| Document and Entity Information Document | Jan. 30, 2020 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Jan. 30, 2020 |
| Entity Registrant Name | FRANKLIN RESOURCES, INC. |
| Entity Central Index Key | 0000038777 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-09318 |
| Entity Tax Identification Number | 13-2670991 |
| Entity Address, Address Line One | One Franklin Parkway |
| Entity Address, City or Town | San Mateo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94403 |
| City Area Code | 650 |
| Local Phone Number | 312-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.10 per share |
| Trading Symbol | BEN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
