2.4.0.8040000 - Disclosure - Risk/Return Detail Data {Elements}truetruefalse1false falsefalseThttp://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:001true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse02false 2dei_DocumentTypedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00485BPOSfalsefalsefalsedei:submissionTypeItemTypestringThe type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word "Other".No definition available.false03false 2dei_DocumentPeriodEndDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-04-30falsefalsetruexbrli:dateItemTypedateThe end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.No definition available.false04false 2dei_EntityRegistrantNamedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00FRANKLIN FEDERAL TAX FREE INCOME FUNDfalsefalsefalsexbrli:normalizedStringItemTypenormalizedstringThe exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false05false 2dei_EntityCentralIndexKeydei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse000000357310falsefalsefalsedei:centralIndexKeyItemTypenaA unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false06false 2dei_AmendmentFlagdei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsexbrli:booleanItemTypenaIf the value is true, then the document is an amendment to previously-filed/accepted document.No definition available.false07false 2dei_DocumentCreationDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-08-27falsefalsetruexbrli:dateItemTypedateThe date the document was made available and submitted, in CCYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.No definition available.false08false 2dei_DocumentEffectiveDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-09-01falsefalsetruexbrli:dateItemTypedateThe date when a document, upon receipt and acceptance, becomes officially effective, in CCYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.No definition available.false09false 2rr_ProspectusDaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-09-01falsefalsetruexbrli:dateItemTypedateThe date of the prospectus.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 1 -Subsection a -Paragraph 3 false010false 2rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Fund Summaryfalsefalsefalsexbrli:stringItemTypestringRisk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicatedReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 false011false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2false USDtruefalse$S000006760http://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse012true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse013false 2rr_ObjectiveHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Investment Goalfalsefalsefalsexbrli:stringItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a false014false 2rr_ObjectivePrimaryTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00To provide investors with as high a level of income exempt from federal income taxes as is consistent with prudent investment management and the preservation of shareholders’ capital.falsefalsefalsenonnum:textBlockItemTypenaInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a false015false 2rr_ExpenseHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Fees and Expenses of the Fundfalsefalsefalsexbrli:stringItemTypestringRisk/Return Summary Fee Table Includes the following information, in plain English under rule 421(d) under the Securities Act, after Item 2 Fees and expenses of the Fund This table describes the fees and expenses that you may pay if you buy and hold shared 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 $[_____] in [name of fund family] funds. Shareholder Fees (fees paid directly from your investment) Example 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 you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be You would pay the following expenses if you did not redeem your shares The Example does not reflect sales charges (loads) on reinvested dividends [and other distributions]. If these sales charges (loads) were included, your costs would be higher. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs. 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 __% of the average value of its whole portfolio. Instructions. A.3.instructions.6 New Funds. For purposes of this Item, a "New Fund" is a Fund that does not include in Form N-1A financial statements reporting operating results or that includes financial statements for the Fund's initial fiscal year reporting operating results for a period of 6 months or less. The following Instructions apply to New Funds.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 1 -Subparagraph d false016false 2rr_ExpenseNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00These tables describe the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts in Class A if you and your family invest, or agree to invest in the future, at least $100,000 in Franklin Templeton funds. More information about these and other discounts is available from your financial professional and under “Your Account” on page 25 in the Fund's Prospectus and under “Buying and Selling Shares” on page 36 of the Fund’s Statement of Additional Information.falsefalsefalsenonnum:textBlockItemTypenaThis table describes the fees and expenses that you may pay if you buy and hold shared 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 $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 1 -Subparagraph b false017false 2rr_ShareholderFeesCaptionrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00SHAREHOLDER FEES (fees paid directly from your investment)falsefalsefalsexbrli:stringItemTypestringShareholder Fees (fees paid directly from your investment).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 false018false 2rr_OperatingExpensesCaptionrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>ANNUAL FUND OPERATING EXPENSES</p><p>(expenses that you pay each year as a percentage of the value of your investment)</p></div>falsefalsefalsexbrli:stringItemTypestringAnnual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investment)Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 7 false019false 2rr_PortfolioTurnoverHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Portfolio Turnoverfalsefalsefalsexbrli:stringItemTypestringDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 5 false020false 2rr_PortfolioTurnoverTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>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 6.31% of the average value of its portfolio.</p></div>falsefalsefalsenonnum:textBlockItemTypenaDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 3 false021false 2rr_PortfolioTurnoverRaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.06310.0631falsefalsefalsexbrli:pureItemTypepureThis element represents the rate of portfolio turnover presented as a percentage (SEC Form N-1A 2006-09-14 A.3.example.3 Portfolio Turnover A.3.instructions.5 Portfolio Turnover).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 3 false022false 2rr_ExpenseBreakpointDiscountsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00You may qualify for sales charge discounts in Class A if you and your family invest, or agree to invest in the future, at least $100,000 in Franklin Templeton funds.falsefalsefalsexbrli:stringItemTypestringInclude the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 1 -Subparagraph b false023false 2rr_ExpenseBreakpointMinimumInvestmentRequiredAmountrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse100000100000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThis element represents the minimum level of investment required to qualify for discounted sales charges or fund expenses (SEC Form N-1A 2006-09-14 A.3.instructions.1.b).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 1 -Subparagraph b false224false 2rr_ExpenseExampleHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Examplefalsefalsefalsexbrli:stringItemTypestringHeading for Expense Example.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 false025false 2rr_ExpenseExampleNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00This 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 the period. 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:falsefalsefalsenonnum:textBlockItemTypenaThe Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 1 false026false 2rr_ExpenseExampleNoRedemptionByYearCaptionrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00If you do not sell your shares:falsefalsefalsexbrli:stringItemTypestringYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 2 -Subparagraph 1 false027false 2rr_StrategyHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Principal Investment Strategiesfalsefalsefalsexbrli:stringItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a false028false 2rr_StrategyNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>Under normal market conditions, the Fund invests at least 80% of its total assets in investment grade municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the Fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the Fund's total assets may be in securities that pay interest that may be subject to the federal alternative minimum tax and, although not anticipated, in securities that pay taxable interest.</p><p>The Fund only buys municipal securities rated, at the time of purchase, in one of the top four ratings categories by one or more U.S. nationally recognized rating services (or comparable unrated or short-term rated securities).</p><p>The Fund does not necessarily focus its investments in a particular state. The Fund may invest in municipal securities issued by U.S. territories, such as Puerto Rico.</p><p>Although the investment manager will search for investments across a large number of municipal securities that finance different types of projects, from time to time, based on economic conditions, the Fund may have significant positions in municipal securities that finance similar types of projects.</p><p>The investment manager selects securities that it believes will provide the best balance between risk and return within the Fund&#146;s range of allowable investments and typically uses a buy and hold strategy. This means it generally holds securities in the Fund&#146;s portfolio for income purposes, rather than trading securities for capital gains, although the investment manager may sell a security at any time if it believes it could help the Fund meet its goal.</p></div>falsefalsefalsenonnum:textBlockItemTypenaPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a false029false 2rr_StrategyPortfolioConcentrationrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Under normal market conditions, the Fund invests at least 80% of its total assets in investment grade municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax.falsefalsefalsexbrli:stringItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a false030false 2rr_RiskHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Principal Risksfalsefalsefalsexbrli:stringItemTypestringNarrative Risk Disclosure.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 1 false031false 2rr_RiskNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>You could lose money by investing in the Fund. Mutual fund shares are not deposits or obligations of, or guaranteed or endorsed by, any bank, and are not insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. government.</p><p>Interest Rate</p><p>When interest rates rise, debt security prices generally fall. The opposite is also generally true: debt security prices rise when interest rates fall. In general, securities with longer maturities are more sensitive to these interest rate changes.</p><p>Market</p><p>The market values of securities owned by the Fund will go up or down, sometimes rapidly or unpredictably. A security&#146;s market value may be reduced by market activity or other results of supply and demand unrelated to the issuer. This is a basic risk associated with all securities. When there are more sellers than buyers, prices tend to fall. Likewise, when there are more buyers than sellers, prices tend to rise.</p><p>Credit</p><p>An issuer of debt securities may fail to make interest payments and repay principal when due, in whole or in part. Changes in an issuer's financial strength or in a security's credit rating may affect a security's value.</p><p>A change in the credit rating of a municipal bond insurer that insures securities in the Fund&#146;s portfolio may affect the value of the securities it insures, the Fund&#146;s share price and Fund performance. The Fund might also be adversely impacted by the inability of an insurer to meet its insurance obligations.</p><p>Focus</p><p>The Fund may invest more than 25% of its assets in municipal securities that finance similar types of projects, such as utilities, hospitals, higher education and transportation. A change that affects one project, such as proposed legislation on the financing of the project, a shortage of the materials needed for the project, or a declining need for the project, would likely affect all similar projects, thereby increasing market risk.</p><p>Tax-Exempt Securities</p><p>While the Fund endeavors to purchase only bona fide tax-exempt securities, there are risks that: (a) a security issued as tax-exempt may be reclassified as taxable by the Internal Revenue Service or a state tax authority, and/or (b) future legislative, administrative or court actions could adversely impact the qualification of income from a tax-exempt security as tax-free. Such reclassifications or actions could cause interest from a security to become taxable, possibly retroactively, subjecting you to increased tax liability.</p><p>Income</p><p>Because the Fund can only distribute what it earns, the Fund's distributions to shareholders may decline when prevailing interest rates fall or when the Fund experiences defaults on debt securities it holds.</p><p>Prepayment</p><p>Prepayment risk occurs when a debt security can be repaid in whole or in part prior to the security's maturity and the Fund must reinvest the proceeds it receives, during periods of declining interest rates, in securities that pay a lower rate of interest.</p><p>States and U.S. Territories</p><p>The Fund&#146;s portfolio is generally widely diversified among issuers of municipal securities. From time to time, however, the Fund may have a significant position in the municipal securities of a particular state or territory, such as Puerto Rico. Under these circumstances, changes in the economic conditions in that state or territory are likely to affect the Fund&#146;s investments and performance.</p><p>Management</p><p>The Fund is subject to management risk because it is an actively managed investment portfolio. The Fund's investment manager applies investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that these decisions will produce the desired results.</p></div>falsefalsefalsenonnum:textBlockItemTypenaNarrative Risk Disclosure. A Fund may, in responding to this Item, describe the types of investors for whom the Fund is intended or the types of investment goals that may be consistent with an investment in the Fund.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 1 -Subparagraph i -Clause instruction false032false 2rr_BarChartAndPerformanceTableHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Performancefalsefalsefalsexbrli:stringItemTypestringRisk/Return Bar Chart and Table.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 false033false 2rr_PerformanceNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund's performance from year to year for Class A shares. The table shows how the Fund's average annual returns for 1 year, 5 years, 10 years or since inception, as applicable, compared with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You can obtain updated performance information at franklintempleton.com or by calling (800) DIAL BEN/342-5236.</p><p>Sales charges are not reflected in the bar chart, and if those charges were included, returns would be less than those shown.</p></div>falsefalsefalsenonnum:textBlockItemTypenaRisk/Return Bar Chart and Table.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 false034false 2rr_PerformanceInformationIllustratesVariabilityOfReturnsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund's performance from year to year for Class A shares. The table shows how the Fund's average annual returns for 1 year, 5 years, 10 years or since inception, as applicable, compared with those of a broad measure of market performance.falsefalsefalsexbrli:stringItemTypestringInclude the bar chart and table required by paragraphs (b)(2)(ii) and (iii) of this section. Provide a brief explanation of how the information illustrates the variability of the Fund's returns (e.g., by stating that the information provides some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance). Provide a statement to the effect that the Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph i false035false 2rr_PerformanceAvailabilityPhonerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00(800) DIAL BEN/342-5236falsefalsefalsexbrli:stringItemTypestringIf applicable, include a statement explaining that updated performance information is available and providing a Web site address and/or toll-free (or collect) telephone number where the updated information may be obtained.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph i false036false 2rr_PerformanceAvailabilityWebSiteAddressrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00franklintempleton.comfalsefalsefalsexbrli:stringItemTypestringIf applicable, include a statement explaining that updated performance information is available and providing a Website address and/or toll-free (or collect) telephone number where the updated information may be obtained.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph i false037false 2rr_PerformancePastDoesNotIndicateFuturerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.falsefalsefalsexbrli:stringItemTypestringInclude the bar chart and table required by paragraphs (b)(2)(ii) and (iii) of this section. Provide a brief explanation of how the information illustrates the variability of the Fund's returns (e.g., by stating that the information provides some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance). Provide a statement to the effect that the Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph i false038false 2rr_BarChartHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00CLASS A ANNUAL TOTAL RETURNSfalsefalsefalsexbrli:stringItemTypestringRisk/Return Bar Chart and Table.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 false039false 2rr_BarChartDoesNotReflectSalesLoadsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Sales charges are not reflected in the bar chart, and if those charges were included, returns would be less than those shown.falsefalsefalsexbrli:stringItemTypestringInclude the bar chart and table required by Item 4 (b)(2)(ii) and (iii) of this section. Provide a brief explanation of how the information illustrates the variability of the Fund's returns (e.g., by stating that the information provides some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance). Provide a statement to the effect that the Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Provide annual total returns beginning with the earliest calendar year. Calculate annual returns using the Instructions to Item 8(a), except that the calculations should be based on calendar years. If a Fund's shares are sold subject to a sales load or account fees, state that sales loads or account fees are not reflected in the bar chart and that, if these amounts were reflected, returns would be less than those shown.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph i false040false 2rr_BarChartClosingTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<table style="font: 11px sans-serif; background-color:#DDDDDD" border="0" cellspacing="0" cellpadding="5" width="745"><tr><td style="border-bottom: 2px solid #ffffff;" valign="top">Best Quarter:</td><td style="border-bottom: 2px solid #ffffff;" valign="bottom" align="right">Q3'09</td><td style="border-bottom: 2px solid #ffffff;" valign="bottom" align="right">8.10%</td></tr><tr><td style="border-bottom: 2px solid #ffffff;" valign="top">Worst Quarter:</td><td style="border-bottom: 2px solid #ffffff;" valign="bottom" align="right">Q4'10</td><td style="border-bottom: 2px solid #ffffff;" valign="bottom" align="right">-5.34%</td></tr><tr><td style="border-bottom: 2px solid #ffffff;" valign="top" colspan="3">As of June 30, 2013, the Fund's year-to-date return was -3.71%.</td></tr></table>falsefalsefalsenonnum:textBlockItemTypenaIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false041false 2rr_PerformanceTableHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>AVERAGE ANNUAL TOTAL RETURNS<br/>(figures reflect sales charges)</p><p>For the periods ended December 31, 2012</p></div>falsefalsefalsexbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit c false042false 2rr_PerformanceTableClosingTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><p>The 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. After-tax returns are shown only for Class A and after-tax returns for other classes will vary.</p></div>falsefalsefalsenonnum:textBlockItemTypenaIf the Fund has annual returns for at least one calendar year, provide a table showing the Fund's (A) average annual total return; (B) average annual total return (after taxes on distributions); and (C) average annual total return (after taxes on distributions and redemption). A Money Market Fund should show only the returns described in clause (A) of the preceding sentence. All returns should be shown for 1-, 5-, and 10- calendar year periods ending on the date of the most recently completed calendar year (or for the life of the Fund, if shorter), but only for periods subsequent to the effective date of the Fund's registration statement. The table also should show the returns of an appropriate broad-based securities market index as defined in Instruction 5 to Item 22(b)(7) for the same periods. A Fund that has been in existence for more than 10 years also may include returns for the life of the Fund. A Money Market Fund may provide the Fund's 7-day yield ending on the date of the most recent calendar year or disclose a toll-free (or collect) telephone number that investors can use to obtain the Fund's current 7-day yield. For a Fund (other than a Money Market Fund or a Fund described in General Instruction C.3.(d)(iii)), provide the information in the following table with the specified captions AVERAGE ANNUAL TOTAL RETURNS (For the periods ended December 31, _____)Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii false043false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse3false truefalseS000006760_Index8http://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseBarclays Municipal Bond Indexrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_Index8Memberrr_PerformanceMeasureAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0nanafalse044true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse045false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.06780.0678falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false046false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05910.0591falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false047false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05100.0510falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false048false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse4false USDtruefalse$S000006760_C000018346http://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseClass Arr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_C000018346Memberrr_ProspectusShareClassAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse049true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse050false 2rr_MaximumCumulativeSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04250.0425falsefalsefalserr:NonNegativePure4TypepureMaximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price). If a sales charge (load) is imposed on shares purchased with reinvested capital gains distributions or returns of capital, include the bracketed words in the third caption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 1 false051false 2rr_MaximumDeferredSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.000.00falsefalsefalserr:NonNegativePure4TypepureMaximum Deferred Sales Charge (Load) (as a percentage of ____) A.3.instructions.2.a.i "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). A.3.instructions.2.a.ii If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 2 -Subparagraph a -Clause i false052false 2rr_ManagementFeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00450.0045falsefalsefalserr:NonNegativePure4TypepureManagement Fees include investment advisory fees (including any fees based on the Fund's performance), any other management fees payable to the investment adviser or its affiliates, and administrative fees payable to the investment adviser or its affiliates that are not included as "Other Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph a false053false 2rr_DistributionAndService12b1FeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00100.0010falsefalsefalserr:NonNegativePure4TypepureDistribution [and/or Service] (12b-1) Fees" include all distribution or other expenses incurred during the most recent fiscal year under a plan adopted pursuant to rule 12b-1 [17 CFR 270.12b-1]. Under an appropriate caption or a subcaption of "Other Expenses," disclose the amount of any distribution or similar expenses deducted from the Fund's assets other than pursuant to a rule 12b-1 plan.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 9 false054false 2rr_OtherExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00060.0006falsefalsefalserr:NonNegativePure4Typepure"Other Expenses" include all expenses not otherwise disclosed in the table that are deducted from the Fund's assets or charged to all shareholder accounts. The amount of expenses deducted from the Fund's assets are the amounts shown as expenses in the Fund's statement of operations (including increases resulting from complying with paragraph 2(g) of rule 6-07 of Regulation S-X [17 CFR 210.6-07]). "Other Expenses" do not include extraordinary expenses as determined under generally accepted accounting principles (see Accounting Principles Board Opinion No. 30). If extraordinary expenses were incurred that materially affected the Fund's "Other Expenses," disclose in a footnote to the table what "Other Expenses" would have been had the extraordinary expenses been included.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph c -Clause i false055false 2rr_ExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00610.0061falsefalsefalserr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses. If the Fund is a Feeder Fund, reflect the aggregate expenses of the Feeder Fund and the Master Fund in a single fee table using the captions provided. In a footnote to the fee table, state that the table and Example reflect the expenses of both the Feeder and Master Funds. If the prospectus offers more than one Class of a Multiple Class Fund or more than one Feeder Fund that invests in the same Master Fund, provide a separate response for each Class or Feeder Fund. Base the percentages of "Annual Fund Operating Expenses" on amounts incurred during the Fund's most recent fiscal year, but include in expenses amounts that would have been incurred absent expense reimbursement or fee waiver arrangements. If the Fund has changed its fiscal year and, as a result, the most recent fiscal year is less than three months, use the fiscal year prior to the most recent fiscal year as the basis for determining "Annual Fund Operating Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph d false056false 2rr_ExpenseExampleYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue485485USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 false257false 2rr_ExpenseExampleYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue612612USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false258false 2rr_ExpenseExampleYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue751751USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false259false 2rr_ExpenseExampleYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue11551155USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false260false 2rr_AnnualReturn2003rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.05840.0584falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a false061false 2rr_AnnualReturn2004rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.05390.0539falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a false062false 2rr_AnnualReturn2005rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.04260.0426falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false063false 2rr_AnnualReturn2006rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.05080.0508falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false064false 2rr_AnnualReturn2007rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.02720.0272falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a false065false 2rr_AnnualReturn2008rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.0705-0.0705falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false066false 2rr_AnnualReturn2009rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.16310.1631falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a false067false 2rr_AnnualReturn2010rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.00860.0086falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false068false 2rr_AnnualReturn2011rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.12120.1212falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a false069false 2rr_AnnualReturn2012rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.09030.0903falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false070false 2rr_YearToDateReturnLabelrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00As of June 30, 2013, the Fund's year-to-date return was -3.71%.falsefalsefalsexbrli:stringItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false071false 2rr_HighestQuarterlyReturnLabelrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Best Quarter:falsefalsefalsexbrli:stringItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false072false 2rr_BarChartHighestQuarterlyReturnDaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002009-09-30falsefalsetruexbrli:dateItemTypedateIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false073false 2rr_BarChartHighestQuarterlyReturnrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.08100.0810falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false074false 2rr_LowestQuarterlyReturnLabelrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Worst Quarter:falsefalsefalsexbrli:stringItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false075false 2rr_BarChartLowestQuarterlyReturnDaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002010-12-31falsefalsetruexbrli:dateItemTypedateIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false076false 2rr_BarChartLowestQuarterlyReturnrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.0534-0.0534falsefalsefalsexbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph ii false077false 2rr_AverageAnnualReturnLabelrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Return Before Taxesfalsefalsefalsexbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false078false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04400.0440falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false079false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05000.0500falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false080false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04830.0483falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false081false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse5false truefalseS000006760_C000018346_AfterTaxesOnDistributionshttp://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseClass Arr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_C000018346Memberrr_ProspectusShareClassAxisexplicitMemberfalsefalseAfter Taxes on Distributionsrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldirr_AfterTaxesOnDistributionsMemberrr_PerformanceMeasureAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0nanafalse082true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse083false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04400.0440falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false084false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05000.0500falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false085false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04830.0483falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false086false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse6false truefalseS000006760_C000018346_AfterTaxesOnDistributionsAndSaleshttp://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseClass Arr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_C000018346Memberrr_ProspectusShareClassAxisexplicitMemberfalsefalseAfter Taxes on Distributions and Salesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldirr_AfterTaxesOnDistributionsAndSalesMemberrr_PerformanceMeasureAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0nanafalse087true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse088false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04240.0424falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false089false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04890.0489falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false090false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04760.0476falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false091false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse7false USDtruefalse$S000006760_C000018348http://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseClass Crr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_C000018348Memberrr_ProspectusShareClassAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse092true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse093false 2rr_MaximumCumulativeSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.000.00falsefalsefalserr:NonNegativePure4TypepureMaximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price). If a sales charge (load) is imposed on shares purchased with reinvested capital gains distributions or returns of capital, include the bracketed words in the third caption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 1 false094false 2rr_MaximumDeferredSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.01000.0100falsefalsefalserr:NonNegativePure4TypepureMaximum Deferred Sales Charge (Load) (as a percentage of ____) A.3.instructions.2.a.i "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). A.3.instructions.2.a.ii If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 2 -Subparagraph a -Clause i false095false 2rr_ManagementFeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00450.0045falsefalsefalserr:NonNegativePure4TypepureManagement Fees include investment advisory fees (including any fees based on the Fund's performance), any other management fees payable to the investment adviser or its affiliates, and administrative fees payable to the investment adviser or its affiliates that are not included as "Other Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph a false096false 2rr_DistributionAndService12b1FeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00650.0065falsefalsefalserr:NonNegativePure4TypepureDistribution [and/or Service] (12b-1) Fees" include all distribution or other expenses incurred during the most recent fiscal year under a plan adopted pursuant to rule 12b-1 [17 CFR 270.12b-1]. Under an appropriate caption or a subcaption of "Other Expenses," disclose the amount of any distribution or similar expenses deducted from the Fund's assets other than pursuant to a rule 12b-1 plan.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 9 false097false 2rr_OtherExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00060.0006falsefalsefalserr:NonNegativePure4Typepure"Other Expenses" include all expenses not otherwise disclosed in the table that are deducted from the Fund's assets or charged to all shareholder accounts. The amount of expenses deducted from the Fund's assets are the amounts shown as expenses in the Fund's statement of operations (including increases resulting from complying with paragraph 2(g) of rule 6-07 of Regulation S-X [17 CFR 210.6-07]). "Other Expenses" do not include extraordinary expenses as determined under generally accepted accounting principles (see Accounting Principles Board Opinion No. 30). If extraordinary expenses were incurred that materially affected the Fund's "Other Expenses," disclose in a footnote to the table what "Other Expenses" would have been had the extraordinary expenses been included.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph c -Clause i false098false 2rr_ExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.01160.0116falsefalsefalserr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses. If the Fund is a Feeder Fund, reflect the aggregate expenses of the Feeder Fund and the Master Fund in a single fee table using the captions provided. In a footnote to the fee table, state that the table and Example reflect the expenses of both the Feeder and Master Funds. If the prospectus offers more than one Class of a Multiple Class Fund or more than one Feeder Fund that invests in the same Master Fund, provide a separate response for each Class or Feeder Fund. Base the percentages of "Annual Fund Operating Expenses" on amounts incurred during the Fund's most recent fiscal year, but include in expenses amounts that would have been incurred absent expense reimbursement or fee waiver arrangements. If the Fund has changed its fiscal year and, as a result, the most recent fiscal year is less than three months, use the fiscal year prior to the most recent fiscal year as the basis for determining "Annual Fund Operating Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph d false099false 2rr_ExpenseExampleYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue218218USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 false2100false 2rr_ExpenseExampleYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue368368USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2101false 2rr_ExpenseExampleYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue638638USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2102false 2rr_ExpenseExampleYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue14091409USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2103false 2rr_ExpenseExampleNoRedemptionYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue118118USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 2 -Subparagraph 1 false2104false 2rr_ExpenseExampleNoRedemptionYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue368368USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 2 -Subparagraph 1 false2105false 2rr_ExpenseExampleNoRedemptionYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue638638USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 -Subparagraph f false2106false 2rr_ExpenseExampleNoRedemptionYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue14091409USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 -Subparagraph f false2107false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.07440.0744falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0108false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05320.0532falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0109false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.04700.0470falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0110false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse8false USDtruefalse$S000006760_C000018349http://www.sec.gov/CIK0000357310duration2013-09-01T00:00:002013-09-01T00:00:00falsefalseFranklin Federal Tax-Free Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_S000006760Memberdei_LegalEntityAxisexplicitMemberfalsefalseAdvisor Classrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldifftfif_C000018349Memberrr_ProspectusShareClassAxisexplicitMemberRatioStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0111true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0112false 2rr_MaximumCumulativeSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.000.00falsefalsefalserr:NonNegativePure4TypepureMaximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price). If a sales charge (load) is imposed on shares purchased with reinvested capital gains distributions or returns of capital, include the bracketed words in the third caption.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 1 false0113false 2rr_MaximumDeferredSalesChargeOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.000.00falsefalsefalserr:NonNegativePure4TypepureMaximum Deferred Sales Charge (Load) (as a percentage of ____) A.3.instructions.2.a.i "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). A.3.instructions.2.a.ii If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 2 -Subparagraph a -Clause i false0114false 2rr_ManagementFeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00450.0045falsefalsefalserr:NonNegativePure4TypepureManagement Fees include investment advisory fees (including any fees based on the Fund's performance), any other management fees payable to the investment adviser or its affiliates, and administrative fees payable to the investment adviser or its affiliates that are not included as "Other Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph a false0115false 2rr_DistributionAndService12b1FeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.000.00falsefalsefalserr:NonNegativePure4TypepureDistribution [and/or Service] (12b-1) Fees" include all distribution or other expenses incurred during the most recent fiscal year under a plan adopted pursuant to rule 12b-1 [17 CFR 270.12b-1]. Under an appropriate caption or a subcaption of "Other Expenses," disclose the amount of any distribution or similar expenses deducted from the Fund's assets other than pursuant to a rule 12b-1 plan.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection table -Paragraph 1 -Subparagraph 9 false0116false 2rr_OtherExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00060.0006falsefalsefalserr:NonNegativePure4Typepure"Other Expenses" include all expenses not otherwise disclosed in the table that are deducted from the Fund's assets or charged to all shareholder accounts. The amount of expenses deducted from the Fund's assets are the amounts shown as expenses in the Fund's statement of operations (including increases resulting from complying with paragraph 2(g) of rule 6-07 of Regulation S-X [17 CFR 210.6-07]). "Other Expenses" do not include extraordinary expenses as determined under generally accepted accounting principles (see Accounting Principles Board Opinion No. 30). If extraordinary expenses were incurred that materially affected the Fund's "Other Expenses," disclose in a footnote to the table what "Other Expenses" would have been had the extraordinary expenses been included.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph c -Clause i false0117false 2rr_ExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00510.0051falsefalsefalserr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses. If the Fund is a Feeder Fund, reflect the aggregate expenses of the Feeder Fund and the Master Fund in a single fee table using the captions provided. In a footnote to the fee table, state that the table and Example reflect the expenses of both the Feeder and Master Funds. If the prospectus offers more than one Class of a Multiple Class Fund or more than one Feeder Fund that invests in the same Master Fund, provide a separate response for each Class or Feeder Fund. Base the percentages of "Annual Fund Operating Expenses" on amounts incurred during the Fund's most recent fiscal year, but include in expenses amounts that would have been incurred absent expense reimbursement or fee waiver arrangements. If the Fund has changed its fiscal year and, as a result, the most recent fiscal year is less than three months, use the fiscal year prior to the most recent fiscal year as the basis for determining "Annual Fund Operating Expenses."Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 3 -Subparagraph d false0118false 2rr_ExpenseExampleYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue5252USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection instructions -Paragraph 4 false2119false 2rr_ExpenseExampleYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue164164USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2120false 2rr_ExpenseExampleYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue285285USD$falsefalsefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2121false 2rr_ExpenseExampleYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue640640USD$falsetruefalserr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Subsection example -Paragraph 1 -Subparagraph 2 false2122false 2rr_AverageAnnualReturnYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.09130.0913falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0123false 2rr_AverageAnnualReturnYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.06010.0601falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0124false 2rr_AverageAnnualReturnYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05380.0538falsefalsefalsexbrli:pureItemTypepureReturn Before Taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection b -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 false0falseRisk/Return Detail Data (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://xbrl.sec.gov/rr/role/RiskReturnDetailData1124