| Document and Entity Information | Mar. 02, 2021 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | EMERSON ELECTRIC CO |
| Amendment Flag | false |
| Entity Central Index Key | 0000032604 |
| Document Type | 8-K |
| Document Period End Date | Mar. 2, 2021 |
| Entity Incorporation State Country Code | MO |
| Entity File Number | 1-278 |
| Entity Tax Identification Number | 43-0259330 |
| Entity Address, Address Line One | 8000 West Florissant Avenue |
| Entity Address, City or Town | St. Louis |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 63136 |
| City Area Code | (314) |
| Local Phone Number | 553-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stockof 0.50parvaluepershare [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | NYSE |
| Security 12b Title | Common Stock, $0.50 par value per share |
| Trading Symbol | EMR |
| M 0 [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | NYSEArca |
| M 0.375 Notes Due 2024 [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | NYSE |
| Security 12b Title | 0.375% Notes due 2024 |
| Trading Symbol | EMR 24 |
| M 1.250 Notes Due 2025 [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | NYSE |
| Security 12b Title | 1.250% Notes due 2025 |
| Trading Symbol | EMR 25A |
| M 2.000 Notes Due 2029 [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | NYSE |
| Security 12b Title | 2.000% Notes due 2029 |
| Trading Symbol | EMR 29 |
