| Label | Element | Value | ||
|---|---|---|---|---|
| Class 3 Shares Prospectus | Asset Allocation Fund | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk/Return [Heading] | rr_RiskReturnHeading | Asset Allocation Fund | ||
| Objective [Heading] | rr_ObjectiveHeading | Investment objective | ||
| Objective, Primary [Text Block] | rr_ObjectivePrimaryTextBlock | The fund’s investment objective is to provide high total return (including income and capital gains) consistent with preservation of capital over the long term. |
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| Expense [Heading] | rr_ExpenseHeading | Fees and expenses of the fund | ||
| Expense Narrative [Text Block] | rr_ExpenseNarrativeTextBlock | This table describes the fees and expenses that you may pay if you buy, hold and sell an interest in Class 3 shares of the fund. You may pay other fees, such as insurance contract fees and expenses, which are not reflected in the tables and examples below. If insurance contract fees and expenses were reflected, expenses shown would be higher. |
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| Operating Expenses Caption [Text] | rr_OperatingExpensesCaption | Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment) | ||
| Portfolio Turnover [Heading] | rr_PortfolioTurnoverHeading | Portfolio turnover | ||
| 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. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s investment results. During the most recent fiscal year, the fund’s portfolio turnover rate was 159% of the average value of its portfolio. |
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| Portfolio Turnover, Rate | rr_PortfolioTurnoverRate | 159.00% | ||
| Expense Example [Heading] | rr_ExpenseExampleHeading | Example | ||
| Expense Example Narrative [Text Block] | rr_ExpenseExampleNarrativeTextBlock | This example is intended to help you compare the cost of investing in Class 3 shares of 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 redeem or hold 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 operating expenses remain the same. The example does not reflect insurance contract expenses. If insurance contract expenses were reflected, expenses shown would be higher. No sales charge (load) or other fees are charged by the fund upon redemption, so you would incur these hypothetical costs whether or not you were to redeem your shares at the end of the given period. |
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| Expense Example by, Year, Caption [Text] | rr_ExpenseExampleByYearCaption | Although your actual costs may be higher or lower, based on these assumptions your costs would be: | ||
| Strategy [Heading] | rr_StrategyHeading | Principal investment strategies | ||
| Strategy Narrative [Text Block] | rr_StrategyNarrativeTextBlock | In seeking to pursue its investment objective, the fund varies its mix of equity securities, debt securities and money market instruments. Under normal market conditions, the fund’s investment adviser expects (but is not required) to maintain an investment mix falling within the following ranges: 40%-80% in equity securities, 20%-50% in debt securities and 0%-40% in money market instruments and cash. As of December 31, 2023, the fund was approximately 64% invested in equity securities, 32% invested in debt securities and 4% invested in money market instruments and cash. The proportion of equities, debt and money market securities held by the fund varies with market conditions and the investment adviser’s assessment of their relative attractiveness as investment opportunities. The fund invests in a diversified portfolio of common stocks and other equity securities, bonds and other intermediate and long-term debt securities including U.S. government securities, and money market instruments (debt securities maturing in one year or less). The fund may invest up to 15% of its assets in common stocks and other equity securities of issuers domiciled outside the United States and up to 5% of its assets in debt securities tied economically to countries outside the United States. In addition, the fund may invest up to 25% of its debt assets in lower quality debt securities (rated Ba1 or below and BB+ or below by Nationally Recognized Statistical Rating Organizations designated by the fund’s investment adviser or unrated but determined to be of equivalent quality by the fund’s investment adviser). Such securities are sometimes referred to as “junk bonds.” The investment adviser uses a system of multiple portfolio managers in managing the fund’s assets. Under this approach, the portfolio of the fund is divided into segments managed by individual managers. The fund relies on the professional judgment of its investment adviser to make decisions about the fund’s portfolio investments. The basic investment philosophy of the investment adviser is to seek to invest in attractively priced securities that, in its opinion, represent good, long-term investment opportunities. Securities may be sold when the investment adviser believes that they no longer represent relatively attractive investment opportunities. |
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| Risk [Heading] | rr_RiskHeading | Principal risks | ||
| Bar Chart and Performance Table [Heading] | rr_BarChartAndPerformanceTableHeading | Investment results | ||
| Performance Narrative [Text Block] | rr_PerformanceNarrativeTextBlock | The following bar chart shows how the investment results of the Class 3 shares of the fund have varied from year to year, and the following table shows how the fund’s average annual total returns for various periods compare with a broad measure of securities market results and other applicable measures of market results. This information provides some indication of the risks of investing in the fund. The S&P 500 Index reflects the equity market sectors in which the fund invests. The Bloomberg U.S. Aggregate Index represents the U.S. investment-grade fixed-rate bond market. Past investment results (before and after taxes) are not predictive of future investment results. Figures shown reflect fees and expenses associated with an investment in the fund, but do not reflect insurance contract fees and expenses. If insurance contract fees and expenses were included, results would have been lower. Updated information on the fund’s investment results can be obtained by visiting capitalgroup.com/afis. |
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| Performance Information Illustrates Variability of Returns [Text] | rr_PerformanceInformationIllustratesVariabilityOfReturns | The following bar chart shows how the investment results of the Class 3 shares of the fund have varied from year to year, and the following table shows how the fund’s average annual total returns for various periods compare with a broad measure of securities market results and other applicable measures of market results. | ||
| Performance Additional Market Index [Text] | rr_PerformanceAdditionalMarketIndex | The S&P 500 Index reflects the equity market sectors in which the fund invests. The Bloomberg U.S. Aggregate Index represents the U.S. investment-grade fixed-rate bond market. | ||
| Performance Availability Website Address [Text] | rr_PerformanceAvailabilityWebSiteAddress | capitalgroup.com/afis | ||
| Performance Past Does Not Indicate Future [Text] | rr_PerformancePastDoesNotIndicateFuture | Past investment results (before and after taxes) are not predictive of future investment results. | ||
| Bar Chart [Heading] | rr_BarChartHeading | Calendar year total returns | ||
| Bar Chart Narrative [Text Block] | rr_BarChartNarrativeTextBlock | The following bar chart shows how the investment results of the Class 3 shares of the fund have varied from year to year, and the following table shows how the fund’s average annual total returns for various periods compare with a broad measure of securities market results and other applicable measures of market results.
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| Bar Chart Does Not Reflect Sales Loads [Text] | rr_BarChartDoesNotReflectSalesLoads | Figures shown reflect fees and expenses associated with an investment in the fund, but do not reflect insurance contract fees and expenses. If insurance contract fees and expenses were included, results would have been lower. | ||
| Bar Chart Closing [Text Block] | rr_BarChartClosingTextBlock | Highest/Lowest quarterly results during this period were:
Highest 13.82% (quarter ended June 30, 2020)
Lowest -13.50% (quarter ended March 31, 2020) |
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| Highest Quarterly Return, Label | rr_HighestQuarterlyReturnLabel | Highest | ||
| Highest Quarterly Return, Date | rr_BarChartHighestQuarterlyReturnDate | Jun. 30, 2020 | ||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 13.82% | ||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | Lowest | ||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Mar. 31, 2020 | ||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | (13.50%) | ||
| Average Annual Return, Caption | rr_AverageAnnualReturnCaption | Average annual total returns For the periods ended December 31, 2023: | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Risk Not Insured [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Your investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency, entity or person. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Risk Lose Money [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | You may lose money by investing in the fund. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Market Conditions [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Market conditions — The prices of, and the income generated by, the common stocks, bonds and other securities held by the fund may decline – sometimes rapidly or unpredictably – due to various factors, including events or conditions affecting the general economy or particular industries or companies; overall market changes; local, regional or global political, social or economic instability; governmental, governmental agency or central bank responses to economic conditions; changes in inflation rates; and currency exchange rate, interest rate and commodity price fluctuations.Economies and financial markets throughout the world are highly interconnected. Economic, financial or political events, trading and tariff arrangements, wars, terrorism, cybersecurity events, natural disasters, public health emergencies (such as the spread of infectious disease), bank failures and other circumstances in one country or region, including actions taken by governmental or quasi-governmental authorities in response to any of the foregoing, could have impacts on global economies or markets. As a result, whether or not the fund invests in securities of issuers located in or with significant exposure to the countries affected, the value and liquidity of the fund’s investments may be negatively affected by developments in other countries and regions. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Issuer Risks [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Issuer risks — The prices of, and the income generated by, securities held by the fund may decline in response to various factors directly related to the issuers of such securities, including reduced demand for an issuer’s goods or services, poor management performance, major litigation, investigations or other controversies related to the issuer, changes in the issuer’s financial condition or credit rating, changes in government regulations affecting the issuer or its competitive environment and strategic initiatives such as mergers, acquisitions or dispositions and the market response to any such initiatives. An individual security may also be affected by factors relating to the industry or sector of the issuer or the securities markets as a whole, and conversely an industry or sector or the securities markets may be affected by a change in financial condition or other event affecting a single issuer. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing In Growthoriented Stocks [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing in growth-oriented stocks — Growth-oriented common stocks and other equity-type securities (such as preferred stocks, convertible preferred stocks and convertible bonds) may involve larger price swings and greater potential for loss than other types of investments. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing In Incomeoriented Stocks [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing in income-oriented stocks — The value of the fund’s securities and income provided by the fund may be reduced by changes in the dividend policies of, and the capital resources available for dividend payments at, the companies in which the fund invests. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing In Debt Instruments [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing in debt instruments — The prices of, and the income generated by, bonds and other debt securities held by the fund may be affected by factors such as the interest rates, maturities and credit quality of these securities.Rising interest rates will generally cause the prices of bonds and other debt securities to fall. Also, when interest rates rise, issuers of debt securities that may be prepaid at any time, such as mortgage- or other asset-backed securities, are less likely to refinance existing debt securities, causing the average life of such securities to extend. A general change in interest rates may cause investors to sell debt securities on a large scale, which could also adversely affect the price and liquidity of debt securities and could also result in increased redemptions from the fund. Falling interest rates may cause an issuer to redeem, call or refinance a debt security before its stated maturity, which may result in the fund having to reinvest the proceeds in lower yielding securities. Longer maturity debt securities generally have greater sensitivity to changes in interest rates and may be subject to greater price fluctuations than shorter maturity debt securities.Bonds and other debt securities are also subject to credit risk, which is the possibility that the credit strength of an issuer or guarantor will weaken or be perceived to be weaker, and/or an issuer of a debt security will fail to make timely payments of principal or interest and the security will go into default. Changes in actual or perceived creditworthiness may occur quickly. A downgrade or default affecting any of the fund’s securities could cause the value of the fund’s shares to decrease. Lower quality debt securities generally have higher rates of interest and may be subject to greater price fluctuations than higher quality debt securities. Credit risk is gauged, in part, by the credit ratings of the debt securities in which the fund invests. However, ratings are only the opinions of the rating agencies issuing them and are not guarantees as to credit quality or an evaluation of market risk. The fund’s investment adviser relies on its own credit analysts to research issuers and issues in assessing credit and default risks. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing In Lower Rated Debt Instruments [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing in lower rated debt instruments — Lower rated bonds and other lower rated debt securities generally have higher rates of interest and involve greater risk of default or price declines due to changes in the issuer’s creditworthiness than those of higher quality debt securities. The market prices of these securities may fluctuate more than the prices of higher quality debt securities and may decline significantly in periods of general economic difficulty. These risks may be increased with respect to investments in junk bonds. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing In Securities Backed By The USGovernment [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing in securities backed by the U.S. government — Securities backed by the U.S. Treasury or the full faith and credit of the U.S. government are guaranteed only as to the timely payment of interest and principal when held to maturity. Accordingly, the current market values for these securities will fluctuate with changes in interest rates and the credit rating of the U.S. government. Notwithstanding that these securities are backed by the full faith and credit of the U.S. government, circumstances could arise that would prevent or delay the payment of interest or principal on these securities, which could adversely affect their value and cause the fund to suffer losses. Such an event could lead to significant disruptions in U.S. and global markets. Securities issued by U.S. government-sponsored entities and federal agencies and instrumentalities that are not backed by the full faith and credit of the U.S. government are neither issued nor guaranteed by the U.S. government. U.S. government securities are subject to market risk, interest rate risk and credit risk. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Liquidity Risk [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Liquidity risk — Certain fund holdings may be or may become difficult or impossible to sell, particularly during times of market turmoil. Liquidity may be impacted by the lack of an active market for a holding, legal or contractual restrictions on resale, or the reduced number and capacity of market participants to make a market in such holding. Market prices for less liquid or illiquid holdings may be volatile or difficult to determine, and reduced liquidity may have an adverse impact on the market price of such holdings. Additionally, the sale of less liquid or illiquid holdings may involve substantial delays (including delays in settlement) and additional costs and the fund may be unable to sell such holdings when necessary to meet its liquidity needs or to try to limit losses, or may be forced to sell at a loss. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Investing Outside The United States [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Investing outside the United States — Securities of issuers domiciled outside the United States or with significant operations or revenues outside the United States, and securities tied economically to countries outside the United States, may lose value because of adverse political, social, economic or market developments (including social instability, regional conflicts, terrorism and war) in the countries or regions in which the issuers are domiciled, operate or generate revenue or to which the securities are tied economically. These securities may also lose value due to changes in foreign currency exchange rates against the U.S. dollar and/or currencies of other countries. Issuers of these securities may be more susceptible to actions of foreign governments, such as nationalization, currency blockage or the imposition of price controls, sanctions, or punitive taxes, each of which could adversely impact the value of these securities. Securities markets in certain countries may be more volatile and/or less liquid than those in the United States. Investments outside the United States may also be subject to different regulatory, legal, accounting, auditing, financial reporting and recordkeeping requirements, and may be more difficult to value, than those in the United States. In addition, the value of investments outside the United States may be reduced by foreign taxes, including foreign withholding taxes on interest and dividends. Further, there may be increased risks of delayed settlement of securities purchased or sold by the fund, which could impact the liquidity of the fund’s portfolio. The risks of investing outside the United States may be heightened in connection with investments in emerging markets. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Asset Allocation [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Asset allocation — The fund’s percentage allocation to equity securities, debt securities and money market instruments could cause the fund to underperform relative to relevant benchmarks and other funds with similar investment objectives. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | Management [Member] | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Risk [Text Block] | rr_RiskTextBlock | Management — The investment adviser to the fund actively manages the fund’s investments. Consequently, the fund is subject to the risk that the methods and analyses, including models, tools and data, employed by the investment adviser in this process may be flawed or incorrect and may not produce the desired results. This could cause the fund to lose value or its investment results to lag relevant benchmarks or other funds with similar objectives. | ||
| Class 3 Shares Prospectus | Asset Allocation Fund | 60%/40% S&P 500 Index/Bloomberg U.S. Aggregate Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes) | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Average Annual Returns, 1 Year | rr_AverageAnnualReturnYear01 | 17.67% | ||
| Average Annual Returns, 5 Years | rr_AverageAnnualReturnYear05 | 9.98% | ||
| Average Annual Returns, 10 Years | rr_AverageAnnualReturnYear10 | 8.09% | ||
| Average Annual Returns, Since Inception | rr_AverageAnnualReturnSinceInception | 8.43% | [1] | |
| Class 3 Shares Prospectus | Asset Allocation Fund | S&P 500 Index (reflects no deduction for sales charges, account fees, expenses or U.S. federal income taxes) | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Average Annual Returns, 1 Year | rr_AverageAnnualReturnYear01 | 26.29% | ||
| Average Annual Returns, 5 Years | rr_AverageAnnualReturnYear05 | 15.69% | ||
| Average Annual Returns, 10 Years | rr_AverageAnnualReturnYear10 | 12.03% | ||
| Average Annual Returns, Since Inception | rr_AverageAnnualReturnSinceInception | 10.21% | [1] | |
| Class 3 Shares Prospectus | Asset Allocation Fund | Bloomberg U.S. Aggregate Index (reflects no deduction for sales charges, account fees, expenses or U.S. federal income taxes) | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Average Annual Returns, 1 Year | rr_AverageAnnualReturnYear01 | 5.53% | ||
| Average Annual Returns, 5 Years | rr_AverageAnnualReturnYear05 | 1.10% | ||
| Average Annual Returns, 10 Years | rr_AverageAnnualReturnYear10 | 1.81% | ||
| Average Annual Returns, Since Inception | rr_AverageAnnualReturnSinceInception | 5.12% | [1] | |
| Class 3 Shares Prospectus | Asset Allocation Fund | Class 3 | ||||
| Risk/Return: | rr_RiskReturnAbstract | |||
| Management fee | rr_ManagementFeesOverAssets | 0.27% | ||
| Distribution and/or service (12b-1) fees | rr_DistributionAndService12b1FeesOverAssets | 0.18% | ||
| Other expenses | rr_OtherExpensesOverAssets | 0.03% | ||
| Total annual fund operating expenses | rr_ExpensesOverAssets | 0.48% | ||
| Expense Example, with Redemption, 1 Year | rr_ExpenseExampleYear01 | $ 49 | ||
| Expense Example, with Redemption, 3 Years | rr_ExpenseExampleYear03 | 154 | ||
| Expense Example, with Redemption, 5 Years | rr_ExpenseExampleYear05 | 269 | ||
| Expense Example, with Redemption, 10 Years | rr_ExpenseExampleYear10 | $ 604 | ||
| Annual Return 2014 | rr_AnnualReturn2014 | 5.47% | ||
| Annual Return 2015 | rr_AnnualReturn2015 | 1.46% | ||
| Annual Return 2016 | rr_AnnualReturn2016 | 9.49% | ||
| Annual Return 2017 | rr_AnnualReturn2017 | 16.29% | ||
| Annual Return 2018 | rr_AnnualReturn2018 | (4.49%) | ||
| Annual Return 2019 | rr_AnnualReturn2019 | 21.30% | ||
| Annual Return 2020 | rr_AnnualReturn2020 | 12.50% | ||
| Annual Return 2021 | rr_AnnualReturn2021 | 15.22% | ||
| Annual Return 2022 | rr_AnnualReturn2022 | (13.37%) | ||
| Annual Return 2023 | rr_AnnualReturn2023 | 14.37% | ||
| Average Annual Returns, 1 Year | rr_AverageAnnualReturnYear01 | 14.37% | ||
| Average Annual Returns, 5 Years | rr_AverageAnnualReturnYear05 | 9.27% | ||
| Average Annual Returns, 10 Years | rr_AverageAnnualReturnYear10 | 7.32% | ||
| Average Annual Returns, Since Inception | rr_AverageAnnualReturnSinceInception | 8.21% | [1] | |
| Average Annual Returns, Inception Date | rr_AverageAnnualReturnInceptionDate | Jan. 16, 2004 | ||
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