Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Oct. 01, 2012
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	American Funds Short-Term Tax-Exempt Bond Fund®
Objective [Heading]	rr_ObjectiveHeading	Investment objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The fund's investment objective is to provide you with current income exempt from regular federal income tax, consistent with its maturity and quality standards described in the prospectus, and to preserve capital.
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 $500,000 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 48 of the prospectus and on page 70 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)
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 14% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	14.00%
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 $500,000 in American Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	500,000
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.
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal investment strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the fund will invest at least 80% of its assets in, or derive at least 80% of its income from, securities that are exempt from regular federal income tax and that do not subject you to federal alternative minimum tax. The fund may also invest up to 20% of its assets in securities that may subject you to federal alternative minimum tax. The fund invests primarily in municipal bonds rated AA- or better or Aa3 or better by Nationally Recognized Statistical Rating Organizations designated by the fund's investment adviser, or unrated but determined by the fund's investment adviser to be of equivalent quality. The fund may also invest in municipal bonds rated A- or better or A3 or better by Nationally Recognized Statistical Rating Organizations designated by the fund's investment adviser or unrated but determined by the fund's investment adviser to be of equivalent quality. Some of the securities in which the fund invests may have credit and liquidity support features, including guarantees and letters of credit. The fund's aggregate portfolio will have a dollar-weighted average maturity no greater than three years. In addition, the fund may invest significantly in municipal obligations of issuers in the same state, or engaged in the same types of projects or industries. 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 priced securities that, in its opinion, represent good, long-term investment opportunities. The investment adviser believes that an important way to accomplish this is by analyzing various factors, which may include the credit strength of the issuer, prices of similar securities issued by comparable issuers, anticipated changes in interest rates, general market conditions and other factors pertinent to the particular security being evaluated. 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. Market conditions -- The prices of, and the income generated by, the 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 bonds -- Rising interest rates will generally cause the prices of bonds and other debt securities to fall. Longer maturity debt securities may be subject to greater price fluctuations than shorter maturity debt securities. In addition, falling interest rates may cause an issuer to redeem, call or refinance a security before its stated maturity, which may result in the fund having to reinvest the proceeds in lower yielding securities. Bonds and other debt securities are 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. Thinly traded securities -- There may be little trading in the secondary market for particular bonds or other debt securities, which may make them more difficult to value, acquire or sell. Credit and liquidity support -- Changes in the credit quality of banks and financial institutions providing credit and liquidity support features with respect to securities held by the fund could cause the values of these securities to decline. Investing in similar municipal bonds -- Investing significantly in municipal obligations of issuers in the same state or backed by revenues of similar types of projects or industries may make the fund more susceptible to certain economic, political or regulatory occurrences. As a result, the potential for fluctuations in the fund's share price may increase. 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 different broad measures of market results. This information provides some indication of the risks of investing in the fund. The Lipper Short Municipal Debt Funds Average includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to the fund's objective and/or strategies. The results below and on the following page for certain periods shown reflect the operation of the fund as a money market fund prior to its conversion on August 7, 2009 to a short-term tax-exempt bond fund. Accordingly, results for such periods are not representative of the fund's results had the fund been operated as a short-term tax-exempt bond fund during the entire period. 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 different broad measures of market results.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The Lipper Short Municipal Debt Funds Average includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to the fund's objective and/or strategies. The results below and on the following page for certain periods shown reflect the operation of the fund as a money market fund prior to its conversion on August 7, 2009 to a short-term tax-exempt bond 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	Calender 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 different broad 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 returns during this period were: Highest  1.29% (quarter ended September 30, 2010) Lowest  -0.76% (quarter ended December 31, 2010)
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.
Performance Table One Class of after Tax Shown [Text]	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.
Performance Table Footnotes	rr_PerformanceTableFootnotesTextBlock	Class A annualized 30-day yield at July 31, 2012: 0.36% (For current yield information, please call American    FundsLine® at 800/325-3590.)
Caption	rr_AverageAnnualReturnCaption	Average annual total returns For the periods ended December 31, 2011 (with maximum sales charge):
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | Barclays Municipal Short 1-5 Years Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Barclays Municipal Short 1-5 Years Index (reflects no deductions for sales charges, account fees, expenses or taxes)
1 Year	rr_AverageAnnualReturnYear01	3.45%
5 Years	rr_AverageAnnualReturnYear05	4.22%
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | Lipper Short Municipal Debt Funds Average
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Lipper Short Municipal Debt Funds Average (reflects no deductions for sales charges, account fees or taxes)
1 Year	rr_AverageAnnualReturnYear01	2.40%
5 Years	rr_AverageAnnualReturnYear05	2.52%
10 Years	rr_AverageAnnualReturnYear10	2.50%
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | Class A
Risk Return [Abstract]	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	2.50%
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	0.38%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.15%
Other expenses	rr_OtherExpensesOverAssets	0.06%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.59%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	309
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	434
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	571
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	969
Annual Return 2002	rr_AnnualReturn2002	0.89%
Annual Return 2003	rr_AnnualReturn2003	0.46%
Annual Return 2004	rr_AnnualReturn2004	0.66%
Annual Return 2005	rr_AnnualReturn2005	1.93%
Annual Return 2006	rr_AnnualReturn2006	2.95%
Annual Return 2007	rr_AnnualReturn2007	3.18%
Annual Return 2008	rr_AnnualReturn2008	1.54%
Annual Return 2009	rr_AnnualReturn2009	0.88%
Annual Return 2010	rr_AnnualReturn2010	1.90%
Annual Return 2011	rr_AnnualReturn2011	2.62%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2010
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.29%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2010
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(0.76%)
Label	rr_AverageAnnualReturnLabel	Share class A - Before taxes
1 Year	rr_AverageAnnualReturnYear01	0.05%
5 Years	rr_AverageAnnualReturnYear05	1.42%
10 Years	rr_AverageAnnualReturnYear10	1.40%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 24, 1989
Thirty Day Yield Caption	rr_ThirtyDayYieldCaption	Class A annualized 30-day yield at July 31, 2012:
Thirty Day Yield Phone	rr_ThirtyDayYieldPhone	800/325-3590
Thirty Day Yield	rr_ThirtyDayYield	0.36%
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | Class A | After Taxes on Distributions
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Share class A - After taxes on distributions
1 Year	rr_AverageAnnualReturnYear01	0.05%
5 Years	rr_AverageAnnualReturnYear05	1.42%
10 Years	rr_AverageAnnualReturnYear10	1.40%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 24, 1989
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | Class A | After Taxes on Distributions and Sales
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Share class A - After taxes on distributions and sale of fund shares
1 Year	rr_AverageAnnualReturnYear01	0.45%
5 Years	rr_AverageAnnualReturnYear05	1.42%
10 Years	rr_AverageAnnualReturnYear10	1.40%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 24, 1989
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | 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_RedemptionFeeOverRedemption	none
Management fees	rr_ManagementFeesOverAssets	0.38%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.15%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.78%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	80
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	249
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	433
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	966
Label	rr_AverageAnnualReturnLabel	Share class F-1 - Before taxes
1 Year	rr_AverageAnnualReturnYear01	2.43%
Since Inception	rr_AverageAnnualReturnSinceInception	2.13%
Inception Date	rr_AverageAnnualReturnInceptionDate	Aug. 27, 2009
American Funds Short-Term Tax Exempt Bond Fund (Prospectus Summary) | American Funds Short-Term Tax Exempt Bond Fund | 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_RedemptionFeeOverRedemption	none
Management fees	rr_ManagementFeesOverAssets	0.38%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.14%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.52%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	53
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	167
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	291
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	653
Label	rr_AverageAnnualReturnLabel	Share class F-2 - Before taxes
1 Year	rr_AverageAnnualReturnYear01	2.68%
Since Inception	rr_AverageAnnualReturnSinceInception	2.33%
Inception Date	rr_AverageAnnualReturnInceptionDate	Aug. 12, 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.