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AMERICAN MUTUAL FUND®  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading AMERICAN MUTUAL FUND®
Objective [Heading] rr_ObjectiveHeading Investment objectives
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The fund strives for the balanced accomplishment of three objectives: current income, growth of capital and conservation of principal.
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 and hold shares of the fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in American Funds. More information about these and other discounts is available from your financial professional and in the “Sales charge reductions and waivers” section on page 27 of the prospectus and on page 62 of the fund’s statement of additional information.

Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder fees (fees paid directly from your investment)
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)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination Jan. 01, 2018
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 and may result in higher taxes when fund 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 investment results. During the most recent fiscal year, the fund’s portfolio turnover rate was 18% of the average value of its portfolio.

Portfolio Turnover, Rate rr_PortfolioTurnoverRate 18.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in American Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 25,000
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 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 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 reflects the expense reimbursement described above through the expiration date of such reimbursement and total annual fund operating expenses thereafter.
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:
Expense Example, No Redemption, By Year, Caption [Text] rr_ExpenseExampleNoRedemptionByYearCaption For the share classes listed to the right, you would pay the following if you did not redeem your shares:
Strategy [Heading] rr_StrategyHeading Principal investment strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

The fund seeks to invest primarily in common stocks of companies that are likely to participate in the growth of the American economy and whose dividends appear to be sustainable. The fund invests primarily in securities of issuers domiciled in the United States and Canada.


The fund’s equity investments are limited to securities of companies that are included on its eligible list. Securities are added to, or deleted from, the eligible list based upon a number of factors, such as the fund’s investment objectives and policies, whether a company is deemed to be an established company of sufficient quality and a company’s dividend payment prospects. Although the fund focuses on investments in medium to larger capitalization companies, the fund’s investments are not limited to a particular capitalization size.


The fund may also invest in bonds and other debt securities, including those issued by the U.S. government and by federal agencies and instrumentalities. Debt securities purchased by the fund are rated investment grade or better or determined by the fund’s investment adviser to be of equivalent quality.


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 who decide how their respective segments will be invested.


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 valued companies that, in its opinion, represent good, long-term investment opportunities. The investment adviser believes that an important way to accomplish this is through fundamental analysis, which may include meeting with company executives and employees, suppliers, customers and competitors. Securities may be sold when the investment adviser believes that they no longer represent relatively attractive investment opportunities.
Risk [Heading] rr_RiskHeading Principal risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

This section describes the principal risks associated with the fund’s principal investment strategies. You may lose money by investing in the fund. The likelihood of loss may be greater if you invest for a shorter period of time. Investors in the fund should have a long-term perspective and be able to tolerate potentially sharp declines in value.


Market conditions — The prices of, and the income generated by, the common stocks 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; overall market changes; local, regional or global political, social or economic instability; governmental or governmental agency responses to economic conditions; and currency exchange rate, interest rate and commodity price fluctuations. These risks may be heightened in the case of smaller capitalization stocks.


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 and strategic initiatives such as mergers, acquisitions or dispositions and the market response to any such initiatives.


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.


Investing in income-oriented stocks — 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.


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 changing interest rates and by changes in the effective maturities and credit ratings of these securities.


Rising interest rates will generally cause the prices of bonds and other debt securities to fall. 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 will weaken 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. 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 seeking to mitigate various credit and default risks.


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 employed by the investment adviser in this process 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.


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. You should consider how this fund fits into your overall investment program.
Risk Lose Money [Text] rr_RiskLoseMoney You may lose money by investing in the fund.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution 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.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Investment results
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The following bar chart shows how the fund’s investment results 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 Lipper Growth and Income Funds Index and the Lipper Large-Cap Core Funds Index include the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund. The Lipper Large-Cap Value Funds Index includes other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund. Past investment results (before and after taxes) are not predictive of future investment results. Updated information on the fund’s investment results can be obtained by visiting americanfunds.com.

Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following bar chart shows how the fund’s investment results 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 Lipper Growth and Income Funds Index and the Lipper Large-Cap Core Funds Index include the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund. The Lipper Large-Cap Value Funds Index includes other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americanfunds.com
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 for Class A shares (Results do not include a sales charge; if a sales charge were included, results would be lower.)
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The following bar chart shows how the fund’s investment results 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.
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads (Results do not include a sales charge; if a sales charge were included, results would be lower.)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Highest/Lowest quarterly results during this period were:


Highest 13.40% (quarter ended June 30, 2009)


Lowest -17.52% (quarter ended December 31, 2008)


The fund's total return for the nine months ended September 30, 2016, was 10.72%.
Year to Date Return, Label rr_YearToDateReturnLabel The fund's total return for the nine months ended
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2016
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 10.72%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 13.40%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2008
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (17.52%)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the highest individual federal income tax rates in effect during each year of the periods shown and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Your actual after-tax returns depend on your individual tax situation and likely will differ from the results shown above. In addition, after-tax returns are not relevant if you hold your fund shares through a tax-favored arrangement, such as a 401(k) plan, individual retirement account (IRA) or 529 college savings plan.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown only for Class A shares; after-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

After-tax returns are shown only for Class A shares; after-tax returns for other share classes will vary. After-tax returns are calculated using the highest individual federal income tax rates in effect during each year of the periods shown and do not reflect the impact of state and local taxes. Your actual after-tax returns depend on your individual tax situation and likely will differ from the results shown above. In addition, after-tax returns are not relevant if you hold your fund shares through a tax-favored arrangement, such as a 401(k) plan, individual retirement account (IRA) or 529 college savings plan.
Caption rr_AverageAnnualReturnCaption Average annual total returns For the periods ended December 31, 2015 (with maximum sales charge):
AMERICAN MUTUAL FUND® | S&P 500 Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel S&P 500 Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 1.38%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 12.57%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 7.31%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 11.20%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 21, 1950
AMERICAN MUTUAL FUND® | Lipper Growth and Income Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper Growth and Income Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (1.61%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.00%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.50%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 21, 1950
AMERICAN MUTUAL FUND® | Lipper Large-Cap Core Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper Large-Cap Core Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (0.67%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.97%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.35%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 21, 1950
AMERICAN MUTUAL FUND® | Lipper Large-Cap Value Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper Large-Cap Value Funds Index (reflects no deductions for sales charges, account fees or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.65%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.07%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.71%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 21, 1950
AMERICAN MUTUAL FUND® | Class A  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00% [1]
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.24%
Other expenses rr_OtherExpensesOverAssets 0.11%
Total annual fund operating expenses rr_ExpensesOverAssets 0.59%
Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock A contingent deferred sales charge of 1.00% applies on certain redemptions made within one year following purchases of $1 million or more made without an initial sales charge. Contingent deferred sales charge is calculated based on the lesser of the offering price and market value of shares being sold.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 632
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 753
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 885
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,270
Annual Return 2006 rr_AnnualReturn2006 16.24%
Annual Return 2007 rr_AnnualReturn2007 3.33%
Annual Return 2008 rr_AnnualReturn2008 (30.04%)
Annual Return 2009 rr_AnnualReturn2009 25.43%
Annual Return 2010 rr_AnnualReturn2010 12.23%
Annual Return 2011 rr_AnnualReturn2011 4.77%
Annual Return 2012 rr_AnnualReturn2012 12.33%
Annual Return 2013 rr_AnnualReturn2013 27.91%
Annual Return 2014 rr_AnnualReturn2014 12.60%
Annual Return 2015 rr_AnnualReturn2015 (2.83%)
Label rr_AverageAnnualReturnLabel A Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (8.43%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.20%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.27%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 11.45%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 21, 1950
Thirty Day Yield Caption rr_ThirtyDayYieldCaption Class A annualized 30-day yield at October 31, 2016:
Thirty Day Yield Phone rr_ThirtyDayYieldPhone (800) 325-3590
Thirty Day Yield rr_ThirtyDayYield 2.14%
AMERICAN MUTUAL FUND® | Class A | After Taxes on Distributions  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel A After taxes on distributions
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (9.79%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 8.23%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.47%
AMERICAN MUTUAL FUND® | Class A | After Taxes on Distributions and Sale of Fund Shares  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel A After taxes on distributions and sale of fund shares
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.67%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 7.28%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.05%
AMERICAN MUTUAL FUND® | Class 529-A  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00% [1]
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.23%
Other expenses rr_OtherExpensesOverAssets 0.22%
Total annual fund operating expenses rr_ExpensesOverAssets 0.69%
Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock A contingent deferred sales charge of 1.00% applies on certain redemptions made within one year following purchases of $1 million or more made without an initial sales charge. Contingent deferred sales charge is calculated based on the lesser of the offering price and market value of shares being sold.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 641
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 783
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 937
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,384
Label rr_AverageAnnualReturnLabel 529-A Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (8.51%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.09%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.17%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.37%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 19, 2002
AMERICAN MUTUAL FUND® | Class B  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 5.00%
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.99%
Other expenses rr_OtherExpensesOverAssets 0.13%
Total annual fund operating expenses rr_ExpensesOverAssets 1.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 638
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 831
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 945
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,424
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 138
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 431
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 745
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,424
Label rr_AverageAnnualReturnLabel B Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (8.13%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.38%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.24%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.99%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 15, 2000
AMERICAN MUTUAL FUND® | Class 529-B  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 5.00%
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.97%
Other expenses rr_OtherExpensesOverAssets 0.27%
Total annual fund operating expenses rr_ExpensesOverAssets 1.48%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 651
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 868
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,008
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,554
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 151
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 468
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 808
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,554
Label rr_AverageAnnualReturnLabel 529-B Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (8.23%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.25%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.11%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.31%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 19, 2002
AMERICAN MUTUAL FUND® | Class C  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.15%
Total annual fund operating expenses rr_ExpensesOverAssets 1.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 242
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 440
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 761
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,669
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 142
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 440
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 761
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,669
Label rr_AverageAnnualReturnLabel C Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (4.51%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.61%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.03%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.12%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 15, 2001
AMERICAN MUTUAL FUND® | Class 529-C  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.99%
Other expenses rr_OtherExpensesOverAssets 0.23%
Total annual fund operating expenses rr_ExpensesOverAssets 1.46%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 249
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 462
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 797
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,746
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 149
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 462
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 797
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,746
Label rr_AverageAnnualReturnLabel 529-C Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (4.60%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.53%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.96%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 5.89%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 20, 2002
