| IRS990EZ/ActivitiesNotPreviouslyRptInd | 0 | 0 |
| IRS990EZ/BooksInCareOfDetail/BusinessName/BusinessNameLine1Txt | 0 | MARYLOU BRANNAN |
| IRS990EZ/BooksInCareOfDetail/PhoneNum | 0 | 4258853500 |
| IRS990EZ/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | PO BOX 3474 |
| IRS990EZ/BooksInCareOfDetail/USAddress/CityNm | 0 | REDMOND |
| IRS990EZ/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | WA |
| IRS990EZ/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 980733474 |
| IRS990EZ/ChgMadeToOrgnzngDocNotRptInd | 0 | 0 |
| IRS990EZ/DirectIndirectPltclExpendAmt | 0 | 0 |
| IRS990EZ/DonorAdvisedFndsInd | 0 | 0 |
| IRS990EZ/EngagedInExcessBenefitTransInd | 0 | 0 |
| IRS990EZ/ExcessOrDeficitForYearAmt | 0 | -1172414 |
| IRS990EZ/FiledScheduleAInd | 0 | 1 |
| IRS990EZ/FinalReturnInd | 0 | X |
| IRS990EZ/ForeignFinancialAccountInd | 0 | 0 |
| IRS990EZ/ForeignOfficeInd | 0 | 0 |
| IRS990EZ/Form990TotalAssetsGrp/BOYAmt | 0 | 1172414 |
| IRS990EZ/Form990TotalAssetsGrp/EOYAmt | 0 | 0 |
| IRS990EZ/GrantsAndSimilarAmountsPaidAmt | 0 | 1172414 |
| IRS990EZ/GrossReceiptsAmt | 0 | 0 |
| IRS990EZ/InfoInScheduleOPartIIIInd | 0 | X |
| IRS990EZ/InfoInScheduleOPartIIInd | 0 | X |
| IRS990EZ/InfoInScheduleOPartIInd | 0 | X |
| IRS990EZ/InfoInScheduleOPartVInd | 0 | X |
| IRS990EZ/LobbyingActivitiesInd | 0 | 0 |
| IRS990EZ/MadeLoansToFromOfficersInd | 0 | 0 |
| IRS990EZ/MethodOfAccountingAccrualInd | 0 | X |
| IRS990EZ/NetAssetsOrFundBalancesBOYAmt | 0 | 1172414 |
| IRS990EZ/NetAssetsOrFundBalancesEOYAmt | 0 | 0 |
| IRS990EZ/NetAssetsOrFundBalancesGrp/BOYAmt | 0 | 1172414 |
| IRS990EZ/NetAssetsOrFundBalancesGrp/EOYAmt | 0 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 0 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 1 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 2 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 3 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 4 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 5 | 1.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 6 | 10.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 0 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 0 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 0 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 0 | STEVE WELLS |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 1 | SHARON MAGHIE |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 2 | AKHTAR BADSHAH |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 3 | JANE BROOM DAVIDSON |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 4 | CARLA LEWIS |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 5 | CRAIG BRUYA |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 6 | MARYLOU BRANNAN |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 0 | CHAIR |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 1 | SECRETARY |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 2 | TREASURER |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 3 | TRUSTEE |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 4 | TRUSTEE |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 5 | TRUSTEE |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 6 | EXECUTIVE DIRECTOR |
| IRS990EZ/OperateHospitalInd | 0 | 0 |
| IRS990EZ/Organization501c3Ind | 0 | X |
| IRS990EZ/OrganizationDissolvedEtcInd | 0 | 1 |
| IRS990EZ/OrganizationHadUBIInd | 0 | 0 |
| IRS990EZ/OtherAssetsTotalDetail/BOYAmt | 0 | 1172414 |
| IRS990EZ/OtherAssetsTotalDetail/EOYAmt | 0 | 0 |
| IRS990EZ/OtherChangesInNetAssetsAmt | 0 | 0 |
| IRS990EZ/PartVIHghstPdCntrctProfSrvcTxt | 0 | NONE |
| IRS990EZ/PartVIOfCompOfHghstPdEmplTxt | 0 | NONE |
| IRS990EZ/PoliticalCampaignActyInd | 0 | 0 |
| IRS990EZ/PrimaryExemptPurposeTxt | 0 | TO CATALYZE THE COLLECTIVE POWER OF THE MICROSOFT ALUMNI FAMILY AND LEVERAGE OUR RESOURCES TO MAKE A DIFFERENCE FOR OTHERS. |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/DescriptionProgramSrvcAccomTxt | 0 | DURING THE YEAR ENDED JUNE 30, 2017, THE ORGANIZATION ESTABLISHED A DONOR ADVISED FUND (DAF) AT THE SEATTLE FOUNDATION AS PART OF ITS PLAN OF CONVERTING OPERATIONS TO THE DAF. THE PROGRAM EXPENSES HERE REPRESENT THE FINAL DISTRIBUTION OF ASSETS TO THE DAF. |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/GrantsAndAllocationsAmt | 0 | 1172414 |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/ProgramServiceExpensesAmt | 0 | 1172414 |
| IRS990EZ/ProhibitedTaxShelterTransInd | 0 | 0 |
| IRS990EZ/RelatedOrganizationCtrlEntInd | 0 | 0 |
| IRS990EZ/ScheduleBNotRequiredInd | 0 | X |
| IRS990EZ/SchoolOperatingInd | 0 | 0 |
| IRS990EZ/StatesWhereCopyOfReturnIsFldCd | 0 | OR |
| IRS990EZ/SubjectToProxyTaxInd | 0 | 0 |
| IRS990EZ/SumOfTotalLiabilitiesGrp/BOYAmt | 0 | 0 |
| IRS990EZ/SumOfTotalLiabilitiesGrp/EOYAmt | 0 | 0 |
| IRS990EZ/TanningServicesProvidedInd | 0 | 0 |
| IRS990EZ/TaxImposedOnOrganizationMgrAmt | 0 | 0 |
| IRS990EZ/TaxImposedUnderIRC4911Amt | 0 | 0 |
| IRS990EZ/TaxImposedUnderIRC4912Amt | 0 | 0 |
| IRS990EZ/TaxImposedUnderIRC4955Amt | 0 | 0 |
| IRS990EZ/TaxReimbursedByOrganizationAmt | 0 | 0 |
| IRS990EZ/TotalExpensesAmt | 0 | 1172414 |
| IRS990EZ/TotalProgramServiceExpensesAmt | 0 | 1172414 |
| IRS990EZ/TotalRevenueAmt | 0 | 0 |
| IRS990EZ/TrnsfrExmptNonChrtblRltdOrgInd | 0 | 0 |
| IRS990EZ/TypeOfOrganizationCorpInd | 0 | X |
| IRS990EZ/WebsiteAddressTxt | 0 | WWW.MICROSOFTALUMNI.COM |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus1YearAmt | 0 | 327929 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 379003 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 560595 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 350158 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/TotalAmt | 0 | 1617685 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus1YearAmt | 0 | 109443 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 160962 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 148661 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 129364 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/TotalAmt | 0 | 548430 |
| IRS990ScheduleA/GrossReceiptsRltdActivitiesAmt | 0 | 26632 |
| IRS990ScheduleA/OtherIncome170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 1320 |
| IRS990ScheduleA/OtherIncome170Grp/TotalAmt | 0 | 1320 |
| IRS990ScheduleA/PrivateFoundation170Ind | 0 | X |
| IRS990ScheduleA/PublicOrganization170Ind | 0 | X |
| IRS990ScheduleA/PublicSupportCY170Pct | 0 | 0.24330 |
| IRS990ScheduleA/PublicSupportPY170Pct | 0 | 0.29250 |
| IRS990ScheduleA/PublicSupportTotal170Amt | 0 | 527405 |
| IRS990ScheduleA/SubstantialContributorsTotAmt | 0 | 1090280 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus1YearAmt | 0 | 327929 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 379003 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 560595 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 350158 |
| IRS990ScheduleA/TotalCalendarYear170Grp/TotalAmt | 0 | 1617685 |
| IRS990ScheduleA/TotalSupportAmt | 0 | 2167435 |
| IRS990ScheduleN/AssetsDistributedInd | 0 | 1 |
| IRS990ScheduleN/AttorneyGeneralNotifiedInd | 0 | 1 |
| IRS990ScheduleN/BondsOutstandingInd | 0 | 0 |
| IRS990ScheduleN/DirectorOfSuccessorInd | 0 | 0 |
| IRS990ScheduleN/EmployeeOfSuccessorInd | 0 | 0 |
| IRS990ScheduleN/LiabilitiesPaidInd | 0 | 1 |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/AssetsDistriOrExpnssPaidDesc | 0 | ACCOUNTS RECEIVABLE AND NOTE RECEIVABLE |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/BusinessName/BusinessNameLine1Txt | 0 | SEATTLE FOUNDATION |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/DistributionDt | 0 | 2018-06-30 |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/EIN | 0 | 916013536 |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/FairMarketValueOfAssetAmt | 0 | 1172414 |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/IRCSectionTxt | 0 | 501(C)(3) |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/MethodOfFMVDeterminationTxt | 0 | BOOK VALUE |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/USAddress/AddressLine1Txt | 0 | 1601 5TH AVE SUITE 1900 |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/USAddress/CityNm | 0 | SEATTLE |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/USAddress/StateAbbreviationCd | 0 | WA |
| IRS990ScheduleN/LiquidationOfAssetsTableGrp/LiquidationOfAssetsDetail/USAddress/ZIPCd | 0 | 98101 |
| IRS990ScheduleN/OwnerOfSuccessorInd | 0 | 0 |
| IRS990ScheduleN/ReceiveCompensationInd | 0 | 0 |
| IRS990ScheduleN/RequiredToNotifyAGInd | 0 | 1 |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 0 | ACTIVITY CLASSIFICATION: . GRANTEE NAME: SEATTLE FOUNDATION. GRANTEE ADDRESS: 1601 5TH AVE, SUITE 1900 SEATTLE, WA 98101. PROPERTY DESCRIPTION: ACCOUNTS RECEIVABLE AND NOTE RECEIVABLE. BOOK VALUE OF PROPERTY: 1,172,414. DATE OF GIFT: 06/30/18. AMOUNT GIVEN: 1,172,414. |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 1 | DESCRIPTION: ACCOUNTS RECEIVABLE. BEG. OF YEAR AMOUNT: 21,614. END OF YEAR AMOUNT: 0. DESCRIPTION: NOTE RECEIVABLE. BEG. OF YEAR AMOUNT: 1,150,800. END OF YEAR AMOUNT: 0. |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 0 | FORM 990-EZ, PART I, LINE 10 - GRANTS AND SIMILAR AMOUNTS PAID |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 1 | FORM 990-EZ, PART II, LINE 24 - OTHER ASSETS |
| TransferPrsnlBnftContractsDecl/DeclarationDesc | 0 | THE ORGANIZATION DID NOT, DURING THE YEAR, RECEIVE ANY FUNDS, DIRECTLY,OR INDIRECTLY, TO PAY PREMIUMS ON A PERSONAL BENEFIT CONTRACT.THE ORGANIZATION, DID NOT, DURING THE YEAR, PAY ANY PREMIUMS, DIRECTLY,OR INDIRECTLY, ON A PERSONAL BENEFIT CONTRACT. |
| ReturnHeader/BuildTS | 0 | 2019-02-21 02:37:17Z |
| ReturnHeader/BusinessOfficerGrp/DiscussWithPaidPreparerInd | 0 | 1 |
| ReturnHeader/BusinessOfficerGrp/PersonNm | 0 | AKHTAR BADSHAH |
| ReturnHeader/BusinessOfficerGrp/PersonTitleTxt | 0 | TREASURER |
| ReturnHeader/BusinessOfficerGrp/PhoneNum | 0 | 4258853500 |
| ReturnHeader/BusinessOfficerGrp/SignatureDt | 0 | 2019-01-09 |
| ReturnHeader/Filer/BusinessName/BusinessNameLine1Txt | 0 | MICROSOFT ALUMNI FOUNDATION |
| ReturnHeader/Filer/BusinessNameControlTxt | 0 | MICR |
| ReturnHeader/Filer/EIN | 0 | 753159070 |
| ReturnHeader/Filer/PhoneNum | 0 | 4258853500 |
| ReturnHeader/Filer/USAddress/AddressLine1Txt | 0 | PO BOX 3474 |
| ReturnHeader/Filer/USAddress/CityNm | 0 | REDMOND |
| ReturnHeader/Filer/USAddress/StateAbbreviationCd | 0 | WA |
| ReturnHeader/Filer/USAddress/ZIPCd | 0 | 980733474 |
| ReturnHeader/FilingSecurityInformation/AtSubmissionCreationDeviceId | 0 | C070BA3AF7F6D7D87E83B9D9DF9412DF7C2C6F3F |
| ReturnHeader/FilingSecurityInformation/AtSubmissionFilingDeviceId | 0 | C070BA3AF7F6D7D87E83B9D9DF9412DF7C2C6F3F |
| ReturnHeader/FilingSecurityInformation/FilingLicenseTypeCd | 0 | P |
| ReturnHeader/FilingSecurityInformation/IPAddress/IPv4AddressTxt | 0 | 65.158.230.202 |
| ReturnHeader/FilingSecurityInformation/IPDt | 0 | 2019-01-09 |
| ReturnHeader/FilingSecurityInformation/IPTimezoneCd | 0 | PS |
| ReturnHeader/FilingSecurityInformation/IPTm | 0 | 12:47:35 |
| ReturnHeader/PreparerFirmGrp/PreparerFirmEIN | 0 | 911194016 |
| ReturnHeader/PreparerFirmGrp/PreparerFirmName/BusinessNameLine1Txt | 0 | CLARK NUBER PS |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/AddressLine1Txt | 0 | 10900 NE 4TH STREET SUITE 1400 |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/CityNm | 0 | BELLEVUE |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/StateAbbreviationCd | 0 | WA |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/ZIPCd | 0 | 98004 |
| ReturnHeader/PreparerPersonGrp/PhoneNum | 0 | 4254544919 |
| ReturnHeader/PreparerPersonGrp/PreparationDt | 0 | 2018-11-19 |
| ReturnHeader/PreparerPersonGrp/PreparerPersonNm | 0 | JANE M SEARING |
| ReturnHeader/ReturnTs | 0 | 2019-01-09T14:57:11-06:00 |
| ReturnHeader/ReturnTypeCd | 0 | 990EZ |
| ReturnHeader/TaxPeriodBeginDt | 0 | 2017-07-01 |
| ReturnHeader/TaxPeriodEndDt | 0 | 2018-06-30 |
| ReturnHeader/TaxYr | 0 | 2017 |