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:

Strategy:

rr_StrategyHeading

Primary Investment Policies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund invests solely in high-quality, short-term money market securities whose interest and principal payments are backed by the full faith and credit of the U.S. government. At least 80% of the Fund's assets will be invested in U.S. Treasury securities; the remainder of the assets may be invested in securities issued by U.S. governmental agencies. The Fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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:

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.

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.

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.

Money Market Fund

rr_RiskMoneyMarketFund

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:

Not Insured Depository Institution

rr_RiskNotInsuredDepositoryInstitution

Bar Chart and Performance Table

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Past Performance Does Not Indiciate Future Returns

rr_PerformancePastDoesNotIndicateFuture

Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard Admiral Treasury Money Market Fund Investor Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

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 comparative benchmarks, which have investment characteristics similar to those of the Fund. Returns for the iMoneyNet Money Fund Report's 100% Treasury Funds Average are derived from data provided by iMoneyNet, Inc.; returns for the U.S. Treasury 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 online at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 1.25% (quarter ended December 31, 2006 ), and the lowest return for a quarter was 0.00% (quarter ended March 31, 2010 ).

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2006 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended March 31, 2010 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Vanguard Admiral Treasury Money Market Fund | Retail

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to provide current income while maintaining liquidity and a stable share price of $1.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

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

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Policies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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:

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.

Money Market Fund

rr_RiskMoneyMarketFund

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:

Not Insured Depository Institution

rr_RiskNotInsuredDepositoryInstitution

Bar Chart and Performance Table

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance Additional Market Index

rr_PerformanceAdditionalMarketIndex

, which have investment characteristics similar to those of the Fund.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Past Performance Does Not Indiciate Future Returns

rr_PerformancePastDoesNotIndicateFuture

Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future.

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard Admiral Treasury Money Market Fund Investor Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 0.01%

Bar Chart Closing

rr_BarChartClosingTextBlock

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2006 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended March 31, 2010 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Vanguard Admiral Treasury Money Market Fund | Vanguard Admiral Treasury Money Market Fund - Investor Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.08%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.10%

^[1]

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

128

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Dec. 14, 1992

2002

rr_AnnualReturn2002

1.69%

2003

rr_AnnualReturn2003

0.99%

2004

rr_AnnualReturn2004

1.18%

2005

rr_AnnualReturn2005

2.94%

2006

rr_AnnualReturn2006

4.71%

2007

rr_AnnualReturn2007

4.76%

2008

rr_AnnualReturn2008

2.10%

2009

rr_AnnualReturn2009

0.25%

2010

rr_AnnualReturn2010

0.01%

2011

rr_AnnualReturn2011

0.02%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2006

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

1.25%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2010

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

0.00%

One Year

rr_AverageAnnualReturnYear01

0.02%

Five Years

rr_AverageAnnualReturnYear05

1.41%

Ten Years

rr_AverageAnnualReturnYear10

1.85%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 14, 1992

Vanguard S&P 500 Growth Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of large-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold ETF Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or 'turns over' its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, reduce the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 22%.

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

22.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P 500 Growth ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P 500 Growth ETF. This example assumes that S&P 500 Growth ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P 500(r) Growth Index, which represents the growth companies of the S&P 500 Index. The Index measures the performance of large-capitalization growth stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

An investment in the Fund could lose money over short or even long periods. You should expect the Fund's share price and total return to fluctuate within a wide range, like the fluctuations of the overall stock market. The Fund is subject to the following risks, which could affect the Fund's performance:

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's target index may, at times, become focused in stocks of a particular sector, category, or group of companies, which could cause the Fund to underperform the overall stock market.

Investment style risk, which is the chance that returns from large-capitalization growth stocks will trail returns from the overall stock market. Large-cap growth stocks tend to go through cycles of doing better-or worse-than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P 500 Growth ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P 500 Growth ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P 500 Growth ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P 500 Growth ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P 500 Growth ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P 500 Growth ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P 500 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of those of the Fund's target 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 16.88%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 10.78% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -11.65% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

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.