AMERICAN MUTUAL FUND® | Class 529-E  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.19%
Total annual fund operating expenses rr_ExpensesOverAssets 0.93%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 95
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 296
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 515
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,143
Label rr_AverageAnnualReturnLabel 529-E Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.18%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.11%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.51%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.02%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 07, 2002
AMERICAN MUTUAL FUND® | Class F-1  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.18%
Total annual fund operating expenses rr_ExpensesOverAssets 0.67%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 68
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 214
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 373
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 835
Label rr_AverageAnnualReturnLabel F-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.89%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.43%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.85%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.67%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 15, 2001
AMERICAN MUTUAL FUND® | Class F-2  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.18%
Total annual fund operating expenses rr_ExpensesOverAssets 0.42%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 43
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 135
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 235
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 530
Label rr_AverageAnnualReturnLabel F-2 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.66%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.71%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 8.21%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Aug. 05, 2008
AMERICAN MUTUAL FUND® | Class F-3  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.06% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.30%
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates Based on estimated amounts for the current fiscal year.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 31
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 97
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 169
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 381
AMERICAN MUTUAL FUND® | Class 529-F-1  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.22%
Total annual fund operating expenses rr_ExpensesOverAssets 0.46%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 47
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 148
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 258
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 579
Label rr_AverageAnnualReturnLabel 529-F-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.71%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.64%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 7.03%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 8.20%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Sep. 17, 2002
AMERICAN MUTUAL FUND® | Class R-1  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.19%
Total annual fund operating expenses rr_ExpensesOverAssets 1.43%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 146
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 452
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 782
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,713
Label rr_AverageAnnualReturnLabel R-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.64%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.59%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.02%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.06%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jun. 11, 2002
AMERICAN MUTUAL FUND® | Class R-2  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.42%
Total annual fund operating expenses rr_ExpensesOverAssets 1.41%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 144
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 446
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 771
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,691
Label rr_AverageAnnualReturnLabel R-2 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.62%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 9.61%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.00%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 5.77%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 31, 2002
AMERICAN MUTUAL FUND® | Class R-3  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.23%
Total annual fund operating expenses rr_ExpensesOverAssets 0.97%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.97%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 99
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 309
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 536
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,190
Label rr_AverageAnnualReturnLabel R-3 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.19%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.11%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.51%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.49%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jun. 06, 2002
AMERICAN MUTUAL FUND® | Class R-4  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.18%
Total annual fund operating expenses rr_ExpensesOverAssets 0.67%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.67%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 68
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 214
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 373
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 835
Label rr_AverageAnnualReturnLabel R-4 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.87%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.44%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 6.83%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 7.07%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jun. 27, 2002
AMERICAN MUTUAL FUND® | Class R-5  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.12%
Total annual fund operating expenses rr_ExpensesOverAssets 0.36%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 37
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 116
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 202
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 456
Label rr_AverageAnnualReturnLabel R-5 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.59%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.77%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 7.15%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.81%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 15, 2002
AMERICAN MUTUAL FUND® | Class R-6  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.06%
Total annual fund operating expenses rr_ExpensesOverAssets 0.30%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.30%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 31
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 97
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 169
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 381
Label rr_AverageAnnualReturnLabel R-6 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (2.58%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 10.82%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 13.93%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2009
AMERICAN MUTUAL FUND® | Class R-2E  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.60%
Other expenses rr_OtherExpensesOverAssets 0.25%
Total annual fund operating expenses rr_ExpensesOverAssets 1.09%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 111
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 347
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 601
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,329
Label rr_AverageAnnualReturnLabel R-2E Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.22%)
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 0.79%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Aug. 29, 2014
AMERICAN MUTUAL FUND® | Class R-5E  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage of the amount redeemed) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.24%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.28%
Total annual fund operating expenses rr_ExpensesOverAssets 0.52%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.06%) [3],[4]
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.46%
Expenses Restated to Reflect Current [Text] rr_ExpensesRestatedToReflectCurrent Restated to reflect current fees.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 47
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 161
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 285
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 647
[1] A contingent deferred sales charge of 1.00% applies on certain redemptions made within one year following purchases of $1 million or more made without an initial sales charge. Contingent deferred sales charge is calculated based on the lesser of the offering price and market value of shares being sold.
[2] Based on estimated amounts for the current fiscal year.
[3] Restated to reflect current fees.
[4] The investment adviser is currently reimbursing a portion of the other expenses. This reimbursement will be in effect through at least January 1, 2018. The adviser may elect at its discretion to extend, modify or terminate the reimbursement at that time.