Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	Vanguard Variable Insurance Funds
Prospectus Date	rr_ProspectusDate	Apr. 29, 2025
Balanced 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 long-term capital appreciation and reasonable current income.
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 64% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	64.00%
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 Balanced Portfolio (the Portfolio) invests 60% to 70% of its assets in dividend-paying and, to a lesser extent, non-dividend-paying common stocks of established large companies. In choosing these stocks, the advisor seeks durable businesses that appear to be undervalued but have prospects for improvement. These stocks are commonly referred to as value stocks. The remaining 30% to 40% of the Portfolio’s assets are invested mainly in fixed income securities that the advisor believes will generate a moderate level of current income. These securities include investment-grade corporate bonds, with some exposure to U.S. Treasury bonds, government agency bonds, and mortgage-backed securities.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</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 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 relevant market indexes and a composite stock/bond index, which have investment characteristics similar to those of the Portfolio. The Composite Stock/Bond Index is weighted 65% in the S&P 500 Index and 35% in the Bloomberg U.S. Credit A or Better Bond Index. 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 relevant market indexes and a composite stock/bond 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 performance does not </span><span style="font-family:Arial;font-size:9.5pt;">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 — Balanced Portfolio</span>
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	<span style="font-family:Arial;font-size:9.5pt;"> The Composite </span><span style="font-family:Arial;font-size:9.5pt;">Stock/Bond Index is weighted 65% in the S&P 500 Index and 35% in the Bloomberg U.S. Credit A or Better Bond Index. 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.</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>
Balanced Portfolio | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	The Portfolio is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money, and the level of risk may vary based on market conditions. However, because stock and bond prices can move in different directions or to different degrees, the Portfolio’s bond holdings may counteract some of the volatility experienced by the Portfolio’s stock holdings. The Portfolio is subject to the following risks, which could affect the Portfolio’s performance:
Balanced 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.
Balanced 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 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.
Balanced 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.
Balanced Portfolio | Income Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Income risk, which is the chance that the Portfolio’s income will decline because of falling interest rates. A fund holding bonds will experience a decline in income when interest rates fall because the fund then must invest new cash flow and cash from maturing bonds in lower-yielding bonds.
Balanced Portfolio | Interest Rate Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Interest rate risk, which is the chance that bond prices overall will decline because of rising interest rates. Interest rate risk should be moderate for the Portfolio because the Portfolio invests only a portion of its assets in bonds and because the average duration of the Portfolio’s bond portfolio is generally intermediate-term. The prices of short- and intermediate-term bonds are less sensitive to interest rate changes than are the prices of long-term bonds.
Balanced Portfolio | Credit Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Credit risk, which is the chance that a bond issuer will fail to pay interest or principal in a timely manner or that negative perceptions of the issuer’s ability to make such payments will cause the price of that bond to decline. Credit risk should be low for the Portfolio because it invests only a portion of its assets in bonds and because it purchases investment-grade bonds.
Balanced Portfolio | Call Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Call risk, which is the chance that during periods of falling interest rates, issuers of callable bonds may call (redeem) securities with higher coupon rates or interest rates before their maturity dates. The Portfolio would then lose any price appreciation above the bond’s call price and would be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Portfolio’s income. Such redemptions and subsequent reinvestments would also increase the Portfolio’s turnover rate. For mortgage-backed securities, this risk is known as prepayment risk.
Balanced Portfolio | Liquidity Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	• Liquidity risk, which is the chance that the Fund may not be able to sell a security in a timely manner at a desired price.
Balanced 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.
Balanced Portfolio | Balanced Portfolio
Risk Return Abstract	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.19%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Portfolio Operating Expenses	rr_ExpensesOverAssets	0.20%
1 Year	rr_ExpenseExampleYear01	$ 20
3 Years	rr_ExpenseExampleYear03	64
5 Years	rr_ExpenseExampleYear05	113
10 Years	rr_ExpenseExampleYear10	$ 255
2015	rr_AnnualReturn2015	0.09%
2016	rr_AnnualReturn2016	11.01%
2017	rr_AnnualReturn2017	14.72%
2018	rr_AnnualReturn2018	(3.41%)
2019	rr_AnnualReturn2019	22.48%
2020	rr_AnnualReturn2020	10.68%
2021	rr_AnnualReturn2021	19.02%
Annual Return 2022	rr_AnnualReturn2022	(14.30%)
2023	rr_AnnualReturn2023	14.33%
2024	rr_AnnualReturn2024	14.80%
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	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	12.21%
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	(13.84%)
1 Year	rr_AverageAnnualReturnYear01	14.80%
5 Years	rr_AverageAnnualReturnYear05	8.18%
10 Years	rr_AverageAnnualReturnYear10	8.37%
Balanced Portfolio | Composite Stock/Bond Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.35%
5 Years	rr_AverageAnnualReturnYear05	9.48%
10 Years	rr_AverageAnnualReturnYear10	9.29%
Balanced 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%
Balanced Portfolio | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.25%
5 Years	rr_AverageAnnualReturnYear05	(0.33%)
10 Years	rr_AverageAnnualReturnYear10	1.35%