Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	COLUMBIA FUNDS SERIES TRUST I
Prospectus Date	rr_ProspectusDate	Sep. 01, 2013
Columbia U.S. Treasury Index Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary of the Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Columbia U.S. Treasury Index Fund (the Fund) seeks total return that corresponds to the total return of the Citigroup Bond U.S. Treasury Index, before fees and expenses.
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 members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. More information about these and other discounts is available from your financial intermediary, in the Choosing a Share Class section beginning on page 17 of the Fund’s prospectus and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.
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	August 31, 2014
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay 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 99% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	99.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. More information about these and other discounts is available from your financial intermediary, in the Choosing a Share Class section beginning on page 17 of the Fund’s prospectus and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 50,000
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Other expenses for Class R5 are based on estimated amounts for the Fund’s current fiscal year.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following 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 illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that: you invest $10,000 in the applicable class of Fund shares for the periods indicated, your investment has a 5% return each year, and the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above. Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in securities that comprise the Citigroup Bond U.S. Treasury Index (the Index). The Index is an unmanaged index composed of U.S. Treasury notes and bonds with remaining maturities of at least one year and outstanding principal of at least $5 billion and which are included in the Citigroup Broad Investment-Grade Bond Index. Different securities have different weightings in the Index. Securities in the Index are weighted by market value, that is, the price per bond or note multiplied by the number of bonds or notes outstanding. In seeking to match the performance of the Index, before fees and expenses, the investment manager attempts to allocate the Fund’s assets among securities in the Index. The Fund will not hold all of the securities in the Index.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and Fund share price may go down. Credit Risk. Credit risk is the risk that the issuer of a fixed-income security may or will default or otherwise become unable or unwilling, or is perceived to be unable or unwilling, to honor a financial obligation, such as making payments to the Fund when due. If the Fund purchases unrated securities, or if the rating of a security is lowered after purchase, the Fund will depend on analysis of credit risk more heavily than usual. Unrated securities held by the Fund may present increased credit risk as compared to higher-rated securities. Index Risk.  The Fund's value will generally decline when the performance of its targeted index declines. In addition, because the Fund may not hold all issues included in its index, it may not always be fully invested. The Fund also bears advisory, administrative and other expenses and transaction costs in trading securities, which the index does not bear. Accordingly, the Fund's performance will likely fail to match the performance of its targeted index, after taking expenses into account. It is not possible to invest directly in an index. Interest Rate  Risk. Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates rise, the values of debt securities will tend to fall, and if interest rates fall, the values of debt securities will tend to rise. Changes in the value of a debt security usually will not affect the amount of income the Fund receives from it but may affect the value of the Fund's shares. In general, the longer the maturity or duration of a debt security, the greater its sensitivity to changes in interest rates. Interest rate declines also may increase prepayments of debt obligations, which, in turn, would increase prepayment risk. As interest rates rise or spreads widen, the likelihood of prepayment decreases. Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or even long periods. Tracking Error Risk. The Fund will not track its benchmark index perfectly and the Fund may not outperform the index. The tools that the Investment Manager uses to replicate the index are not perfect and the Fund’s performance may be impacted by the size of the Fund’s portfolio, the effectiveness of sampling techniques, transaction costs, management fees and expenses, brokerage commissions and fees, the extent and timing of cash flows in and out of the Fund and changes in the index. U.S. Government Obligations Risk. While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government.
Risk Lose Money [Text]	rr_RiskLoseMoney	There is no assurance that the Fund will achieve its investment objective and you may lose money.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class A share performance (without sales charges) has varied for each full calendar year shown. If the sales charges were reflected, returns shown would be lower. Class A share performance (without sales charges) is shown in the bar chart because Class A shares have at least ten calendar years of performance and Class A shares are the most common share class across the Columbia Funds complex that are available for investment by the general public. The table below the bar chart compares the Fund’s returns (after applicable sales charges) for the periods shown with benchmark performance. The performance of one or more share classes shown in the table below begins before the indicated inception date for such share class. The returns shown for each such share class include the returns of the Fund’s Class Z shares (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to its inception date. Except for differences in annual returns resulting from differences in expenses and sales charges (where applicable), the share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. The after-tax returns shown in the table below are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class A shares and will vary for other share classes. Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares. After-tax returns are shown for Class A shares because Class A shares have at least ten calendar years of performance and Class A shares are the most common share class across the Columbia Funds complex that are available for investment by the general public. The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class A share performance (without sales charges) has varied for each full calendar year shown. If the sales charges were reflected, returns shown would be lower. Class A share performance (without sales charges) is shown in the bar chart because Class A shares have at least ten calendar years of performance and Class A shares are the most common share class across the Columbia Funds complex that are available for investment by the general public. The table below the bar chart compares the Fund’s returns (after applicable sales charges) for the periods shown with benchmark performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800.345.6611
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	columbiamanagement.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year by Year Total Return (%) as of December 31 Each Year
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The bar chart shows how the Fund’s Class A share performance (without sales charges) has varied for each full calendar year shown. If the sales charges were reflected, returns shown would be lower.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best                            4th Quarter 2008                            8.75% Worst                         2nd Quarter 2004                            -3.27%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2012)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns shown in the table below are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	The after-tax returns are shown only for Class A shares and will vary for other share classes.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares.
Columbia U.S. Treasury Index Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.75%
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.66%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	0.45%
1 year	rr_ExpenseExampleYear01	519
3 years	rr_ExpenseExampleYear03	656
5 years	rr_ExpenseExampleYear05	805
10 years	rr_ExpenseExampleYear10	1,239
1 year	rr_ExpenseExampleNoRedemptionYear01	519
3 years	rr_ExpenseExampleNoRedemptionYear03	656
5 years	rr_ExpenseExampleNoRedemptionYear05	805
10 years	rr_ExpenseExampleNoRedemptionYear10	1,239
2003	rr_AnnualReturn2003	1.63%	[3]
2004	rr_AnnualReturn2004	2.85%	[3]
2005	rr_AnnualReturn2005	2.24%	[3]
2006	rr_AnnualReturn2006	2.51%	[3]
2007	rr_AnnualReturn2007	8.55%	[3]
2008	rr_AnnualReturn2008	13.57%	[3]
2009	rr_AnnualReturn2009	(4.01%)	[3]
2010	rr_AnnualReturn2010	5.41%	[3]
2011	rr_AnnualReturn2011	9.18%	[3]
2012	rr_AnnualReturn2012	1.51%	[3]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year to Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(2.24%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2008
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	8.75%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2004
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.27%)
1 Year	rr_AverageAnnualReturnYear01	(3.33%)
5 Years	rr_AverageAnnualReturnYear05	3.95%
10 Years	rr_AverageAnnualReturnYear10	3.73%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 25, 2002
Columbia U.S. Treasury Index Fund | Class B
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	5.00%	[4]
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	1.41%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	1.20%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	This charge decreases over time.
1 year	rr_ExpenseExampleYear01	622
3 years	rr_ExpenseExampleYear03	726
5 years	rr_ExpenseExampleYear05	951
10 years	rr_ExpenseExampleYear10	1,468
1 year	rr_ExpenseExampleNoRedemptionYear01	122
3 years	rr_ExpenseExampleNoRedemptionYear03	426
5 years	rr_ExpenseExampleNoRedemptionYear05	751
10 years	rr_ExpenseExampleNoRedemptionYear10	1,468
1 Year	rr_AverageAnnualReturnYear01	(4.12%)
5 Years	rr_AverageAnnualReturnYear05	3.83%
10 Years	rr_AverageAnnualReturnYear10	3.46%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 25, 2002
Columbia U.S. Treasury Index Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[5]
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	1.41%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	1.20%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	This charge applies to redemptions within one year of purchase, with certain limited exceptions.
1 year	rr_ExpenseExampleYear01	222
3 years	rr_ExpenseExampleYear03	426
5 years	rr_ExpenseExampleYear05	751
10 years	rr_ExpenseExampleYear10	1,673
1 year	rr_ExpenseExampleNoRedemptionYear01	122
3 years	rr_ExpenseExampleNoRedemptionYear03	426
5 years	rr_ExpenseExampleNoRedemptionYear05	751
10 years	rr_ExpenseExampleNoRedemptionYear10	1,673
1 Year	rr_AverageAnnualReturnYear01	(0.07%)
5 Years	rr_AverageAnnualReturnYear05	4.33%
10 Years	rr_AverageAnnualReturnYear10	3.62%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 25, 2002
Columbia U.S. Treasury Index Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.41%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	0.20%
1 year	rr_ExpenseExampleYear01	20
3 years	rr_ExpenseExampleYear03	110
5 years	rr_ExpenseExampleYear05	209
10 years	rr_ExpenseExampleYear10	497
1 year	rr_ExpenseExampleNoRedemptionYear01	20
3 years	rr_ExpenseExampleNoRedemptionYear03	110
5 years	rr_ExpenseExampleNoRedemptionYear05	209
10 years	rr_ExpenseExampleNoRedemptionYear10	497
1 Year	rr_AverageAnnualReturnYear01	1.76%
5 Years	rr_AverageAnnualReturnYear05	5.22%
10 Years	rr_AverageAnnualReturnYear10	4.49%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 27, 2010
Columbia U.S. Treasury Index Fund | Class R5
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.41%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	0.20%
1 year	rr_ExpenseExampleYear01	20
3 years	rr_ExpenseExampleYear03	110
5 years	rr_ExpenseExampleYear05	209
10 years	rr_ExpenseExampleYear10	497
1 year	rr_ExpenseExampleNoRedemptionYear01	20
3 years	rr_ExpenseExampleNoRedemptionYear03	110
5 years	rr_ExpenseExampleNoRedemptionYear05	209
10 years	rr_ExpenseExampleNoRedemptionYear10	497
1 Year	rr_AverageAnnualReturnYear01	1.76%
5 Years	rr_AverageAnnualReturnYear05	5.22%
10 Years	rr_AverageAnnualReturnYear10	4.49%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 08, 2012
Columbia U.S. Treasury Index Fund | Class W
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.66%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	0.45%
1 year	rr_ExpenseExampleYear01	46
3 years	rr_ExpenseExampleYear03	190
5 years	rr_ExpenseExampleYear05	347
10 years	rr_ExpenseExampleYear10	803
1 year	rr_ExpenseExampleNoRedemptionYear01	46
3 years	rr_ExpenseExampleNoRedemptionYear03	190
5 years	rr_ExpenseExampleNoRedemptionYear05	347
10 years	rr_ExpenseExampleNoRedemptionYear10	803
1 Year	rr_AverageAnnualReturnYear01	1.41%
5 Years	rr_AverageAnnualReturnYear05	4.76%
10 Years	rr_AverageAnnualReturnYear10	4.03%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 18, 2012
Columbia U.S. Treasury Index Fund | Class Z
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.10%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.31%	[1]
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.41%
Less: Fee waivers and/or expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[2]
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	rr_NetExpensesOverAssets	0.20%
1 year	rr_ExpenseExampleYear01	20
3 years	rr_ExpenseExampleYear03	110
5 years	rr_ExpenseExampleYear05	209
10 years	rr_ExpenseExampleYear10	497
1 year	rr_ExpenseExampleNoRedemptionYear01	20
3 years	rr_ExpenseExampleNoRedemptionYear03	110
5 years	rr_ExpenseExampleNoRedemptionYear05	209
10 years	rr_ExpenseExampleNoRedemptionYear10	$ 497
1 Year	rr_AverageAnnualReturnYear01	1.76%
5 Years	rr_AverageAnnualReturnYear05	5.22%
10 Years	rr_AverageAnnualReturnYear10	4.49%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 04, 1991
Columbia U.S. Treasury Index Fund | returns after taxes on distributions | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.35%)
5 Years	rr_AverageAnnualReturnYear05	2.73%
10 Years	rr_AverageAnnualReturnYear10	2.39%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 25, 2002
Columbia U.S. Treasury Index Fund | returns after taxes on distributions and sale of Fund shares | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.84%)
5 Years	rr_AverageAnnualReturnYear05	2.71%
10 Years	rr_AverageAnnualReturnYear10	2.41%
Share Class Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 25, 2002
Columbia U.S. Treasury Index Fund | Citigroup Bond U.S. Treasury Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.97%
5 Years	rr_AverageAnnualReturnYear05	5.34%
10 Years	rr_AverageAnnualReturnYear10	4.73%

[1] Other expenses for Class R5 are based on estimated amounts for the Fund's current fiscal year.

[2] Columbia Management Investment Advisers, LLC and certain of its affiliates have contractually agreed to waive fees and/or to reimburse expenses (excluding certain fees and expenses, such as transaction costs and certain other investment related expenses, interest, taxes, acquired fund fees and expenses, and extraordinary expenses) until August 31, 2014, unless sooner terminated at the sole discretion of the Fund's Board of Trustees. Under this agreement, the Fund's net operating expenses, subject to applicable exclusions, will not exceed the annual rates of 0.45% for Class A, 1.20% for Class B, 1.20% for Class C, 0.20% for Class I, 0.20% for Class R5, 0.45% for Class W and 0.20% for Class Z.

[3] Year to Date return as of June 30, 2013: -2.24%

[4] This charge decreases over time.

[5] This charge applies to redemptions within one year of purchase, with certain limited exceptions.