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 A5, B5 And C5 | Invesco Money Market Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary - Invesco Money Market Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective(s)
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund’s investment objective is to provide current income consistent with preservation of capital and liquidity.
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)
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 only in the following high-quality U.S. dollar-denominated short-term debt obligations: (i) securities issued by the U.S. Government or its agencies; (ii) bankers’ acceptances, certificates of deposit, and time deposits from U.S. or foreign banks; (iii) repurchase agreements; (iv) commercial paper; (v) municipal securities; (vi) master notes; and (vii) cash equivalents.           The Fund will limit investments to those securities that are First Tier Securities (defined below) at the time of purchase.           As permitted by Rule 2a-7 under the Investment Company Act of 1940 (“Rule 2a-7”), the Fund seeks to maintain a stable price of $1.00 per share by using the amortized cost method to value portfolio securities and rounding the share value to the nearest cent. The Fund invests in conformity with SEC rules and regulations requirements for money market funds for the quality, maturity, diversification and liquidity of investments. The Fund invests only in U.S. dollar-denominated securities maturing within 397 days of the date of purchase, with certain exceptions permitted by applicable regulations. The Fund maintains a dollar-weighted average portfolio maturity of no more than 60 days, and a dollar-weighted average portfolio maturity as determined without exceptions regarding certain interest rate adjustments under Rule 2a-7 of no more than 120 days. Each investment must be determined to present minimal credit risks by the Fund’s Adviser pursuant to guidelines approved by the Fund’s Board of Trustees, and must be an “Eligible Security” as defined under applicable regulations. First Tier Securities generally means Eligible Securities rated within the highest short-term rating category, unrated securities of comparable quality as determined by the Adviser under the supervision of the Board of Trustees, U.S. Government Securities as defined by applicable regulations, and securities issued by other registered money market funds.           The Fund may invest up to 50% of its assets in U.S. dollar-denominated foreign securities. The Fund may also invest in securities, whether or not considered foreign securities, which carry foreign credit exposure.           In selecting securities for the Fund’s portfolio, the portfolio managers focus on safety, liquidity, and a competitive yield. The Adviser conducts a credit analysis of each potential issuer prior to the purchase of its securities.           The portfolio managers normally hold portfolio securities to maturity, but may sell a particular security when they deem it advisable, such as when market or credit factors materially change.
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. Although the Fund seeks to preserve the value of your investment at $1.00 per share, you may lose money by investing in the Fund. 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:           Cash/Cash Equivalents Risk. Holding cash or cash equivalents may negatively affect performance.           Counterparty Risk. Counterparty risk is the risk that the other party to the contract will not fulfill its contractual obligations, which may cause losses or additional costs to the Fund.           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.           Foreign Securities Risk. The Fund’s foreign investments may be affected by changes in a foreign country’s exchange rates, political and social instability, changes in economic or taxation policies, difficulties when enforcing obligations, decreased liquidity, and increased volatility. Foreign companies may be subject to less regulation resulting in less publicly available information about the companies.           Industry Focus Risk. To the extent the Fund invests in securities issued or guaranteed by companies in the banking and financial services industries, the Fund’s performance will depend on the overall condition of those industries, which may be affected by the following factors: the supply of short-term financing, changes in government regulation and interest rates, and overall economy.           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.           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.           Money Market Fund Risk. Although the Fund seeks to preserve the value of your investment at $1.00 per share, you may lose money by investing in the Fund. The share price of money market funds can fall below the $1.00 share price. You should not rely on or expect the Fund’s adviser or its affiliates to enter into support agreements or take other actions to maintain the Fund’s $1.00 share price. The credit quality of the Fund’s holdings can change rapidly in certain markets, and the default of a single holding could have an adverse impact on the Fund’s share price. The Fund’s share price can also be negatively affected during periods of high redemption pressures and/or illiquid markets. Further regulation could impact the way the Fund is managed, possibly negatively impacting its return. Additionally, the Fund’s yield will vary as the short-term securities in its portfolio mature or are sold and the proceeds are reinvested in other securities.           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.           Repurchase Agreement Risk. If the seller of a repurchase agreement in which the Fund invests defaults on its obligation or declares bankruptcy, the Fund may experience delays in selling the securities underlying the repurchase agreement resulting in losses.           U.S. Government Obligations Risk. The Fund may invest in obligations issued by U.S. Government agencies and instrumentalities that may receive varying levels of support from the government, which could affect the Fund’s ability to recover should they default.           Variable-Rate Demand Notes Risk. The absence of an active secondary market for certain variable and floating rate notes could make it difficult to dispose of the instruments, and a portfolio could suffer a loss if the issuer defaults during periods in which a portfolio is not entitled to exercise its demand rights.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any mutual fund investment, loss of money is a risk of investing.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	Money Market Fund Risk. Although the Fund seeks to preserve the value of your investment at $1.00 per share, you may lose money by investing in the Fund. The share price of money market funds can fall below the $1.00 share price. You should not rely on or expect the Fund’s adviser or its affiliates to enter into support agreements or take other actions to maintain the Fund’s $1.00 share price. The credit quality of the Fund’s holdings can change rapidly in certain markets, and the default of a single holding could have an adverse impact on the Fund’s share price. The Fund’s share price can also be negatively affected during periods of high redemption pressures and/or illiquid markets. Further regulation could impact the way the Fund is managed, possibly negatively impacting its return. Additionally, the Fund’s yield will vary as the short-term securities in its portfolio mature or are sold and the proceeds are reinvested in other securities.
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 Fund’s past performance 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.
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 is not necessarily an indication of its future performance.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Class A5 shares year-to-date (ended March 31, 2012): 0.01% Best Quarter (ended March 31, 2011, June 30, 2011, September 30, 2011 and December 31, 2011): 0.01% Worst Quarter (ended March 31, 2011, June 30, 2011, September 30, 2011 and December 31, 2011): 0.01%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for the periods ended December 31, 2011)
Performance Table Closing [Text Block]	rr_PerformanceTableClosingTextBlock	Class A5 shares’ seven day yield on December 30, 2011, was 0.02%. For the current seven day yield, call (800) 959-4246.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 959-4246
Money Market Seven Day Yield	rr_MoneyMarketSevenDayYield	0.02%
Class A5, B5 And C5 | Invesco Money Market Fund | Class A5
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 (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.38%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.15%
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.31%
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	0.84%
1 Year	rr_ExpenseExampleYear01	86
3 Years	rr_ExpenseExampleYear03	268
5 Years	rr_ExpenseExampleYear05	466
10 Years	rr_ExpenseExampleYear10	1,037
1 Year	rr_ExpenseExampleNoRedemptionYear01	86
3 Years	rr_ExpenseExampleNoRedemptionYear03	268
5 Years	rr_ExpenseExampleNoRedemptionYear05	466
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,037
2011	rr_AnnualReturn2011	0.03%
Year to Date Return, Label	rr_YearToDateReturnLabel	Class A5 shares year-to-date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.01%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2011
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.01%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.01%
1 Year	rr_AverageAnnualReturnYear01	0.03%	[1]
5 Years	rr_AverageAnnualReturnYear05	1.32%	[1]
10 Years	rr_AverageAnnualReturnYear10	1.52%	[1]
Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 07, 2010
Class A5, B5 And C5 | Invesco Money Market Fund | Class B5
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	5.00%
Management Fees (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.38%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.90%
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.31%
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	1.59%
1 Year	rr_ExpenseExampleYear01	662
3 Years	rr_ExpenseExampleYear03	802
5 Years	rr_ExpenseExampleYear05	1,066
10 Years	rr_ExpenseExampleYear10	1,688
1 Year	rr_ExpenseExampleNoRedemptionYear01	162
3 Years	rr_ExpenseExampleNoRedemptionYear03	502
5 Years	rr_ExpenseExampleNoRedemptionYear05	866
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,688
1 Year	rr_AverageAnnualReturnYear01	(4.97%)	[2]
5 Years	rr_AverageAnnualReturnYear05	0.41%	[2]
10 Years	rr_AverageAnnualReturnYear10	0.88%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 07, 2010
Class A5, B5 And C5 | Invesco Money Market Fund | Class C5
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	1.00%
Management Fees (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.38%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.90%
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.31%
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	1.59%
1 Year	rr_ExpenseExampleYear01	262
3 Years	rr_ExpenseExampleYear03	502
5 Years	rr_ExpenseExampleYear05	866
10 Years	rr_ExpenseExampleYear10	1,889
1 Year	rr_ExpenseExampleNoRedemptionYear01	162
3 Years	rr_ExpenseExampleNoRedemptionYear03	502
5 Years	rr_ExpenseExampleNoRedemptionYear05	866
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,889
1 Year	rr_AverageAnnualReturnYear01	(0.97%)	[2]
5 Years	rr_AverageAnnualReturnYear05	0.80%	[2]
10 Years	rr_AverageAnnualReturnYear10	0.88%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 07, 2010

[1] Class A5 shares' performance shown prior to the inception date is that of the Fund's Invesco Cash Reserve Shares and includes the 12b-1 fees applicable to Invesco Cash Reserve Shares.

[2] Class B5 and Class C5 shares' performance shown prior to the inception date is that of the Fund's Invesco Cash Reserve Shares restated to reflect the higher the 12b-1 fees applicable to Invesco Cash Reserve Shares.