Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	Vanguard Variable Insurance Funds
Prospectus Date	rr_ProspectusDate	Apr. 29, 2025
Equity Income Portfolio
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Portfolio Summary</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 Portfolio seeks to provide an above-average level of current income and reasonable long-term capital appreciation.
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 shares of the Portfolio. The expenses shown in the table and in the example that follows do not reflect additional fees and expenses associated with the annuity or life insurance program through which you invest. If those additional fees and expenses were included, overall expenses would be higher.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Annual Portfolio Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;">(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 Portfolio 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. These costs, which are not reflected in annual portfolio operating expenses or in the previous expense example, reduce the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s turnover rate was 45% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	45.00%
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 Portfolio with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Portfolio’s shares. This example assumes that the Portfolio provides a return of 5% each year and that total annual portfolio operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Vanguard Variable Insurance Funds Equity Income Portfolio (the Portfolio) invests mainly in common stocks of mid-size and large companies whose stocks typically pay above-average levels of dividend income and are, in the opinion of the purchasing advisor, undervalued relative to similar stocks. In addition, the advisors generally look for companies that they believe are committed to paying dividends consistently. Under normal circumstances, the Portfolio will invest at least 80% of its assets in equity securities. The Portfolio uses two investment advisors. Each advisor independently selects and maintains a portfolio of common stocks for the Portfolio.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</span>
Risk [Text Block]	rr_RiskTextBlock	An investment in the Portfolio could lose money over short or long periods of time. You should expect the Portfolio’s share price and total return to fluctuate within a wide range. The Portfolio is subject to the following risks, which could affect the Portfolio’s performance:
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 Portfolio. The bar chart shows how the performance of the Portfolio has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Portfolio compare with those of a relevant market index and another comparative index, which have investment characteristics similar to those of the Portfolio. The Portfolio’s returns are net of its expenses but do not reflect additional fees and expenses that are deducted by the annuity or life insurance program through which you invest. If such fees and expenses were included in the calculation of the Portfolio’s returns, the returns would be lower. Keep in mind that the Portfolio’s past performance does not indicate how the Portfolio will perform in the future.Updated performance information is available on our website for Financial Advisors at advisors.vanguard.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="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 Portfolio. The bar chart shows how the performance of the Portfolio has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Portfolio compare with those of a relevant market index and another comparative index, which have investment characteristics similar to those of the Portfolio.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.5pt;font-style:italic;">advisors.vanguard.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="font-family:Arial;font-size:9.5pt;"> Keep in mind that the Portfolio’s past </span><span style="font-family:Arial;font-size:9.5pt;">performance does not indicate how the Portfolio 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 — Equity Income Portfolio</span>
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	<span style="font-family:Arial;font-size:9.5pt;"> The Portfolio’s returns </span><span style="font-family:Arial;font-size:9.5pt;">are net of its expenses but do not reflect additional fees and expenses that are deducted by the annuity or life insurance program through which you invest. If such fees and expenses were included in the calculation of the Portfolio’s returns, the returns would be lower.</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, 2024</span>
Equity Income Portfolio | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Portfolio could lose money over short or long periods of time.
Equity Income Portfolio | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Portfolio is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Equity Income Portfolio | Stock Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• 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.
Equity Income Portfolio | Investment Style Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Investment style risk, which is the chance that returns from mid- and large- capitalization dividend-paying value stocks will trail returns from the overall stock market. Mid-cap, large-cap, and value stocks all 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. Historically, mid-cap stocks have been more volatile in price than large-cap stocks. The stock prices of mid-size companies tend to experience greater volatility because, among other things, these companies tend to be more sensitive to changing economic conditions.
Equity Income Portfolio | Manager Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Manager risk, which is the chance that poor security selection will cause the Portfolio to underperform relevant benchmarks or other funds with a similar investment objective.
Equity Income Portfolio | Equity Income Portfolio
Risk Return Abstract	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.28%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Portfolio Operating Expenses	rr_ExpensesOverAssets	0.29%
1 Year	rr_ExpenseExampleYear01	$ 30
3 Years	rr_ExpenseExampleYear03	93
5 Years	rr_ExpenseExampleYear05	163
10 Years	rr_ExpenseExampleYear10	$ 368
2015	rr_AnnualReturn2015	0.85%
2016	rr_AnnualReturn2016	15.07%
2017	rr_AnnualReturn2017	18.25%
2018	rr_AnnualReturn2018	(5.96%)
2019	rr_AnnualReturn2019	24.43%
2020	rr_AnnualReturn2020	3.25%
2021	rr_AnnualReturn2021	25.33%
Annual Return 2022	rr_AnnualReturn2022	(0.66%)
2023	rr_AnnualReturn2023	8.10%
2024	rr_AnnualReturn2024	15.12%
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, 2022
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	13.78%
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	(22.71%)
1 Year	rr_AverageAnnualReturnYear01	15.12%
5 Years	rr_AverageAnnualReturnYear05	9.85%
10 Years	rr_AverageAnnualReturnYear10	9.89%
Equity Income Portfolio | 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	23.88%
5 Years	rr_AverageAnnualReturnYear05	13.78%
10 Years	rr_AverageAnnualReturnYear10	12.48%
Equity Income Portfolio | FTSE High Dividend Yield Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.65%
5 Years	rr_AverageAnnualReturnYear05	9.79%
10 Years	rr_AverageAnnualReturnYear10	9.83%