v3.24.3
Label Element Value
Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName VANGUARD MUNICIPAL BOND FUNDS
Prospectus Date rr_ProspectusDate Nov. 19, 2024
ETF | Vanguard Core Tax-Exempt Bond ETF  
Risk Return Abstract rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading <span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">ETF Summary</span>
Objective [Heading] rr_ObjectiveHeading <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The Fund seeks to provide total return, through current income that is exempt from federal personal income taxes, and capital appreciation.
Expense [Heading] rr_ExpenseHeading <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Fees and Expenses</span>
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following tables describe the fees and expenses you may pay if you buy, hold, and sell shares 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 example below.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;">(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</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;">(Expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading <span style="color:#000000;font-family:Arial;font-size:9.5pt;">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 more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, reduce the Fund’s performance. The Fund has no operating history and therefore has no portfolio turnover information.
Expense Example [Heading] rr_ExpenseExampleHeading <span style="color:#000000;font-family:Arial;font-size:9.5pt;">Example</span>
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund’s shares. This example assumes that the Fund provides a return of 5% each year and that total annual fund operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to sell your shares at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock This example does not include the brokerage commissions that you may pay to buy and sell shares of the Fund.
Strategy [Heading] rr_StrategyHeading <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock Under normal circumstances, the Fund will invest at least 80% of its assets (plus any borrowings for investment purposes) in municipal bonds denominated in U.S. dollars from a variety of issuers that are primarily U.S. states or local governments or agencies whose interest is exempt from federal income taxes and the federal alternative minimum tax (AMT). The Fund has no limitations on the maturity of individual securities. The Fund is expected to maintain, under normal market conditions, a dollar-weighted average maturity of 8 to 20 years.Although the Fund may invest in municipal bonds of any quality, the Fund’s advisor intends to invest a majority of the Fund’s assets in investment-grade municipal bonds. High-quality fixed income securities are those rated the equivalent of A3 or better by Moody’s Investors Service, Inc. (Moody’s), or another independent rating agency or, if unrated, are determined to be of comparable quality by the Fund’s advisor. Medium-quality fixed income securities are those rated the equivalent of Baa1, Baa2, or Baa3 by Moody’s or another independent rating agency or, if unrated, are determined to be of comparable quality by the Fund’s advisor. Both high-quality and medium-quality fixed income securities are considered to be “investment-grade.” Lower-range credit quality ratings – commonly known as “junk bonds” – are those rated the equivalent of Ba1 or lower by Moody’s or another independent rating agency or, if unrated, are determined to be of comparable quality by the Fund’s advisor. No more than 20% of the Fund’s assets may be invested in non-investment-grade fixed income securities, or junk bonds.
Risk [Heading] rr_RiskHeading <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</span>
Risk [Text Block] rr_RiskTextBlock • Interest rate risk, which is the chance that bond prices overall will decline because of rising interest rates.• Income risk, which is the chance that the Fund’s income will decline because of falling interest rates.• Call risk, which is the chance that during periods of falling interest rates, issuers of callable bonds may call (redeem) securities with higher coupon rates or interest rates before their maturity dates. The Fund would then lose any price appreciation above the bond’s call price and would be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund’s income. Such redemptions and subsequent reinvestments would also increase the Fund’s portfolio turnover rate.• Prepayment risk, which is the chance that during periods of falling interest rates, homeowners will refinance their mortgages before their maturity dates, resulting in prepayment of mortgage-backed securities held by the Fund. The Fund would then lose any price appreciation above the mortgage’s principal and would be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund’s income. Such prepayments and subsequent reinvestments would also increase the Fund’s portfolio turnover rate.• Extension risk, which is the chance that during periods of rising interest rates, certain debt securities will be paid off substantially more slowly than originally anticipated, and the value of those securities may fall.• Credit risk, which is the chance that a bond issuer will fail to pay interest or principal in a timely manner or that negative perceptions of the issuer’s ability to make such payments will cause the price of that bond to decline. In general, credit risk should be relatively low for the Fund because it invests primarily in bonds that are considered to be of high quality.• Liquidity risk, which is the chance that the Fund may not be able to sell a security in a timely manner at a desired price.• Manager risk, which is the chance that poor security selection will cause the Fund to underperform relevant benchmarks or other funds with a similar investment objective.• Tax risk, which is the chance that all or a portion of the tax-exempt income from municipal bonds held by the Fund will be declared taxable, possibly with retroactive effect, because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state or local tax authorities, or noncompliant conduct of a bond issuer.• Regional risk, which is the chance that economic, political, or regulatory occurrences within a certain state may adversely affect the value of securities offered by issuers located within that state. Because the Fund may invest a large portion of its assets in securities located in any one state, the Fund’s performance may be hurt disproportionately by the poor performance of its investments in that area.Because the Fund is an exchange-traded fund (ETF) and the Fund’s shares are traded on an exchange, the Fund is subject to additional risks:• The Fund’s ETF Shares are listed for trading on Cboe BZX Exchange, Inc. and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.• Trading of the Fund’s ETF Shares may be halted by the activation of individual or marketwide trading halts (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of the Fund’s ETF Shares may also be halted if (1) the shares are delisted from Cboe BZX Exchange, Inc. without first being listed on another exchange or (2) Cboe BZX Exchange, Inc. officials determine that such action is appropriate in the interest of a fair and orderly market or for the protection of investors.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Annual Total Returns</span>
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock This is the Fund’s initial prospectus, so it does not contain performance data.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess <span style="color:#000000;font-family:Arial;font-size:9.5pt;">This is the Fund’s initial prospectus, so it does not contain performance data.</span>
ETF | Vanguard Core Tax-Exempt Bond ETF | Risk Lose Money [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock The Fund is designed for investors with a low tolerance for risk, but you could still lose money by investing in it.
ETF | Vanguard Core Tax-Exempt Bond ETF | Risk Not Insured Depository Institution [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
ETF | Vanguard Core Tax-Exempt Bond ETF | Nondiversification Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock • Nondiversification risk, which is the chance that the Fund’s performance may be hurt disproportionately by the poor performance of bonds issued by just a few issuers or even a single issuer. The Fund is considered nondiversified, which means that it may invest a greater percentage of its assets in bonds issued by a small number of issuers as compared with diversified funds.
ETF | Vanguard Core Tax-Exempt Bond ETF | ETF Shares  
Risk Return Abstract rr_RiskReturnAbstract  
Management Fees rr_ManagementFeesOverAssets 0.10%
12b-1 Distribution Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.02%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.12% [1]
1 Year rr_ExpenseExampleYear01 $ 12
3 Years rr_ExpenseExampleYear03 39
Transaction Fee on Purchases and Sales municipal_TransactionFeeOnPurchasesandSales none [2]
Transaction Fee on Reinvested Dividends municipal_TransactionFeeOnReinvestedDividends none [2]
[1] The expense information shown in the table reflects estimated amounts for the current fiscal year.
[2] None through Vanguard (Broker fees vary)