Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	AIM INVESTMENT SECURITIES FUNDS (INVESCO INVESTMENT SECURITIES FUNDS)
Prospectus Date	rr_ProspectusDate	Jun. 28, 2012
Invesco Municipal Bond Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary - Invesco Municipal Bond Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective(s)
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund’s investment objective is federal tax-exempt current income.
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 $50,000 in the Invesco Funds. More information about these and other discounts is available from your financial professional and in the section “Shareholder Account Information-Initial Sales Charges (Class A Shares Only)” on page A-3 of the prospectus and the section “Purchase, Redemption and Pricing of Shares-Purchase and Redemption of Shares” on page L-1 of the statement of additional information (SAI).
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 performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	18.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Invesco Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
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.           Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	You would pay the following expenses if you did not redeem your shares:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests under normal circumstances at least 80% of its net assets (plus any borrowings for investment purposes) in municipal debt securities that (1) pay interest that is excluded from gross income for federal income tax purposes, and (2) do not produce income that will be considered to be an item of preference for purposes of the alternative minimum tax.           In complying with the 80% investment requirement, the Fund may include synthetic securities that have economic characteristics similar to the Fund’s direct investments that are counted toward the 80% investment requirement.            Municipal Securities include debt obligations of states, territories or possessions of the United States and the District of Columbia and their political subdivisions, agencies and instrumentalities, the interest on which, in the opinion of bond counsel or other counsel to the issuers of such securities, is, at the time of issuance, exempt from federal income tax.           The principal types of municipal debt securities purchased by the Fund are revenue obligations and general obligations. Revenue obligations are usually payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source, but not from the general taxing power. Revenue obligations may include industrial development, pollution control, public utility, housing, housing, and health care issues. Under normal market conditions, the Fund invests primarily in municipal securities classified as revenue bonds. General obligation securities are secured by the issuer’s pledge of its faith, credit and taxing power for the payment of principal and interest. The Fund may also invest in other types of municipal securities.           Although the portfolio managers consider the Fund to be a long maturity bond fund, the Fund has no restrictions on its maturity or duration.           At least 80% of the Fund’s total assets will normally be invested in municipal bonds that are determined to be of investment grade quality because they (i) are rated within the four highest credit quality ratings for long-term municipal obligations by Moody’s Investors Service, Inc. (Moody’s), Standard & Poor’s Ratings Services (S&P), or have received a comparable rating from any other nationally recognized statistical rating organization (NRSRO), or (ii) are determined by the portfolio managers to be of comparable quality to such rated securities. Principal and/or interest payments of certain municipal bonds are insured by a bond insurance company.           The portfolio managers generally take a buy and hold approach while focusing on municipal securities they believe have favorable prospects for current income exempt from Federal taxes. While the managers actively manage the funds capital gains and losses to minimize taxable income to shareholders there is a possibility of capital gains or losses.           In selecting securities for the fund’s portfolio, the portfolio managers generally favor high quality securities whose revenue stream is tied to specific projects and they believe make good economic and business sense. Prior to investing in a municipal security, the portfolio managers and/or fund analysts assess the creditworthiness of individual securities based upon financial characteristics and covenants of the issuers. Geographic considerations are evaluated to assess the potential for future tax and revenue streams for the municipality or taxing authority backing the bond.           Portfolio managers intend to purchase and hold municipal bonds to maturity to avoid selling-related capital gains. But there are times when the portfolio managers will sell securities based on factors such as: (i) degradation of credit quality; (ii) a conscious decision to shorten or lengthen the Fund’s duration; or (iii) limiting or reducing exposure to a particular sector or issuer.
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any mutual fund investment, loss of money is a risk of investing. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The risks associated with an investment in the Fund can increase during times of significant market volatility. The principal risks of investing in the Fund are:            Call Risk. If interest rates fall, it is possible that issuers of debt securities with high interest rates will prepay or call their securities before their maturity dates. In this event, the proceeds from the called securities would likely be reinvested by the Fund in securities bearing the new, lower interest rates, resulting in a possible decline in the Fund’s income and distributions to shareholders.            Credit Risk. The issuer of instruments in which the Fund invests may be unable to meet interest and/or principal payments, thereby causing its instruments to decrease in value and lowering the issuer’s credit rating.            Income Risk. The income you receive from an underlying fund is based primarily on prevailing interest rates, which can vary widely over the short- and long-term. If interest rates drop, your income from an underlying fund may drop as well.            Interest Rate Risk. Interest rate risk refers to the risk that bond prices generally fall as interest rates rise; conversely, bond prices generally rise as interest rates fall. Specific bonds differ in their sensitivity to changes in interest rates depending on their individual characteristics, including duration.            Liquidity Risk. The Fund may hold illiquid securities that it may be unable to sell at the preferred time or price and could lose its entire investment in such securities.           Management Risk. The investment techniques and risk analysis used by the Fund’s portfolio managers may not produce the desired results.           Market Risk. The prices of and the income generated by the Fund’s securities may decline in response to, among other things, investor sentiment, general economic and market conditions, regional or global instability, and currency and interest rate fluctuations.            Municipal Issuer Focus Risk. The Fund generally considers investments in municipal securities not to be subject to industry concentration policies (issuers of municipal securities as a group is not an industry) and the Fund may invest in municipal securities issued by entities having similar characteristics. The issuers may be located in the same geographic area or may pay their interest obligations from revenue of similar projects, such as hospitals, airports, utility systems and housing finance agencies. This may make the Fund’s investments more susceptible to similar social, economic, political or regulatory occurrences. As the similarity in issuers increases, the potential for fluctuation in the Fund’s net asset value also increases.            Municipal Securities Risk. The Fund may invest in municipal securities. Constitutional amendments, legislative enactments, executive orders, administrative regulations, voter initiatives, and the issuer’s regional economic conditions may affect the municipal security’s value, interest payments, repayment of principal and the Fund’s ability to sell it. Failure of a municipal security issuer to comply with applicable tax requirements may make income paid thereon taxable, resulting in a decline in the security’s value. In addition, there could be changes in applicable tax laws or tax treatments that reduce or eliminate the current federal income tax exemption on municipal securities or otherwise adversely affect the current federal or state tax status of municipal securities.            Reinvestment Risk. Reinvestment risk is the risk that a bond’s cash flows (coupon income and principal repayment) will be reinvested at an interest rate below that on the original bond.            Synthetic Securities Risk. Fluctuations in the values of synthetic securities may not correlate perfectly with the instruments they are designed to replicate. Synthetic securities may be subject to interest rate changes, market price fluctuations, counterparty risk and liquidity risk.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any mutual fund investment, loss of money is a risk of investing.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and performance table provide an indication of the risks of investing in the Fund. The bar chart shows changes in the performance of the Fund from year to year as of December 31. The performance table compares the Fund’s performance to that of a broad-based securities market/style specific benchmark and a peer group benchmark comprised of funds with similar investment objectives of the Fund. The Fund’s past performance (before and after taxes) is not necessarily an indication of its future performance. Updated performance information is available on the Fund’s website at www.invesco.com/us.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and performance table provide an indication of the risks of investing in the Fund. The bar chart shows changes in the performance of the Fund from year to year as of December 31. The performance table compares the Fund’s performance to that of a broad-based securities market/style specific benchmark and a peer group benchmark comprised of funds with similar investment objectives of the Fund.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.invesco.com/us
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance (before and after taxes) is not necessarily an indication of its future performance.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns
Bar Chart Narrative [Text Block]	rr_BarChartNarrativeTextBlock	The bar chart does not reflect sales loads. If it did, the annual total returns shown would be lower.
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The bar chart does not reflect sales loads. If it did, the annual total returns shown would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Class A shares year-to-date (ended March 31, 2012): 2.30% Best Quarter (ended September 30, 2009): 6.55% Worst Quarter (ended December 31, 2010): -3.98%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for the periods ended December 31, 2011)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Class A shares only and after-tax returns for other classes will vary.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only and after-tax returns for other classes will vary.
