Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	VANGUARD MALVERN FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 25, 2019
Retail | Vanguard Emerging Markets Bond Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide total return while generating a moderate level of current income.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy and hold Investor Shares or Admiral Shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees<br/><br/>(Fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses<br/><br/>(Expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
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 examples, reduce the Fund’s performance. During the most recent fiscal year, the Fund‘s portfolio turnover rate was 350% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	350.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Examples
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following examples are intended to help you compare the cost of investing in the Fund’s Investor Shares or Admiral Shares with the cost of investing in other mutual funds. They illustrate the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund’s shares. These examples assume that the shares provide 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 redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests in fixed income securities of various maturities, yields, and qualities. Under normal circumstances, the Fund will invest at least 80% of its assets in fixed income securities of issuers that are tied economically to emerging market countries. The Fund seeks to have a majority of its assets denominated in or hedged back to the U.S. dollar but has the ability to invest in bonds denominated in a local currency on an unhedged basis. Emerging market bonds include sovereign debt securities, which include fixed income securities that are issued or guaranteed by foreign governments or their agencies, authorities, political subdivisions or instrumentalities, or other supranational agencies, as well as debt securities issued or guaranteed by foreign corporations and foreign financial institutions. Emerging market countries include countries whose economies or bond markets are less developed, which includes most countries except for Australia, Canada, Japan, New Zealand, the United States, the United Kingdom, and most European Monetary Union countries. The Fund may invest in emerging market bonds of any maturity or quality. The Fund may invest in bonds that have lower-range quality ratings (including those in default), which are those rated the equivalent of Ba1 or lower by Moody’s Investors Service, Inc., or another independent rating agency, or if unrated, are determined to be of comparable quality by the Fund’s advisor. These are commonly referred to as “junk bonds.” The Fund’s duration is expected to be similar to that of the Fund’s benchmark. Duration is a measure of the price sensitivity of a fixed income security or a portfolio of fixed income securities to relative changes in interest rates. For instance, a duration of “four” means that a security’s or portfolio’s price would be expected to decrease by approximately 4% with a 1% increase in interest rates (assuming a parallel shift in yield curve). The Fund is considered nondiversified and may invest a greater portion of its assets in fewer issuers. The Fund may invest a large percentage of its assets in issuers of a single country, a small number of countries, or a geographic region. Although the Fund may use derivatives for any investment purpose, it expects to use derivatives predominantly to adjust interest rate or currency exposure; to adjust exposure to a particular market, segment of the market, or security; or as a substitute to direct investment.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund could lose money over short or long periods of time. You should expect the Fund’s share price and total return to fluctuate within a wide range. The Fund is subject to the following risks, which could affect the Fund’s performance, and the level of risk may vary based on market conditions: • Country/regional risk, which is the chance that world events—such as political upheaval, financial troubles, or natural disasters—will adversely affect the value and/or liquidity of securities issued by foreign governments, government agencies, government-owned corporations, and foreign companies. Because the Fund may invest a large portion of its assets in bonds of issuers located in any one country or region, the Fund’s performance may be hurt disproportionately by the poor performance of its investments in that area. Country/regional risk is especially high in emerging market countries. • Emerging markets risk, which is the chance that the bonds of governments, government agencies, government-owned corporations, and foreign companies located in emerging market countries will be substantially more volatile, and substantially less liquid, than the bonds of governments, government agencies, government-owned corporations, and foreign companies located in more developed foreign markets because, among other factors, emerging market countries can have greater custodial and operational risks; less developed legal, tax, regulatory, and accounting systems; and greater political, social, and economic instability than developed markets. Emerging markets risk is especially high for the Fund. • Currency risk, which is the chance that the value of a foreign investment, measured in U.S. dollars, will decrease because of unfavorable changes in currency exchange rates. Currency risk is especially high in emerging markets. • 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 significant percentage of its assets in bonds issued by a small number of issuers as compared with diversified mutual funds. • 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. Because the Fund invests in both investment-grade and below-investment-grade bonds (also known as high-yield or junk bonds), credit risk should be high for the Fund. • 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. • Derivatives risk, which is the chance that the use of derivatives—such as futures contracts, foreign currency exchange forward contracts, swap agreements, and options—can lead to losses because of adverse movements in the price or value of the underlying security, asset, index, or reference rate. The use of derivatives presents risks different from, and possibly greater than, the risks associated with investing directly in the underlying securities or assets. Also, a liquid market may not always exist for the Fund’s derivative positions at times when the Fund might wish to terminate or sell. The use of a derivative subjects the investor to the risk of nonperformance by the counterparty (i.e., counterparty risk), potentially resulting in delayed or partial payment or even nonpayment of amounts due under the derivative contract. • Interest rate risk, which is the chance that bond prices will decline because of rising interest rates. Interest rate risk should be moderate for the Fund based on expected sensitivity of the portfolio to interest rate movement. • Income risk, which is the chance that the Fund’s income will decline because of falling interest rates. Income risk should be moderate for the Fund, so investors should expect the Fund’s monthly income to fluctuate accordingly. • Call risk, which is the chance that during periods of low or 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. Call risk should be low for the Fund. • 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. A Note on Risk: Many investors invest in bonds and bond funds in an attempt to lower the overall risk of their portfolios. This strategy makes sense when the bonds owned are U.S. bonds because U.S. bond returns typically are not highly correlated with, and are far less volatile than, stock returns. The strategy is less likely to be effective, however, when the bonds owned are emerging market bonds. Returns of emerging market bonds, even dollar-denominated bonds like those owned by the Fund, can be quite volatile. The correlation between emerging market bond and stock returns (both U.S. and foreign) is often higher than the correlation between U.S. bond and stock returns. Consequently, if your goal is to lower risk and volatility, this Fund may not be an appropriate investment. 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	An investment in the Fund could lose money over short or long periods of time.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	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.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	• 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 significant percentage of its assets in bonds issued by a small number of issuers as compared with diversified mutual funds.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Annual Total Returns
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of a relevant market index, which has investment characteristics similar to those of the Fund. Keep in mind that the Fund’s past performance (before and after taxes) 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.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of a relevant market index, which has investment characteristics similar to those of the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-662-7447
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	vanguard.com/performance
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Keep in mind that the Fund’s past performance (before and after taxes) does not indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns — Vanguard Emerging Markets Bond Fund Investor Shares
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest return for a calendar quarter was 4.49% (quarter ended March 31, 2017), and the lowest return for a quarter was –2.19% (quarter ended June 30, 2018).
