Cash used to support bank letter or credit arrangement

No definition available.

Name:	pnm_CashUsedToSupportBankLetterOrCreditArrangement
Namespace Prefix:	pnm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long Term Contract For Purchase of Electric Power Fixed Charges

+ References

No definition available.

+ Details

Name:	pnm_LongTermContractForPurchaseOfElectricPowerFixedCosts
Namespace Prefix:	pnm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Long Term Contract for Purchase of Electric Power Variable Charges

+ References

No definition available.

+ Details

Name:	pnm_LongTermContractForPurchaseOfElectricPowerVariableCharges
Namespace Prefix:	pnm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Long term contract option to purchase, ownership percentage

+ References

No definition available.

+ Details

Name:	pnm_LongTermContractOptionToPurchaseOwnershipPercentage
Namespace Prefix:	pnm_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Long term contract option to purchase, purchase price - percentage of adjusted NBV

+ References

No definition available.

+ Details

Name:	pnm_LongTermContractOptionToPurchasePurchasePricePercentageOfAdjustedNBV
Namespace Prefix:	pnm_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Long term contract option to purchase, purchase price - percentage of FMV

+ References

No definition available.

+ Details

Name:	pnm_LongTermContractOptionToPurchasePurchasePricePercentageOfFMV
Namespace Prefix:	pnm_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Mega Watts Purchased

+ References

No definition available.

+ Details

Name:	pnm_NumberOfMegaWattsPurchased
Namespace Prefix:	pnm_
Data Type:	dtr-types1:powerItemType
Balance Type:	na
Period Type:	instant

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481203/810-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481231/810-10-45-25

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (bb)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481203/810-10-50-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481231/810-10-45-25

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481420/860-30-50-1A

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-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481420/860-30-50-1A

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481420/860-30-50-1A

+ Details

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

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=pnm_SanJuanGeneratingStationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=pnm_CoalSupplyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=pnm_PublicServiceCompanyOfNewMexicoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongTermContractForPurchaseOfElectricPowerAxis=pnm_PurchasedThroughMay302028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Variable Interest Entities (Details) $ in Millions	3 Months Ended
Variable Interest Entities (Details) $ in Millions	Mar. 31, 2024 USD ($) MW	Mar. 31, 2023 USD ($)	Dec. 05, 2022 MW	Jan. 31, 2016 USD ($)
San Juan Generating Station \| Coal supply
Variable Interest Entity [Line Items]
Cash used to support bank letter or credit arrangement				$ 30.3
PNM
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) \| MW			64.1
PNM \| Valencia
Variable Interest Entity [Line Items]
Payment for fixed costs	$ 5.1	$ 5.0
Payment for variable costs	$ 0.1	$ 1.6
Long-term contract option to purchase, ownership percentage (up to)	50.00%
Long-term contract option to purchase, purchase price - percentage of adjusted NBV	50.00%
Long-term contract option to purchase, purchase price - percentage of FMV	50.00%
PNM \| Purchased through May 2028 \| Valencia
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) \| MW	155