Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	Vanguard Variable Insurance Funds
Prospectus Date	rr_ProspectusDate	May 02, 2022
Conservative Allocation Portfolio
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Conservative Allocation Portfolio</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 current income and low to moderate 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;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 Portfolio may pay transaction costs, such as purchase fees, 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 12% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	12.00%
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 (based on the fees and expenses of the acquired funds) 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 operating expenses (of the Portfolio and its underlying funds) 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	The Portfolio invests in a mix of Vanguard mutual funds and other portfolios of Vanguard Variable Insurance Funds (collectively, the underlying funds) according to an asset-allocation strategy that reflects an allocation of approximately 60% of the Portfolio’s assets to fixed income securities and 40% to common stocks. The targeted percentage of the Portfolio’s assets allocated to the underlying asset classes is:• U.S. fixed income securities - 42%• Large-cap U.S. stocks - 20%• Foreign fixed income securities - 18%• Foreign stocks - 16%• Small- and mid-cap U.S. stocks - 4%The Portfolio’s indirect fixed income holdings are a diversified mix of short-, intermediate-, and long-term U.S. government, U.S. agency, and investment-grade U.S. corporate bonds; mortgage-backed and asset-backed securities; and government, agency, corporate, and investment-grade foreign bonds issued in currencies other than the U.S. dollar (but hedged by Vanguard, typically with foreign currency exchange forward contracts, to minimize foreign currency exposure). The Portfolio’s indirect stock holdings are a diversified mix of U.S. and foreign large-, mid-, and small-capitalization stocks.The Portfolio uses its investment in large-cap U.S. stocks and small- and mid-cap U.S. stocks to gain exposure to the overall domestic stock market. Although the percentage of the Portfolio’s assets invested in either of these two asset classes may deviate slightly from the target allocation, the combination of the two asset classes will equal approximately 24% of the Portfolio’s assets in the aggregate.The board of trustees of Vanguard Variable Insurance Funds may change the targeted allocation to the underlying asset classes without shareholder approval.
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	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 fixed income securities such as bonds usually are less volatile than stocks and because the Portfolio invests more than half of its assets in fixed income securities, the Portfolio's overall level of risk should be low to moderate.• With a target allocation of approximately 60% of its assets to fixed income securities, the Portfolio is proportionately subject to bond risks, including the following: interest rate risk, which is the chance that bond prices overall will decline because of rising interest rates; credit risk, which is the chance that the issuer of a security 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 security to decline, thus reducing an underlying fund’s return; and income risk, which is the chance that an underlying fund’s income will decline because of falling interest rates. If an underlying fund holds securities that are callable, the underlying fund’s income may decline because of 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. An underlying fund 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 underlying fund’s income. For mortgage-backed securities, this risk is known as prepayment risk. The Portfolio is also subject to the following risks associated with investments in currency-hedged foreign bonds: country/regional risk, which is the chance that world events—such as political upheaval, financial troubles, or natural disasters—will adversely affect the value and/or liquidity of securities issued by foreign governments, government agencies, or companies; and currency hedging risk, which is the chance that the currency hedging transactions entered into by the underlying international bond fund may not perfectly offset the fund’s foreign currency exposure.• With approximately 40% of its assets allocated to stocks, the Portfolio is proportionately subject to 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 Portfolio is also subject to the following risks associated with investments in foreign stocks: country/regional risk, which is the chance that world events—such as political upheaval, financial troubles, or natural disasters—will adversely affect the value of securities issued by companies in foreign countries or regions; and currency risk, which is the chance that the value of a foreign investment, measured in U.S. dollars, will decrease because of unfavorable changes in currency exchange rates. Country/regional risk and currency risk are especially high in emerging markets.• Asset allocation risk, which is the chance that the selection of underlying funds, and the allocation of assets to them, will cause the Portfolio to underperform other funds with a similar investment objective.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.