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Also, figures captioned Return After Taxes on Distributions and Sale of Fund Shares will 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 Closing

rr_PerformanceTableClosingTextBlock

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 will 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 S&P 500 Growth Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of large-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

22.00%

EXAMPLE

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'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:

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P 500 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P 500 Growth Index Fund. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 16.88%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

The bar chart shows how the performance of the Fund's ETF Shares has varied from one calendar year to another over the periods shown. The Fund's Institutional Shares were not available during the time periods shown.

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P 500 Growth Index Fund | Vanguard S&P 500 Growth Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.02%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.06%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.08%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

103

Vanguard S&P 500 Growth Index Fund | Vanguard S&P 500 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.09%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.06%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.15%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

192

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

4.44%

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

16.88%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

10.78%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(11.65%)

One Year

rr_AverageAnnualReturnYear01

4.44%

Since Inception

rr_AverageAnnualReturnSinceInception

16.60%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P 500 Value Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of large-capitalization value stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold ETF Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

20.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P 500 Value ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P 500 Value ETF. This example assumes that S&P 500 Value ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P 500(r) Value Index, which represents the value companies of the S&P 500 Index. The Index measures the performance of large-capitalization value stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from large-capitalization value stocks will trail returns from the overall stock market. Large-cap value stocks tend to go through cycles of doing better-or worse-than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P 500 Value ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P 500 Value ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P 500 Value ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P 500 Value ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P 500 Value ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P 500 Value ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P 500 Value Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 15.69%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 12.91% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -16.37% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P 500 Value Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of large-capitalization value stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

20.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from large-capitalization value stocks will trail returns from the overall stock market. Large-cap stocks tend to go through cycles of doing better-or worse-than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P 500 Value Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Vanguard 500 Value Index. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows how the performance of the Fund's ETF Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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 online at vanguard.com or by calling 800-662-7447.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 15.69%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P 500 Value Index Fund | Vanguard S&P 500 Value Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.01%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.08%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

103

Vanguard S&P 500 Value Index Fund | Vanguard S&P 500 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.06%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.09%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.15%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

192

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

(0.70%)

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

15.69%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.91%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(16.37%)

One Year

rr_AverageAnnualReturnYear01

(0.70%)

Since Inception

rr_AverageAnnualReturnSinceInception

10.30%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Mid-Cap 400 Growth Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold ETF Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

26.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Mid-Cap 400 Growth ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Mid-Cap 400 Growth ETF. This example assumes that S&P Mid-Cap 400 Growth ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P MidCap 400(r) Growth Index, which represents the growth companies of the S&P MidCap 400 Index. The Index measures the performance of mid-capitalization growth stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from mid-capitalization growth stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Mid-Cap 400 Growth ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Mid-Cap 400 Growth ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Mid-Cap 400 Growth ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Mid-Cap 400 Growth ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Mid-Cap 400 Growth ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Mid-Cap 400 Growth ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 14.01%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 10.19% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -18.88% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Growth Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

26.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Mid-Cap 400 Growth Index Fund. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 14.01%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Growth Index Fund | Vanguard S&P Mid-Cap 400 Growth Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.02%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.06%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.08%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

103

Vanguard S&P Mid-Cap 400 Growth Index Fund | Vanguard S&P Mid-Cap 400 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.15%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.05%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.20%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

113

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

255

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

(1.15%)

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

14.01%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

10.19%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(18.88%)

One Year

rr_AverageAnnualReturnYear01

(1.15%)

Since Inception

rr_AverageAnnualReturnSinceInception

15.70%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Mid-Cap 400 Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold ETF Shares of the Fund. 'Acquired Fund Fees and Expenses' are expenses incurred indirectly by the Fund through its ownership of shares in other investment companies, such as business development companies. Business development company expenses are similar to the expenses paid by any operating company held by the Fund. They are not direct costs paid by Fund shareholders and are not used to calculate the Fund's net asset value. They have no impact on the costs associated with fund operations.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

