2.4.0.8020000 - Document - Risk/Return Summary {Unlabeled} - MFS Diversified Income Fundfalsefalsetrue1false falsefalseS000012219Memberhttp://www.sec.gov/CIK0000356349duration2013-02-28T00:00:002013-02-28T00:00:001false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00MFS Diversified Income Fundfalsefalsefalse1false truefalseS000012219Memberhttp://www.sec.gov/CIK0000356349duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseck0000356349_S000012219Memberdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMembernanafalse0MFS Diversified Income Fund2false 4rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00MFS Diversified Income Fund Summary of Key Informationfalsefalsefalsexbrli: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 false0Risk/Return [Heading]3false 4rr_ObjectiveHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Investment Objectivefalsefalsefalsexbrli: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 false0Objective [Heading]4false 4rr_ObjectivePrimaryTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 The fund’s investment objective is to seek total return with an emphasis on current income, but also considering capital appreciation. 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 false0Objective, Primary [Text Block]5false 4rr_ExpenseHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Fees and Expensesfalsefalsefalsexbrli: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 false0Expense [Heading]6false 4rr_ExpenseNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 This table describes the fees and expenses that you may pay when you buy and hold shares of the fund. Expenses have been adjusted to reflect the estimated expenses of investing in another MFS fund. You may qualify for sales charge reductions if you and certain members of your family invest, or agree to invest in the future, at least $50,000 in MFS Funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers or Reductions” on page 11 of the fund’s prospectus and “Waivers of Sales Charges” on page I-15 of the fund’s statement of additional information Part I. 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. 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USDfalsefalseduration2013-02-28T00:00:002013-02-28T00:00:00$1falseRowprimaryElement*3false 4rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPricerr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabelrr: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. 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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. 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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 false0Management Fee 0rr_ManagementFeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truetruetrue0.00650.0065falsefalsefalse2truetruetrue0.00650.0065falsefalsefalse3truetruetrue0.00650.0065falsefalsefalse4truetruetrue0.00650.0065falsefalsefalse5truetruetrue0.00650.0065falsefalsefalse6truetruetrue0.00650.0065falsefalsefalse7truetruetrue0.00650.0065falsefalsefalse8truetruetrue0.00650.0065falsefalsefalserr: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 false0Management Fee2falseRowprimaryElement*4false 4rr_DistributionAndService12b1FeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabelrr: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 false0Distribution and/or Service (12b-1) Fees 0rr_DistributionAndService12b1FeesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truetruetrue0.00250.0025falsefalsefalse2truetruetrue0.01000.0100falsefalsefalse3truetruetrue0.00000.0000falsefalsefalse4truetruetrue0.01000.0100falsefalsefalse5truetruetrue0.00500.0050falsefalsefalse6truetruetrue0.00250.0025falsefalsefalse7truetruetrue0.00000.0000falsefalsefalse8truetruetrue0.00000.0000falsefalsefalserr: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 false0Distribution and/or Service (12b-1) Fees3falseRowprimaryElement*5false 4rr_OtherExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabelrr: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 false0Other Expenses 0rr_OtherExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truetruetrue0.00180.0018falsefalsefalse2truetruetrue0.00180.0018falsefalsefalse3truetruetrue0.00180.0018falsefalsefalse4truetruetrue0.00180.0018falsefalsefalse5truetruetrue0.00180.0018falsefalsefalse6truetruetrue0.00180.0018falsefalsefalse7truetruetrue0.00180.0018falsefalsefalse8truetruetrue0.00100.0010falsefalsefalserr: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 false0Other Expenses4falseRowprimaryElement*6false 4rr_AcquiredFundFeesAndExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabelrr:NonNegativePure4TypepureTotal 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 table -Paragraph 1 -Subparagraph 11 false0Acquired Fund Fees and Expenses 0rr_AcquiredFundFeesAndExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truetruetrue0.00010.0001falsefalsefalse2truetruetrue0.00010.0001falsefalsefalse3truetruetrue0.00010.0001falsefalsefalse4truetruetrue0.00010.0001falsefalsefalse5truetruetrue0.00010.0001falsefalsefalse6truetruetrue0.00010.0001falsefalsefalse7truetruetrue0.00010.0001falsefalsefalse8truetruetrue0.00010.0001falsefalsefalserr:NonNegativePure4TypepureTotal 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 table -Paragraph 1 -Subparagraph 11 false0Acquired Fund Fees and Expenses5falseRowprimaryElement*7false 4rr_ExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabelrr: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 false0Total Annual Fund Operating Expenses 0rr_ExpensesOverAssetsrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truetruetrue0.01090.0109falsefalsefalse2truetruetrue0.01840.0184falsefalsefalse3truetruetrue0.00840.0084falsefalsefalse4truetruetrue0.01840.0184falsefalsefalse5truetruetrue0.01340.0134falsefalsefalse6truetruetrue0.01090.0109falsefalsefalse7truetruetrue0.00840.0084falsefalsefalse8truetruetrue0.00760.0076falsefalsefalserr: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 false0Total Annual Fund Operating ExpensesfalseAnnual Fund Operating Expenses MFS Diversified Income FundUnKnownUnKnownUnKnownUnKnownfalsefalsefalseSheet85353285058ColumnperiodPeriod*Columndei_LegalEntityAxisAxisck0000356349_S000012219MemberColumnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsenonnum:textBlockItemTypenaContains a command for the SEC Viewer for the role corresponding to OperatingExpensesData.No definition available.false0Annual Fund Operating Expenses [Table]11false 4rr_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 false0Expense Example [Heading]12false 4rr_ExpenseExampleNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 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 you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. 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 false0Expense Example Narrative [Text Block]13false 4rr_ExpenseExampleByYearCaptionrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Although your actual costs will likely be higher or lower, under these assumptions your costs would be:falsefalsefalsexbrli:stringItemTypestringThe 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 false0Expense Example by, Year, Caption [Text]14false 4rr_ExpenseExampleWithRedemptionTableTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00~ http://mfs.com/20130627/role/ScheduleExpenseExampleTransposed20003 column dei_LegalEntityAxis compact ck0000356349_S000012219Member row primary compact * ~falsefalse~ http://mfs.com/20130627/role/ScheduleExpenseExampleTransposed20003 column dei_LegalEntityAxis compact ck0000356349_S000012219Member row primary compact * ~truehttp://mfs.com/20130627/role/ScheduleExpenseExampleTransposed20003020003 - Schedule - Expense Example {Transposed}truefalsefalse1falseColumnprimaryElement*3false 4rr_ExpenseExampleYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false21 YEAR USDfalsefalse$2falseColumnprimaryElement*4false 4rr_ExpenseExampleYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false23 YEARS USDfalsefalse$3falseColumnprimaryElement*5false 4rr_ExpenseExampleYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false25 YEARS USDfalsefalse$4falseColumnprimaryElement*6false 4rr_ExpenseExampleYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false210 YEARS USDfalsefalse$1falseRowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseArr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_C000033358Memberrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundAusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170 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0truefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue111111falsefalsefalse2truefalsetrue347347falsefalsefalse3truefalsetrue601601falsefalsefalse4truefalsetrue13291329falsefalsefalsenanafalse0R37falseRowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseR4rr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_C000068412Memberrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundR4usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170 0truefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue8686falsefalsefalse2truefalsetrue268268falsefalsefalse3truefalsetrue466466falsefalsefalse4truefalsetrue10371037falsefalsefalsenanafalse0R48falseRowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseR5rr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_C000117928Memberrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundR5usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170 0truefalsefalsefalsefalsefalsefalsefalsefalse1truefalsetrue7878falsefalsefalse2truefalsetrue243243falsefalsefalse3truefalsetrue422422falsefalsefalse4truefalsetrue942942falsefalsefalsenanafalse0R5falseExpense Example MFS Diversified Income Fund (USD $)UnKnownUnKnownUnKnownUnKnownfalsefalsefalseSheet48242848076ColumnprimaryElement*RowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsenonnum:textBlockItemTypenaContains a command for the SEC Viewer for the role corresponding to ExpenseExample.No definition available.false0Expense Example, With Redemption [Table]15false 4rr_ExpenseExampleNoRedemptionTableTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00~ http://mfs.com/20130627/role/ScheduleExpenseExampleNoRedemptionTransposed20004 column dei_LegalEntityAxis compact ck0000356349_S000012219Member row primary compact * ~falsefalse~ http://mfs.com/20130627/role/ScheduleExpenseExampleNoRedemptionTransposed20004 column dei_LegalEntityAxis compact ck0000356349_S000012219Member row primary compact * ~truehttp://mfs.com/20130627/role/ScheduleExpenseExampleNoRedemptionTransposed20004020004 - Schedule - Expense Example No Redemption {Transposed}truefalsefalse1falseColumnprimaryElement*3false 4rr_ExpenseExampleNoRedemptionYear01rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false21 YEAR USDfalsefalse$2falseColumnprimaryElement*4false 4rr_ExpenseExampleNoRedemptionYear03rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false23 YEARS USDfalsefalse$3falseColumnprimaryElement*5false 4rr_ExpenseExampleNoRedemptionYear05rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr: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 false25 YEARS USDfalsefalse$4falseColumnprimaryElement*6false 4rr_ExpenseExampleNoRedemptionYear10rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabelrr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. 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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 false0Portfolio Turnover [Heading]17false 4rr_PortfolioTurnoverTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 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 shares are held in a taxable account. These transaction 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 64% of the average value of its portfolio. 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 false0Portfolio Turnover [Text Block]18false 4rr_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 false0Strategy [Heading]19false 4rr_StrategyNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 MFS (Massachusetts Financial Services Company, the fund’s investment adviser) normally invests the fund’s assets primarily in a broad range of debt instruments and equity securities of U.S. and foreign issuers, including convertible securities, real estate-related investments, and emerging market securities. MFS may invest the fund’s assets in other mutual funds advised by MFS that invest in such instruments and securities instead of investing directly in such instruments and securities. MFS allocates the fund’s assets across these categories based on its interpretation of economic and money market conditions, fiscal and monetary policy and asset class and/or security values. These allocations may vary from time to time. MFS focuses the fund’s debt investments on U.S. Government securities, less than investment grade quality debt instruments (lower quality debt instruments), and debt instruments of emerging market issuers. Of the fund’s investments in debt instruments, MFS may invest up to 100% of these investments directly or indirectly in lower quality debt instruments. For the equity portion of the fund, MFS focuses on investing the fund’s assets in dividend-paying stocks and/or in the stocks of companies it believes are undervalued compared to their perceived worth (value companies). While MFS may invest the equity portion of the fund’s assets in companies of any size, MFS generally focuses on companies with large capitalizations. For the real estate-related portion of the fund, MFS invests the fund’s assets in real estate investment trusts (REITs) and other companies principally engaged in the real estate industry. MFS generally focuses the fund’s investments in equity REITs, but may also invest in mortgage REITs and other real estate-related investments.  Issuers of real estate-related investments tend to be small- to medium-sized. While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, structured securities, inverse floating rate instruments, and swaps. MFS uses a bottom-up investment approach to buying and selling investments for the fund. Investments are selected based on fundamental analysis of individual issuers and instruments and quantitative models that systematically evaluate issuers and instruments. In structuring the fund, MFS may also consider top-down factors. 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 false0Strategy Narrative [Text Block]20false 4rr_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 false0Risk [Heading]21false 4rr_RiskNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The principal risks of investing in the fund are: Investment Selection and Allocation Risk: MFS’ investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. Interest Rate Risk:  The price of a debt instrument falls when interest rates rise and rises when interest rates fall. Instruments with longer maturities, or that do not pay current interest, are more sensitive to interest rate changes. Credit Risk:  The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in the financial condition of the issuer, borrower, counterparty, or underlying collateral or assets, or changes in specific or general market, economic, industry, political, regulatory, geopolitical, and other conditions. Lower quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Lower quality debt instruments are regarded as having predominantly speculative characteristics. Lower quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments. Foreign and Emerging Markets Risk:  Exposure to foreign markets, especially emerging markets, through issuers or currencies can involve additional risks relating to market, economic, industry, political, regulatory, geopolitical, and other conditions. These factors can make foreign investments, especially those in emerging markets, more volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to these conditions than the U.S. market. Emerging markets can have less developed markets, greater custody and operational risk, less developed legal, regulatory, and accounting systems, and greater political, social, and economic instability than developed markets. Currency Risk:  The value of foreign currencies relative to the U.S. dollar fluctuates in response to market, economic, industry, political, regulatory, geopolitical, and other conditions, and a decline in the value of a foreign currency versus the U.S. dollar reduces the value in U.S. dollars of investments denominated in that foreign currency. Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Municipal Risk:  The price of a municipal instrument can be volatile and significantly affected by adverse tax or court rulings, legislative or political changes, changes in specific or general market and economic conditions, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in these industries can significantly affect the fund and the overall municipal market. Stock Market/Company Risk:  Stock markets are volatile and can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical, and other conditions, as well as to investor perceptions of these conditions. The price of an equity security can decrease significantly in response to these conditions, and these conditions can affect a single issuer or type of security, issuers within a broad market sector, industry or geographic region, or the market in general. Value Company Risk:  The stocks of value companies can continue to be undervalued for long periods of time and not realize their expected value and can be more volatile than the market in general. Real Estate-Related Investment Risk: The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates and property tax rates; shifts in zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. Derivatives Risk:  Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost.  Derivatives can involve leverage. Leveraging Risk:  Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. Counterparty and Third Party Risk:  Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability to perform in accordance with the terms of the transaction. Liquidity Risk:  It may not be possible to sell certain investments, types of investments, and/or segments of the market at any particular time or at an acceptable price. 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 false0Risk Narrative [Text Block]22false 4rr_BarChartAndPerformanceTableHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Performance Informationfalsefalsefalsexbrli: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 false0Bar Chart and Performance Table [Heading]23false 4rr_PerformanceNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance and one or more other measures of performance for markets in which the fund may invest. The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at mfs.com or by calling 1-800-225-2606. 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 false0Performance Narrative [Text Block]24false 4rr_BarChartNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund's shares. If these sales charges were included, they would reduce the returns shown. falsefalsefalsenonnum:textBlockItemTypenaProvide 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 false0Bar Chart Narrative [Text Block]25false 4rr_BarChartHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class A Bar Chart.falsefalsefalsexbrli: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 false0Bar Chart [Heading]26false 4rr_BarChartTableTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00~ http://mfs.com/20130627/role/ScheduleAnnualTotalReturnsBarChart20005 column dei_LegalEntityAxis compact ck0000356349_S000012219Member column rr_ProspectusShareClassAxis compact ck0000356349_C000033358Member row primary compact * ~falsefalseBarChart1.jpg~ http://mfs.com/20130627/role/ScheduleAnnualTotalReturnsBarChart20005 column dei_LegalEntityAxis compact ck0000356349_S000012219Member column rr_ProspectusShareClassAxis compact ck0000356349_C000033358Member row primary compact * ~falsehttp://mfs.com/20130627/role/ScheduleAnnualTotalReturnsBarChart20005020005 - Schedule - Annual Total Returns [Bar Chart]truefalsefalse1falseColumnperiodPeriod*Columndei_LegalEntityAxisAxisck0000356349_S000012219MemberColumnrr_ProspectusShareClassAxisAxisck0000356349_C000033358MemberColumnunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseArr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_C000033358Memberrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundApureStandardhttp://www.xbrl.org/2003/instancepurexbrli0Standard0 USDfalsefalseduration2013-02-28T00:00:002013-02-28T00:00:00$1falseRowprimaryElement*3false3false 4rr_AnnualReturn2007rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.00790.0079falsefalsefalsexbrli: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 false0Annual Return 2007 4rr_AnnualReturn2007rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalsexbrli: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 false0Annual Return 2007 0rr_AnnualReturn2007rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.00790.0079falsefalsefalsexbrli: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 false0Annual Return 20072falseRowprimaryElement*4false4false 4rr_AnnualReturn2008rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.2041-0.2041falsefalsefalsexbrli: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 false0Annual Return 2008 4rr_AnnualReturn2008rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalsexbrli: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 false0Annual Return 2008 0rr_AnnualReturn2008rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.2041-0.2041falsefalsefalsexbrli: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 false0Annual Return 20083falseRowprimaryElement*5false5false 4rr_AnnualReturn2009rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.30260.3026falsefalsefalsexbrli: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 false0Annual Return 2009 4rr_AnnualReturn2009rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalsexbrli: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 false0Annual Return 2009 0rr_AnnualReturn2009rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.30260.3026falsefalsefalsexbrli: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 false0Annual Return 20094falseRowprimaryElement*6false6false 4rr_AnnualReturn2010rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.13920.1392falsefalsefalsexbrli: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 false0Annual Return 2010 4rr_AnnualReturn2010rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalsexbrli: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 false0Annual Return 2010 0rr_AnnualReturn2010rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.13920.1392falsefalsefalsexbrli: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 false0Annual Return 20105falseRowprimaryElement*7false7false 4rr_AnnualReturn2011rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.05130.0513falsefalsefalsexbrli: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 false0Annual Return 2011 4rr_AnnualReturn2011rr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalsexbrli: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. 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Globalrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_index_JPMorgan_Emerging_Markets_Bond_Index_GlobalMemberrr_PerformanceMeasureAxisexplicitMembertruefalse[ShareClassDomain]rr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundJPMorgan Emerging Markets Bond Index Global[ShareClassDomain]pureStandardhttp://www.xbrl.org/2003/instancepurexbrli0Standard0 0truefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Index Comparisons (Reflects no deduction for fees, expenses or taxes) JPMorgan Emerging Markets Bond Index Globalfalsefalsefalse2truetruetrue0.18540.1854falsefalsefalse3truetruetrue0.10470.1047falsefalsefalse4truetruetrue0.10460.1046falsefalsefalse5falsetruefalse002006-05-26falsefalsetruenanafalse0JPMorgan Emerging Markets Bond Index Global15falseRowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseMSCI U.S. REIT Index (gross div)rr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_index_MSCI_US_REIT_Index_gross_divMemberrr_PerformanceMeasureAxisexplicitMembertruefalse[ShareClassDomain]rr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundMSCI U.S. REIT Index (gross div)[ShareClassDomain]pureStandardhttp://www.xbrl.org/2003/instancepurexbrli0Standard0 0truefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Index Comparisons (Reflects no deduction for fees, expenses or taxes) MSCI U.S. REIT Index (gross div)falsefalsefalse2truetruetrue0.17770.1777falsefalsefalse3truetruetrue0.05580.0558falsefalsefalse4truetruetrue0.04970.0497falsefalsefalse5falsetruefalse002006-05-26falsefalsetruenanafalse0MSCI U.S. REIT Index (gross div)16falseRowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2013-02-28T00:00:002013-02-28T00:00:00falsefalseMFS Diversified Income Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_S000012219Memberdei_LegalEntityAxisexplicitMemberfalsefalseRussell 1000 Value Indexrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldick0000356349_index_Russell_1000_Value_IndexMemberrr_PerformanceMeasureAxisexplicitMembertruefalse[ShareClassDomain]rr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberMFS Diversified Income FundRussell 1000 Value Index[ShareClassDomain]pureStandardhttp://www.xbrl.org/2003/instancepurexbrli0Standard0 0truefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Index Comparisons (Reflects no deduction for fees, expenses or taxes) Russell 1000 Value Indexfalsefalsefalse2truetruetrue0.17510.1751falsefalsefalse3truetruetrue0.00590.0059falsefalsefalse4truetruetrue0.02660.0266falsefalsefalse5falsetruefalse002006-05-26falsefalsetruenanafalse0Russell 1000 Value IndexfalseAverage Annual Returns MFS Diversified Income FundUnKnownUnKnownUnKnownUnKnownfalsefalsefalseSheet51664755160220ColumnprimaryElement*RowperiodPeriod*Rowdei_LegalEntityAxisAxisck0000356349_S000012219MemberRowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsenonnum:textBlockItemTypenaContains a command for the SEC Viewer for the role corresponding to PerformanceTableData.No definition available.false0Performance [Table]31false 4rr_PerformanceTableClosingTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00 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. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. 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 false0Performance Table Closing [Text Block]falseRisk/Return Summary - MFS Diversified Income Fund (MFS Diversified Income Fund)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://mfs.com/20130627/role/DocumentRiskReturnSummaryUnlabeledMFSDiversifiedIncomeFund131