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First Trust Variable Insurance Trust

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First Trust Multi Income Allocation Portfolio

Objective, Primary [Text Block]

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The First Trust Multi Income Allocation Portfolio’s (the “Fund”) primary investment objective is to maximize current income, with a secondary objective of capital appreciation.

Expense Narrative [Text Block]

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The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. The Total Annual Fund Operating Expenses reflected below do not include contract level fees of the variable annuity or variable life insurance contracts offered by a Participating Insurance Company (each a “Contract”). If such fees were included, the Total Annual Fund Operating Expenses would be higher. More information about eligibility requirements for Class I is available from your Participating Insurance Company.

Operating Expenses Caption [Text]

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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

Portfolio Turnover, Rate

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44.00%

Expense Example Narrative [Text Block]

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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. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s annual operating expenses (before any fee waiver or expense reimbursement) remain at current levels for the time periods indicated. Additionally, the example assumes that the Fund’s investment advisor’s agreement to waive fees and/or pay the Fund’s expenses to the extent necessary to prevent the operating expenses of the Class I shares (excluding interest expense, brokerage commissions and other trading expenses, acquired fund fees and expenses, taxes and extraordinary expenses) from exceeding 1.20% of the Fund’s average daily net assets will be terminated following May 1, 2026. The example does not take into account Contract level fees. If such fees were included, the estimated expenses would be higher. Although your actual costs may be higher or lower, based on these assumptions, your cost would be:

Strategy Narrative [Text Block]

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The Fund seeks to achieve its objectives through diversified exposure to nine income generating asset classes: dividend-paying stocks, preferred stocks, energy infrastructure companies and master limited partnerships (“MLPs”), real estate investment trusts (“REITs”), high yield or “junk” bonds, floating rate loans, corporate bonds, mortgage-backed securities and Treasury Inflation Protected Securities (“TIPS”). First Trust Advisors L.P. serves as the investment advisor (“First Trust” or the “Advisor”) to the Fund and Energy Income Partners, LLC (“EIP” or a “Sub-Advisor”) and Stonebridge Advisors LLC (“Stonebridge” or a “Sub-Advisor”) each serve as investment sub-advisors. The Advisor’s Investment Committee determines the Fund’s strategic allocation among the various asset classes and allocates the Fund’s assets to a portfolio management team that has expertise in the particular asset class. Each management team is composed of personnel of either the Advisor or a Sub-Advisor. The Advisor will tactically adjust allocation weights in a manner deemed to offer attractive levels of total return relative to the level of expected risk. The Advisor intends to adjust asset allocation weights quarterly but may do so more or less frequently depending upon market conditions. The maximum weight of any asset class, at the time of adjustment, will be 20%. The minimum weight of any asset class, at the time of adjustment, will be 5%. The Fund may, at certain times, invest in exchange-traded funds (“ETFs”) that generally provide exposure to the nine asset classes in lieu of investing directly in such assets classes. Certain of the ETFs may be advised by First Trust, as a result, First Trust will also earn advisory fees on the underlying ETFs. In general, the U.S. dollar-denominated fixed income securities in which the Fund invests may be issued by U.S. and non-U.S. issuers, of any credit quality, including high yield securities. The high yield securities in which the Fund invests are rated below investment grade at the time of purchase or unrated and deemed by the Advisor to be of comparable quality, commonly referred to as “junk” bonds. The Fund also invests in the equity securities of domestic and foreign issuers (including emerging markets) listed on a U.S. or foreign securities exchange and non-U.S. securities that are listed on a U.S. securities exchange in the form of American Depository Receipts (“ADRs”) and Global Depository Receipts (“GDRs”). The Fund may invest in equity securities issued by small, mid or large capitalization companies. The Fund may also invest in bank loans, covenant-lite loans, hybrid capital securities, senior loans and when-issued, TBA and delayed delivery securities.

Risk Caption

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You could lose money by investing in the Fund.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 governmental agency. There can be no assurance that the Fund’s investment objectives will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

Performance Narrative [Text Block]

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The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of two broad-based market indices and two blended benchmarks. Returns for the market indices do not include expenses, which are deducted from Fund returns, or taxes. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

Performance Additional Market Index [Text]

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The Broad Blended Benchmark returns are split between the Bloomberg U.S. Aggregate Bond Index (60%) and the Russell 3000® Index (40%).The Asset Class Blended Benchmark is weighted to include nine indexes: Dow Jones U.S. Select DividendTM Index (15%), ICE BofA Fixed Rate Preferred Securities Index (8%), Alerian MLP Index (15%), S&P U.S. REIT Index (15%), ICE BofA U.S. High Yield Constrained Index (8%), Morningstar® LSTA® U.S. Leveraged Loan Index (15%), Bloomberg U.S. Corporate Investment-Grade Index (8%), ICE BofA U.S. MBS Index (8%), and ICE BofA U.S. Inflation-Linked Treasury Index (8%).

Performance Past Does Not Indicate Future [Text]

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The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.

Bar Chart Closing [Text Block]

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During the periods shown in the chart above:ReturnPeriod EndedBest Quarter11.49%June 30, 2020Worst Quarter-16.02%March 31, 2020

Performance Table Narrative

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The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.