v3.26.1
Label Element Value
Risk/Return: oef_RiskReturnAbstract  
Document Type dei_DocumentType 485BPOS
Document Period End Date dei_DocumentPeriodEndDate Nov. 30, 2025
Registrant Name dei_EntityRegistrantName General Money Market Fund, Inc.
Entity Central Index Key dei_EntityCentralIndexKey 0000353560
Amendment Flag dei_AmendmentFlag false
Document Creation Date dei_DocumentCreationDate Mar. 27, 2026
Document Effective Date dei_DocumentEffectiveDate Mar. 31, 2026
Entity Investment Company Type dei_EntityInvCompanyType N-1A
Prospectus Date oef_ProspectusDate Mar. 31, 2026
Prospectus Summary | Dreyfus Money Market Fund | Premier Shares  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol GMGXX
Prospectus Summary | Dreyfus Money Market Fund | Service Shares  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol GMBXX
Prospectus Summary | Dreyfus Money Market Fund | Wealth Shares  
Risk/Return: oef_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol GMMXX