XML 131 R41.htm IDEA: XBRL DOCUMENT
v3.23.3

Summary of Significant Accounting Policies [Table Text Block] | 12 Months Ended
--- | ---
Sep. 30, 2023
Accounting Policies [Abstract] |
Property, Plant, and Equipment Depreciation Rates | Average depreciation rates by asset class are as follows:
Property, Plant, and Equipment Depreciation Rates At September 30 (percent)
| 2023 |  | 2022 |  | 2021
Asset Class |  |  |  |  |
Nuclear | 2.73 |  |  | 2.72 |  |  | 2.38 |
Coal-fired(1) | 4.98 |  |  | 4.27 |  |  | 1.95 |
Hydroelectric | 1.82 |  |  | 1.85 |  |  | 1.60 |
Gas and oil-fired | 3.17 |  |  | 3.38 |  |  | 2.98 |
Transmission | 1.52 |  |  | 1.51 |  |  | 1.34 |
Other | 4.43 |  |  | 3.64 |  |  | 7.12 |

X
- Definition Tabular disclosure of average depreciation rates by asset class. + References No definition available. + Details
Name: | tve_DepreciationRatesTableTextBlock
Namespace Prefix: | tve_
Data Type: | dtr-types1:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration