XML 129 R106.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Pension and Other Postretirement Benefits - Assumptions Used (Details) | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected return on plan assets | 4.00% |  |
PNM | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.46% | 5.74% | 3.00%
Discount rate for determining net periodic benefit cost | 5.74% | 3.00% | 2.66%
Expected return on plan assets | 6.30% | 5.50% | 5.50%
PNM | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.48% | 5.75% | 2.99%
Discount rate for determining net periodic benefit cost | 5.75% | 2.99% | 2.65%
Expected return on plan assets | 5.90% | 4.75% | 4.75%
PNM | Executive Retirement Program |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.45% | 5.73% | 3.02%
Discount rate for determining net periodic benefit cost | 5.73% | 3.02% | 2.68%
TNMP | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.47% | 5.75% | 3.01%
Discount rate for determining net periodic benefit cost | 5.75% | 3.01% | 2.69%
Expected return on plan assets | 5.50% | 4.40% | 5.50%
TNMP | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.48% | 5.75% | 2.99%
Discount rate for determining net periodic benefit cost | 5.75% | 2.99% | 2.65%
Expected return on plan assets | 4.70% | 3.80% | 3.80%
TNMP | Executive Retirement Program |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Discount rate for determining PBO and APBO | 5.47% | 5.75% | 3.01%
Discount rate for determining net periodic benefit cost | 5.75% | 3.01% | 2.69%

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-8 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix: | us-gaap_
Data Type: | dtr-types: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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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_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: |