Invesco Municipal Bond Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.75%
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.44%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.16%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.85%
1 Year	rr_ExpenseExampleYear01	558
3 Years	rr_ExpenseExampleYear03	733
5 Years	rr_ExpenseExampleYear05	924
10 Years	rr_ExpenseExampleYear10	1,474
1 Year	rr_ExpenseExampleNoRedemptionYear01	558
3 Years	rr_ExpenseExampleNoRedemptionYear03	733
5 Years	rr_ExpenseExampleNoRedemptionYear05	924
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,474
2002	rr_AnnualReturn2002	8.26%
2003	rr_AnnualReturn2003	5.14%
2004	rr_AnnualReturn2004	4.40%
2005	rr_AnnualReturn2005	3.36%
2006	rr_AnnualReturn2006	4.48%
2007	rr_AnnualReturn2007	2.73%
2008	rr_AnnualReturn2008	(3.62%)
2009	rr_AnnualReturn2009	12.41%
2010	rr_AnnualReturn2010	1.69%
2011	rr_AnnualReturn2011	10.40%
Year to Date Return, Label	rr_YearToDateReturnLabel	Class A shares year-to-date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	2.30%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	6.55%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2010
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.98%)
1 Year	rr_AverageAnnualReturnYear01	5.20%
5 Years	rr_AverageAnnualReturnYear05	3.55%
10 Years	rr_AverageAnnualReturnYear10	4.33%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 28, 1977
Invesco Municipal Bond Fund | Class B
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	5.00%
Management Fees	rr_ManagementFeesOverAssets	0.44%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.16%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.60%
1 Year	rr_ExpenseExampleYear01	663
3 Years	rr_ExpenseExampleYear03	805
5 Years	rr_ExpenseExampleYear05	1,071
10 Years	rr_ExpenseExampleYear10	1,699
1 Year	rr_ExpenseExampleNoRedemptionYear01	163
3 Years	rr_ExpenseExampleNoRedemptionYear03	505
5 Years	rr_ExpenseExampleNoRedemptionYear05	871
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,699
1 Year	rr_AverageAnnualReturnYear01	4.58%
5 Years	rr_AverageAnnualReturnYear05	3.40%
10 Years	rr_AverageAnnualReturnYear10	4.20%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1993
Invesco Municipal Bond Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Management Fees	rr_ManagementFeesOverAssets	0.44%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.16%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.60%
1 Year	rr_ExpenseExampleYear01	263
3 Years	rr_ExpenseExampleYear03	505
5 Years	rr_ExpenseExampleYear05	871
10 Years	rr_ExpenseExampleYear10	1,900
1 Year	rr_ExpenseExampleNoRedemptionYear01	163
3 Years	rr_ExpenseExampleNoRedemptionYear03	505
5 Years	rr_ExpenseExampleNoRedemptionYear05	871
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,900
1 Year	rr_AverageAnnualReturnYear01	8.60%
5 Years	rr_AverageAnnualReturnYear05	3.75%
10 Years	rr_AverageAnnualReturnYear10	4.05%
Inception Date	rr_AverageAnnualReturnInceptionDate	Aug. 04, 1997
Invesco Municipal Bond Fund | Class Y
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.44%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.16%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.60%
1 Year	rr_ExpenseExampleYear01	61
3 Years	rr_ExpenseExampleYear03	192
5 Years	rr_ExpenseExampleYear05	335
10 Years	rr_ExpenseExampleYear10	750
1 Year	rr_ExpenseExampleNoRedemptionYear01	61
3 Years	rr_ExpenseExampleNoRedemptionYear03	192
5 Years	rr_ExpenseExampleNoRedemptionYear05	335
10 Years	rr_ExpenseExampleNoRedemptionYear10	750
1 Year	rr_AverageAnnualReturnYear01	10.68%	[1]
5 Years	rr_AverageAnnualReturnYear05	4.72%	[1]
10 Years	rr_AverageAnnualReturnYear10	4.92%	[1]
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 03, 2008	[1]
Invesco Municipal Bond Fund | Investor Class
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (as a percentage)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.44%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.16%
Other Expenses	rr_OtherExpensesOverAssets	0.16%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.76%
1 Year	rr_ExpenseExampleYear01	78
3 Years	rr_ExpenseExampleYear03	243
5 Years	rr_ExpenseExampleYear05	422
10 Years	rr_ExpenseExampleYear10	942
1 Year	rr_ExpenseExampleNoRedemptionYear01	78
3 Years	rr_ExpenseExampleNoRedemptionYear03	243
5 Years	rr_ExpenseExampleNoRedemptionYear05	422
10 Years	rr_ExpenseExampleNoRedemptionYear10	942
1 Year	rr_AverageAnnualReturnYear01	10.48%	[1]
5 Years	rr_AverageAnnualReturnYear05	4.64%	[1]
10 Years	rr_AverageAnnualReturnYear10	4.93%	[1]
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 2003	[1]
Return After Taxes on Distributions | Invesco Municipal Bond Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	5.20%
5 Years	rr_AverageAnnualReturnYear05	3.55%
10 Years	rr_AverageAnnualReturnYear10	4.33%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 28, 1977
Return After Taxes on Distributions and Sale of Fund Shares | Invesco Municipal Bond Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.97%
5 Years	rr_AverageAnnualReturnYear05	3.65%
10 Years	rr_AverageAnnualReturnYear10	4.34%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 28, 1977
Barclays Municipal Bond Index (reflects no deduction for fees, expenses or taxes) | Invesco Municipal Bond Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.70%
5 Years	rr_AverageAnnualReturnYear05	5.22%
10 Years	rr_AverageAnnualReturnYear10	5.38%
Lipper General Municipal Debt Funds Index | Invesco Municipal Bond Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.96%
5 Years	rr_AverageAnnualReturnYear05	4.18%
10 Years	rr_AverageAnnualReturnYear10	4.77%

[1] Class Y shares' and Investor Class shares' performance shown prior to the inception date is that of Class A shares and includes the 12b-1 fees applicable to Class A shares. Class A shares' performance reflects any applicable fee waiver and/or expense reimbursement.