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
Class Institutional | Invesco Limited Maturity Treasury Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summaries - INVESCO LIMITED MATURITY TREASURY FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective(s)
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund’s investment objective is total return, comprised of current income and capital appreciation.
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.
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 138% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	138.00%
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:
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 direct obligations of the U.S. Treasury, including bills, notes and bonds. The Fund invests principally in short-term U.S. Treasury notes with remaining maturities of five years or less at the time of purchase.           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.           The Fund may invest in interest rate futures to gain or reduce its exposure to interest rates. An interest rate futures contract is an exchange-traded contact in which the specified underlying security is either an interest-bearing fixed income security or an inter-bank deposit. Interest rate futures are based off an underlying security which is a debt obligation and moves in value as interest rates change.           The Fund intends to maintain an average weighted maturity of three years or less.           The portfolio managers utilize an appropriate benchmark index in structuring the portfolio. The portfolio managers then decide on risk factors to use in managing the Fund relative to that benchmark. In doing so, the portfolio managers consider recommendations from a team of independent specialists in positioning the Fund to generate alpha (specific factors affecting the return on investments in excess of the benchmark). The portfolio managers generally rely upon a different team of specialists for trade execution and for assistance in determining the most efficient way (in terms of cost-efficiency and security selection) to implement those recommendations. Although a variety of specialists provide input in the management of the Fund, the portfolio managers retain responsibility for ensuring the Fund is positioned appropriately in terms of risk exposures and position sizes. The portfolio managers rely on the specialists for adjusting the Fund’s risk exposures and security selection. Decisions to purchase or sell securities are determined by the relative value considerations of the investment professionals that factor in economic and credit-related fundamentals, market supply and demand, market dislocations and situation-specific opportunities. The purchase or sale of securities may be related to a decision to alter the Fund’s macro risk exposure (e.g., duration, yield, curve positioning or sector exposure), a need to limit or reduce the Fund’s exposure to a particular security or issuer, degradation of an issuer’s credit quality, or general liquidity needs of the Fund.           In attempting to meet its investment objective, the Fund engages in active and frequent trading of portfolio securities.
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:           Active Trading Risk. The Fund engages in frequent trading of portfolio securities. Active trading results in added expenses and may result in a lower return and increased tax liability.           Derivatives Risk. The performance of derivative instruments is tied to the performance of an underlying currency, security, index or other instrument. In addition to risks relating to their underlying instruments, the use of derivatives may include other, possibly greater, risks. Derivatives involve costs, may be volatile, and may involve a small initial investment relative to the risk assumed. Risks associated with the use of derivatives may include counterparty, leverage, correlation, liquidity, tax, market, interest rate and management risks. Derivatives may also be more difficult to purchase, sell or value than other investments. The Fund may lose more than the cash amount invested on investments in derivatives. Investors should bear in mind that, while the Fund intends to use derivative strategies, it is not obligated to actively engage in these transactions, generally or in any particular kind of derivative, if the investment manager elects not to do so due to availability, cost, market conditions or other factors.           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.           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 benchmark, a style specific benchmark and a peer group benchmark comprised of funds with investment objectives and strategies similar to 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 benchmark, a style specific benchmark and a peer group benchmark comprised of funds with investment objectives and strategies similar to 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 Closing [Text Block]	rr_BarChartClosingTextBlock	Institutional Class shares year-to-date (ended March 31, 2012): -0.17% Best Quarter (ended March 31, 2008): 2.72% Worst Quarter (ended June 30, 2004): -1.00%
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 arrangement, such as 401(k) plans or individual retirement accounts.
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 arrangement, such as 401(k) plans or individual retirement accounts.
Class Institutional | Invesco Limited Maturity Treasury Fund | Class Institutional
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 original purchase price or redemption proceeds, whichever is less)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.20%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.43%
1 Year	rr_ExpenseExampleYear01	44
3 Years	rr_ExpenseExampleYear03	138
5 Years	rr_ExpenseExampleYear05	241
10 Years	rr_ExpenseExampleYear10	542
2002	rr_AnnualReturn2002	5.01%
2003	rr_AnnualReturn2003	1.65%
2004	rr_AnnualReturn2004	0.47%
2005	rr_AnnualReturn2005	1.45%
2006	rr_AnnualReturn2006	3.72%
2007	rr_AnnualReturn2007	6.46%
2008	rr_AnnualReturn2008	5.85%
2009	rr_AnnualReturn2009	0.43%
2010	rr_AnnualReturn2010	1.12%
2011	rr_AnnualReturn2011	0.74%
Year to Date Return, Label	rr_YearToDateReturnLabel	Institutional Class shares year-to-date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(0.17%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2008
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	2.72%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2004
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(1.00%)
1 Year	rr_AverageAnnualReturnYear01	0.74%
5 Years	rr_AverageAnnualReturnYear05	2.88%
10 Years	rr_AverageAnnualReturnYear10	2.67%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 13, 1987
Class Institutional | Return After Taxes on Distributions | Invesco Limited Maturity Treasury Fund | Class Institutional
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.53%
5 Years	rr_AverageAnnualReturnYear05	2.22%
10 Years	rr_AverageAnnualReturnYear10	1.76%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 13, 1987
Class Institutional | Return After Taxes on Distributions and Sale of Fund Shares | Invesco Limited Maturity Treasury Fund | Class Institutional
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.50%
5 Years	rr_AverageAnnualReturnYear05	2.09%
10 Years	rr_AverageAnnualReturnYear10	1.75%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 13, 1987
Class Institutional | Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses or taxes) | Invesco Limited Maturity Treasury Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	7.84%
5 Years	rr_AverageAnnualReturnYear05	6.50%
10 Years	rr_AverageAnnualReturnYear10	5.78%
Class Institutional | Barclays 1-2 Year U.S. Government Index (reflects no deduction for fees, expenses or taxes) | Invesco Limited Maturity Treasury Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.01%
5 Years	rr_AverageAnnualReturnYear05	3.28%
10 Years	rr_AverageAnnualReturnYear10	3.04%
Class Institutional | Lipper Short U.S. Treasury Funds Category Average | Invesco Limited Maturity Treasury Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.86%
5 Years	rr_AverageAnnualReturnYear05	3.31%
10 Years	rr_AverageAnnualReturnYear10	2.88%