S 000006850 Summary1 [Member] Prospectus Summary Prospectus Summary S 000006850 [Member] FRANKLIN ADJUSTABLE U.S. GOVERNMENT SECURITIES FUND FRANKLIN ADJUSTABLE U.S. GOVERNMENT SECURITIES FUND C 000018509 [Member] Class A Class A C 000140480 [Member] Class A1 Class A1 C 000018510 [Member] Class C Class C C 000133492 [Member] Class R6 Class R6 C 000064441 [Member] Advisor Class Advisor Class cik0000225375_BloombergUSGovernment1-2YearIndex1Member [Member] Bloomberg US Government (1-2 Year) Index Bloomberg US Government (1-2 Year) Index S 000006911 Summary2 [Member] Prospectus Summary Prospectus Summary S 000006911 [Member] FRANKLIN ALABAMA TAX-FREE INCOME FUND FRANKLIN ALABAMA TAX-FREE INCOME FUND C 000205892 [Member] Class A Class A C 000018753 [Member] CLASS A1 CLASS A1 C 000018754 [Member] CLASS C CLASS C C 000194353 [Member] Class R6 Class R6 C 000173665 [Member] Advisor Class Advisor Class cik0000225375_BloombergBarclaysMunicipalBondIndex2Member [Member] Bloomberg Barclays Municipal Bond Index Bloomberg Barclays Municipal Bond Index S 000006930 Summary3 [Member] Prospectus Summary Prospectus Summary S 000006930 [Member] FRANKLIN CONNECTICUT TAX-FREE INCOME FUND FRANKLIN CONNECTICUT TAX-FREE INCOME FUND C 000205909 [Member] Class A Class A C 000018798 [Member] CLASS A1 CLASS A1 C 000018799 [Member] CLASS C CLASS C C 000194371 [Member] Class R6 Class R6 C 000079644 [Member] ADVISOR CLASS ADVISOR CLASS cik0000225375_BloombergBarclaysMunicipalBondIndex3Member [Member] Bloomberg Barclays Municipal Bond Index Bloomberg Barclays Municipal Bond Index Amendment Flag Amendment Flag Document Creation Date Document Creation Date Prospectus Prospectus Document Effective Date Document Effective Date Document [Axis] Document [Axis] Document Period End Date Document Period End Date Document Type Document Type Entity Central Index Key Entity Central Index Key EntityInvCompanyType EntityInvCompanyType Registrant Name Registrant Name Series [Axis] Series [Axis] After Taxes on Distributions and Sales After Taxes on Distributions and Sales After Taxes on Distributions After Taxes on Distributions Annual Fund Operating Expenses [Table] Annual Fund Operating Expenses [Table] Annual Return 2011 Annual Return 2011 Annual Return 2012 Annual Return 2012 Annual Return 2013 Annual Return 2013 Annual Return 2014 Annual Return 2014 Annual Return 2015 Annual Return 2015 Annual Return 2016 Annual Return 2016 Annual Return 2017 Annual Return 2017 Annual Return 2018 Annual Return 2018 Annual Return 2019 Annual Return 2019 Annual Return 2020 Annual Return 2020 Annual Return 2021 Annual Return 2021 Label Label Since Inception Since Inception 1 Year 1 Year 5 Years 5 Years 10 Years 10 Years Bar Chart and Performance Table [Heading] Bar Chart and Performance Table [Heading] Bar Chart Closing [Text Block] Bar Chart Closing [Text Block] Bar Chart Does Not Reflect Sales Loads [Text] Bar Chart Does Not Reflect Sales Loads [Text] Bar Chart [Heading] Bar Chart [Heading] Highest Quarterly Return Highest Quarterly Return Highest Quarterly Return, Date Highest Quarterly Return, Date Lowest Quarterly Return Lowest Quarterly Return Lowest Quarterly Return, Date Lowest Quarterly Return, Date Bar Chart [Table] Bar Chart [Table] Bar Chart, Year to Date Return Bar Chart, Year to Date Return Bar Chart, Year to Date Return, Date Bar Chart, Year to Date Return, Date Expense Breakpoint Discounts [Text] Expense Breakpoint Discounts [Text] Expense Breakpoint, Minimum Investment Required [Amount] Expense Breakpoint, Minimum Investment Required [Amount] Expense Example [Heading] Expense Example [Heading] Expense Example Narrative [Text Block] Expense Example Narrative [Text Block] Expense Example, No Redemption, By Year, Caption [Text] Expense Example, No Redemption, By Year, Caption [Text] Expense Example, No Redemption [Table] Expense Example, No Redemption [Table] Expense Example, No Redemption, 1 Year 1 Year Expense Example, No Redemption, 3 Years 3 Years Expense Example, No Redemption, 5 Years 5 Years Expense Example, No Redemption, 10 Years 10 Years Expense Example, With Redemption [Table] Expense Example, With Redemption [Table] Expense Example, with Redemption, 1 Year 1 Year Expense Example, with Redemption, 3 Years 3 Years Expense Example, with Redemption, 5 Years 5 Years Expense Example, with Redemption, 10 Years 10 Years Expense [Heading] Expense [Heading] Expense Narrative [Text Block] Expense Narrative [Text Block] Highest Quarterly Return, Label Label Index No Deduction for Fees, Expenses, Taxes [Text] Index No Deduction for Fees, Expenses, Taxes [Text] Lowest Quarterly Return, Label Label Market Index Performance [Table] Market Index Performance [Table] Maximum Deferred Sales Charge (as a percentage of Offering Price) Maximum Deferred Sales Charge (as a percentage of Offering Price) Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) Objective [Heading] Objective [Heading] Objective, Primary [Text Block] Objective, Primary [Text Block] Operating Expenses Caption [Text] Operating Expenses Caption [Text] Performance Availability Phone [Text] Performance Availability Phone [Text] Performance Availability Website Address [Text] Performance Availability Website Address [Text] Performance Information Illustrates Variability of Returns [Text] Performance Information Illustrates Variability of Returns [Text] Performance Measure [Axis] Performance Measure [Axis] Before Taxes Before Taxes Performance Narrative [Text Block] Performance Narrative [Text Block] Performance One Year or Less [Text] Performance One Year or Less [Text] Performance Past Does Not Indicate Future [Text] Performance Past Does Not Indicate Future [Text] Performance Table Closing [Text Block] Performance Table Closing [Text Block] Performance Table Heading Performance Table Heading Performance [Table] Performance [Table] Portfolio Turnover [Heading] Portfolio Turnover [Heading] Portfolio Turnover, Rate Portfolio Turnover, Rate Portfolio Turnover [Text Block] Portfolio Turnover [Text Block] Share Class [Axis] Share Class [Axis] Prospectus: Prospectus: Risk [Heading] Risk [Heading] Risk Lose Money [Text] Risk Lose Money [Text] Risk Money Market Fund May Not Preserve Dollar [Text] Risk Money Market Fund May Not Preserve Dollar [Text] Risk Money Market Fund Price Fluctuates [Text] Risk Money Market Fund Price Fluctuates [Text] Risk Money Market Fund Sponsor May Not Provide Support [Text] Risk Money Market Fund Sponsor May Not Provide Support [Text] Risk Narrative [Text Block] Risk Narrative [Text Block] Risk Nondiversified Status [Text] Risk Nondiversified Status [Text] Risk Not Insured Depository Institution [Text] Risk Not Insured Depository Institution [Text] Risk/Return: Risk/Return: Risk/Return [Heading] Risk/Return [Heading] Shareholder Fees Caption [Text] Shareholder Fees Caption [Text] Shareholder Fees [Table] Shareholder Fees [Table] Strategy [Heading] Strategy [Heading] Strategy Narrative [Text Block] Strategy Narrative [Text Block] Strategy Portfolio Concentration [Text] Strategy Portfolio Concentration [Text] Year to Date Return, Label Year to Date Return, Label Management fees Distribution and service (12b-1) fees Other expenses Total annual Fund operating expenses Fee waiver and/or expense reimbursement Total annual Fund operating expenses after fee waiver and/or expense reimbursement