XML 105 R82.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Pension and Other Postretirement Benefits Narrative (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected return on plan assets | 4.00% |  |
Amortization of gains and losses that are outside the corridor | 5 years |  |
Maximum annual contributions per employee | 75.00% |  |
Employer matching contribution, percent of employees' gross pay | 6.00% |  |
Minimum [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Non-matching contribution of eligible compensation based on eligible employee's age | 3.00% |  |
Maximum [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Non-matching contribution of eligible compensation based on eligible employee's age | 10.00% |  |
Pension Plan [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected long-term return resulting from effect of 1% change | 1.00% |  |
Expected long-term return resulting from effect of one-percentage point increase (as a percent) | 1.00% |  |
Expected employer contributions to pension plans | $ 0 |  |
Pension Plan [Member] | Minimum [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Weighted average discount rate related to anticipated contributions | 4.80% |  |
Pension Plan [Member] | Maximum [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Weighted average discount rate related to anticipated contributions | 5.70% |  |
Pension Plan [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 21.00% |  |
Pension Plan [Member] | Equity Securities [Member] | Developed Countries Outside of United States [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 6.00% |  |
Pension Plan [Member] | Debt Securities [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 65.00% |  |
Pension Plan [Member] | Alternative Investments [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 14.00% |  |
Other Postretirement Benefits [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected long-term return resulting from effect of 1% change | 1.00% |  |
Other Postretirement Benefits [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 70.00% |  |
Other Postretirement Benefits [Member] | Debt Securities [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Target plan asset allocations | 30.00% |  |
Public Service Company of New Mexico [Member] | Pension Plan [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected return on plan assets | 6.80% | 7.20% | 7.65%
Defined benefit plan, other changes | $ (45,900,000) | $ 50,600,000 |
Actuarial gain (loss) resulting from changes in demographics and other trends | (2,800,000) | (200,000) |
Actuarial gain (loss) resulting from changes in other assumptions and experience | (4,900,000) | 200,000 |
Increased PBO |  | $ 21,900,000 |
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year | $ 5,400,000 |  |
Actual rate of return for pension plans | (1.70%) |  |
Actuarial gains (losses) recorded as regulatory assets | $ (11,397,000) |  |
Public Service Company of New Mexico [Member] | Other Postretirement Benefits [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected return on plan assets | 7.70% | 8.50% | 8.50%
Defined benefit plan, other changes | $ (7,300,000) | $ 6,700,000 |
Actuarial gain (loss) resulting from changes in demographics and other trends | (700,000) | 5,400,000 |
Increased PBO |  | $ 3,200,000 |
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year | $ 700,000 |  |
Actual rate of return for pension plans | (0.80%) |  |
Actuarial gains (losses) recorded as regulatory assets | $ 300,000 |  |
Estimated future employer contributions in next fiscal year | 3,500,000 |  |
Estimated future employer contributions in years two through five | $ 14,000,000 |  |
Texas-New Mexico Power Company [Member] | Pension Plan [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected return on plan assets | 6.80% | 7.20% | 7.65%
Defined benefit plan, other changes | $ (6,100,000) | $ 5,100,000 |
Actuarial gain (loss) resulting from changes in demographics and other trends | (900,000) | 400,000 |
Actuarial gain (loss) resulting from changes in other assumptions and experience | (100,000) | (1,300,000) |
Increased PBO |  | $ 2,500,000 |
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year | $ 600,000 |  |
Actual rate of return for pension plans | (1.70%) |  |
Actuarial gains (losses) recorded as regulatory assets | $ (365,000) |  |
Texas-New Mexico Power Company [Member] | Other Postretirement Benefits [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expected return on plan assets | 5.70% | 6.50% | 6.50%
Defined benefit plan, other changes | $ (1,300,000) | $ 1,100,000 |
Actuarial gain (loss) resulting from changes in demographics and other trends | (700,000) | (100,000) |
Increased PBO |  | $ 500,000 |
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year | $ 100,000 |  |
Actual rate of return for pension plans | (0.50%) |  |
Actuarial gains (losses) recorded as regulatory assets | $ (100,000) |  |
Effect of 1%-point change in assumed health care cost trend rates on net periodic expense and APBO | 0 |  |
Estimated future employer contributions in next fiscal year | 300,000 |  |
Estimated future employer contributions in years two through five | $ 1,400,000 |  |

X
- Definition Defined Benefit Plan, Actuarial Gain (Loss) resulting from changes in demographics and other trends + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanActuarialGainLossresultingfromchangesindemographicsandothertrends
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Benefit Plan, Actuarial Gain (Loss) resulting from changes in other assumptions and experience + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanActuarialGainLossresultingfromchangesinotherassumptionsandexperience
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation Related To Anticipated Contributions, Weighted Average Discount Rate + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRelatedToAnticipatedContributionsWeightedAverageDiscountRate
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Decrease Resulting in Increase Net Periodic Costs In Next Fiscal Year + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsDecreaseResultingInIncreaseNetPeriodicCostsInNextFiscalYear
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return Resulting from Effect of One-Percentage Point Decrease + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnResultingFromEffectOfOnePercentagePointDecrease
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return Resulting from Effect of One-Percentage Point Increase + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnResultingFromEffectOfOnePercentagePointIncrease
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Estimated Future Employer Contributions After Current Fiscal Year + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanEstimatedFutureEmployerContributionsAfterCurrentFiscalYear
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Defined Benefit Plan, Estimated Future Employer Contributions in Year Two Through Year Five + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanEstimatedFutureEmployerContributionsinYearTwoThroughYearFive
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Defined Benefit Plans, Actual Return On Plan Assets + References No definition available. + Details
Name: | pnm_DefinedBenefitPlansActualReturnOnPlanAssets
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plans, Gains and losses that lie outside the corridor, amortized in years + References No definition available. + Details
Name: | pnm_DefinedBenefitPlansGainsAndLossesThatLieOutsideCorridorAmortizedInYears
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan, non matching contribution of eligible compensation based on eligible employee's age + References No definition available. + Details
Name: | pnm_DefinedContributionPlanNonMatchingContributionOfEligibleCompensationBasedOnEligibleEmployeesAge
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates, Net periodic expense and APBO + References No definition available. + Details
Name: | pnm_EffectofOnePercentagePointChangeinAssumedHealthCareCostTrendRatesNetperiodicexpenseandAPBO
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net increase or decrease in the plan benefit obligation during the reporting period. + 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 (a) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Changes in the defined benefit obligation, not otherwise separately disclosed in the financial statements. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanOtherChanges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Target allocation of investments of this type to total plan assets presented on a weighted average basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(i) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
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_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. + 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 (g) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentGeographicRegionAxis=pnm_DevelopedCountriesOutsideOfUnitedStatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=pnm_AlternativeInvestmentsMember
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: | 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: |