Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Mar. 01, 2012
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	The Investment Company of America®
Investment Objective, Heading	rr_ObjectiveHeading	Investment objectives
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The fund's investment objectives are to achieve long-term growth of capital and income.
Expense, Heading	rr_ExpenseHeading	Fees and expenses of the fund
Expense, Narrative	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 26 of the prospectus and on page 57 of the fund's statement of additional information.
Shareholder Fees, Caption	rr_ShareholderFeesCaption	Shareholder fees (fees paid directly from your investment)
Operating Expenses, Caption	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	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 28% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	28.00%
Expense Breakpoint, Discounts	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	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.
Expense Example, By Year, Caption	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	rr_ExpenseExampleNoRedemptionByYearCaption	For the share classes listed below, you would pay the following if you did not redeem your shares:
Investment Strategy, Heading	rr_StrategyHeading	Principal investment strategies
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	The fund invests primarily in common stocks, most of which have a history of paying dividends. The fund's investments are limited to securities of companies that are included on its eligible list. In light of the fund's investment objectives and policies, securities are added to, or deleted from, the eligible list by the fund's board of trustees after reviewing and acting upon the recommendations of the fund's investment adviser. The investment adviser bases its recommendations on a number of factors, such as the fund's investment objectives and policies, whether a company is considered a leader in its industry 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. In the selection of common stocks and other securities for investment, potential for capital appreciation and future dividends are given more weight than current yield. The fund may invest up to 15% of its assets, at the time of purchase, in securities of issuers domiciled outside the United States. The investment adviser uses a system of multiple portfolio counselors in managing the fund's assets. Under this approach, the portfolio of the fund is divided into segments managed by individual counselors 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	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 due to market conditions and other factors, including those directly involving the issuers of securities held by the fund. 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 at, the companies in which the fund invests. Investing in growth-oriented stocks - Growth-oriented stocks may involve larger price swings and greater potential for loss than other types of investments. Investing outside the United States - Securities of issuers domiciled outside the United States, or with significant operations outside the United States, may lose value because of political, social, economic or market developments or instability in the countries or regions in which the issuer operates. 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. 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 settlement and accounting practices and different regulatory, legal and reporting standards, and may be more difficult to value, than those in the United States. 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	rr_RiskLoseMoney	You may lose money by investing in the fund.
Risk, Not Insured Depository Institution	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	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 different broad measures of market results. This information provides some indication of the risks of investing in the fund. The Lipper Growth & Income Funds Index includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to the fund's objective and/or strategies. 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	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 different broad measures of market results.
Performance, Additional Market Index	rr_PerformanceAdditionalMarketIndex	The Lipper Growth & Income Funds Index includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to the fund's objective and/or strategies.
Performance, Availability Website Address	rr_PerformanceAvailabilityWebSiteAddress	americanfunds.com
Performance, Past Does Not Indicate Future	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
Bar Chart, Narrative	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 different broad measures of market results.
Bar Chart, Does Not Reflect Sales Loads	rr_BarChartDoesNotReflectSalesLoads	(Results do not include a sales charge; if a sales charge were included, results would be lower.)
Bar Chart, Closing	rr_BarChartClosingTextBlock	Highest/Lowest quarterly results during this period were: Highest 15.30% (quarter ended June 30, 2009) Lowest -18.97% (quarter ended December 31, 2008)
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-deferred arrangement, such as a 401(k) plan, individual retirement account (IRA) or 529 college savings plan.
Performance Table, One Class of after Tax Shown	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown only for Class A shares
Performance Table, Narrative	rr_PerformanceTableNarrativeTextBlock	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-deferred arrangement, such as a 401(k) plan, individual retirement account (IRA) or 529 college savings plan.
Performance Table, Footnotes	rr_PerformanceTableFootnotesTextBlock	Class A annualized 30-day yield at December 31, 2011: 2.05% (For current yield information, please call American FundsLine® at 800/325-3590.)
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average annual total returns For the periods ended December 31, 2011 (with maximum sales charge):
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | S&P 500
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	S&P 500 (reflects no deductions for sales charges, account fees, expenses or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	2.09%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(0.25%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.92%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	10.55%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 01, 1934
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Lipper Growth & Income Funds Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Lipper Growth & Income Funds Index (reflects no deductions for sales charges, account fees or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.82%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.17%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	3.12%
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class A
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.23%
Other expenses	rr_OtherExpensesOverAssets	0.14%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.61%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	634
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	759
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	896
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,293
Annual Return 2002	rr_AnnualReturn2002	(14.47%)
Annual Return 2003	rr_AnnualReturn2003	26.30%
Annual Return 2004	rr_AnnualReturn2004	9.78%
Annual Return 2005	rr_AnnualReturn2005	6.87%
Annual Return 2006	rr_AnnualReturn2006	15.94%
Annual Return 2007	rr_AnnualReturn2007	5.94%
Annual Return 2008	rr_AnnualReturn2008	(34.74%)
Annual Return 2009	rr_AnnualReturn2009	27.18%
Annual Return 2010	rr_AnnualReturn2010	10.86%
Annual Return 2011	rr_AnnualReturn2011	(1.76%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	15.30%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(18.97%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share class A - Before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(7.41%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(2.03%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.87%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	11.88%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 01, 1934
Thirty Day Yield, Caption	rr_ThirtyDayYieldCaption	Class A annualized 30-day yield at December 31, 2011:
Thirty Day Yield, Phone Number	rr_ThirtyDayYieldPhone	800/325-3590
Thirty Day Yield	rr_ThirtyDayYield	2.05%
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class A | After Taxes on Distributions
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share class A - After taxes on distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(7.70%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(2.53%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.19%
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class A | After Taxes on Distributions and Sales
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share class A - After taxes on distributions and sale of fund shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(4.42%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.73%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.36%
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class B
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.14%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.38%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	640
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	837
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	955
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,447
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	140
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	437
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	755
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,447
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes B (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(7.34%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.97%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.83%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.54%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 15, 2000
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class C
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.18%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.42%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	245
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	449
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	776
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,702
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	145
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	449
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	776
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,702
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes C (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(3.54%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.67%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.62%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.46%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 15, 2001
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class F-1
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.17%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.66%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	67
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	211
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	368
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	822
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes F-1 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.84%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(0.91%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	3.41%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.20%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 15, 2001
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class F-2
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.16%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.40%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	41
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	128
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	224
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	505
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes F-2 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.54%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	1.16%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Aug. 01, 2008
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class 529-A
Risk Return [Abstract]	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_RedemptionFee	none
Maximum annual account fee (529 share classes only)	rr_MaximumAccountFee	10
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.22%
Other expenses	rr_OtherExpensesOverAssets	0.24%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.70%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	662
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	825
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,001
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,501
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes 529-A (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(7.50%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(2.11%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.05%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 15, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class 529-B
Risk Return [Abstract]	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_RedemptionFee	none
Maximum annual account fee (529 share classes only)	rr_MaximumAccountFee	10
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.26%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.50%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	672
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	913
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,076
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,676
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	172
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	513
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	876
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,676
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes 529-B (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(7.44%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(2.08%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.97%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 15, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class 529-C
Risk Return [Abstract]	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_RedemptionFee	none
Maximum annual account fee (529 share classes only)	rr_MaximumAccountFee	10
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.99%
Other expenses	rr_OtherExpensesOverAssets	0.26%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.49%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	271
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	510
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	870
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,879
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	171
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	510
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	870
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,879
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes 529-C (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(3.58%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.72%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.98%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 19, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class 529-E
Risk Return [Abstract]	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_RedemptionFee	none
Maximum annual account fee (529 share classes only)	rr_MaximumAccountFee	10
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%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	119
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	348
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	594
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,293
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes 529-E (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.15%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.23%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.13%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 01, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class 529-F-1
Risk Return [Abstract]	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_RedemptionFee	none
Maximum annual account fee (529 share classes only)	rr_MaximumAccountFee	10
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.25%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.49%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	70
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	197
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	333
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	723
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes 529-F-1 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.62%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(0.74%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	5.53%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 16, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-1
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.17%
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
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-1 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.55%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.66%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.17%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 06, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-2
Risk Return [Abstract]	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_RedemptionFee	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
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-2 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.55%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.70%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.77%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	May 21, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-3
Risk Return [Abstract]	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_RedemptionFee	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%
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
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-3 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.11%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(1.21%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.51%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 04, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-4
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.16%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.65%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	66
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	208
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	362
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	810
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-4 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.83%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(0.91%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.58%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	May 28, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-5
Risk Return [Abstract]	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_RedemptionFee	none
Management fees	rr_ManagementFeesOverAssets	0.24%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.11%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.35%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	36
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	113
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	197
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	443
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-5 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.50%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(0.61%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	3.82%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	May 15, 2002
INVESTMENT CO OF AMERICA (Prospectus Summary) | INVESTMENT CO OF AMERICA | Class R-6
Risk Return [Abstract]	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_RedemptionFee	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%
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
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Share classes R-6 (before taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.45%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	13.43%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	May 01, 2009

[1] A contingent deferred sales charge of 1.00% applies on certain redemptions within one year following purchases of $1 million or more made without an initial sales charge.