Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	VANGUARD INDEX FUNDS
Prospectus Date	rr_ProspectusDate	Apr. 29, 2022
ETF | Vanguard Small-Cap Value Index Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Vanguard Small-Cap Value ETF</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to track the performance of a benchmark index that measures the investment return of small-capitalization value stocks.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Fees and Expenses</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold, and sell ETF Shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;margin-left:0%;">(Fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;margin-left:0%;">(Expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, reduce the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 16% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	16.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Example</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund’s ETF Shares with the cost of investing in other funds. It illustrates the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund’s shares. This example assumes that the shares provide a return of 5% each year and that total annual fund operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to sell your shares at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example Closing [Text Block]	rr_ExpenseExampleClosingTextBlock	This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund employs an indexing investment approach designed to track the performance of the CRSP US Small Cap Value Index, a broadly diversified index of value stocks of small U.S. companies. 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 [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</span>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund could lose money over short or long periods of time.You should expect the Fund’s share price and total return to fluctuate within a wide range. The Fund is subject to the following risks, which could affect the Fund’s performance:• 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 tracks a subset of the U.S. stock market, which could cause the Fund to perform differently from the overall stock market. In addition, the Fund’s target index may, at times, become focused in stocks of a particular market sector, which would subject the Fund to proportionately higher exposure to the risks of that sector.• 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. The stock prices of small companies tend to experience greater volatility because, among other things, these companies tend to be more sensitive to changing economic conditions.Because ETF Shares are traded on an exchange, they are subject to additional risks:• The Fund’s 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 ETF Share typically will approximate its net asset value (NAV), there may be times when the market price and the NAV differ significantly. Thus, you may pay more or less than NAV when you buy ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.• Although the Fund’s ETF Shares are listed for trading on NYSE Arca, it is possible that an active trading market may not be maintained.• Trading of the Fund’s ETF Shares may be halted by the activation of individual or marketwide trading halts (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of the Fund’s ETF Shares may also be halted if (1) the shares are delisted from 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 for the protection of 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">An investment in the Fund could lose money over short or long periods of time.</span>
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	<span style="color:#000000;font-family:Arial;font-size:9.5pt;font-weight:bold;">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.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Annual Total Returns</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s ETF Shares (based on NAV) 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 and other comparative indexes, which have investment characteristics similar to those of the Fund. The Spliced Small Cap Value Index reflects the performance of the MSCI US Small Cap Value Index through April 16, 2013, and the CRSP US Small Cap Value Index thereafter. Keep in mind that the Fund’s past performance (before and after taxes) does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s ETF Shares (based on NAV) 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 and other </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">comparative indexes, which have investment characteristics similar to those of the Fund.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">800-662-7447</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="color:#000000;font-family:Arial;font-size:9.5pt;font-style:italic;">vanguard.com/performance</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Keep in mind that the Fund’s past performance </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">(before and after taxes) does not indicate how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:8pt;font-weight:bold;">Annual Total Returns — Vanguard Small-Cap Value Index Fund ETF Shares</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest and lowest returns for a calendar quarter were:
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:8.5pt;font-weight:bold;">Average Annual Total Returns for Periods Ended December 31, 2021</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">When after-tax returns are calculated, it is </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">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. </span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Please note that after-tax returns are not relevant for a shareholder </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. </span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Also, figures captioned </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;font-style:italic;">Return After Taxes on Distributions and Sale of Fund Shares</span><span style="color:#000000;font-family:Arial;font-size:9.5pt;"> may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.</span>
Performance Table Closing [Text Block]	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 may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.
ETF | Vanguard Small-Cap Value Index Fund | ETF Shares
Risk Return Abstract	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.06%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.07%
1 Year	rr_ExpenseExampleYear01	$ 7
3 Years	rr_ExpenseExampleYear03	23
5 Years	rr_ExpenseExampleYear05	40
10 Years	rr_ExpenseExampleYear10	$ 90
2012	rr_AnnualReturn2012	18.78%
2013	rr_AnnualReturn2013	36.57%
2014	rr_AnnualReturn2014	10.55%
2015	rr_AnnualReturn2015	(4.67%)
2016	rr_AnnualReturn2016	24.80%
2017	rr_AnnualReturn2017	11.79%
2018	rr_AnnualReturn2018	(12.22%)
2019	rr_AnnualReturn2019	22.76%
2020	rr_AnnualReturn2020	5.82%
2021	rr_AnnualReturn2021	28.07%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="color:#000000;font-family:Arial;font-size:8pt;margin-left:0.0pt;">Highest</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	29.34%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="color:#000000;font-family:Arial;font-size:8pt;margin-left:0.0pt;">Lowest</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(34.87%)
Transaction Fee on Purchases and Sales	index_TransactionFeeOnPurchasesandSales	none	[1]
Transaction Fee on Reinvested Dividends	index_TransactionFeeOnReinvestedDividends	none	[1]
Transaction Fee on Conversion to ETF Shares	index_TransactionFeeOnConversionToETFShares	none	[1]
ETF | Vanguard Small-Cap Value Index Fund | Return After Taxes on Distributions | ETF Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	27.48%
5 Years	rr_AverageAnnualReturnYear05	9.70%
10 Years	rr_AverageAnnualReturnYear10	12.68%
ETF | Vanguard Small-Cap Value Index Fund | Return After Taxes on Distributions and Sale of Fund Shares | ETF Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.94%
5 Years	rr_AverageAnnualReturnYear05	7.98%
10 Years	rr_AverageAnnualReturnYear10	10.92%
ETF | Vanguard Small-Cap Value Index Fund | Dow Jones U.S. Total Stock Market Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.66%
5 Years	rr_AverageAnnualReturnYear05	17.92%
10 Years	rr_AverageAnnualReturnYear10	16.24%
ETF | Vanguard Small-Cap Value Index Fund | Based on NAV | ETF Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.07%
5 Years	rr_AverageAnnualReturnYear05	10.30%
10 Years	rr_AverageAnnualReturnYear10	13.29%
ETF | Vanguard Small-Cap Value Index Fund | Based on Market Price | ETF Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.00%
5 Years	rr_AverageAnnualReturnYear05	10.30%
10 Years	rr_AverageAnnualReturnYear10	13.29%
ETF | Vanguard Small-Cap Value Index Fund | CRSP US Small Cap Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.15%
5 Years	rr_AverageAnnualReturnYear05	10.30%
10 Years	rr_AverageAnnualReturnYear10
ETF | Vanguard Small-Cap Value Index Fund | Spliced Small Cap Value Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.15%
5 Years	rr_AverageAnnualReturnYear05	10.30%
10 Years	rr_AverageAnnualReturnYear10	13.31%

[1] None through Vanguard (Broker fees vary)