XML 59 R26.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Gallatin Coal Combustion Residual Facilities Regulatory Accounting Treatment (Policies) | 6 Months Ended
--- | ---
Mar. 31, 2018
Regulatory Asset Accounting Treatment [Abstract] |
Regulatory Asset Accounting Treatment [Table Text Block] | In August 2017, TVA began using regulatory accounting treatment to defer expected future costs of compliance with orders or settlements related to lawsuits involving the Gallatin CCR facilities. The TVA Board approved a plan to amortize these costs over the anticipated duration of the Gallatin CCR facilities project (excluding post-closure care), beginning October 1, 2018, as amounts are included in rates or paid out.

X
- Definition Regulatory Asset Accounting Treatment [Abstract] + References No definition available. + Details
Name: | tve_RegulatoryAssetAccountingTreatmentAbstract
Namespace Prefix: | tve_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition [Table Text Block] for Regulatory Asset Accounting Treatment [Table] + References No definition available. + Details
Name: | tve_RegulatoryAssetAccountingTreatmentTableTextBlock
Namespace Prefix: | tve_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration