XML 106 R85.htm IDEA: XBRL DOCUMENT
v3.24.3

Commitments and Contingencies - Coal Supply (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Sep. 30, 2024 | Mar. 31, 2024 | Sep. 30, 2024 | Dec. 31, 2023 | Jan. 31, 2016
PNM | Four Corners CSA |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Funds contributed, mine reclamation trust |  |  | $ 3.2 | $ 0.2 |
Reclamation trust funding, 2025 |  |  | 2.1 |  |
Reclamation trust funding, year 2026 |  |  | 2.9 |  |
Coal supply | San Juan Generating Station |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Cash used to support bank letter or credit arrangement |  |  |  |  | $ 30.3
Coal supply | NM Capital | San Juan Generating Station |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Requirement to post reclamation bonds | $ 118.7 |  | 118.7 |  |
Cash used to support bank letter or credit arrangement | 30.3 |  | 30.3 |  |
Underground | PNM | Loss on long-term purchase commitment |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Loss contingency accrual | 54.5 |  | 54.5 | 26.2 |
Underground | PNM | San Juan Generating Station | Loss on long-term purchase commitment |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Estimate of possible loss | 65.0 |  | 65.0 |  |
Surface | PNM | Loss on long-term purchase commitment |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Loss contingency accrual | 42.2 |  | 42.2 | 50.0 |
Surface | PNM | San Juan Generating Station | Loss on long-term purchase commitment |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Estimate of possible loss | 48.7 |  | 48.7 |  |
San Juan Generating Station |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Reclamation costs | 12.1 | $ 20.9 |  |  |
Regulatory disallowance |  | 4.0 |  |  |
Regulatory disallowance related to other costs |  | 0.5 |  |  |
San Juan Generating Station | PNM | Loss on long-term purchase commitment |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Annual funding post-term reclamation trust |  |  |  | $ 2.7 |
Annual funding post-term reclamation trust, remainder of year |  |  | 25.1 |  |
Annual funding post-term reclamation trust, year one |  |  | 2.4 |  |
Annual funding post-term reclamation trust, year two |  |  | 0.6 |  |
San Juan Generating Station | Underground |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Increase in regulatory liabilities | 6.0 | 17.0 |  |  |
San Juan Generating Station | Surface |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Increase in regulatory liabilities | $ 6.1 |  |  |  |
Reclamation, maximum collection from customers |  | $ 100.0 |  |  |
San Juan Generating Station and Four Corners | PNM | Mine Reclamation Trust |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |
Customer reclamation funding cost |  |  | $ 100.0 |  |

X
- Definition Cash used to support bank letter or credit arrangement + References No definition available. + Details
Name: | pnm_CashUsedToSupportBankLetterOrCreditArrangement
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Coal Mine Reclamation Bonds To Be Posted With NMMMD + References No definition available. + Details
Name: | pnm_CoalMineReclamationBondsToBePostedWithNMMMD
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Customer Reclamation Funding Cost, Maximum + References No definition available. + Details
Name: | pnm_CustomerReclamationFundingCostMaximum
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Funds Contributed, Mine Reclamation Trust + References No definition available. + Details
Name: | pnm_FundsContributedMineReclamationTrust
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Other Costs Related to Regulatory Disallowance + References No definition available. + Details
Name: | pnm_OtherCostsRelatedToRegulatoryDisallowance
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Annual Funding Post-Term Reclamation Trust + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFundingPostTermReclamationTrust
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Annual Funding Post-Term Reclamation Trust, Remainder Of Year + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFundingPostTermReclamationTrustRemainderOfYear
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Annual Funding Post-Term Reclamation Trust, Year One + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFundingPostTermReclamationTrustYearOne
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Annual Funding Post-Term Reclamation Trust, Year Two + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFundingPostTermReclamationTrustYearTwo
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Commitments And Contingencies [Line Items] + References No definition available. + Details
Name: | pnm_PublicUtilitiesCommitmentsAndContingenciesLineItems
Namespace Prefix: | pnm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Regulatory Disallowance + References No definition available. + Details
Name: | pnm_PublicUtilitiesRegulatoryDisallowance
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reclamation, Maximum Collection From Customers + References No definition available. + Details
Name: | pnm_ReclamationMaximumCollectionFromCustomers
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Reclamation Trust Funding, Year One + References No definition available. + Details
Name: | pnm_ReclamationTrustFundingYearOne
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reclamation Trust Funding, Year Two + References No definition available. + Details
Name: | pnm_ReclamationTrustFundingYearTwo
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The increase (decrease) during the reporting period in regulated liabilities. Regulated liabilities are created when regulatory agency permits an entity to defer revenues to the balance sheet. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_IncreaseDecreaseInRegulatoryLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-1 Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-10 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 720 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483359/720-20-50-1 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 27 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482395/460-10-55-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-9 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-4 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482425/460-10-50-3 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482425/460-10-50-2 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Adjustment of the mine reclamation or mine shutdown liability account that is made when estimates of future costs are changed. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_ReclamationAndMineShutdownProvision
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=pnm_PublicServiceCompanyOfNewMexicoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis=pnm_FourCornersCSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=pnm_CoalSupplyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=pnm_SanJuanGeneratingStationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnm_NMCapitalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ClassificationOfMineAxis=pnm_UndergroundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_LossOnLongTermPurchaseCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ClassificationOfMineAxis=pnm_SurfaceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_JointlyOwnedGeneratingFacilitiesAxis=pnm_SanJuanGeneratingStationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis=us-gaap_LossOnLongTermPurchaseCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_JointlyOwnedGeneratingFacilitiesAxis=pnm_SanJuanGeneratingStationAndFourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis=pnm_MineReclamationTrustMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |