XML 78 R51.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Pension and Other Postretirement Benefit Plans (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
PNM | Pension Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | $ 0 | $ 0 | $ 0 | $ 0
Interest cost | 6,727,000 | 7,577,000 | 20,181,000 | 22,731,000
Expected return on plan assets | (8,451,000) | (8,854,000) | (25,352,000) | (26,562,000)
Amortization of net (gain) loss | 4,001,000 | 3,455,000 | 12,004,000 | 10,365,000
Amortization of prior service cost | (241,000) | (241,000) | (724,000) | (724,000)
Net Periodic Benefit Cost | 2,036,000 | 1,937,000 | 6,109,000 | 5,810,000
Contributions by employer | 0 | 0 | 0 | 0
Total expected employer contributions for future fiscal years | 0 |  | $ 0 |
PNM | Pension Plan | Minimum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 4.10% |
PNM | Pension Plan | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 4.90% |
PNM | OPEB Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 24,000 | 35,000 | $ 72,000 | 105,000
Interest cost | 1,006,000 | 1,087,000 | 3,019,000 | 3,260,000
Expected return on plan assets | (1,308,000) | (1,371,000) | (3,923,000) | (4,113,000)
Amortization of net (gain) loss | 921,000 | 286,000 | 2,762,000 | 858,000
Amortization of prior service cost | (416,000) | (7,000) | (1,248,000) | (22,000)
Net Periodic Benefit Cost | 227,000 | 30,000 | 682,000 | 88,000
Contributions by employer | 0 | 800,000 | 0 | 2,400,000
Total expected employer contributions for future fiscal years | 0 |  | 0 |
PNM | Executive Retirement Program |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 174,000 | 203,000 | 523,000 | 609,000
Expected return on plan assets | 0 | 0 | 0 | 0
Amortization of net (gain) loss | 78,000 | 64,000 | 235,000 | 192,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost | 252,000 | 267,000 | 758,000 | 801,000
Contributions by employer | 400,000 | 400,000 | 1,200,000 | 1,200,000
Total expected employer contributions for future fiscal years | 5,800,000 |  | 5,800,000 |
Total expected employer contributions for fiscal year | 1,500,000 |  | 1,500,000 |
Texas-New Mexico Power Company | Pension Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 722,000 | 826,000 | 2,165,000 | 2,478,000
Expected return on plan assets | (945,000) | (986,000) | (2,834,000) | (2,957,000)
Amortization of net (gain) loss | 231,000 | 175,000 | 692,000 | 525,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost | 8,000 | 15,000 | 23,000 | 46,000
Contributions by employer | 0 | 0 | 0 | 0
Total expected employer contributions for future fiscal years | 0 |  | $ 0 |
Texas-New Mexico Power Company | Pension Plan | Minimum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 4.10% |
Texas-New Mexico Power Company | Pension Plan | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 4.90% |
Texas-New Mexico Power Company | OPEB Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 36,000 | 46,000 | $ 107,000 | 139,000
Interest cost | 139,000 | 169,000 | 417,000 | 508,000
Expected return on plan assets | (114,000) | (122,000) | (342,000) | (367,000)
Amortization of net (gain) loss | (20,000) | (10,000) | (60,000) | (30,000)
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost | 41,000 | 83,000 | 122,000 | 250,000
Contributions by employer | 0 | 0 | 700,000 | 0
Total expected employer contributions for future fiscal years | 1,400,000 |  | 1,400,000 |
Total expected employer contributions for fiscal year | 0 |  | 0 |
Texas-New Mexico Power Company | Executive Retirement Program |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 8,000 | 10,000 | 25,000 | 30,000
Expected return on plan assets | 0 | 0 | 0 | 0
Amortization of net (gain) loss | 2,000 | 1,000 | 7,000 | 1,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost | 10,000 | 11,000 | 32,000 | 31,000
Total expected employer contributions for future fiscal years | 400,000 |  | 400,000 |
Total expected employer contributions for fiscal year | 100,000 |  | 100,000 |
Texas-New Mexico Power Company | Executive Retirement Program | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Contributions by employer | $ 100,000 | $ 100,000 | $ 100,000 | $ 100,000

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 Plan Total Expected Employer Contributions for Fiscal Year + References No definition available. + Details
Name: | pnm_DefinedBenefitPlanTotalExpectedEmployerContributionsForFiscalYear
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + 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 (h)(4) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. + 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 (h)(5) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan. + 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 (k)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contribution received by defined benefit plan from employer which increases plan assets. + 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 (d)(5)(ii) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2709-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=82843861&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 (d)(5)(iv)(01) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + 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 (h)(3) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cost recognized for passage of time related to defined benefit plan. + 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 (h)(2) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanInterestCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + 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 (h) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + 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 (h)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanServiceCost
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: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPensionPlansDefinedBenefitMember
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: |