XML 112 R81.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Income Taxes - Carryforwards (Details) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2013 | Dec. 31, 2012
Operating Loss Carryforwards [Line Items] |  |  |  |  |
New Mexico corporate tax rate being phased in |  |  |  |  | 7.60%
New Mexico Corporate tax rate, effective by 2018 |  |  |  | 5.90% |
Regulatory liability | $ (10,109) | $ (7,132) | $ (1,903) |  |
Income tax expense | 1,259 | (712) | 674 |  |
Income Taxes, Impairment of Carryforwards |  |  |  |  |
State tax credit carryforwards | 0 | 0 | 3,092 |  |
State net operating loss carryforwards | 819 | (311) | 5,278 |  |
Charitable contribution carryforwards | 909 | 0 | 2,042 |  |
Income Taxes, Reserve Balances |  |  |  |  |
State tax credit carryforwards | 2,487 | 3,986 |  |  |
State net operating loss carryforwards | 1,131 | 361 |  |  |
Charitable contribution carryforwards | 952 | 659 |  |  |
Internal Revenue Service (IRS) |  |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |  |
Federal net operating loss carryforwards | 410,400 |  |  |  |
Federal tax credit carryforwards that expire beginning in 2023 | 71,800 |  |  |  |
Public Service Company of New Mexico |  |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |  |
Regulatory liability | (10,109) | (7,132) | (1,903) |  |
Income tax expense | 1,179 | (804) | 470 |  |
Income Taxes, Impairment of Carryforwards |  |  |  |  |
State tax credit carryforwards | 0 | 0 | 0 |  |
State net operating loss carryforwards | 627 | (213) | 3,619 |  |
Charitable contribution carryforwards | 0 | 0 | 0 |  |
Income Taxes, Reserve Balances |  |  |  |  |
State tax credit carryforwards | 0 | 0 |  |  |
State net operating loss carryforwards | 839 | 248 |  |  |
Charitable contribution carryforwards | 0 | 0 |  |  |
Texas-New Mexico Power Company |  |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |  |
Regulatory liability | 0 | 0 | 0 |  |
Income tax expense | 0 | 0 | 0 |  |
Income Taxes, Impairment of Carryforwards |  |  |  |  |
State tax credit carryforwards | 0 | 0 | 0 |  |
State net operating loss carryforwards | 0 | 0 | 0 |  |
Charitable contribution carryforwards | 0 | 0 | $ 0 |  |
Income Taxes, Reserve Balances |  |  |  |  |
State tax credit carryforwards | 0 | 0 |  |  |
State net operating loss carryforwards | 0 | 0 |  |  |
Charitable contribution carryforwards | 0 | $ 0 |  |  |
2015 Electric Rate Case | Public Service Company of New Mexico |  |  |  |  |
Income Taxes, Reserve Balances |  |  |  |  |
Approval to recover impairment of net operating loss carryforward | (2,100) |  |  |  |
Recovery period of regulatory asset |  | 2 years |  |  |
2016 Electric Rate Case | Public Service Company of New Mexico |  |  |  |  |
Income Taxes, Reserve Balances |  |  |  |  |
Approval to recover impairment of net operating loss carryforward | $ (3,300) |  |  |  |

X
- Definition Charitable contribution carryforward, Impairment + References No definition available. + Details
Name: | pnm_CharitablecontributioncarryforwardImpairment
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Decrease in regulatory liabilities due to change in state corporate tax rate + References No definition available. + Details
Name: | pnm_Decreaseinregulatoryliabilitiesduetochangeinstatecorporatetaxrate
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Federal Tax Credit Carryforwards that Expire Beginning in 2023 + References No definition available. + Details
Name: | pnm_FederalTaxCreditCarryforwardsThatExpireBeginningIn2023
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Income Taxes, Impairment of Carryforwards [Abstract] + References No definition available. + Details
Name: | pnm_IncomeTaxesImpairmentofCarryforwardsAbstract
Namespace Prefix: | pnm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Income Taxes, Reserve Balances [Abstract] + References No definition available. + Details
Name: | pnm_IncomeTaxesReserveBalancesAbstract
Namespace Prefix: | pnm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Increase/Decrease in Income Tax expense due to tax rate change + References No definition available. + Details
Name: | pnm_IncreaseDecreaseinIncomeTaxexpenseduetotaxratechange
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition New Mexico Corporate tax rate, 2014 + References No definition available. + Details
Name: | pnm_NewMexicoCorporatetaxrate2014
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition New Mexico Corporate tax rate, effective by 2018 + References No definition available. + Details
Name: | pnm_NewMexicoCorporatetaxrateeffectiveby2018
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Regulatory Asset, Recovery Period + References No definition available. + Details
Name: | pnm_RegulatoryAssetRecoveryPeriod
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reserve balance, Charitable contribution carryforward + References No definition available. + Details
Name: | pnm_ReservebalanceCharitablecontributioncarryforward
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reserve balance, State tax credit carryforward + References No definition available. + Details
Name: | pnm_ReservebalanceStatetaxcreditcarryforward
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition State Net Operating Loss Carryforward, Impairment + References No definition available. + Details
Name: | pnm_StateNetOperatingLossCarryforwardImpairment
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition State Tax Credit Carryforward, Impairment + References No definition available. + Details
Name: | pnm_StateTaxCreditCarryforwardImpairment
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 + Details
Name: | us-gaap_OperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_OperatingLossCarryforwardsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 30 -Paragraph 5 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=75018887&loc=d3e30536-109315 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
Name: | us-gaap_OperatingLossCarryforwardsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28446-109314 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28511-109314 + Details
Name: | us-gaap_TaxAdjustmentsSettlementsAndUnusualProvisions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_InternalRevenueServiceIRSMember
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: | dei_LegalEntityAxis=pnm_TexasNewMexicoPowerCompanyMember
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: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_ElectricRateCase2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |