| Cover | Jun. 08, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 8, 2020 |
| Entity File Number | 001-3274 |
| Entity Registrant Name | DUKE ENERGY FLORIDA, LLC |
| Entity Central Index Key | 0000037637 |
| Entity Tax Identification Number | 59-0247770 |
| Entity Incorporation, State or Country Code | FL |
| Entity Address, Address Line One | 299 First Avenue North |
| Entity Address, City or Town | St. Petersburg |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33701 |
| City Area Code | 704 |
| Local Phone Number | 382-3853 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
