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<rr:ShareholderFeesCaption
contextRef="v_Retail_S000004462">Shareholder Fees (Fees paid directly from your investment)</rr:ShareholderFeesCaption>
<rr:ShareholderFeesCaption
contextRef="v_Participant_S000004462">Shareholder Fees (Fees paid directly from your investment)</rr:ShareholderFeesCaption>
<rr:OperatingExpensesCaption
contextRef="v_Retail_S000004462">Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
<rr:OperatingExpensesCaption
contextRef="v_Participant_S000004462">Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
<rr:PerformanceTableHeading
contextRef="v_Retail_S000004462">Average Annual Total Returns for Periods Ended December 31, 2011</rr:PerformanceTableHeading>
<rr:PerformanceTableHeading
contextRef="v_Participant_S000004462">Average Annual Total Returns for Periods Ended December 31, 2011</rr:PerformanceTableHeading>
<rr:BarChartAndPerformanceTableHeading
contextRef="v_Participant_S000004462">Annual Total Returns</rr:BarChartAndPerformanceTableHeading>
<rr:ExpenseHeading
contextRef="v_Participant_S000004462">Fees and Expenses</rr:ExpenseHeading>
<rr:ObjectiveHeading
contextRef="v_Participant_S000004462">Investment Objective</rr:ObjectiveHeading>
<rr:RiskHeading
contextRef="v_Participant_S000004462">Primary Risks</rr:RiskHeading>
<rr:RiskReturnHeading
contextRef="v_Participant_S000004462">Risk/Return</rr:RiskReturnHeading>
<rr:StrategyHeading
contextRef="v_Participant_S000004462">Primary Investment Policies</rr:StrategyHeading>
<rr:ProspectusDate
contextRef="v_Participant_S000004462">2012-12-28</rr:ProspectusDate>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004462">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:BarChartAndPerformanceTableHeading
contextRef="v_Retail_S000004462">Annual Total Returns</rr:BarChartAndPerformanceTableHeading>
<rr:ExpenseHeading
contextRef="v_Retail_S000004462">Fees and Expenses</rr:ExpenseHeading>
<rr:ObjectiveHeading
contextRef="v_Retail_S000004462">Investment Objective</rr:ObjectiveHeading>
<rr:RiskHeading
contextRef="v_Retail_S000004462">Primary Risks</rr:RiskHeading>
<rr:RiskReturnHeading
contextRef="v_Retail_S000004462">Risk/Return</rr:RiskReturnHeading>
<rr:StrategyHeading
contextRef="v_Retail_S000004462">Primary Investment Policies</rr:StrategyHeading>
<rr:ProspectusDate
contextRef="v_Retail_S000004462">2012-12-28</rr:ProspectusDate>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004462">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:ExpenseExampleHeading
contextRef="v_Participant_S000004462">&lt;p&gt;Example&lt;/p&gt;</rr:ExpenseExampleHeading>
<rr:ExpenseExampleNarrativeTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund's shares. This example assumes that the Fund provides a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you 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:&lt;/p&gt;</rr:ExpenseExampleNarrativeTextBlock>
<rr:ExpenseNarrativeTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;The following table describes the fees and expenses you may pay if you buy and hold shares of the Fund.&lt;/p&gt;</rr:ExpenseNarrativeTextBlock>
<rr:ObjectivePrimaryTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.&lt;/p&gt;</rr:ObjectivePrimaryTextBlock>
<rr:PerformanceNarrativeTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;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 compare with those of a relevant market index and a comparative benchmark, which have investment characteristics similar to those of the Fund. Returns for the U.S. Government Money Market Funds Average are derived from data provided by Lipper Inc. 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.&lt;/p&gt;</rr:PerformanceNarrativeTextBlock>
<rr:RiskNarrativeTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;&lt;p&gt;Income risk, which is the chance that the Fund's income will decline because of falling interest rates. Because the Fund's income is based on short-term interest rates-which can fluctuate significantly over short periods-income risk is expected to be high.&lt;/p&gt;&lt;p&gt;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. &lt;/p&gt;&lt;p&gt;Credit risk, which is the chance that the issuer of a security will fail to pay interest and principal in a timely manner, or that negative perceptions of the issuer's ability to make such payments will cause the price of that security to decline. Credit risk should be very low for the Fund because it invests primarily in securities that are considered to be of high quality.&lt;/p&gt;&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNarrativeTextBlock>
<rr:StrategyNarrativeTextBlock
contextRef="v_Participant_S000004462">&lt;p&gt;The Fund invests primarily in high-quality, short-term money market instruments. At least 80% of the Fund's assets are invested in securities issued by the U.S. government and its agencies and instrumentalities. Although these securities are high-quality, most of the securities held by the Fund are neither guaranteed by the U.S. Treasury nor supported by the full faith and credit of the U.S. government. To be considered high-quality, a security generally must be rated in one of the two highest credit-quality categories for short-term securities by at least two nationally recognized rating services (or by one, if only one rating service has rated the security). The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.&lt;/p&gt;</rr:StrategyNarrativeTextBlock >
<rr:RiskNotInsuredDepositoryInstitution
contextRef="v_Participant_S000004462">&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNotInsuredDepositoryInstitution>
<rr:RiskMoneyMarketFund
contextRef="v_Participant_S000004462">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;</rr:RiskMoneyMarketFund>
<rr:PerformanceInformationIllustratesVariabilityOfReturns
contextRef="v_Participant_S000004462">&lt;p&gt;The following bar chart and table are intended to help you understand the risks of investing in the Fund.&lt;/p&gt;</rr:PerformanceInformationIllustratesVariabilityOfReturns>
<rr:PerformanceAdditionalMarketIndex
contextRef="v_Participant_S000004462">&lt;p&gt;, which have investment characteristics similar to those of the Fund.&lt;/p&gt;</rr:PerformanceAdditionalMarketIndex>
<rr:PerformanceAvailabilityPhone
contextRef="v_Participant_S000004462">&lt;p&gt;800-662-7447&lt;/p&gt;</rr:PerformanceAvailabilityPhone>
<rr:PerformanceAvailabilityWebSiteAddress
contextRef="v_Participant_S000004462">&lt;p&gt;vanguard.com/performance &lt;/p&gt;</rr:PerformanceAvailabilityWebSiteAddress>
<rr:PerformancePastDoesNotIndicateFuture
contextRef="v_Participant_S000004462">&lt;p&gt;Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.&lt;/p&gt;</rr:PerformancePastDoesNotIndicateFuture>
<rr:ExpenseExampleHeading
contextRef="v_Retail_S000004462">&lt;p&gt;Example&lt;/p&gt;</rr:ExpenseExampleHeading>
<rr:ExpenseExampleNarrativeTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund's shares. This example assumes that the Fund provides a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you 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:&lt;/p&gt;</rr:ExpenseExampleNarrativeTextBlock>
