XML 159 R105.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Benefit Plans Actuarial Assumptions (Details) |  | 3 Months Ended | 12 Months Ended | 48 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 01, 2021 | Sep. 30, 2016 | Sep. 30, 2020 | Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2018 | Sep. 30, 2017 | Oct. 01, 2016 | Sep. 30, 2012
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Amortization Period for Change in Benefit Obligation Related to 2016 Amendments to TVA Pension Plan |  |  |  | 11 years |  |  |  |  |  |  |  |
Rate of compensation increase |  | 5.55% |  | 5.55% | 5.70% |  |  |  |  |  |  |
Expected return on plan assets |  |  |  |  |  | 7.25% |  |  |  |  |  |
Period during which actual company compensation experience study performed |  |  |  | 5 years |  |  |  |  |  |  |  |
Rate of compensation increase |  |  |  | 5.70% | 5.70% | 5.72% |  |  |  |  |  |
Cost of living adjustment assumption |  |  |  |  |  |  |  |  |  |  |  | 2.50%
Calculation Factor for Cola Calculation for TVA Pension Plan |  |  |  |  |  |  |  |  |  |  | 0.25% |
Pension Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Discount rate |  | 3.65% |  | 3.65% | 4.50% | 4.45% |  |  |  |  |  |
Rate of compensation increase |  | 5.55% |  | 5.55% | 5.70% |  |  |  |  |  |  |
Discount rate |  |  |  | 4.50% | 4.45% |  |  |  |  |  |  |
Expected return on plan assets |  |  |  | 7.00% | 7.00% |  |  |  |  |  |  |
Rate of compensation increase |  |  |  | 5.70% | 5.70% |  |  |  |  |  |  |
Other Post-retirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Discount rate |  | 3.70% |  | 3.70% | 4.65% | 4.50% |  |  |  |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year |  |  |  | 7.00% | 7.50% | 8.00% |  |  |  |  |  |
Discount rate |  |  |  | 4.65% | 4.50% |  |  |  |  |  |  |
Minimum |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Rate of compensation increase |  | 3.50% |  | 3.50% |  |  |  |  |  |  |  |
Cost of living adjustment assumption |  | 1.00% |  | 1.00% |  |  |  |  |  |  | 1.00% |
Maximum |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Rate of compensation increase |  | 13.00% |  | 13.00% |  |  |  |  |  |  |  |
Cost of living adjustment assumption |  | 5.00% |  | 5.00% |  |  |  |  |  |  | 6.00% |
Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Cost of living adjustment assumption |  |  | 2.50% |  |  |  | 2.50% | 2.40% | 2.00% | 1.25% |  |
Pre-Medicare Eligible [Member] | Other Post-retirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year |  |  |  | 6.50% | 7.00% |  |  |  |  |  |  |
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate |  |  |  | 5.00% | 5.00% |  |  |  |  |  |  |
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate |  | 2019 |  | 2019 | 2019 |  |  |  |  |  |  |
Pre-Medicare Eligible [Member] | Scenario, Forecast | Other Post-retirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate |  |  | 5.00% |  |  |  |  |  |  |  |  |
Post-Medicare Eligible [Member] [Member] | Other Post-retirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year |  |  |  | 0.00% | 7.00% | 7.50% |  |  |  |  |  |
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate |  | 4.00% |  | 5.00% | 5.00% |  |  |  |  |  |  |
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate |  | 2019 |  | 2019 | 2019 |  |  |  |  |  | 2021 |
Post-Medicare Eligible [Member] [Member] | Scenario, Forecast | Other Post-retirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year | 4.00% |  |  |  |  |  | 0.00% |  |  |  |  |

X
- Definition Amortization Period for Change in Benefit Obligation Related to 2016 Amendments to TVA Pension Plan + References No definition available. + Details
Name: | tve_AmortizationPeriodforChangeinBenefitObligationRelatedto2016AmendmentstoTVAPensionPlan
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Calculation Factor for Cola Calculation for TVA Pension Plan + References No definition available. + Details
Name: | tve_CalculationFactorforColaCalculationforTVAPensionPlan
Namespace Prefix: | tve_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cost of living adjustment percentage used for defined benefit plans. + References No definition available. + Details
Name: | tve_DefinedBenefitPlanCostOfLivingAdjustmentAssumption
Namespace Prefix: | tve_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The period in which an actual compensation experience study is performed at TVA to determine assumptions related to compensation increases for defined benefit plans. + References No definition available. + Details
Name: | tve_PeriodDuringWhichActualCompanyCompensationExperienceStudyPerformed
Namespace Prefix: | tve_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The interest rate used to adjust for the time value of money for the plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Expected rate of compensation increases (for pay-related plans). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(2) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The interest rate used to adjust for the time value of money. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Expected Long-Term Rate of Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512046 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(3) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected rate of compensation increases (for pay-related plans). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(2) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Health Care Cost Trend Rate -URI http://asc.fasb.org/extlink&oid=6514820 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The ultimate trend rate for health care costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Year the ultimate health care cost trend rate is expected to be reached, in CCYY format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanYearThatRateReachesUltimateTrendRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | tve_BenefitPlanParticipantClassAxis=tve_PreMedicareEligibleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | tve_BenefitPlanParticipantClassAxis=tve_PostMedicareEligibleMemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |