Objective, Primary [Text Block]

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Risk/Return [Heading]

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FRANKLIN S&P 500 INDEX FUND

Objective [Heading]

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Investment objective

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The fund seeks to provide investment results that, before fees and expenses, correspond to the price and yield performance of the S&P 500^® Index (the “Index”).

Expense [Heading]

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Fees and expenses of the fund

Expense Narrative [Text Block]

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The accompanying table describes the fees and expenses that you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Shareholder Fees Caption [Text]

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Shareholder fees(fees paid directly from your investment)

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)

Fee Waiver or Reimbursement over Assets, Date of Termination

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December 31, 2024

Portfolio Turnover [Heading]

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Portfolio turnover.

Portfolio Turnover [Text Block]

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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 and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Portfolio Turnover, Rate

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9.00%

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This 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:

•

You invest $10,000 in the fund for the time periods indicated

•

Your investment has a 5% return each year and the fund’s operating expenses remain the same (except that any applicable fee waiver or expense reimbursement is reflected only through its expiration date)

•

You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example by, Year, Caption [Text]

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Number of years you own your shares ($)

Expense Example, No Redemption, By Year, Caption [Text]

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Number of years you own your shares ($)

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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Under normal circumstances, the fund invests at least 80% of its net assets, plus borrowings for investment purposes, if any, in equity securities, or other investments with similar economic characteristics, included in the Index. The fund seeks to be fully invested in stocks included in the Index. The fund seeks to hold a portfolio of common stocks that is comparable to the Index in terms of economic sector weightings, market capitalization and liquidity. The Index is a well-known stock market index that includes common stocks of 500 companies from a number of sectors and that measures the performance of large capitalization companies of the U.S. equities market.

By seeking to track the Index, from time to time, the fund may be significantly invested in companies in a particular sector. In recent years, the Index, which is market capitalization-weighted, has become significantly more exposed to companies in the information technology sector relative to other sectors, as a result of the increased market capitalization of companies in this sector.

The fund may also use derivatives to track the performance of the Index. The fund might do so, for example, in order to increase its investment exposure pending investment of cash in the stocks comprising the Index.

Risk [Heading]

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Principal risks

Risk Narrative [Text Block]

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Risk is inherent in all investing. The value of your investment in the fund, as well as the amount of return you receive on your investment, may fluctuate significantly. You may lose part or all of your investment in the fund or your investment may not perform as well as other similar investments. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency. The following is a summary description of certain risks of investing in the fund.

Index investing risk. As an index fund, the fund does not attempt to manage market volatility, use defensive strategies or reduce the effects of any periods of poor stock performance. The fund’s expenses, changes in securities markets, changes in the composition of the Index and the timing of purchases and redemptions of fund shares may affect the correlation between fund and Index performance. The fund may not perform as well as other investments if, among other things, the Index declines or performs poorly relative to other related indexes or individual securities or the securities issued by companies that comprise the Index fall out of favor with investors. Certain regulatory limitations, such as fund diversification requirements, may limit the fund’s ability to completely replicate the Index. The index used by the fund is weighted by market capitalization, which means that poor performance by one or a few stocks with large market capitalizations could adversely affect the fund’s performance relative to other investments.

Stock market and equity securities risk. The stock markets are volatile and the market prices of the fund’s equity securities may decline generally. Equity securities may include warrants, rights, exchange-traded and over‑the‑counter common stocks, preferred stock, depositary receipts, trust certificates, limited partnership interests and shares of other investment companies, including exchange-traded funds and real estate investment trusts. Equity securities may have greater price volatility than other asset classes, such as fixed income securities, and may fluctuate in price based on actual or perceived changes in a company’s financial condition and overall market and economic conditions and perceptions. If the market prices of the equity securities owned by the fund fall, the value of your investment in the fund will decline.

Market events risk. The market values of securities or other assets will fluctuate, sometimes sharply and unpredictably, due to changes in general market conditions, overall economic trends or events, governmental actions or intervention, actions taken by the U.S. Federal Reserve or foreign

central banks, market disruptions caused by trade disputes or other factors, political developments, armed conflicts, economic sanctions, major cybersecurity events, investor sentiment, the global and domestic effects of a pandemic, and other factors that may or may not be related to the issuer of the security or other asset. Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or political events, trading and tariff arrangements, public health events, terrorism, wars, natural disasters and other circumstances in one country or region could have profound 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 or markets directly affected, the value and liquidity of the fund’s investments may be negatively affected.

Following Russia’s recent invasion of Ukraine, Russian stocks lost all, or nearly all, of their market value. Other securities or markets could be similarly affected by past or future geopolitical or other events or conditions.

For example, the ongoing impact of COVID‑19 and its subsequent variants have been rapidly evolving and have resulted in extreme volatility in the financial markets; reduced liquidity of many instruments; restrictions on international and, in some cases, local travel; significant disruptions to business operations (including business closures); strained healthcare systems; and disruptions to supply chains, consumer demand and employee availability. Some sectors of the economy and individual issuers have experienced particularly large losses. While in the process of gradually reversing, these circumstances may continue for an extended period of time and may result in a sustained domestic or even global economic downturn or recession, domestic and foreign political and social instability, damage to diplomatic and international trade relations and increased volatility and/or decreased liquidity in the securities markets. Developing or emerging market countries may be more impacted by the COVID‑19 pandemic as they may have less established health care systems and may be less able to control or mitigate the effects of the pandemic. The ultimate economic fallout from the pandemic, and the long-term impact on economies, markets, industries and individual issuers, are not known. The U.S. government and the Federal Reserve, as well as certain foreign governments and central banks, have taken extraordinary actions to support local and global economies and the financial markets in response to the COVID‑19 pandemic. This and other government intervention into the economy and financial markets to address the COVID‑19 pandemic may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Government actions to mitigate the economic impact of the pandemic have resulted in a large expansion of government deficits and debt, the long term consequences of which are not known. Recently, inflation and interest rates have increased and may rise further. The COVID‑19 pandemic could adversely affect the value and liquidity of the fund’s investments, impair the fund’s ability to satisfy redemption requests, and negatively impact the fund’s performance. In addition, the COVID‑19 pandemic, and measures taken to mitigate its effects, could result in disruptions to the services provided to the fund by its service providers.

Issuer risk. The market price of a security can go up or down more than the market as a whole and can perform differently from the value of the market as a whole, due to factors specifically relating to the security’s issuer, such as disappointing earnings reports by the issuer, unsuccessful products or services, loss of major customers, changes in management, corporate actions, negative perception in the marketplace, or major litigation or changes in government regulations affecting the issuer or the competitive environment. An individual security may also be affected by factors relating to the industry or sector of the issuer. The fund may experience a substantial or complete loss on an individual security. Historically, the prices of securities of small and medium capitalization companies have generally been more volatile than those of large capitalization companies. A change in financial condition or other event affecting a single issuer may adversely impact the industry or sector of the issuer or securities markets as a whole.

Industry or sector focus risk. The fund may be susceptible to an increased risk of loss, including losses due to events that adversely affect the fund’s investments more than the market as a whole, to the extent that the fund may, from time to time, have greater exposure to the securities of a particular issuer or issuers within the same industry or sector.

Information technology sector risk. Companies in the rapidly changing field of information technology face special risks. Additionally, companies in this field are dependent upon consumer and business acceptance as new technologies evolve. Information technology companies face intense competition and potentially rapid product obsolescence. They are also heavily dependent on intellectual property rights and may be adversely affected by the loss or impairment of, or inability to enforce, those rights.

Derivatives risk. Using derivatives can increase fund losses and reduce opportunities for gains, such as when market prices, interest rates, currencies, or the derivatives themselves, behave in a way not anticipated by the fund’s subadviser. Using derivatives also can have a leveraging effect and increase fund volatility. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivatives may not be available at the time or price desired, may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the fund. Derivatives are generally subject to the risks applicable to the assets, rates, indices or other indicators underlying the derivative. The value of a derivative may fluctuate more than the underlying assets, rates, indices or other indicators to which it relates. Use of derivatives may have different tax consequences for the fund than an investment in the underlying asset, and those differences may affect the amount, timing and character of income distributed to shareholders. The U.S. government and foreign governments have adopted and implemented or are in the process of adopting and implementing regulations governing derivatives markets, including mandatory clearing of certain derivatives, margin and reporting requirements. The ultimate impact of the regulations remains unclear. Additional regulation of derivatives may make derivatives more costly, limit their availability or utility, otherwise adversely affect their performance or disrupt markets.

Illiquidity risk. Some assets held by the fund may be or become impossible or difficult to sell, particularly during times of market turmoil. These illiquid assets may also be difficult to value. Markets may become illiquid when, for instance, there are few, if any, interested buyers or sellers or when dealers are unwilling or unable to make a market for certain securities. As a general matter, dealers have been less willing to make markets

for fixed income securities. If the fund is forced to sell an illiquid asset to meet redemption requests or other cash needs, or to try to limit losses, the fund may be forced to sell at a substantial loss or may not be able to sell at all.

Valuation risk. The sales price the fund could receive for any particular portfolio investment may differ from the fund’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair value methodology. These differences may increase significantly and affect fund investments more broadly during periods of market volatility. Investors who purchase or redeem fund shares on days when the fund is holding fair-valued securities may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the fund had not fair-valued securities or had used a different valuation methodology. The fund’s ability to value its investments may be impacted by technological issues and/or errors by pricing services or other third party service providers. The valuation of the fund’s investments involves subjective judgment, which may prove to be incorrect.

Cybersecurity risk. Cybersecurity incidents, whether intentionally caused by third parties or otherwise, may allow an unauthorized party to gain access to fund assets, fund or customer data (including private shareholder information) or proprietary information, cause the fund, the manager, the subadvisers and/or their service providers (including, but not limited to, fund accountants, custodians, sub‑custodians, transfer agents and financial intermediaries) to suffer data breaches, data corruption or loss of operational functionality, or prevent fund investors from purchasing, redeeming or exchanging shares, receiving distributions or receiving timely information regarding the fund or their investment in the fund. The fund, the manager, and the subadvisers have limited ability to prevent or mitigate cybersecurity incidents affecting third party service providers, and such third party service providers may have limited indemnification obligations to the fund, the manager and/or the subadviser. Cybersecurity incidents may result in financial losses to the fund and its shareholders, and substantial costs may be incurred in order to prevent or mitigate any future cybersecurity incidents. Issuers of securities in which the fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers experience cybersecurity incidents.

Because technology is frequently changing, new ways to carry out cyber attacks are always developing. Therefore, there is a chance that some risks have not been identified or prepared for, or that an attack may not be detected, which puts limitations on the fund’s ability to plan for or respond to a cyber attack. Like other funds and business enterprises, the fund, the manager, the subadvisers and their service providers are subject to the risk of cyber incidents occurring from time to time.

These and other risks are discussed in more detail in the Prospectus or in the Statement of Additional Information.

Risk Lose Money [Text]

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You may lose part or all of your investment in the fund or your investment may not perform as well as other similar investments.

Risk Not Insured Depository Institution [Text]

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An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

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The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Class A shares. The table shows the average annual total returns of each class of the fund that has been in operation for at least one full calendar year and also compares the fund’s performance with the average annual total returns of an index or other benchmark. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated performance information, including its current net asset value, available at www.franklintempleton.com/mutualfunds (select fund and share class), or by calling the fund at (877) 6LM‑FUND/656‑3863.

The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Performance Information Illustrates Variability of Returns [Text]

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The bar chart shows changes in the fund’s performance from year to year for Class A shares. The table shows the average annual total returns of each class of the fund that has been in operation for at least one full calendar year and also compares the fund’s performance with the average annual total returns of an index or other benchmark.

Performance Availability Phone [Text]

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(877) 6LM‑FUND/656‑3863

Performance Availability Website Address [Text]

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www.franklintempleton.com/mutualfunds (select fund and share class)

Performance Past Does Not Indicate Future [Text]

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The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Bar Chart [Heading]

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Total returns (%) Before taxes

Bar Chart Closing [Text Block]

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Calendar Years ended December 31 Best Quarter (06/30/2020): 20.37 Worst Quarter (03/31/2020): (19.68)

Performance Table Heading

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Average annual total returns (%)(for periods ended December 31, 2022)

Performance Table Uses Highest Federal Rate

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Performance Table Not Relevant to Tax Deferred

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Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown, and the after‑tax returns shown are not relevant to investors who hold their fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

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The after‑tax returns are shown only for Class A shares, are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown, and the after‑tax returns shown are not relevant to investors who hold their fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts. After‑tax returns for classes other than Class A will vary from returns shown for Class A. Returns after taxes on distributions and sale of fund shares are higher than returns before taxes for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of fund shares.

Performance Table Explanation after Tax Higher

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Returns after taxes on distributions and sale of fund shares are higher than returns before taxes for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of fund shares.

Performance Table Narrative

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Franklin S&P 500 Index Fund | Class A

Maximum sales charge (load) imposed on purchases (as a % of offering price)

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none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

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none

Small account fee ($)

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$ 15

^[1]

Management fees

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0.25%

Distribution and/or service (12b-1) fees

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0.20%

Other expenses

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0.16%

Total annual fund operating expenses

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0.61%

Fees waived and/or expenses reimbursed

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(0.07%)

^[2]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

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0.54%

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$ 55

rr_ExpenseExampleYear03

188

rr_ExpenseExampleYear05

333

rr_ExpenseExampleYear10

755

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

188

rr_ExpenseExampleNoRedemptionYear05

333

Highest Quarterly Return, Label

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$ 755

2013

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31.69%

2014

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12.97%

2015

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0.82%

2016

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11.37%

2017

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21.14%

2018

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(4.93%)

2019

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30.67%

2020

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17.81%

2021

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27.96%

2022

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(18.41%)

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Best Quarter

Highest Quarterly Return, Date

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Jun. 30, 2020

Highest Quarterly Return

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20.37%

Lowest Quarterly Return, Label

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Worst Quarter

Lowest Quarterly Return, Date

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Mar. 31, 2020

Lowest Quarterly Return

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(19.68%)

rr_AverageAnnualReturnYear01

(18.41%)

rr_AverageAnnualReturnYear05

8.85%

Franklin S&P 500 Index Fund | Class D

rr_AverageAnnualReturnYear10

11.95%

Maximum sales charge (load) imposed on purchases (as a % of offering price)

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rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a % of the lower of net asset value at purchase or redemption)

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none

Small account fee ($)

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none

^[1]

Management fees

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0.25%

Distribution and/or service (12b-1) fees

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none

Other expenses

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0.18%

Total annual fund operating expenses

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0.43%

Fees waived and/or expenses reimbursed

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(0.09%)

^[2]

Total annual fund operating expenses after waiving fees and/or reimbursing expenses

rr_NetExpensesOverAssets

0.34%

rr_ExpenseExampleYear01

$ 35

rr_ExpenseExampleYear03

129

rr_ExpenseExampleYear05

232

rr_ExpenseExampleYear10

534

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

129

rr_ExpenseExampleNoRedemptionYear05

232

rr_ExpenseExampleNoRedemptionYear10

$ 534

rr_AverageAnnualReturnYear01

(18.26%)

rr_AverageAnnualReturnYear05

9.06%

Franklin S&P 500 Index Fund | Return after taxes on distributions | Class A

rr_AverageAnnualReturnYear10

12.17%

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

(19.18%)

rr_AverageAnnualReturnYear05

7.53%

Franklin S&P 500 Index Fund | Return after taxes on distributions and sale of fund shares | Class A

rr_AverageAnnualReturnYear10

10.84%

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

(10.36%)

rr_AverageAnnualReturnYear05

6.89%

Franklin S&P 500 Index Fund | S&P 500 Index (reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnYear10

9.74%

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rr_AverageAnnualReturnYear01

(18.11%)

rr_AverageAnnualReturnYear05

9.42%