XML 144 R74.htm IDEA: XBRL DOCUMENT
v3.24.3

Asset Retirement Obligations Asset Retirement Obligations (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022
Liabilities Settled [Line Items] |  |  |  |
Increase in ARO liability |  | $ 3,300 |  |
Change in estimate | [1] | 132 | $ 369 |
Additional obligations |  | 3,136 |  |
Balance | [1] | 10,806 | 7,489 | $ 7,162
Asset Retirement Obligation, Liabilities Settled | [1] | 257 | 279 |
Accretion (recorded as regulatory asset) | [1] | 306 | 237 |
Asset Retirement Obligation, Current |  | 283 | 272 |
Amortization and Depreciation of Decontaminating and Decommissioning Assets |  | 188 | 188 | 137
Total ARO change due to CCR |  |  | 458 |
Change in estimate due to Gallatin CCR closure |  |  | 60 |
Changes in closure liabilities |  |  | 15 |
Increase in Asset Retirement Obligation, Revisions in Estimate |  |  | 9 |
estimate revision of SLR |  | (164) |  |
Nuclear |  |  |  |
Liabilities Settled [Line Items] |  |  |  |
Change in estimate |  | (160) | 7 |
Additional obligations |  | 0 |  |
Balance |  | 3,814 | 3,808 | 3,643
Asset Retirement Obligation, Liabilities Settled |  | 4 | 8 |
Accretion (recorded as regulatory asset) |  | 170 | 166 |
Non-nuclear |  |  |  |
Liabilities Settled [Line Items] |  |  |  |
Change in estimate |  | 292 | 362 |
Additional obligations |  | 3,136 |  |
Balance |  | 6,992 | 3,681 | $ 3,519
Asset Retirement Obligation, Liabilities Settled |  | 253 | 271 |
Accretion (recorded as regulatory asset) |  | $ 136 | $ 71 |
[1] | (1) Includes $283 million and $272 million at September 30, 2024 and 2023, respectively, in Current liabilities.

X
- Definition The amount of accretion recorded as a regulatory asset during the period. + References No definition available. + Details
Name: | tve_AccretionRecordedAsRegulatoryAsset
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition [Line Items] for Asset Retirement Obligation Disclosure [Table] + References No definition available. + Details
Name: | tve_AssetRetirementObligationDisclosureLineItems
Namespace Prefix: | tve_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Change in estimate due to Gallatin CCR closure + References No definition available. + Details
Name: | tve_ChangeInEstimateDueToGallatinCCRClosure
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Changes in closure liabilities + References No definition available. + Details
Name: | tve_ChangesInClosureLiabilities
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition estimate revision of SLR + References No definition available. + Details
Name: | tve_EstimateRevisionOfSLR
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Increase in Asset Retirement Obligation, Revisions in Estimate + References No definition available. + Details
Name: | tve_IncreaseinAssetRetirementObligationRevisionsinEstimate
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Total ARO change due to CCR + References No definition available. + Details
Name: | tve_TotalAROChangeDueToCCR
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The current period expense charged against earnings on decontaminating and decommissioning of facilities used in the normal conduct of business and not intended for resale to allocate or recognize the cost of the assets over their useful lives. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_AmortizationAndDepreciationOfDecontaminatingAndDecommissioningAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481999/410-20-25-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligationCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of asset retirement obligations incurred during the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesIncurred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesSettled
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in asset retirement obligations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligationPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
Name: | us-gaap_AssetRetirementObligationRevisionOfEstimate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | tve_ReconciliationOfAssetRetirementObligationLiabilityAxis=tve_NuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | tve_ReconciliationOfAssetRetirementObligationLiabilityAxis=tve_NonNuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |