2.4.0.8020000 - Document - Risk/Return Summary {Unlabeled} - MFS® Global Multi-Asset Fundfalsefalsefalse1false falsefalseS000031673Memberhttp://www.sec.gov/CIK0000063067duration2013-08-28T00:00:002013-08-28T00:00:001false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00MFS® Global Multi-Asset Fundfalsefalsefalse1false truefalseS000031673Memberhttp://www.sec.gov/CIK0000063067duration2013-08-28T00:00:002013-08-28T00:00:00falsefalseMFS® Global Multi-Asset Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000063067_S000031673Memberdei_LegalEntityAxisexplicitMembernanafalse0MFS® Global Multi-Asset Fund2false 4rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00MFS&#174; Global Multi-Asset Fundfalsefalsefalsexbrli: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 4ck0000063067_SupplementTextBlockck0000063067_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;" align="left"> <font style="display: inline; font-family: Times New Roman; font-size: 10pt; font-weight: bold;">Supplement To Prospectus<br /> <em>The date of this supplement is August 28, 2013.</em><br /> <br /> </font> </div> <br/><div style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;" align="left"> <font style="display: inline; font-family: Times New Roman; font-size: 18pt; font-weight: bold;">For Certain MFS&#174; Funds:</font> </div>falsefalsefalsenonnum:textBlockItemTypenaNo authoritative reference available.No definition available.false0Supplement [Text Block]4false 4rr_ExpenseNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="TEXT-INDENT: 0pt; DISPLAY: block; MARGIN-LEFT: 0pt; MARGIN-RIGHT: 0pt" align="left"> <font style="DISPLAY: inline; FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt; FONT-WEIGHT: bold">Effective immediately, in the second paragraph of the sub-section entitled &#8220;Fees and Expenses&#8221; beneath the main heading &#8220;Summary of Key Information,&#8221; the reference to the page number of the &#8220;Waivers of Sales Charges&#8221; is replaced by reference to page H-1 of the fund&#8217;s Statement of Additional Information (&#8220;SAI&#8221;).</font> </div>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 false0Expense Narrative [Text Block]falseRisk/Return Summary - MFS® Global Multi-Asset Fund (MFS® Global Multi-Asset Fund)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://mfs.com/20130828/role/DocumentRiskReturnSummaryUnlabeledMFS174GlobalMultiAssetFund14