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for Periods Ended December 31, 2018
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	When after-tax returns are calculated, it is assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	After-tax returns are not relevant for a shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	Please note that after-tax returns are shown only for the Investor Shares and may differ for each share class.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Also, figures captioned Return After Taxes on Distributions and Sale of Fund Shares may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	Actual after-tax returns depend on your tax situation and may differ from those shown in the preceding table. When after-tax returns are calculated, it is assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations. Please note that after-tax returns are shown only for the Investor Shares and may differ for each share class. After-tax returns are not relevant for a shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. Also, figures captioned Return After Taxes on Distributions and Sale of Fund Shares may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.
Retail | Vanguard Emerging Markets Bond Fund | Investor Shares
Risk/Return:	rr_RiskReturnAbstract
Purchase Fee	rr_MaximumCumulativeSalesChargeOverOther	none
Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Account Service Fee (for certain fund account balances below $10,000)	rr_MaximumAccountFee	$ 20	[1]
Management Fees	rr_ManagementFeesOverAssets	0.50%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.60%
1 Year	rr_ExpenseExampleYear01	$ 61
3 Years	rr_ExpenseExampleYear03	192
5 Years	rr_ExpenseExampleYear05	335
10 Years	rr_ExpenseExampleYear10	750
1 Year	rr_ExpenseExampleNoRedemptionYear01	61
3 Years	rr_ExpenseExampleNoRedemptionYear03	192
5 Years	rr_ExpenseExampleNoRedemptionYear05	335
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 750
2017	rr_AnnualReturn2017	13.35%
2018	rr_AnnualReturn2018	(0.88%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	4.49%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(2.19%)
1 Year	rr_AverageAnnualReturnYear01	(0.88%)
Since Inception	rr_AverageAnnualReturnSinceInception	7.60%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 10, 2016
Retail | Vanguard Emerging Markets Bond Fund | Admiral Shares
Risk/Return:	rr_RiskReturnAbstract
Purchase Fee	rr_MaximumCumulativeSalesChargeOverOther	none
Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Account Service Fee (for certain fund account balances below $10,000)	rr_MaximumAccountFee	$ 20	[1]
Management Fees	rr_ManagementFeesOverAssets	0.35%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.45%
1 Year	rr_ExpenseExampleYear01	$ 46
3 Years	rr_ExpenseExampleYear03	144
5 Years	rr_ExpenseExampleYear05	252
10 Years	rr_ExpenseExampleYear10	567
1 Year	rr_ExpenseExampleNoRedemptionYear01	46
3 Years	rr_ExpenseExampleNoRedemptionYear03	144
5 Years	rr_ExpenseExampleNoRedemptionYear05	252
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 567
1 Year	rr_AverageAnnualReturnYear01	(0.70%)
Since Inception	rr_AverageAnnualReturnSinceInception	(0.25%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 06, 2017
Retail | Vanguard Emerging Markets Bond Fund | Return After Taxes on Distributions | Investor Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.77%)
Since Inception	rr_AverageAnnualReturnSinceInception	4.46%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 10, 2016
Retail | Vanguard Emerging Markets Bond Fund | Return After Taxes on Distributions and Sale of Fund Shares | Investor Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.52%)
Since Inception	rr_AverageAnnualReturnSinceInception	4.43%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 10, 2016
Retail | Vanguard Emerging Markets Bond Fund | JP Morgan EMBI Global Diversified (reflects no deduction for fees, expenses, or taxes) | Investor Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.26%)
Since Inception	rr_AverageAnnualReturnSinceInception	4.39%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 10, 2016
Retail | Vanguard Emerging Markets Bond Fund | JP Morgan EMBI Global Diversified (reflects no deduction for fees, expenses, or taxes) | Admiral Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.26%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.66%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 06, 2017

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