XML 115 R85.htm IDEA: XBRL DOCUMENT v3.20.4

Pension and Other Postretirement Benefits - Pre-Tax Information about Prior Service Cost and Net Actuarial (Gain) loss in AOCI (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Public Service Company of New Mexico | Pension Plan
Net actuarial (gain) loss
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	$ 146,391
Experience (gain) loss	(21,393)
Regulatory asset (liability) adjustment	15,211
Amortization recognized in net periodic benefit cost (income)	(8,131)
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	132,078
Public Service Company of New Mexico | Executive Retirement Program
Net actuarial (gain) loss
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	2,395
Experience (gain) loss	78
Regulatory asset (liability) adjustment	(45)
Amortization recognized in net periodic benefit cost (income)	(169)
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	2,259
Texas-New Mexico Power Company | Pension Plan
Net actuarial (gain) loss
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	0
Experience (gain) loss	3,860
Regulatory asset (liability) adjustment	(3,860)
Amortization recognized in net periodic benefit cost (income)	0
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	0
Texas-New Mexico Power Company | Executive Retirement Program
Net actuarial (gain) loss
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	0
Experience (gain) loss	58
Regulatory asset (liability) adjustment	(58)
Amortization recognized in net periodic benefit cost (income)	0
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	$ 0

X

- Definition

Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Actuarial (Gain) Loss, Regulatory Asset (Liability) Adjustment, before Tax

+ References

No definition available.

+ Details

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

X

- Definition

Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669686-108580

+ Details

Name:	us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669646-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e637-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e689-108580

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17A
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL34724391-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax
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_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: