Cover
| Cover | May 13, 2021 | Dec. 08, 2020 |
| Document Information [Line Items] | ||
| City Area Code | (865) | |
| Local Phone Number | 632-2101 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Entity Address, Postal Zip Code | 37902 | |
| Entity Address, Address Line One | 400 W. Summit Hill Drive | |
| Entity Address, City or Town | Knoxville | |
| Entity Address, State or Province | TN | |
| Entity File Number | 000-52313 | |
| Entity Tax Identification Number | 62-0474417 | |
| Entity Registrant Name | TENNESSEE VALLEY AUTHORITY | |
| Document Period End Date | May 13, 2021 | |
| Document Type | 8-K | |
| Entity Central Index Key | 0001376986 | |
| Document Fiscal Year Focus | 2021 | |
| Document Fiscal Period Focus | FY | |
| Amendment Flag | false |