XML 139 R109.htm IDEA: XBRL DOCUMENT
v3.20.4

Regulatory and Rate Matters - New Mexico General Rate Cases (Details) $ in Thousands |  |  |  |  | 1 Months Ended | 12 Months Ended | 24 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Feb. 01, 2018 | Jan. 10, 2018 USD ($) | Dec. 07, 2016 USD ($) | Sep. 28, 2016 USD ($) lease MW | Aug. 31, 2016 USD ($) lease MW | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) MW | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2018 USD ($) | May 16, 2019 MW | Sep. 30, 2016 MW | Jan. 31, 2016 MW
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income taxes (benefit) |  |  |  |  |  | $ 20,636 | $ (25,282) | $ 7,775 |  |  |  |  |  |
Regulatory disallowances and restructuring costs |  |  |  |  |  | 1,098 | 151,095 | 65,598 |  |  |  |  |  |
Percent of non-fuel revenue requirement change implemented | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |
NMPRC |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  | $ 99,200 |  |  |  |  |  |  |  |  |  |  |
Requested return on equity |  |  | 10.125% |  |  |  |  |  |  |  |  |  |  |
Proposed term for providing benefits to customers related to reduction in state corporate tax |  |  |  |  |  |  |  |  | 23 years |  |  |  |  |
Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income taxes (benefit) |  |  |  |  |  | 21,857 | (25,962) | (5,971) |  |  |  |  |  |
Regulatory disallowances and restructuring costs |  |  |  |  |  | 1,098 | 150,599 | 66,339 |  |  |  |  |  |
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2 Leases |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts purchased (in megawatts) | MW |  |  |  | 64.1 | 64.1 |  |  |  |  |  |  |  | 64.1 | 64.1
Number of megawatts (in megawatts) | MW |  |  |  | 114.6 | 114.6 |  |  |  |  |  |  |  | 114.6 |
Number of leases under which assets were purchased | lease |  |  |  | 3 | 3 |  |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 1 Leases, extended |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated annual rent expense |  |  |  |  | $ 18,100 |  |  |  |  |  |  |  |  |
Public Service Company of New Mexico | NMPRC |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  | $ 10,300 |  |  |  |  |  |  |  |  |  |  |  |
Requested return on equity |  | 9.575% |  |  |  |  |  |  |  |  |  |  |  |
Proposed term for providing benefits to customers related to reduction in state corporate tax |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |
Public Service Company of New Mexico | 2015 Electric Rate Case |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  |  |  |  |  |  |  |  | $ 123,500 |  |  |  |
Approved rate increase (decrease) |  |  |  | $ 61,200 |  |  |  |  |  |  |  |  |  |
Public Service Company of New Mexico | 2015 Electric Rate Case | Palo Verde Nuclear Generating Station, Unit 2 Leases |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed disallowance of recovery of purchase price of assets |  |  |  |  | $ 163,300 |  |  |  |  |  |  |  |  |
Approved lease acquisition costs |  |  |  | 83,700 |  |  |  |  |  |  |  |  |  |
Disallowed leasehold improvements |  |  |  | $ 43,800 |  |  |  |  |  |  |  |  |  |
Public Service Company of New Mexico | 2015 Electric Rate Case | Non-Fuel Energy |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  |  |  |  |  |  |  |  | $ 121,700 |  |  |  |
Four Corners |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory disallowances and restructuring costs |  | $ 47,600 |  |  |  |  |  |  |  |  |  |  |  |
Pre-tax regulatory disallowance |  | $ 148,100 |  |  |  |  |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts purchased (in megawatts) | MW |  |  |  |  | 64.1 |  |  |  |  |  |  |  |  |
Number of megawatts (in megawatts) | MW |  |  |  |  | 114.6 |  |  |  |  |  |  | 114.6 |  |
Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico | 2015 Electric Rate Case |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts purchased (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  | 64.1 |  |
Pre-tax regulatory disallowance for capital costs |  |  |  |  |  |  |  | $ 4,000 | $ 3,100 |  | $ 18,400 |  |  |
New Mexico 2015 Rate Case | Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Recorded pre-tax impairments |  |  |  |  |  |  | 150,600 |  |  |  |  |  |  |
Amount of impairment to carrying amount of regulatory assets |  |  |  |  |  |  | 39,700 |  |  |  |  |  |  |
Income taxes (benefit) |  |  |  |  |  | $ 45,700 | $ (45,700) |  |  |  |  |  |  |
New Mexico 2015 Rate Case | Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts purchased (in megawatts) | MW |  |  |  |  |  |  | 64.1 |  |  |  |  |  |  |
Recorded pre-tax impairments portion of purchase price |  |  |  |  |  |  | $ 73,200 |  |  |  |  |  |  |
Income taxes (benefit) |  |  |  |  |  |  | (45,700) |  |  |  |  |  |  |
Leaseholds and Leasehold Improvements | New Mexico 2015 Rate Case | Palo Verde Nuclear Generating Station, Units 1 And 4 | Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of impairment to carrying amount of regulatory assets |  |  |  |  |  |  | $ 37,700 |  |  |  |  |  |  |

X
- Definition Estimated annual rent expense + References No definition available. + Details
Name: | pnm_Estimatedannualrentexpense
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of Mega Watts Purchased + References No definition available. + Details
Name: | pnm_NumberOfMegaWattsPurchased
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Approved lease acquisition costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesApprovedleaseacquisitioncosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Disallowed leasehold improvements + References No definition available. + Details
Name: | pnm_PublicUtilitiesDisallowedleaseholdimprovements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Hearing Examiner Proposed disallowance, Lease Acquisition costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesHearingExaminerProposeddisallowanceLeaseAcquisitioncosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Number of Megawatts Nuclear Generation + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofMegawattsNuclearGeneration
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of leases under which assets were purchased + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofleasesunderwhichassetswerepurchased
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Percent of Non-fuel Revenue Requirement Change Implemented + References No definition available. + Details
Name: | pnm_PublicUtilitiesPercentofNonfuelRevenueRequirementChangeImplemented
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Proposed Term to Provide Customers with Benefits Related to Reduction in State Corporate Income Tax Rate + References No definition available. + Details
Name: | pnm_PublicUtilitiesProposedTermtoProvideCustomerswithBenefitsRelatedtoReductioninStateCorporateIncomeTaxRate
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

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

X
- Definition Regulatory Disallowances And Restructuring Costs + References No definition available. + Details
Name: | pnm_RegulatoryDisallowancesAndRestructuringCosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Utilities Operating Expense, Impairments, Portion Of Purchase Price + References No definition available. + Details
Name: | pnm_UtilitiesOperatingExpenseImpairmentsPortionOfPurchasePrice
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Discloses the amount of any reduction to the carrying amounts of regulated assets that result from impairment (for example, rate actions of a regulator). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6066304&loc=d3e44026-110379 + Details
Name: | us-gaap_AmountOfImpairmentToCarryingAmountOfRegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I.7) -URI http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32672-109319 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22663-107794 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120385591&loc=d3e38679-109324 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(9)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22658-107794 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's requested return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of operating expense for impairments of regulated operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
Name: | us-gaap_UtilitiesOperatingExpenseImpairments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=pnm_NMPRCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=pnm_PaloVerdeNuclearGeneratingStationUnit2LeasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=pnm_PaloVerdeNuclearGeneratingStationUnit1LeasesextendedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_A2015ElectricRateCaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_EnergyAxis=pnm_NonFuelEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=pnm_FourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=pnm_PaloVerdeNuclearGeneratingStationUnit2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnm_NewMexico2015RateCaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LeaseholdsAndLeaseholdImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=pnm_PaloVerdeNuclearGeneratingStationUnits1And4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |