XML 57 R113.htm IDEA: XBRL DOCUMENT v3.10.0.1
Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName VANGUARD CHESTER FUNDS
Prospectus Date rr_ProspectusDate Jan. 28, 2019
Vanguard Institutional Target Retirement 2020 Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Vanguard Institutional Target Retirement 2020 Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The Fund seeks to provide capital appreciation and current income consistent with its current asset allocation.
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 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 may pay transaction costs, such as purchase fees, 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. During the most recent fiscal year, the Fund’s portfolio turnover rate was 8% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 8.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The following example is intended to help you compare the cost of investing in the Fund (based on the fees and expenses of the acquired funds) with the cost of investing in other mutual 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 of the Fund and its underlying funds 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 other Vanguard mutual funds (underlying funds) according to an asset allocation strategy designed for investors planning to retire and leave the workforce in or within a few years of 2020 (the target year). The Fund is designed for an investor who plans to withdraw the value of an account in the Fund over a period of many years after the target year. The Fund’s asset allocation will become more conservative over time, meaning that the percentage of assets allocated to stocks will decrease while the percentage of assets allocated to bonds and other fixed income investments will increase. Within seven years after 2020, the Fund’s asset allocation should become similar to that of the Institutional Target Retirement Income Fund. As of September 30, 2018, the Fund’s asset allocation among the underlying funds was as follows:

• Vanguard Total Stock Market Index Fund 32.4%
• Vanguard Total Bond Market II Index Fund 28.9%
• Vanguard Total International Stock Index Fund 21.2%
• Vanguard Total International Bond Index Fund 12.3%
• Vanguard Short-Term Inflation-Protected Securities Index Fund 5.2%

At any given time, the Fund’s asset allocation may be affected by a variety of factors, such as whether the underlying funds are accepting additional investments.

The Fund’s indirect stock holdings are a diversified mix of U.S. and foreign large-, mid-, and small-capitalization stocks.

The Fund’s indirect bond holdings are a diversified mix of short-, intermediate-, and long-term U.S. government, U.S. agency, and investment-grade U.S. corporate bonds; inflation-protected public obligations issued by the U.S. Treasury; mortgage-backed and asset-backed securities; and government, agency, corporate, and securitized investment-grade foreign bonds issued in currencies other than the U.S. dollar (but hedged by Vanguard to minimize foreign currency exposure).
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock The Fund is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money. An investment in the Fund is not guaranteed. An investor may experience losses, including losses near, at, or after the target year. There is no guarantee that the Fund will provide adequate income at or after the target year. Because stocks are typically more volatile than bonds and because the Fund currently invests most of its assets in stocks, the Fund’s overall level of risk should be higher than that of funds that invest the majority of their assets in bonds; however, the level of risk is expected to be lower than that of funds investing entirely in stocks.

• With approximately 53.5% of its assets allocated to stocks, the Fund is proportionately subject to stock market risk, which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices. The Fund is also subject to the following risks associated with investments in foreign stocks: country/regional risk, which is the chance that world events—such as political upheaval, financial troubles, or natural disasters—will adversely affect the value of companies in any one country or region; and 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. Country/regional risk and currency risk are especially high in emerging markets.

• With approximately 46.5% of its assets allocated to bonds, the Fund is proportionately subject to the following bond risks: interest rate risk, which is the chance that bond prices will decline because of rising interest rates; income risk, which is the chance that an underlying fund’s income will decline because of falling interest rates; 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, thus reducing the underlying fund’s return; and 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. An underlying 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 underlying fund’s income. The Fund is also subject to the following risks associated with investments in currency-hedged foreign bonds: 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, or companies; and currency hedging risk, which is the chance that the currency hedging transactions entered into by the underlying international bond fund may not perfectly offset the fund’s foreign currency exposure.

• The Fund is also subject to asset allocation risk, which is the chance that the selection of underlying funds, and the allocation of assets to them, will cause the Fund to underperform other funds with a similar investment objective.

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 The Fund is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money.
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.
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 has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund compare with those of relevant market indexes and a composite stock/bond index, which have 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 has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund compare with those of relevant market indexes and a composite stock/bond index, which have 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 Institutional Target Retirement 2020 Fund Institutional Shares
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock During the periods shown in the bar chart, the highest return for a calendar quarter was 4.12% (quarter ended March 31, 2017), and the lowest return for a quarter was –6.49% (quarter ended December 31, 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 Please note that 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 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 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.
Vanguard Institutional Target Retirement 2020 Fund | Institutional 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
Management Fees rr_ManagementFeesOverAssets none
12b-1 Distribution Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets none
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.09%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.09%
1 Year rr_ExpenseExampleYear01 $ 9
3 Years rr_ExpenseExampleYear03 29
5 Years rr_ExpenseExampleYear05 51
10 Years rr_ExpenseExampleYear10 115
1 Year rr_ExpenseExampleNoRedemptionYear01 9
3 Years rr_ExpenseExampleNoRedemptionYear03 29
5 Years rr_ExpenseExampleNoRedemptionYear05 51
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 115
2016 rr_AnnualReturn2016 7.04%
2017 rr_AnnualReturn2017 14.13%
2018 rr_AnnualReturn2018 (4.21%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2017
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.12%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2018
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.49%)
1 Year rr_AverageAnnualReturnYear01 (4.21%)
Since Inception rr_AverageAnnualReturnSinceInception 3.60%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015
Vanguard Institutional Target Retirement 2020 Fund | Return After Taxes on Distributions | Institutional Shares  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (5.00%)
Since Inception rr_AverageAnnualReturnSinceInception 2.90%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015
Vanguard Institutional Target Retirement 2020 Fund | Return After Taxes on Distributions and Sale of Fund Shares | Institutional Shares  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (2.29%)
Since Inception rr_AverageAnnualReturnSinceInception 2.57%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015
Vanguard Institutional Target Retirement 2020 Fund | MSCI US Broad Market Index  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (5.28%) [1]
Since Inception rr_AverageAnnualReturnSinceInception 6.60% [1]
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015 [1]
Vanguard Institutional Target Retirement 2020 Fund | Bloomberg Barclays U.S. Aggregate Bond Index  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.01% [1]
Since Inception rr_AverageAnnualReturnSinceInception 2.12% [1]
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015 [1]
Vanguard Institutional Target Retirement 2020 Fund | Target 2020 Composite Index  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (4.13%) [1]
Since Inception rr_AverageAnnualReturnSinceInception 3.76% [1]
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 26, 2015 [1]
[1] Comparative Indexes (reflect no deduction for fees, expenses, or taxes)