13.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Mid-Cap 400 ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Mid-Cap 400 ETF. This example assumes that S&P Mid-Cap 400 ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P MidCap 400(r) Index. The Index measures the performance of mid-capitalization stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from large-capitalization stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Mid-Cap 400 ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Mid-Cap 400 ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Mid-Cap 400 ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Mid-Cap 400 ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Mid-Cap 400 ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Mid-Cap 400 ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.67%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 12.94% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -19.93% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund. 'Acquired Fund Fees and Expenses' are expenses incurred indirectly by the Fund through its ownership of shares in other investment companies, such as business development companies. Business development company expenses are similar to the expenses paid by any operating company held by the Fund. They are not direct costs paid by Fund shareholders and are not used to calculate the Fund's net asset value. They have no impact on the costs associated with fund operations.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

13.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from mid-cap stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Mid-Cap 400 Index. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.67%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Index Fund | Vanguard S&P Mid-Cap 400 Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.02%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.06%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.09%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

115

Vanguard S&P Mid-Cap 400 Index Fund | Vanguard S&P Mid-Cap 400 Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.08%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.16%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

205

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

(1.89%)

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

13.67%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.94%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(19.93%)

One Year

rr_AverageAnnualReturnYear01

(1.89%)

Since Inception

rr_AverageAnnualReturnSinceInception

13.67%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Mid-Cap 400 Value Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization value stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

31.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Mid-Cap 400 Value ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Mid-Cap 400 Value ETF. This example assumes that S&P Mid-Cap 400 Value ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P MidCap 400(r) Value Index, which represents the value companies of the S&P MidCap 400 Index. The Index measures the performance of mid-capitalization value stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from mid-capitalization value stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Mid-Cap 400 Value ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Mid-Cap 400 Value ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Mid-Cap 400 Value ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Mid-Cap 400 Value ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Mid-Cap 400 Value ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Mid-Cap 400 Value ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Value Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.26%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 15.79% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -20.98% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Value Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization value stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

31.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Mid-Cap 400 Value Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Mid-Cap 400 Value Index Fund. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.26%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Mid-Cap 400 Value Index Fund | Vanguard S&P Mid-Cap 400 Value Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.01%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.10%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

128

Vanguard S&P Mid-Cap 400 Value Index Fund | Vanguard S&P Mid-Cap 400 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.12%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.08%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.22%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

124

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

280

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

(2.65%)

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

13.26%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.79%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(20.98%)

One Year

rr_AverageAnnualReturnYear01

(2.65%)

Since Inception

rr_AverageAnnualReturnSinceInception

11.60%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Small-Cap 600 Growth Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold ETF Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

45.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Small-Cap 600 Growth ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Small-Cap 600 Growth ETF. This example assumes that S&P Small-Cap 600 Growth ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P SmallCap 600(r) Growth Index, which represents the growth companies of the S&P SmallCap 600 Index. The Index measures the performance of small-capitalization growth stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from small-capitalization growth stocks will trail returns from the overall stock market. Historically, small-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Small-Cap 600 Growth ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Small-Cap 600 Growth ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Small-Cap 600 Growth ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Small-Cap 600 Growth ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Small-Cap 600 Growth ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Small-Cap 600 Growth ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Small-Cap 600 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 12.99%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 15.80% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -19.68% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Small-Cap 600 Growth Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization growth stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

45.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Small-Cap 600 Growth Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Small-Cap 600 Growth Index Fund. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 12.99%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Small-Cap 600 Growth Index Fund | Vanguard S&P Small-Cap 600 Growth Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.01%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.08%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

103

Vanguard S&P Small-Cap 600 Growth Index Fund | Vanguard S&P Small-Cap 600 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.03%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.17%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.20%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

113

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

255

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

3.41%

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

12.99%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.80%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(19.68%)

One Year

rr_AverageAnnualReturnYear01

3.41%

Since Inception

rr_AverageAnnualReturnSinceInception

21.24%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Small-Cap 600 Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

12.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Small-Cap 600 ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Small-Cap 600 ETF. This example assumes that S&P Small-Cap 600 ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P SmallCap 600(r) Index. The Index measures the performance of small-capitalization stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from small-capitalization stocks will trail returns from the overall stock market. Historically, small-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Small-Cap 600 ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Small-Cap 600 ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Small-Cap 600 ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Small-Cap 600 ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Small-Cap 600 ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Small-Cap 600 ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

rr_PerformanceOneYearOrLess

The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Small-Cap 600 Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.68%

Bar Chart Closing

rr_BarChartClosingTextBlock

During the periods shown in the bar chart, the highest return for a calendar quarter was 17.07% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -19.90% (quarter ended September 30, 2011 ).

