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U.S. Government Securities Fund®  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading U.S. Government Securities Fund®
Objective [Heading] rr_ObjectiveHeading Investment objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The fund’s investment objective is to provide a high level of current income consistent with prudent investment risk and preservation of 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. In addition to the fees and expenses described below, you may also be required to pay brokerage commissions on purchases and sales of Class F-2 or F-3 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 $100,000 in American Funds. More information about these and other discounts is available from your financial professional, in the “Sales charge reductions and waivers” sections on page 28 of the prospectus and on page 64 of the fund’s statement of additional information, and in the sales charge waiver appendix to this prospectus.

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 Nov. 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 577% of the average value of its portfolio.

Portfolio Turnover, Rate rr_PortfolioTurnoverRate 577.00%
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 $100,000 in American Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 100,000
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. You may be required to pay brokerage commissions on your purchases and sales of Class F-2 or F-3 shares of the fund, which are not reflected in the example.
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

Normally at least 80% of the fund’s assets will be invested in securities that are guaranteed or sponsored by the U.S. government, its agencies and instrumentalities, including bonds and other debt securities denominated in U.S. dollars, which may be represented by other investment instruments, including derivatives. The fund may also invest in mortgage-backed securities issued by federal agencies and instrumentalities that are not backed by the full faith and credit of the U.S. government. The fund invests in debt securities with a wide range of maturities.


The fund may invest in inflation linked bonds issued by U.S. and non-U.S. governments, their agencies or instrumentalities, and corporations. Inflation linked bonds are structured to protect against inflation by linking the bond’s principal and interest payments to an inflation index, such as the Consumer Price Index for Urban Consumers, so that principal and interest adjust to reflect changes in the index.


The fund may invest in certain derivative instruments, such as futures contracts and swaps. A derivative is a financial contract, the value of which is based on the value of an underlying financial asset (such as a stock, bond or currency), a reference rate or a market index. The fund may invest in a derivative only if, in the opinion of the investment adviser, the expected risks and rewards of the proposed investment are consistent with the investment objective and strategies of the fund as disclosed in this prospectus and in the fund’s statement of additional information.


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 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 – 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.


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 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. 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.


Investing in securities backed by the U.S. government — Securities backed by the U.S. Treasury or the full faith and credit of the U.S. government are guaranteed only as to the timely payment of interest and principal when held to maturity. Accordingly, the current market values for these securities will fluctuate with changes in interest rates. Securities issued by government-sponsored entities and federal agencies and instrumentalities that are not backed by the full faith and credit of the U.S. government are neither issued nor guaranteed by the U.S. government.


Investing in mortgage-related and other asset-backed securities — Mortgage-related securities, such as mortgage-backed securities, and other asset-backed securities, include debt obligations that represent interests in pools of mortgages or other income-bearing assets, such as consumer loans or receivables. Such securities often involve risks that are different from or more acute than the risks associated with investing in other types of debt securities. Mortgage-backed and other asset-backed securities are subject to changes in the payment patterns of borrowers of the underlying debt. When interest rates fall, borrowers are more likely to refinance or prepay their debt before its stated maturity. This may result in the fund having to reinvest the proceeds in lower yielding securities, effectively reducing the fund’s income. Conversely, if interest rates rise and borrowers repay their debt more slowly than expected, the time in which the mortgage-backed and other asset-backed securities are paid off could be extended, reducing the fund’s cash available for reinvestment in higher yielding securities.


Investing in future delivery contracts — The fund may enter into contracts, such as to-be-announced contracts and mortgage dollar rolls, that involve the fund selling mortgage-related securities and simultaneously contracting to repurchase similar securities for delivery at a future date at a predetermined price. This can increase the fund’s market exposure, and the market price of the securities that the fund contracts to repurchase could drop below their purchase price. While the fund can preserve and generate capital through the use of such contracts by, for example, realizing the difference between the sale price and the future purchase price, the income generated by the fund may be reduced by engaging in such transactions. In addition, these transactions may increase the turnover rate of the fund.


Investing in inflation linked bonds — The values of inflation linked bonds generally fluctuate in response to changes in real interest rates — i.e., rates of interest after factoring in inflation. A rise in real interest rates may cause the prices of inflation linked securities to fall, while a decline in real interest rates may cause the prices to increase. Inflation linked bonds may experience greater losses than other debt securities with similar durations when real interest rates rise faster than nominal interest rates. There can be no assurance that the value of an inflation linked security will be directly correlated to changes in interest rates; for example, if interest rates rise for reasons other than inflation, the increase may not be reflected in the security’s inflation measure.


Investing in inflation linked bonds may also reduce the fund’s distributable income during periods of extreme deflation. If prices for goods and services decline throughout the economy, the principal and income on inflation linked securities may decline and result in losses to the fund.


Investing in derivatives — The use of derivatives involves a variety of risks, which may be different from, or greater than, the risks associated with investing in traditional cash securities, such as stocks and bonds. Changes in the value of a derivative may not correlate perfectly with, and may be more sensitive to market events than, the underlying asset, rate or index, and a derivative instrument may expose the fund to losses in excess of its initial investment. Derivatives may be difficult for the fund to buy or sell at an opportune time or price and may be difficult to terminate or otherwise offset. The fund’s use of derivatives may result in losses to the fund, and investing in derivatives may reduce the fund’s returns and increase the fund’s price volatility. The fund’s counterparty to a derivative transaction (including, if applicable, the fund’s clearing broker, the derivatives exchange or the clearinghouse) may be unable or unwilling to honor its financial obligations in respect of the transaction. A description of the derivative instruments in which the fund may invest and the various risks associated with those derivatives is included in the fund’s statement of additional information under “Description of certain securities, investment techniques and 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.


It is important to note that neither your investment in the fund nor the fund’s yield is guaranteed by the U.S. government.


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 General U.S. Government Funds Average includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund. The Consumer Price Index provides a comparison of the fund’s results to inflation. 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 This information provides some indication of the risks of investing in the fund.
Performance Additional Market Index [Text] rr_PerformanceAdditionalMarketIndex The Lipper General U.S. Government Funds Average includes the fund and other funds that disclose investment objectives and/or strategies reasonably comparable to those of the fund. The Consumer Price Index provides a comparison of the fund’s results to inflation.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone (800) 325-3590
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 5.34% (quarter ended December 31, 2008)

 

Lowest -2.41% (quarter ended December 31, 2016)

The fund's total return for the nine months ended September 30, 2017, was 2.08%.
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, 2017
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 2.08%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2008
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 5.34%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2016
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (2.41%)
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, 2016 (with maximum sales charge):
U.S. Government Securities Fund® | Bloomberg Barclays U.S. Government/Mortgage-Backed Securities Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Bloomberg Barclays U.S. Government/Mortgage-Backed Securities Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 1.31%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.57%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 4.04%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 6.55%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Oct. 17, 1985
U.S. Government Securities Fund® | Lipper General U.S. Government Funds Average (reflects no deductions for sales charges, account fees or U.S. federal income taxes)  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper General U.S. Government Funds Average (reflects no deductions for sales charges, account fees or U.S. federal income taxes)
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 2.07%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.36%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 1.81%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 2.59%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Oct. 17, 1985
U.S. Government Securities Fund® | Consumer Price Index  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Consumer Price Index
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.64%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.95%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.35%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 5.55%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Oct. 17, 1985
U.S. Government Securities Fund® | Class A  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 3.75%
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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.27% [2]
Other expenses rr_OtherExpensesOverAssets 0.18%
Total annual fund operating expenses rr_ExpensesOverAssets 0.65%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock A contingent deferred sales charge of 1.00% applies on certain redemptions made within 18 months 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.
Expenses Restated to Reflect Current [Text] rr_ExpensesRestatedToReflectCurrent Restated to reflect current fees.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 439
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 575
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 724
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,155
Annual Return 2007 rr_AnnualReturn2007 6.67%
Annual Return 2008 rr_AnnualReturn2008 7.73%
Annual Return 2009 rr_AnnualReturn2009 2.16%
Annual Return 2010 rr_AnnualReturn2010 5.69%
Annual Return 2011 rr_AnnualReturn2011 7.77%
Annual Return 2012 rr_AnnualReturn2012 2.10%
Annual Return 2013 rr_AnnualReturn2013 (3.16%)
Annual Return 2014 rr_AnnualReturn2014 4.84%
Annual Return 2015 rr_AnnualReturn2015 1.53%
Annual Return 2016 rr_AnnualReturn2016 0.74%
Label rr_AverageAnnualReturnLabel A Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.03%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.41%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.16%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 5.55%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Oct. 17, 1985
Thirty Day Yield Caption rr_ThirtyDayYieldCaption Class A annualized 30-day yield at August 31, 2017:
Thirty Day Yield Phone rr_ThirtyDayYieldPhone (800) 325-3590
Thirty Day Yield rr_ThirtyDayYield 1.28%
U.S. Government Securities 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 (3.91%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 (0.39%)
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.05%
U.S. Government Securities 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 (1.61%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.05%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.10%
U.S. Government Securities Fund® | Class 529-A  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 3.75%
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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.23% [2]
Other expenses rr_OtherExpensesOverAssets 0.27%
Total annual fund operating expenses rr_ExpensesOverAssets 0.70%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock A contingent deferred sales charge of 1.00% applies on certain redemptions made within 18 months 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.
Expenses Restated to Reflect Current [Text] rr_ExpensesRestatedToReflectCurrent Restated to reflect current fees.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 444
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 590
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 750
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,213
Label rr_AverageAnnualReturnLabel 529-A Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (3.09%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.33%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.08%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.26%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 20, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.22%
Total annual fund operating expenses rr_ExpensesOverAssets 1.42%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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
Label rr_AverageAnnualReturnLabel C Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (1.02%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.39%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.75%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.18%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 15, 2001
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.98%
Other expenses rr_OtherExpensesOverAssets 0.28%
Total annual fund operating expenses rr_ExpensesOverAssets 1.46%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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 (1.11%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.32%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.68%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 2.69%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Feb. 19, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.49%
Other expenses rr_OtherExpensesOverAssets 0.23%
Total annual fund operating expenses rr_ExpensesOverAssets 0.92%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 94
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 293
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 509
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,131
Label rr_AverageAnnualReturnLabel 529-E Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.45%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.86%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.21%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.31%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 07, 2002
U.S. Government Securities Fund® | Class 529-T  
Risk/Return: 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 none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.28% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 0.73%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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 $ 323
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 478
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 646
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,134
U.S. Government Securities Fund® | Class T  
Risk/Return: 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 none
Maximum sales charge (load) imposed on reinvested dividends rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther none
Redemption or exchange fees rr_RedemptionFeeOverRedemption none
Management fees rr_ManagementFeesOverAssets 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.21% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 0.66%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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 $ 316
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 456
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 609
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,052
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.66%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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
Label rr_AverageAnnualReturnLabel F-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.74%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.18%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.56%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.69%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Mar. 15, 2001
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.27%
Total annual fund operating expenses rr_ExpensesOverAssets 0.47%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 48
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 151
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 263
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 591
Label rr_AverageAnnualReturnLabel 529-F-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.91%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.32%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.71%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.41%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Oct. 11, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.19%
Total annual fund operating expenses rr_ExpensesOverAssets 0.39%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 40
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 125
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 219
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 493
Label rr_AverageAnnualReturnLabel F-2 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 1.00%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.43%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.54%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Aug. 07, 2008
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.07% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 0.27%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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 $ 28
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 87
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 152
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 343
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 1.41%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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-1 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 (0.02%)
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.41%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.74%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 2.74%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jun. 13, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.74%
Other expenses rr_OtherExpensesOverAssets 0.46%
Total annual fund operating expenses rr_ExpensesOverAssets 1.40%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 143
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 443
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 766
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,680
Label rr_AverageAnnualReturnLabel R-2 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 none
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.41%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.77%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 2.79%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 31, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.25%
Total annual fund operating expenses rr_ExpensesOverAssets 0.95%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.95%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 97
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 303
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 525
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,166
Label rr_AverageAnnualReturnLabel R-3 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.45%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 0.86%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.21%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.22%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Jun. 06, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.17%
Total annual fund operating expenses rr_ExpensesOverAssets 0.62%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.62%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 63
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 199
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 346
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 774
Label rr_AverageAnnualReturnLabel R-4 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.77%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.19%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.55%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.59%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 28, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.12%
Total annual fund operating expenses rr_ExpensesOverAssets 0.32%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.32%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 33
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 103
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 180
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 406
Label rr_AverageAnnualReturnLabel R-5 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 1.06%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.49%
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.86%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.94%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 15, 2002
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.06%
Total annual fund operating expenses rr_ExpensesOverAssets 0.26%
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.26%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 27
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 84
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 146
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 331
Label rr_AverageAnnualReturnLabel R-6 Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 1.11%
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 1.54%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 3.06%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2009
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.60%
Other expenses rr_OtherExpensesOverAssets 0.29%
Total annual fund operating expenses rr_ExpensesOverAssets 1.09%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets none
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 0.36%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 1.09%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Aug. 29, 2014
U.S. Government Securities 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 0.20%
Distribution and/or service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.34%
Total annual fund operating expenses rr_ExpensesOverAssets 0.54%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.11% [2],[4]
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.43%
Expenses Restated to Reflect Current [Text] rr_ExpensesRestatedToReflectCurrent Restated to reflect current fees.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 44
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 162
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 291
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 667
Label rr_AverageAnnualReturnLabel R-5E Before taxes
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 0.96%
Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 0.82%
Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Nov. 20, 2015
[1] A contingent deferred sales charge of 1.00% applies on certain redemptions made within 18 months 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] Restated to reflect current fees.
[3] Based on estimated amounts for the current fiscal year.
[4] The investment adviser is currently reimbursing a portion of the other expenses. This reimbursement will be in effect through at least November 1, 2018. The adviser may elect at its discretion to extend, modify or terminate the reimbursement at that time.