Risk Lose Money [Text]	rr_RiskLoseMoney	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">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 fixed income securities such as bonds usually are less volatile than stocks and because the Portfolio invests more than half of its assets in fixed income securities, the Portfolio's overall level of risk should be low to moderate.</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 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.</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 bond/stock index, which have investment characteristics similar to those of the Portfolio. The Conservative Allocation Composite Index is weighted 42% Bloomberg U.S. Aggregate Float Adjusted Index, 24% S&P Total Market Index, 18% Bloomberg Global Aggregate ex-USD Float Adjusted RIC Capped Index (USD Hedged), and 16% FTSE Global All Cap ex US Index as of April 28, 2017. Previously, the composite was weighted 48% Bloomberg U.S. Aggregate Float Adjusted Index, 28% S&P Total Market Index, 12% Bloomberg Global Aggregate ex-USD Float Adjusted RIC Capped Index (USD Hedged), and 12% FTSE Global All Cap ex US Index from June 3, 2013, through April 27, 2017; and 60% Bloomberg U.S. Aggregate Float Adjusted Index, 28% S&P Total Market Index, and 12% MSCI ACWI ex USA IMI Index through June 2, 2013. International stock benchmark returns are adjusted for withholding taxes. 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 or by calling Vanguard toll-free at 800-522-5555.
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 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 bond/stock index, which have investment characteristics similar to those of the Portfolio. The Conservative Allocation Composite Index is weighted 42% Bloomberg U.S. Aggregate Float Adjusted Index, 24% S&P Total Market Index, 18% Bloomberg Global Aggregate ex-USD Float Adjusted RIC Capped Index (USD Hedged), and 16% FTSE Global All Cap ex US Index as of April 28, 2017. Previously, the composite was weighted 48% Bloomberg U.S. Aggregate Float Adjusted Index, 28% S&P Total Market Index, 12% Bloomberg Global Aggregate ex-USD Float Adjusted RIC Capped Index (USD Hedged), and 12% FTSE Global All Cap ex US Index from June 3, 2013, through April 27, 2017; and 60% Bloomberg U.S. Aggregate Float Adjusted Index, 28% S&P Total Market Index, and 12% MSCI ACWI ex USA IMI Index through June 2, 2013. International stock benchmark returns are adjusted for withholding taxes.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">800-522-5555</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="color:#000000;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="color:#000000;font-family:Arial;font-size:9.5pt;"> Keep in mind that the Portfolio's </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">past 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 — Conservative Allocation Portfolio</span>
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	<span style="color:#000000;font-family:Arial;font-size:9.5pt;"> The Portfolio’s </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">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, 2021</span>
Conservative Allocation Portfolio | Conservative Allocation Portfolio
Risk Return Abstract	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	none
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.13%
Total Annual Portfolio Operating Expenses	rr_ExpensesOverAssets	0.13%
1 Year	rr_ExpenseExampleYear01	$ 13
3 Years	rr_ExpenseExampleYear03	42
5 Years	rr_ExpenseExampleYear05	73
10 Years	rr_ExpenseExampleYear10	$ 166
2012	rr_AnnualReturn2012	9.25%
2013	rr_AnnualReturn2013	9.06%
2014	rr_AnnualReturn2014	6.91%
2015	rr_AnnualReturn2015	0.20%
2016	rr_AnnualReturn2016	6.02%
2017	rr_AnnualReturn2017	10.89%
2018	rr_AnnualReturn2018	(2.98%)
2019	rr_AnnualReturn2019	15.83%
2020	rr_AnnualReturn2020	11.73%
2021	rr_AnnualReturn2021	5.99%
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	9.74%
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	(7.86%)
1 Year	rr_AverageAnnualReturnYear01	5.99%
5 Years	rr_AverageAnnualReturnYear05	8.09%
10 Years	rr_AverageAnnualReturnYear10	7.16%
Conservative Allocation 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	25.66%
5 Years	rr_AverageAnnualReturnYear05	17.92%
10 Years	rr_AverageAnnualReturnYear10	16.24%
Conservative Allocation Portfolio | Conservative Allocation Composite Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	6.23%
5 Years	rr_AverageAnnualReturnYear05	8.31%
10 Years	rr_AverageAnnualReturnYear10	7.37%
Conservative Allocation Portfolio | Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.58%)
5 Years	rr_AverageAnnualReturnYear05	3.64%
10 Years	rr_AverageAnnualReturnYear10	2.94%