<rr:ExpenseNarrativeTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;The following table describes the fees and expenses you may pay if you buy and hold shares of the Fund.&lt;/p&gt;</rr:ExpenseNarrativeTextBlock>
<rr:ObjectivePrimaryTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.&lt;/p&gt;</rr:ObjectivePrimaryTextBlock>
<rr:PerformanceNarrativeTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;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 compare with those of a relevant market index and a comparative benchmark, which have investment characteristics similar to those of the Fund. Returns for the U.S. Government Money Market Funds Average are derived from data provided by Lipper Inc. 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.&lt;/p&gt;</rr:PerformanceNarrativeTextBlock>
<rr:RiskNarrativeTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;&lt;p&gt;Income risk, which is the chance that the Fund's income will decline because of falling interest rates. Because the Fund's income is based on short-term interest rates-which can fluctuate significantly over short periods-income risk is expected to be high.&lt;/p&gt;&lt;p&gt;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. &lt;/p&gt;&lt;p&gt;Credit risk, which is the chance that the issuer of a security will fail to pay interest and principal in a timely manner, or that negative perceptions of the issuer's ability to make such payments will cause the price of that security to decline. Credit risk should be very low for the Fund because it invests primarily in securities that are considered to be of high quality.&lt;/p&gt;&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNarrativeTextBlock>
<rr:StrategyNarrativeTextBlock
contextRef="v_Retail_S000004462">&lt;p&gt;The Fund invests primarily in high-quality, short-term money market instruments. At least 80% of the Fund's assets are invested in securities issued by the U.S. government and its agencies and instrumentalities. Although these securities are high-quality, most of the securities held by the Fund are neither guaranteed by the U.S. Treasury nor supported by the full faith and credit of the U.S. government. To be considered high-quality, a security generally must be rated in one of the two highest credit-quality categories for short-term securities by at least two nationally recognized rating services (or by one, if only one rating service has rated the security). The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.&lt;/p&gt;</rr:StrategyNarrativeTextBlock >
<rr:RiskNotInsuredDepositoryInstitution
contextRef="v_Retail_S000004462">&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNotInsuredDepositoryInstitution>
<rr:RiskMoneyMarketFund
contextRef="v_Retail_S000004462">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;</rr:RiskMoneyMarketFund>
<rr:PerformanceInformationIllustratesVariabilityOfReturns
contextRef="v_Retail_S000004462">&lt;p&gt;The following bar chart and table are intended to help you understand the risks of investing in the Fund.&lt;/p&gt;</rr:PerformanceInformationIllustratesVariabilityOfReturns>
<rr:PerformanceAdditionalMarketIndex
contextRef="v_Retail_S000004462">&lt;p&gt;, which have investment characteristics similar to those of the Fund.&lt;/p&gt;</rr:PerformanceAdditionalMarketIndex>
<rr:PerformanceAvailabilityPhone
contextRef="v_Retail_S000004462">&lt;p&gt;800-662-7447&lt;/p&gt;</rr:PerformanceAvailabilityPhone>
<rr:PerformanceAvailabilityWebSiteAddress
contextRef="v_Retail_S000004462">&lt;p&gt;vanguard.com/performance &lt;/p&gt;</rr:PerformanceAvailabilityWebSiteAddress>
<rr:PerformancePastDoesNotIndicateFuture
contextRef="v_Retail_S000004462">&lt;p&gt;Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.&lt;/p&gt;</rr:PerformancePastDoesNotIndicateFuture>
<rr:ShareholderFeesTableTextBlock
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<rr:ShareholderFeesTableTextBlock
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<rr:AnnualFundOperatingExpensesTableTextBlock
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<rr:AnnualFundOperatingExpensesTableTextBlock
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<rr:ExpenseExampleNoRedemptionTableTextBlock
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<rr:ExpenseExampleNoRedemptionTableTextBlock
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<rr:ShareholderFeesCaption
contextRef="v_Retail_S000004463">Shareholder Fees (Fees paid directly from your investment)</rr:ShareholderFeesCaption>
<rr:ShareholderFeesCaption
contextRef="v_Participant_S000004463">Shareholder Fees (Fees paid directly from your investment)</rr:ShareholderFeesCaption>
<rr:ShareholderFeesCaption
contextRef="v_Institutional_S000004463">Shareholder Fees (Fees paid directly from your investment)</rr:ShareholderFeesCaption>
<rr:OperatingExpensesCaption
contextRef="v_Retail_S000004463">Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
<rr:OperatingExpensesCaption
contextRef="v_Participant_S000004463">Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
<rr:OperatingExpensesCaption
contextRef="v_Institutional_S000004463">Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
<rr:PerformanceTableHeading
contextRef="v_Retail_S000004463">Average Annual Total Returns for Periods Ended December 31, 2011</rr:PerformanceTableHeading>
<rr:PerformanceTableHeading
contextRef="v_Participant_S000004463">Average Annual Total Returns for Periods Ended December 31, 2011</rr:PerformanceTableHeading>
<rr:PerformanceTableHeading
contextRef="v_Institutional_S000004463">Average Annual Total Returns for Periods Ended December 31, 2011</rr:PerformanceTableHeading>
<rr:BarChartAndPerformanceTableHeading
contextRef="v_Institutional_S000004463">Annual Total Returns</rr:BarChartAndPerformanceTableHeading>
<rr:ExpenseHeading
contextRef="v_Institutional_S000004463">Fees and Expenses</rr:ExpenseHeading>
<rr:ObjectiveHeading
contextRef="v_Institutional_S000004463">Investment Objective</rr:ObjectiveHeading>
<rr:RiskHeading
contextRef="v_Institutional_S000004463">Primary Risks</rr:RiskHeading>
<rr:RiskReturnHeading
contextRef="v_Institutional_S000004463">Risk/Return</rr:RiskReturnHeading>
<rr:StrategyHeading
contextRef="v_Institutional_S000004463">Primary Investment Policies</rr:StrategyHeading>
<rr:ProspectusDate
contextRef="v_Institutional_S000004463">2012-12-28</rr:ProspectusDate>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Institutional_S000004463">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:BarChartAndPerformanceTableHeading
contextRef="v_Participant_S000004463">Annual Total Returns</rr:BarChartAndPerformanceTableHeading>
<rr:ExpenseHeading
contextRef="v_Participant_S000004463">Fees and Expenses</rr:ExpenseHeading>
<rr:ObjectiveHeading
contextRef="v_Participant_S000004463">Investment Objective</rr:ObjectiveHeading>
<rr:RiskHeading
contextRef="v_Participant_S000004463">Primary Risks</rr:RiskHeading>
<rr:RiskReturnHeading
contextRef="v_Participant_S000004463">Risk/Return</rr:RiskReturnHeading>
<rr:StrategyHeading
contextRef="v_Participant_S000004463">Primary Investment Policies</rr:StrategyHeading>
<rr:ProspectusDate
contextRef="v_Participant_S000004463">2012-12-28</rr:ProspectusDate>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004463">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:BarChartAndPerformanceTableHeading
contextRef="v_Retail_S000004463">Annual Total Returns</rr:BarChartAndPerformanceTableHeading>
<rr:ExpenseHeading
contextRef="v_Retail_S000004463">Fees and Expenses</rr:ExpenseHeading>
<rr:ObjectiveHeading
contextRef="v_Retail_S000004463">Investment Objective</rr:ObjectiveHeading>
<rr:RiskHeading
contextRef="v_Retail_S000004463">Primary Risks</rr:RiskHeading>
<rr:RiskReturnHeading
contextRef="v_Retail_S000004463">Risk/Return</rr:RiskReturnHeading>
<rr:StrategyHeading
contextRef="v_Retail_S000004463">Primary Investment Policies</rr:StrategyHeading>
<rr:ProspectusDate
contextRef="v_Retail_S000004463">2012-12-28</rr:ProspectusDate>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004463">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:BarChartNarrativeTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;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 Institutional Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund's Institutional Shares compare with those of a relevant market index and a comparative benchmark, which have investment characteristics similar to those of the Fund. Returns for the Institutional Money Market Funds Average are derived from data provided by Lipper Inc. 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.&lt;/p&gt;</rr:BarChartNarrativeTextBlock>
<rr:ExpenseExampleHeading
contextRef="v_Institutional_S000004463">&lt;p&gt;Example&lt;/p&gt;</rr:ExpenseExampleHeading>
<rr:ExpenseExampleNarrativeTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;The following example is intended to help you compare the cost of investing in the Fund's Institutional Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund's shares. This example assumes that the Shares provide a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you 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:&lt;/p&gt;</rr:ExpenseExampleNarrativeTextBlock>
<rr:ExpenseNarrativeTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.&lt;/p&gt;</rr:ExpenseNarrativeTextBlock>
<rr:ObjectivePrimaryTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.&lt;/p&gt;</rr:ObjectivePrimaryTextBlock>
<rr:RiskNarrativeTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;&lt;p&gt;Income risk, which is the chance that the Fund's income will decline because of falling interest rates. Because the Fund's income is based on short-term interest rates-which can fluctuate significantly over short periods-income risk is expected to be high.&lt;/p&gt;&lt;p&gt;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. &lt;/p&gt;&lt;p&gt;Credit risk, which is the chance that the issuer of a security will fail to pay interest and principal in a timely manner, or that negative perceptions of the issuer's ability to make such payments will cause the price of that security to decline. Credit risk should be very low for the Fund because it invests primarily in securities that are considered to be of high quality.&lt;/p&gt;&lt;p&gt;Industry concentration risk, which is the chance that there will be overall problems affecting a particular industry. Because the Fund invests more than 25% of its assets in securities issued by companies in the financial services industry, the Fund's performance depends to a greater extent on the overall condition of that industry.&lt;/p&gt;&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNarrativeTextBlock>
<rr:StrategyNarrativeTextBlock
contextRef="v_Institutional_S000004463">&lt;p&gt;The Fund invests primarily in high-quality, short-term money market instruments, including certificates of deposit, banker's acceptances, commercial paper, and other money market securities. To be considered high-quality, a security generally must be rated in one of the two highest credit-quality categories for short-term securities by at least two nationally recognized rating services (or by one, if only one rating service has rated the security). If unrated, the security must be determined by Vanguard to be of quality equivalent to securities in the two highest credit-quality categories. The Fund invests more than 25% of its assets in securities issued by companies in the financial services industry. The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.&lt;/p&gt;</rr:StrategyNarrativeTextBlock >
<rr:RiskNotInsuredDepositoryInstitution
contextRef="v_Institutional_S000004463">&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNotInsuredDepositoryInstitution>
<rr:RiskMoneyMarketFund
contextRef="v_Institutional_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;</rr:RiskMoneyMarketFund>
<rr:PerformanceInformationIllustratesVariabilityOfReturns
contextRef="v_Institutional_S000004463">&lt;p&gt;The following bar chart and table are intended to help you understand the risks of investing in the Fund.&lt;/p&gt;</rr:PerformanceInformationIllustratesVariabilityOfReturns>
<rr:PerformanceAvailabilityPhone
contextRef="v_Institutional_S000004463">&lt;p&gt;800-662-7447&lt;/p&gt;</rr:PerformanceAvailabilityPhone>
<rr:PerformanceAvailabilityWebSiteAddress
contextRef="v_Institutional_S000004463">&lt;p&gt;vanguard.com/performance &lt;/p&gt;</rr:PerformanceAvailabilityWebSiteAddress>
<rr:PerformancePastDoesNotIndicateFuture
contextRef="v_Institutional_S000004463">&lt;p&gt;Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.&lt;/p&gt;</rr:PerformancePastDoesNotIndicateFuture>
<rr:BarChartNarrativeTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;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 Fund's Investor Shares compare with those of a relevant market index and a comparative benchmark, which have investment characteristics similar to those of the Fund. Returns for the Money Market Funds Average are derived from data provided by Lipper Inc. 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.&lt;/p&gt;</rr:BarChartNarrativeTextBlock>
<rr:ExpenseExampleHeading
contextRef="v_Participant_S000004463">&lt;p&gt;Example&lt;/p&gt;</rr:ExpenseExampleHeading>
<rr:ExpenseExampleNarrativeTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;The following example is intended to help you compare the cost of investing in the Fund's Investor Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund's shares. This example assumes that the Shares provide a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you 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:&lt;/p&gt;</rr:ExpenseExampleNarrativeTextBlock>
<rr:ExpenseNarrativeTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;The following table describes the fees and expenses you may pay if you buy and hold Investor Shares of the Fund.&lt;/p&gt;</rr:ExpenseNarrativeTextBlock>
<rr:ObjectivePrimaryTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.&lt;/p&gt;</rr:ObjectivePrimaryTextBlock>
<rr:RiskLoseMoney
contextRef="v_Participant_S000004463">&lt;p&gt;The Fund is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money.&lt;/p&gt;</rr:RiskLoseMoney>
<rr:RiskNarrativeTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;&lt;p&gt;Income risk, which is the chance that the Fund's income will decline because of falling interest rates. Because the Fund's income is based on short-term interest rates-which can fluctuate significantly over short periods-income risk is expected to be high.&lt;/p&gt;&lt;p&gt;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. &lt;/p&gt;&lt;p&gt;Credit risk, which is the chance that the issuer of a security will fail to pay interest and principal in a timely manner, or that negative perceptions of the issuer's ability to make such payments will cause the price of that security to decline. Credit risk should be very low for the Fund because it invests primarily in securities that are considered to be of high quality.&lt;/p&gt;&lt;p&gt;Industry concentration risk, which is the chance that there will be overall problems affecting a particular industry. Because the Fund invests more than 25% of its assets in securities issued by companies in the financial services industry, the Fund's performance depends to a greater extent on the overall condition of that industry.&lt;/p&gt;&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNarrativeTextBlock>
<rr:StrategyNarrativeTextBlock
contextRef="v_Participant_S000004463">&lt;p&gt;The Fund invests primarily in high-quality, short-term money market instruments, including certificates of deposit, banker's acceptances, commercial paper, and other money market securities. To be considered high-quality, a security generally must be rated in one of the two highest credit-quality categories for short-term securities by at least two nationally recognized rating services (or by one, if only one rating service has rated the security). If unrated, the security must be determined by Vanguard to be of quality equivalent to securities in the two highest credit-quality categories. The Fund invests more than 25% of its assets in securities issued by companies in the financial services industry. The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.&lt;/p&gt;</rr:StrategyNarrativeTextBlock >
<rr:RiskNotInsuredDepositoryInstitution
contextRef="v_Participant_S000004463">&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNotInsuredDepositoryInstitution>
<rr:RiskMoneyMarketFund
contextRef="v_Participant_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;</rr:RiskMoneyMarketFund>
<rr:PerformanceInformationIllustratesVariabilityOfReturns
contextRef="v_Participant_S000004463">&lt;p&gt;The following bar chart and table are intended to help you understand the risks of investing in the Fund.&lt;/p&gt;</rr:PerformanceInformationIllustratesVariabilityOfReturns>
<rr:PerformanceAdditionalMarketIndex
contextRef="v_Participant_S000004463">&lt;p&gt;, which have investment characteristics similar to those of the Fund.&lt;/p&gt;</rr:PerformanceAdditionalMarketIndex>
<rr:PerformanceAvailabilityPhone
contextRef="v_Participant_S000004463">&lt;p&gt;800-662-7447&lt;/p&gt;</rr:PerformanceAvailabilityPhone>
<rr:PerformanceAvailabilityWebSiteAddress
contextRef="v_Participant_S000004463">&lt;p&gt;vanguard.com/performance &lt;/p&gt;</rr:PerformanceAvailabilityWebSiteAddress>
<rr:PerformancePastDoesNotIndicateFuture
contextRef="v_Participant_S000004463">&lt;p&gt;Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.&lt;/p&gt;</rr:PerformancePastDoesNotIndicateFuture>
<rr:BarChartNarrativeTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;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 Fund's Investor Shares compare with those of a relevant market index and a comparative benchmark, which have investment characteristics similar to those of the Fund. Returns for the Money Market Funds Average are derived from data provided by Lipper Inc. 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.&lt;/p&gt;</rr:BarChartNarrativeTextBlock>
<rr:ExpenseExampleHeading
contextRef="v_Retail_S000004463">&lt;p&gt;Example&lt;/p&gt;</rr:ExpenseExampleHeading>
<rr:ExpenseExampleNarrativeTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;The following example is intended to help you compare the cost of investing in the Fund's Investor Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund's shares. This example assumes that the Shares provide a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you 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:&lt;/p&gt;</rr:ExpenseExampleNarrativeTextBlock>
<rr:ExpenseNarrativeTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;The following table describes the fees and expenses you may pay if you buy and hold Investor Shares of the Fund.&lt;/p&gt;</rr:ExpenseNarrativeTextBlock>
<rr:ObjectivePrimaryTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.&lt;/p&gt;</rr:ObjectivePrimaryTextBlock>
<rr:RiskNarrativeTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;&lt;p&gt;Income risk, which is the chance that the Fund's income will decline because of falling interest rates. Because the Fund's income is based on short-term interest rates-which can fluctuate significantly over short periods-income risk is expected to be high.&lt;/p&gt;&lt;p&gt;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. &lt;/p&gt;&lt;p&gt;Credit risk, which is the chance that the issuer of a security will fail to pay interest and principal in a timely manner, or that negative perceptions of the issuer's ability to make such payments will cause the price of that security to decline. Credit risk should be very low for the Fund because it invests primarily in securities that are considered to be of high quality.&lt;/p&gt;&lt;p&gt;Industry concentration risk, which is the chance that there will be overall problems affecting a particular industry. Because the Fund invests more than 25% of its assets in securities issued by companies in the financial services industry, the Fund's performance depends to a greater extent on the overall condition of that industry.&lt;/p&gt;&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNarrativeTextBlock>
<rr:StrategyNarrativeTextBlock
contextRef="v_Retail_S000004463">&lt;p&gt;The Fund invests primarily in high-quality, short-term money market instruments, including certificates of deposit, banker's acceptances, commercial paper, and other money market securities. To be considered high-quality, a security generally must be rated in one of the two highest credit-quality categories for short-term securities by at least two nationally recognized rating services (or by one, if only one rating service has rated the security). If unrated, the security must be determined by Vanguard to be of quality equivalent to securities in the two highest credit-quality categories. The Fund invests more than 25% of its assets in securities issued by companies in the financial services industry. The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.&lt;/p&gt;</rr:StrategyNarrativeTextBlock >
<rr:RiskNotInsuredDepositoryInstitution
contextRef="v_Retail_S000004463">&lt;p&gt;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. Although the Fund seeks to preserve the value of your investment at $1 per share, it is possible to lose money by investing in the Fund.&lt;/p&gt;</rr:RiskNotInsuredDepositoryInstitution>
<rr:RiskMoneyMarketFund
contextRef="v_Retail_S000004463">&lt;p&gt;The Fund is designed for investors with a low tolerance for risk; however, the Fund is subject to the following risks, which could affect the Fund's performance:&lt;/p&gt;</rr:RiskMoneyMarketFund>
<rr:PerformanceInformationIllustratesVariabilityOfReturns
contextRef="v_Retail_S000004463">&lt;p&gt;The following bar chart and table are intended to help you understand the risks of investing in the Fund.&lt;/p&gt;</rr:PerformanceInformationIllustratesVariabilityOfReturns>
<rr:PerformanceAdditionalMarketIndex
contextRef="v_Retail_S000004463">&lt;p&gt;, which have investment characteristics similar to those of the Fund.&lt;/p&gt;</rr:PerformanceAdditionalMarketIndex>
<rr:PerformanceAvailabilityPhone
contextRef="v_Retail_S000004463">&lt;p&gt;800-662-7447&lt;/p&gt;</rr:PerformanceAvailabilityPhone>
<rr:PerformanceAvailabilityWebSiteAddress
contextRef="v_Retail_S000004463">&lt;p&gt;vanguard.com/performance &lt;/p&gt;</rr:PerformanceAvailabilityWebSiteAddress>
<rr:PerformancePastDoesNotIndicateFuture
contextRef="v_Retail_S000004463">&lt;p&gt;Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.&lt;/p&gt;</rr:PerformancePastDoesNotIndicateFuture>
<rr:ShareholderFeesTableTextBlock
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<rr:AnnualFundOperatingExpensesTableTextBlock
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<rr:ExpenseExampleNoRedemptionTableTextBlock
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<rr:ExpenseExampleNoRedemptionTableTextBlock
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<rr:ExpenseExampleNoRedemptionTableTextBlock
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<rr:AnnualReturn2011
unitRef="pure"
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contextRef="v_S000004463_C000012239">0.0005</rr:AnnualReturn2011>
<rr:AnnualReturn2010
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0006</rr:AnnualReturn2010>
<rr:AnnualReturn2009
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0053</rr:AnnualReturn2009>
<rr:AnnualReturn2008
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0277</rr:AnnualReturn2008>
<rr:AnnualReturn2007
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0514</rr:AnnualReturn2007>
<rr:AnnualReturn2006
contextRef="v_S000004463_C000012239"
unitRef="pure"
decimals="4">0.0488</rr:AnnualReturn2006>
<rr:AnnualReturn2005
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0301</rr:AnnualReturn2005>
<rr:AnnualReturn2004
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0111</rr:AnnualReturn2004>
<rr:AnnualReturn2003
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0090</rr:AnnualReturn2003>
<rr:AnnualReturn2002
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012239">0.0165</rr:AnnualReturn2002>
<rr:AnnualReturnInceptionDate
contextRef="v_S000004463_C000012239">1975-06-04</rr:AnnualReturnInceptionDate>
<rr:BarChartHighestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004463_C000012239"
decimals="4">0.0129</rr:BarChartHighestQuarterlyReturn>
<rr:BarChartLowestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004463_C000012239"
decimals="4">0.0001</rr:BarChartLowestQuarterlyReturn>
<rr:BarChartHighestQuarterlyReturnDate
contextRef="v_S000004463_C000012239">2006-12-31</rr:BarChartHighestQuarterlyReturnDate>
<rr:BarChartLowestQuarterlyReturnDate
contextRef="v_S000004463_C000012239">2010-03-31</rr:BarChartLowestQuarterlyReturnDate>
<rr:BarChartTableTextBlock
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<rr:BarChartHeading
contextRef="v_Retail_S000004463">Annual Total Returns - Vanguard Prime Money Market Fund Investor Shares</rr:BarChartHeading>
<rr:BarChartFootnotesTextBlock
contextRef="v_Retail_S000004463">&lt;p>1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.03%&lt;/p></rr:BarChartFootnotesTextBlock>
<rr:YearToDateReturnLabel
contextRef="v_Retail_S000004463">The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012</rr:YearToDateReturnLabel>
<rr:BarChartClosingTextBlock
contextRef="v_Retail_S000004463">&lt;p>During the periods shown in the bar chart, the highest return for a calendar quarter was 1.29% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.01% (quarter ended March 31, 2010 ).&lt;/p></rr:BarChartClosingTextBlock>
<rr:HighestQuarterlyReturnLabel
contextRef="v_Retail_S000004463">(quarter ended December 31, 2006 )</rr:HighestQuarterlyReturnLabel>
<rr:LowestQuarterlyReturnLabel
contextRef="v_Retail_S000004463">(quarter ended March 31, 2010 )</rr:LowestQuarterlyReturnLabel>
<rr:BarChartTableTextBlock
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<rr:BarChartHeading
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<rr:BarChartFootnotesTextBlock
contextRef="v_Participant_S000004463">&lt;p>1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.03%&lt;/p></rr:BarChartFootnotesTextBlock>
<rr:YearToDateReturnLabel
contextRef="v_Participant_S000004463">The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012</rr:YearToDateReturnLabel>
<rr:BarChartClosingTextBlock
contextRef="v_Participant_S000004463">&lt;p>During the periods shown in the bar chart, the highest return for a calendar quarter was 1.29% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.01% (quarter ended March 31, 2010 ).&lt;/p></rr:BarChartClosingTextBlock>
<rr:HighestQuarterlyReturnLabel
contextRef="v_Participant_S000004463">(quarter ended December 31, 2006 )</rr:HighestQuarterlyReturnLabel>
<rr:LowestQuarterlyReturnLabel
contextRef="v_Participant_S000004463">(quarter ended March 31, 2010 )</rr:LowestQuarterlyReturnLabel>
<rr:BarChartYearToDateReturnDate
contextRef="v_S000004463_C000012239">2012-09-30</rr:BarChartYearToDateReturnDate>
<rr:BarChartYearToDateReturn
contextRef="v_S000004463_C000012239"
decimals="4"
unitRef="pure">0.0003</rr:BarChartYearToDateReturn>
<rr:AverageAnnualReturnInceptionDate
contextRef="v_S000004463_C000012239">1975-06-04</rr:AverageAnnualReturnInceptionDate>
<rr:AverageAnnualReturnYear01
unitRef="pure"
contextRef="v_S000004463_C000012239"
decimals="4">0.0005</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
decimals="4"
contextRef="v_S000004463_C000012239"
unitRef="pure">0.0169</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
decimals="4"
contextRef="v_S000004463_C000012239"
unitRef="pure">0.0199</rr:AverageAnnualReturnYear10>
<vanguard:ComparativeBenchmark
contextRef="v_S000004463_C000012239">Comparative Benchmarks</vanguard:ComparativeBenchmark>
<rr:MaximumCumulativeSalesChargeOverOther
decimals="4"
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contextRef="v_S000004463_C000012239">0.0000</rr:MaximumCumulativeSalesChargeOverOther>
<rr:RedemptionFeeOverRedemption
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012239">0.0000</rr:RedemptionFeeOverRedemption>
<rr:MaximumAccountFee
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unitRef ="usd"
decimals="4">20.</rr:MaximumAccountFee>
<rr:MaximumCumulativeSalesChargeOverOfferingPrice
decimals="4"
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contextRef="v_S000004463_C000012239">0</rr:MaximumCumulativeSalesChargeOverOfferingPrice>
<rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther
contextRef="v_S000004463_C000012239"
unitRef ="pure"
decimals="4">0</rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther>
<rr:ExpenseExampleNoRedemptionYear01
contextRef="v_S000004463_C000012239"
unitRef ="usd"
decimals="4">16.</rr:ExpenseExampleNoRedemptionYear01>
<rr:ExpenseExampleNoRedemptionYear03
decimals="4"
unitRef ="usd"
contextRef="v_S000004463_C000012239">52.</rr:ExpenseExampleNoRedemptionYear03>
<rr:ExpenseExampleNoRedemptionYear05
decimals="4"
unitRef ="usd"
contextRef="v_S000004463_C000012239">90.</rr:ExpenseExampleNoRedemptionYear05>
<rr:ExpenseExampleNoRedemptionYear10
contextRef="v_S000004463_C000012239"
unitRef ="usd"
decimals="4">205.</rr:ExpenseExampleNoRedemptionYear10>
<rr:ManagementFeesOverAssets
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012239">0.0013</rr:ManagementFeesOverAssets>
<rr:DistributionAndService12b1FeesOverAssets
contextRef="v_S000004463_C000012239"
unitRef ="pure"
decimals="4">0</rr:DistributionAndService12b1FeesOverAssets>
<rr:OtherExpensesOverAssets
contextRef="v_S000004463_C000012239"
unitRef ="pure"
decimals="4">0.0003</rr:OtherExpensesOverAssets>
<link:footnoteLink
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xlink:label="footnote_63">Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund's daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund's Board may terminate the temporary expense limitation at any time.</link:footnote>
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xlink:type="resource"
xlink:role="http://www.xbrl.org/2003/role/footnote"
xlink:label="footnote_869">Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund's daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund's Board may terminate the temporary expense limitation at any time.</link:footnote>
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xlink:to="footnote_869"
order="1.0"
xlink:type="arc"
xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
xlink:from="NetExpensesOverAssets_869"/></link:footnoteLink>
<rr:NetExpensesOverAssets
contextRef="v_S000004463_C000012239"
unitRef ="pure"
decimals="4"
id="id_footnote_elem_30">0.0016</rr:NetExpensesOverAssets>
<rr:AnnualReturn2011
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0001</rr:AnnualReturn2011>
<rr:AnnualReturn2010
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0002</rr:AnnualReturn2010>
<rr:AnnualReturn2009
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0040</rr:AnnualReturn2009>
<rr:AnnualReturn2008
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0253</rr:AnnualReturn2008>
<rr:AnnualReturn2007
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0507</rr:AnnualReturn2007>
<rr:AnnualReturn2006
contextRef="v_S000004462_C000012238"
unitRef="pure"
decimals="4">0.0481</rr:AnnualReturn2006>
<rr:AnnualReturn2005
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0296</rr:AnnualReturn2005>
<rr:AnnualReturn2004
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0108</rr:AnnualReturn2004>
<rr:AnnualReturn2003
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0089</rr:AnnualReturn2003>
<rr:AnnualReturn2002
unitRef="pure"
decimals="4"
contextRef="v_S000004462_C000012238">0.0164</rr:AnnualReturn2002>
<rr:AnnualReturnInceptionDate
contextRef="v_S000004462_C000012238">1981-07-13</rr:AnnualReturnInceptionDate>
<rr:BarChartHighestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004462_C000012238"
decimals="4">0.0128</rr:BarChartHighestQuarterlyReturn>
<rr:BarChartLowestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004462_C000012238"
decimals="4">0.0000</rr:BarChartLowestQuarterlyReturn>
<rr:BarChartHighestQuarterlyReturnDate
contextRef="v_S000004462_C000012238">2006-12-31</rr:BarChartHighestQuarterlyReturnDate>
<rr:BarChartLowestQuarterlyReturnDate
contextRef="v_S000004462_C000012238">2011-09-30</rr:BarChartLowestQuarterlyReturnDate>
<rr:BarChartTableTextBlock
contextRef="v_Retail_S000004462">&lt;div style="display:none">~ http://xbrl.sec.gov/rr/role/BarChartData column rr_ProspectusShareClassAxis compact vanguard_C000012238Member ~ &lt;/div> </rr:BarChartTableTextBlock>
<rr:BarChartHeading
contextRef="v_Retail_S000004462">Annual Total Returns - Vanguard Federal Money Market Fund Investor Shares</rr:BarChartHeading>
<rr:BarChartFootnotesTextBlock
contextRef="v_Retail_S000004462">&lt;p>1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.01%&lt;/p></rr:BarChartFootnotesTextBlock>
<rr:YearToDateReturnLabel
contextRef="v_Retail_S000004462">The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012</rr:YearToDateReturnLabel>
<rr:BarChartClosingTextBlock
contextRef="v_Retail_S000004462">&lt;p>During the periods shown in the bar chart, the highest return for a calendar quarter was 1.28% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.00% (quarter ended September 30, 2011 ).&lt;/p></rr:BarChartClosingTextBlock>
<rr:HighestQuarterlyReturnLabel
contextRef="v_Retail_S000004462">(quarter ended December 31, 2006 )</rr:HighestQuarterlyReturnLabel>
<rr:LowestQuarterlyReturnLabel
contextRef="v_Retail_S000004462">(quarter ended September 30, 2011 )</rr:LowestQuarterlyReturnLabel>
<rr:BarChartTableTextBlock
contextRef="v_Participant_S000004462">&lt;div style="display:none">~ http://xbrl.sec.gov/rr/role/BarChartData column rr_ProspectusShareClassAxis compact vanguard_C000012238Member ~ &lt;/div> </rr:BarChartTableTextBlock>
<rr:BarChartHeading
contextRef="v_Participant_S000004462">Annual Total Returns - Vanguard Federal Money Market Fund Investor Shares</rr:BarChartHeading>
<rr:BarChartFootnotesTextBlock
contextRef="v_Participant_S000004462">&lt;p>1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.01%&lt;/p></rr:BarChartFootnotesTextBlock>
<rr:YearToDateReturnLabel
contextRef="v_Participant_S000004462">The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012</rr:YearToDateReturnLabel>
<rr:BarChartClosingTextBlock
contextRef="v_Participant_S000004462">&lt;p>During the periods shown in the bar chart, the highest return for a calendar quarter was 1.28% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.00% (quarter ended September 30, 2011 ).&lt;/p></rr:BarChartClosingTextBlock>
<rr:HighestQuarterlyReturnLabel
contextRef="v_Participant_S000004462">(quarter ended December 31, 2006 )</rr:HighestQuarterlyReturnLabel>
<rr:LowestQuarterlyReturnLabel
contextRef="v_Participant_S000004462">(quarter ended September 30, 2011 )</rr:LowestQuarterlyReturnLabel>
<rr:BarChartYearToDateReturnDate
contextRef="v_S000004462_C000012238">2012-09-30</rr:BarChartYearToDateReturnDate>
<rr:BarChartYearToDateReturn
contextRef="v_S000004462_C000012238"
decimals="4"
unitRef="pure">0.0001</rr:BarChartYearToDateReturn>
<rr:AverageAnnualReturnInceptionDate
contextRef="v_S000004462_C000012238">1981-07-13</rr:AverageAnnualReturnInceptionDate>
<rr:AverageAnnualReturnYear01
unitRef="pure"
contextRef="v_S000004462_C000012238"
decimals="4">0.0001</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
decimals="4"
contextRef="v_S000004462_C000012238"
unitRef="pure">0.0159</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
decimals="4"
contextRef="v_S000004462_C000012238"
unitRef="pure">0.0193</rr:AverageAnnualReturnYear10>
<vanguard:ComparativeBenchmark
contextRef="v_S000004462_C000012238">Comparative Benchmarks</vanguard:ComparativeBenchmark>
<rr:MaximumCumulativeSalesChargeOverOther
decimals="4"
unitRef ="pure"
contextRef="v_S000004462_C000012238">0.0000</rr:MaximumCumulativeSalesChargeOverOther>
<rr:RedemptionFeeOverRedemption
decimals="4"
unitRef ="pure"
contextRef="v_S000004462_C000012238">0.0000</rr:RedemptionFeeOverRedemption>
<rr:MaximumAccountFee
contextRef="v_S000004462_C000012238"
unitRef ="usd"
decimals="4">20.</rr:MaximumAccountFee>
<rr:MaximumCumulativeSalesChargeOverOfferingPrice
decimals="4"
unitRef ="pure"
contextRef="v_S000004462_C000012238">0</rr:MaximumCumulativeSalesChargeOverOfferingPrice>
<rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther
contextRef="v_S000004462_C000012238"
unitRef ="pure"
decimals="4">0</rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther>
<rr:ExpenseExampleNoRedemptionYear01
contextRef="v_S000004462_C000012238"
unitRef ="usd"
decimals="4">16.</rr:ExpenseExampleNoRedemptionYear01>
<rr:ExpenseExampleNoRedemptionYear03
decimals="4"
unitRef ="usd"
contextRef="v_S000004462_C000012238">52.</rr:ExpenseExampleNoRedemptionYear03>
<rr:ExpenseExampleNoRedemptionYear05
decimals="4"
unitRef ="usd"
contextRef="v_S000004462_C000012238">90.</rr:ExpenseExampleNoRedemptionYear05>
<rr:ExpenseExampleNoRedemptionYear10
contextRef="v_S000004462_C000012238"
unitRef ="usd"
decimals="4">205.</rr:ExpenseExampleNoRedemptionYear10>
<rr:ManagementFeesOverAssets
decimals="4"
unitRef ="pure"
contextRef="v_S000004462_C000012238">0.0014</rr:ManagementFeesOverAssets>
<rr:DistributionAndService12b1FeesOverAssets
contextRef="v_S000004462_C000012238"
unitRef ="pure"
decimals="4">0</rr:DistributionAndService12b1FeesOverAssets>
<rr:OtherExpensesOverAssets
contextRef="v_S000004462_C000012238"
unitRef ="pure"
decimals="4">0.0002</rr:OtherExpensesOverAssets>
<link:footnoteLink
xlink:role="http://www.xbrl.org/2003/role/link"
xlink:type="extended">
<link:loc
xlink:label="NetExpensesOverAssets_64"
xlink:href="#id_footnote_elem_60"
xlink:type="locator"/>
<link:footnote
xml:lang="en-US"
xlink:type="resource"
xlink:role="http://www.xbrl.org/2003/role/footnote"
xlink:label="footnote_64">Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund's daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund's Board may terminate the temporary expense limitation at any time.</link:footnote>
<link:footnoteArc
xlink:to="footnote_64"
order="1.0"
xlink:type="arc"
xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
xlink:from="NetExpensesOverAssets_64"/></link:footnoteLink>
<rr:NetExpensesOverAssets
contextRef="v_S000004462_C000012238"
unitRef ="pure"
decimals="4"
id="id_footnote_elem_60">0.0016</rr:NetExpensesOverAssets>
<rr:AnnualReturn2011
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0014</rr:AnnualReturn2011>
<rr:AnnualReturn2010
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0020</rr:AnnualReturn2010>
<rr:AnnualReturn2009
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0068</rr:AnnualReturn2009>
<rr:AnnualReturn2008
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0293</rr:AnnualReturn2008>
<rr:AnnualReturn2007
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0530</rr:AnnualReturn2007>
<rr:AnnualReturn2006
contextRef="v_S000004463_C000012240"
unitRef="pure"
decimals="4">0.0508</rr:AnnualReturn2006>
<rr:AnnualReturn2005
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0321</rr:AnnualReturn2005>
<rr:AnnualReturn2004
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0133</rr:AnnualReturn2004>
<rr:AnnualReturn2003
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0111</rr:AnnualReturn2003>
<rr:AnnualReturn2002
unitRef="pure"
decimals="4"
contextRef="v_S000004463_C000012240">0.0188</rr:AnnualReturn2002>
<rr:AnnualReturnInceptionDate
contextRef="v_S000004463_C000012240">1989-10-03</rr:AnnualReturnInceptionDate>
<rr:BarChartHighestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004463_C000012240"
decimals="4">0.0134</rr:BarChartHighestQuarterlyReturn>
<rr:BarChartLowestQuarterlyReturn
unitRef="pure"
contextRef="v_S000004463_C000012240"
decimals="4">0.0003</rr:BarChartLowestQuarterlyReturn>
<rr:BarChartHighestQuarterlyReturnDate
contextRef="v_S000004463_C000012240">2006-12-31</rr:BarChartHighestQuarterlyReturnDate>
<rr:BarChartLowestQuarterlyReturnDate
contextRef="v_S000004463_C000012240">2011-09-30</rr:BarChartLowestQuarterlyReturnDate>
<rr:BarChartTableTextBlock
contextRef="v_Institutional_S000004463">&lt;div style="display:none">~ http://xbrl.sec.gov/rr/role/BarChartData column rr_ProspectusShareClassAxis compact vanguard_C000012240Member ~ &lt;/div> </rr:BarChartTableTextBlock>
<rr:BarChartHeading
contextRef="v_Institutional_S000004463">Annual Total Returns - Vanguard Prime Money Market Fund Institutional Shares</rr:BarChartHeading>
<rr:BarChartFootnotesTextBlock
contextRef="v_Institutional_S000004463">&lt;p>1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.08%&lt;/p></rr:BarChartFootnotesTextBlock>
<rr:YearToDateReturnLabel
contextRef="v_Institutional_S000004463">The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012</rr:YearToDateReturnLabel>
<rr:BarChartClosingTextBlock
contextRef="v_Institutional_S000004463">&lt;p>During the periods shown in the bar chart, the highest return for a calendar quarter was 1.34% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.03% (quarter ended September 30, 2011 ).&lt;/p></rr:BarChartClosingTextBlock>
<rr:HighestQuarterlyReturnLabel
contextRef="v_Institutional_S000004463">(quarter ended December 31, 2006 )</rr:HighestQuarterlyReturnLabel>
<rr:LowestQuarterlyReturnLabel
contextRef="v_Institutional_S000004463">(quarter ended September 30, 2011 )</rr:LowestQuarterlyReturnLabel>
<rr:BarChartYearToDateReturnDate
contextRef="v_S000004463_C000012240">2012-09-30</rr:BarChartYearToDateReturnDate>
<rr:BarChartYearToDateReturn
contextRef="v_S000004463_C000012240"
decimals="4"
unitRef="pure">0.0008</rr:BarChartYearToDateReturn>
<rr:AverageAnnualReturnInceptionDate
contextRef="v_S000004463_C000012240">1989-10-03</rr:AverageAnnualReturnInceptionDate>
<rr:AverageAnnualReturnYear01
unitRef="pure"
contextRef="v_S000004463_C000012240"
decimals="4">0.0014</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
decimals="4"
contextRef="v_S000004463_C000012240"
unitRef="pure">0.0183</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
decimals="4"
contextRef="v_S000004463_C000012240"
unitRef="pure">0.0217</rr:AverageAnnualReturnYear10>
<vanguard:ComparativeBenchmark
contextRef="v_S000004463_C000012240">Comparative Benchmarks</vanguard:ComparativeBenchmark>
<rr:MaximumCumulativeSalesChargeOverOther
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012240">0.0000</rr:MaximumCumulativeSalesChargeOverOther>
<rr:RedemptionFeeOverRedemption
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012240">0.0000</rr:RedemptionFeeOverRedemption>
<rr:MaximumAccountFee
contextRef="v_S000004463_C000012240"
unitRef ="usd"
decimals="4">20.</rr:MaximumAccountFee>
<rr:MaximumCumulativeSalesChargeOverOfferingPrice
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012240">0</rr:MaximumCumulativeSalesChargeOverOfferingPrice>
<rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther
contextRef="v_S000004463_C000012240"
unitRef ="pure"
decimals="4">0</rr:MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther>
<rr:ExpenseExampleNoRedemptionYear01
contextRef="v_S000004463_C000012240"
unitRef ="usd"
decimals="4">9.</rr:ExpenseExampleNoRedemptionYear01>
<rr:ExpenseExampleNoRedemptionYear03
decimals="4"
unitRef ="usd"
contextRef="v_S000004463_C000012240">29.</rr:ExpenseExampleNoRedemptionYear03>
<rr:ExpenseExampleNoRedemptionYear05
decimals="4"
unitRef ="usd"
contextRef="v_S000004463_C000012240">51.</rr:ExpenseExampleNoRedemptionYear05>
<rr:ExpenseExampleNoRedemptionYear10
contextRef="v_S000004463_C000012240"
unitRef ="usd"
decimals="4">115.</rr:ExpenseExampleNoRedemptionYear10>
<rr:ManagementFeesOverAssets
decimals="4"
unitRef ="pure"
contextRef="v_S000004463_C000012240">0.0006</rr:ManagementFeesOverAssets>
<rr:DistributionAndService12b1FeesOverAssets
contextRef="v_S000004463_C000012240"
unitRef ="pure"
decimals="4">0</rr:DistributionAndService12b1FeesOverAssets>
<rr:OtherExpensesOverAssets
contextRef="v_S000004463_C000012240"
unitRef ="pure"
decimals="4">0.0003</rr:OtherExpensesOverAssets>
<link:footnoteLink
xlink:role="http://www.xbrl.org/2003/role/link"
xlink:type="extended">
<link:loc
xlink:label="NetExpensesOverAssets_852"
xlink:href="#id_footnote_elem_90"
xlink:type="locator"/>
<link:footnote
xml:lang="en-US"
xlink:type="resource"
xlink:role="http://www.xbrl.org/2003/role/footnote"
xlink:label="footnote_852">Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund's daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund's Board may terminate the temporary expense limitation at any time.</link:footnote>
<link:footnoteArc
xlink:to="footnote_852"
order="1.0"
xlink:type="arc"
xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
xlink:from="NetExpensesOverAssets_852"/></link:footnoteLink>
<rr:NetExpensesOverAssets
contextRef="v_S000004463_C000012240"
unitRef ="pure"
decimals="4"
id="id_footnote_elem_90">0.0009</rr:NetExpensesOverAssets>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004462_C000012238_Citigroup3MonthUSTreasuryBillIndexMember">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004462_C000012238_Citigroup3MonthUSTreasuryBillIndexMember">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004462_C000012238_Citigroup3MonthUSTreasuryBillIndexMember">0.0008</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004462_C000012238_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0136</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004462_C000012238_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0185</rr:AverageAnnualReturnYear10>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004462_C000012238_USGovernmentMoneyMarketFundsAverageMember"> </rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004462_C000012238_USGovernmentMoneyMarketFundsAverageMember"> </rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004462_C000012238_USGovernmentMoneyMarketFundsAverageMember">0.0000</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004462_C000012238_USGovernmentMoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0123</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004462_C000012238_USGovernmentMoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0150</rr:AverageAnnualReturnYear10>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004463_C000012239_Citigroup3MonthUSTreasuryBillIndexMember">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004463_C000012239_Citigroup3MonthUSTreasuryBillIndexMember">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004463_C000012239_Citigroup3MonthUSTreasuryBillIndexMember">0.0008</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004463_C000012239_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0136</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004463_C000012239_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0185</rr:AverageAnnualReturnYear10>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Institutional_S000004463_C000012240_Citigroup3MonthUSTreasuryBillIndexMember">(reflects no deduction for fees or expenses)</rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004463_C000012240_Citigroup3MonthUSTreasuryBillIndexMember">0.0008</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004463_C000012240_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0136</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004463_C000012240_Citigroup3MonthUSTreasuryBillIndexMember"
unitRef="pure"
decimals="4">0.0185</rr:AverageAnnualReturnYear10>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Retail_S000004463_C000012239_MoneyMarketFundsAverageMember"> </rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Participant_S000004463_C000012239_MoneyMarketFundsAverageMember"> </rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004463_C000012239_MoneyMarketFundsAverageMember">0.0000</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004463_C000012239_MoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0133</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004463_C000012239_MoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0152</rr:AverageAnnualReturnYear10>
<rr:IndexNoDeductionForFeesExpensesTaxes
contextRef="v_Institutional_S000004463_C000012240_InstitutionalMoneyMarketFundsAverageMember"> </rr:IndexNoDeductionForFeesExpensesTaxes>
<rr:AverageAnnualReturnYear01
decimals="4"
unitRef="pure"
contextRef="v_S000004463_C000012240_InstitutionalMoneyMarketFundsAverageMember">0.0002</rr:AverageAnnualReturnYear01>
<rr:AverageAnnualReturnYear05
contextRef="v_S000004463_C000012240_InstitutionalMoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0157</rr:AverageAnnualReturnYear05>
<rr:AverageAnnualReturnYear10
contextRef="v_S000004463_C000012240_InstitutionalMoneyMarketFundsAverageMember"
unitRef="pure"
decimals="4">0.0186</rr:AverageAnnualReturnYear10>
<xbrli:context
id="v">
<xbrli:entity>
<xbrli:identifier
scheme="http://www.sec.gov/CIK">0000106830</xbrli:identifier></xbrli:entity>
<xbrli:period>
<xbrli:startDate>2011-09-01</xbrli:startDate>
<xbrli:endDate>2012-08-31</xbrli:endDate></xbrli:period></xbrli:context>
<xbrli:context
id="v_Institutional_S000004463">
<xbrli:entity>
<xbrli:identifier
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<xbrldi:explicitMember
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