bond Index 2014 $10,000 $10,000 $10,000 2015 $10,122 $10,097 $10,123 2015 $9,953 $9,879 $10,071 2015 $10,010 $9,871 $10,155 2015 $10,217 $10,134 $10,310 2016 $10,489 $10,416 $10,523 2016 $10,711 $10,627 $10,662 2016 $10,997 $10,956 $10,853 2016 $10,326 $10,275 $10,287 2017 $10,541 $10,515 $10,549 2017 $10,864 $10,792 $10,818 2017 $11,115 $11,033 $10,949 2017 $11,155 $11,074 $10,862 2018 $11,081 $11,030 $10,813 2018 $11,265 $11,179 $10,938 2018 $11,355 $11,321 $11,003 2018 $11,322 $11,277 $10,984 2019 $11,620 $11,600 $11,260 2019 $12,122 $12,080 $11,639 2019 $12,516 $12,490 $11,962 2019 $12,454 $12,425 $11,917 2020 $12,975 $12,916 $12,325 2020 $12,274 $12,064 $12,102 2020 $12,826 $12,795 $12,349 2020 $13,086 $13,002 $12,500 2021 $13,186 $13,160 $12,455 2021 $13,528 $13,439 $12,675 2021 $13,648 $13,610 $12,768 2021 $13,643 $13,554 $12,747 2022 $13,181 $13,100 $12,373 2022 $12,493 $12,466 $11,814 2022 $12,236 $12,375 $11,666 2022 $12,271 $12,351 $11,645 2023 $12,370 $12,507 $11,743 2023 $12,596 $12,691 $11,872 2023 $12,588 $12,723 $11,865 2023 $12,860 $13,018 $12,144 2024 $13,222 $13,295 $12,379 2024 $13,021 $13,088 $12,189 2024 $13,485 $13,531 $12,587 2024 $13,706 $13,704 $12,743 |
| Average Annual Return [Table Text Block] | 1 Year 5 Years 10 Years Investor Shares 6.58% 1.94% 3.20% Bloomberg NJ Municipal Bond Index 5.26% 1.98% 3.20% Bloomberg Municipal Bond Index 4.93% 1.35% 2.45% |
| AssetsNet | $ 2,602,000,000 |
| Holdings Count | Holding | 913 |
| Advisory Fees Paid, Amount | $ 258,000 |
| InvestmentCompanyPortfolioTurnover | 41% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of November 30, 2024 Fund Net Assets (in millions) $2,602 Number of Portfolio Holdings 913 Portfolio Turnover Rate 41% Total Investment Advisory Fees (in thousands) $258 |
| Holdings [Text Block] | This table reflects the Fund's investments, including short-term investments, derivatives and other assets and liabilities. Distribution by Stated Maturity % of Net Assets (as of November 30, 2024) Less than 1 Year 5.5% 1 to 3 Years 4.2% 3 to 5 Years 3.0% 5 to 10 Years 14.0% 10 to 20 Years 39.7% 20 to 30 Years 29.0% Greater than 30 Years 3.2% Other Assets and Liabilities—Net 1.4% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