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Small-Cap 600 Index Fund | Institutional

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

12.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

rr_BarChartAndPerformanceTableHeading

Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

rr_BarChartHeading

Annual Total Returns - Vanguard S&P Small-Cap 600 Index Fund ETF Shares

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Small-Cap 600 Index. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

rr_BarChartFootnotesTextBlock

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 13.68%

Bar Chart Closing

rr_BarChartClosingTextBlock

Bar Chart Returns for Class Not Offered in Prospectus

rr_BarChartReturnsForClassNotOfferedInProspectus

Year to Date Return Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Explains why after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Performance Table Closing

rr_PerformanceTableClosingTextBlock

Vanguard S&P Small-Cap 600 Index Fund | Vanguard S&P Small-Cap 600 Index Fund - Institutional Shares

Risk/Return:

rr_RiskReturnAbstract

Sales charge (load) imposed on purchases

rr_MaximumCumulativeSalesChargeOverOfferingPrice

none

Purchase Fee

rr_MaximumCumulativeSalesChargeOverOther

none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFeeOverRedemption

none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.03%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.05%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.10%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

128

Vanguard S&P Small-Cap 600 Index Fund | Vanguard S&P Small-Cap 600 Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.09%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.06%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.17%

1 YEAR

rr_ExpenseExampleNoRedemptionYear01

3 YEAR

rr_ExpenseExampleNoRedemptionYear03

5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

217

Annual Return Inception Date

rr_AnnualReturnInceptionDate

Sep. 07, 2010

2011

rr_AnnualReturn2011

0.77%

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

13.68%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.07%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

rr_BarChartLowestQuarterlyReturn

(19.90%)

One Year

rr_AverageAnnualReturnYear01

0.77%

Since Inception

rr_AverageAnnualReturnSinceInception

18.33%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

Vanguard S&P Small-Cap 600 Value Index Fund | ETF

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

rr_RiskReturnHeading

Risk/Return

Investment objective:

rr_ObjectiveHeading

Investment Objective

Investment objective

rr_ObjectivePrimaryTextBlock

The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization value stocks in the United States.

Expenses Heading

rr_ExpenseHeading

Fees and Expenses

Fees and Expenses of the Fund

rr_ExpenseNarrativeTextBlock

Shareholder Fees Caption

rr_ShareholderFeesCaption

Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

PortfolioTurnover, Rate

rr_PortfolioTurnoverRate

29.00%

EXAMPLE

rr_ExpenseExampleHeading

Example

Expense Example, Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in S&P Small-Cap 600 Value ETF with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in S&P Small-Cap 600 Value ETF. This example assumes that S&P Small-Cap 600 Value ETF 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:

Expense Example Closing

rr_ExpenseExampleClosingTextBlock

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Strategy:

rr_StrategyHeading

Primary Investment Strategies

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of the S&P SmallCap 600(r) Value Index, which represents the value companies of the S&P SmallCap 600 Index. The Index measures the performance of small-capitalization value stocks. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Risk:

rr_RiskHeading

Primary Risks

Risk Narrative

rr_RiskNarrativeTextBlock

Investment style risk, which is the chance that returns from small-capitalization value stocks will trail returns from the overall stock market. Historically, small-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

Because ETF Shares are traded on an exchange, they are subject to additional risks:

S&P Small-Cap 600 Value ETF Shares are listed for trading on NYSE Arca and are bought and sold on the secondary market at market prices. Although it is expected that the market price of an S&P Small-Cap 600 Value ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy S&P Small-Cap 600 Value ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

Although S&P Small-Cap 600 Value ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.

Trading of S&P Small-Cap 600 Value ETF Shares on NYSE Arca may be halted by the activation of individual or marketwide 'circuit breakers' (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of S&P Small-Cap 600 Value ETF Shares may also be halted if (1) the shares are delisted from NYSE Arca without first being listed on another exchange or (2) NYSE Arca officials determine that such action is appropriate in the interest of a fair and orderly market or to protect investors.

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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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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

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Annual Total Returns

Performance Information Illustrates Variability of Returns

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The following bar chart and table are intended to help you understand the risks of investing in the Fund.

Performance One Year or Less

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The bar chart shows the performance of the Fund's ETF Shares in their first full calendar year.

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

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Annual Total Returns - Vanguard S&P Small-Cap 600 Value Index Fund ETF Shares

Bar Chart Narrative

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Bar Chart Footnotes

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1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 14.41%

Bar Chart Closing

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During the periods shown in the bar chart, the highest return for a calendar quarter was 18.53% (quarter ended December 31, 2011 ), and the lowest return for a quarter was -20.05% (quarter ended September 30, 2011 ).

Year to Date Return Label

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The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

rr_HighestQuarterlyReturnLabel

(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

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Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

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(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

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Performance Table Not Relevant to Tax Deferred

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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 Explains why after Tax Higher

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Performance Table Closing

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Vanguard S&P Small-Cap 600 Value Index Fund | Institutional

Risk/Return:

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Prospectus Date

rr_ProspectusDate

Dec. 28, 2012

Risk/Return

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Risk/Return

Investment objective:

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Investment Objective

Investment objective

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The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization value stocks in the United States.

Expenses Heading

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Fees and Expenses

Fees and Expenses of the Fund

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Shareholder Fees Caption

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Shareholder Fees (Fees paid directly from your investment)

Operating Expenses Caption

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Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover Heading

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Portfolio Turnover

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PortfolioTurnover, Rate

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29.00%

EXAMPLE

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Example

Expense Example, Narrative [Text Block]

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Strategy:

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Primary Investment Strategies

StrategyNarrative

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Risk:

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Primary Risks

Risk Narrative

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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.

May Lose Money

rr_RiskLoseMoney

An investment in the Fund could lose money over short or even long periods.

Not Insured Depository Institution

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

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Annual Total Returns

Performance Availability Phone

rr_PerformanceAvailabilityPhone

800-662-7447

Performance Availability Website Address

rr_PerformanceAvailabilityWebSiteAddress

vanguard.com/performance

Bar Chart

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Annual Total Returns - Vanguard S&P Small-Cap 600 Value Index Fund ETF Shares

Bar Chart Narrative

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The following bar chart and table are intended to help you understand the risks of investing in the Fund. Because there is no calendar-year performance information for the Fund's Institutional Shares, the information presented in the bar chart and table reflects the performance of the ETF Shares of Vanguard S&P Small-Cap 600 Value Index Fund. (ETF Shares are offered through a separate prospectus.) Performance based on net asset value for the Institutional Shares would be substantially similar because both share classes constitute an investment in the same portfolio of securities; their returns generally should differ only to the extent that the expenses of the two classes differ. The bar chart shows the performance of the Fund's ETF Shares (based on NAV) in their first full calendar year. The table shows how the average annual total returns of the ETF Shares compare with those of the Fund's target index. 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.

Bar Chart Footnotes

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1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012 was 14.41%

Bar Chart Closing

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Bar Chart Returns for Class Not Offered in Prospectus

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Year to Date Return Label

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The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2012

Highest Quarterly Return Label

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(quarter ended December 31, 2011 )

Lowest Quarterly Return Label

rr_LowestQuarterlyReturnLabel

(quarter ended September 30, 2011 )

Bar Chart and Performance Table:

rr_PerformanceTableHeading

Average Annual Total Returns for Periods Ended December 31, 2011

Index No Deduction for Fees, Expenses, Taxes

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(reflects no deduction for fees, expenses, or taxes)

Performance Table Uses Highest Federal Rate

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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 Explains why after Tax Higher

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Performance Table Closing

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Vanguard S&P Small-Cap 600 Value Index Fund | Vanguard S&P Small-Cap 600 Value Index Fund - Institutional Shares

Risk/Return:

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Sales charge (load) imposed on purchases

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none

Purchase Fee

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none

Sales charge (load) imposed on reinvested dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

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none

Account Service Fee (for fund account balances below $10,000)

rr_MaximumAccountFee

Management Expenses

rr_ManagementFeesOverAssets

0.01%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.04%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.12%

1 YEAR

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3 YEAR

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5 YEAR

rr_ExpenseExampleNoRedemptionYear05

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

154

Vanguard S&P Small-Cap 600 Value Index Fund | Vanguard S&P Small-Cap 600 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

Management Expenses

rr_ManagementFeesOverAssets

0.02%

12b-1 Distribution Fee

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.18%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.04%

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.24%

1 YEAR

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3 YEAR

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5 YEAR

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135

10 YEAR

rr_ExpenseExampleNoRedemptionYear10

306

Annual Return Inception Date

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Sep. 07, 2010

2011

rr_AnnualReturn2011

(1.54%)

Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Year to Date Return

rr_BarChartYearToDateReturn

14.41%

Bar Chart Highest Quarterly Return Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Bar Chart Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.53%

Bar Chart Lowest Quarter Return Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Bar Chart Lowest Quarter Return

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(20.05%)

One Year

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(1.54%)

Since Inception

rr_AverageAnnualReturnSinceInception

15.71%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 07, 2010

S&P 500 Value Index | Vanguard S&P 500 Value Index Fund | Vanguard S&P 500 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

(0.48%)

Since Inception

rr_AverageAnnualReturnSinceInception

10.52%

S&P 500 Growth Index | Vanguard S&P 500 Growth Index Fund | Vanguard S&P 500 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.65%

Since Inception

rr_AverageAnnualReturnSinceInception

16.83%

U.S. Treasury Money Market Funds Average | Vanguard Admiral Treasury Money Market Fund | Vanguard Admiral Treasury Money Market Fund - Investor Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

none

Five Years

rr_AverageAnnualReturnYear05

1.03%

Ten Years

rr_AverageAnnualReturnYear10

1.36%

S&P MidCap 400 Index | Vanguard S&P Mid-Cap 400 Index Fund | Vanguard S&P Mid-Cap 400 Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

(1.73%)

Since Inception

rr_AverageAnnualReturnSinceInception

13.86%

S&P MidCap 400 Growth Index | Vanguard S&P Mid-Cap 400 Growth Index Fund | Vanguard S&P Mid-Cap 400 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

(0.94%)

Since Inception

rr_AverageAnnualReturnSinceInception

15.91%

S&P MidCap 400 Value Index | Vanguard S&P Mid-Cap 400 Value Index Fund | Vanguard S&P Mid-Cap 400 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

(2.43%)

Since Inception

rr_AverageAnnualReturnSinceInception

11.84%

S&P SmallCap 600 Index | Vanguard S&P Small-Cap 600 Index Fund | Vanguard S&P Small-Cap 600 Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

1.02%

Since Inception

rr_AverageAnnualReturnSinceInception

18.59%

S&P SmallCap 600 Growth Index | Vanguard S&P Small-Cap 600 Growth Index Fund | Vanguard S&P Small-Cap 600 Growth Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.62%

Since Inception

rr_AverageAnnualReturnSinceInception

21.49%

S&P SmallCap 600 Value Index | Vanguard S&P Small-Cap 600 Value Index Fund | Vanguard S&P Small-Cap 600 Value Index Fund - ETF Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

(1.38%)

Since Inception

rr_AverageAnnualReturnSinceInception

15.90%

IMoneyNet Money Fund Report's 100 Percent Treasury Funds Average | Vanguard Admiral Treasury Money Market Fund | Vanguard Admiral Treasury Money Market Fund - Investor Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

none

Five Years

rr_AverageAnnualReturnYear05

1.01%

Ten Years

rr_AverageAnnualReturnYear10

1.35%