Public Service Company of New Mexico PFD 4.58% (PNMXO) 10-K 1 Mar 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Entity Registrant Name	PNM Resources, Inc.
Entity Incorporation, State or Country Code	NM
Entity Address, Address Line One	414 Silver Ave. SW
Entity Address, City or Town	Albuquerque
Entity Address, State or Province	NM
Entity Address, Postal Zip Code	87102
City Area Code	505
Local Phone Number	241-2700
Entity File Number	001-32462
Entity Tax Identification Number	85-0468296
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	PNM
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		85,834,874
Entity Public Float			$ 3,061,885,307
Documents Incorporated by Reference	Portions of the following document are incorporated by reference into Part III of this report: Proxy Statement to be filed by PNMR with the SEC pursuant to Regulation 14A relating to the annual meeting of shareholders of PNMR to be held on May 11, 2021. This combined Form 10-K is separately filed by PNMR, PNM, and TNMP. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants. When this Form 10-K is incorporated by reference into any filing with the SEC made by PNMR, PNM, or TNMP, as a registrant, the portions of this Form 10-K that relate to each other registrant are not incorporated by reference therein.
Entity Central Index Key	0001108426
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Transition Report	false
Public Service Company of New Mexico
Document Information [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	Public Service Company of New Mexico
Entity Address, Address Line One	414 Silver Ave. SW
Entity Address, City or Town	Albuquerque
Entity Address, State or Province	NM
Entity Address, Postal Zip Code	87102
City Area Code	505
Local Phone Number	241-2700
Entity File Number	001-06986
Entity Tax Identification Number	85-0019030
Title of 12(b) Security	1965 Series, 4.58% Cumulative Preferred Stock
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		39,117,799
Entity Central Index Key	0000081023
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Texas-New Mexico Power Company
Document Information [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	Texas-New Mexico Power Company
Entity Address, Address Line One	577 N. Garden Right Blvd.
Entity Address, City or Town	Lewisville
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75067
City Area Code	972
Local Phone Number	420-4189
Entity File Number	002-97230
Entity Tax Identification Number	75-0204070
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		6,358
Entity Central Index Key	0000022767
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Electric Operating Revenues
Contracts with customers	$ 1,469,799	$ 1,377,208	$ 1,359,740
Alternative revenue programs	(11,994)	(542)	1,756
Other electric operating revenue	65,207	80,937	75,117
Total electric operating revenues	1,523,012	1,457,603	1,436,613
Operating Expenses:
Administrative and general	216,334	189,227	188,470
Regulatory disallowances and restructuring costs	1,098	151,095	65,598
Depreciation and amortization	275,612	267,808	241,188
Transmission and distribution costs	77,943	69,862	76,434
Taxes other than income taxes	81,526	80,054	79,673
Total operating expenses	1,237,731	1,313,403	1,200,566
Operating income	285,281	144,200	236,047
Other Income and Deductions:
Interest income	14,223	14,022	15,540
Gains (losses) on investment securities	21,599	29,589	(17,176)
Other income	19,973	15,382	17,586
Other (deductions)	(18,732)	(15,328)	(15,696)
Net other income and (deductions)	37,063	43,665	254
Interest Charges	114,392	121,016	127,244
Earnings before Income Taxes	207,952	66,849	109,057
Income Taxes (Benefits)	20,636	(25,282)	7,775
Net Earnings	187,316	92,131	101,282
(Earnings) Attributable to Valencia Non-controlling Interest	(14,013)	(14,241)	(15,112)
Preferred Stock Dividends Requirements	(528)	(528)	(528)
Net Earnings Attributable to PNMR	$ 172,775	$ 77,362	$ 85,642
Net Earnings Attributable to PNMR per Common Share:
Basic (in dollars per share)	$ 2.16	$ 0.97	$ 1.07
Diluted (in dollars per share)	$ 2.15	$ 0.97	$ 1.07
Public Service Company of New Mexico
Electric Operating Revenues
Contracts with customers	$ 1,078,158	$ 1,010,898	$ 1,019,291
Alternative revenue programs	(3,531)	1,987	(2,443)
Other electric operating revenue	65,207	80,937	75,117
Total electric operating revenues	1,139,834	1,093,822	1,091,965
Operating Expenses:
Administrative and general	180,113	172,903	173,178
Regulatory disallowances and restructuring costs	1,098	150,599	66,339
Depreciation and amortization	165,325	160,368	151,866
Transmission and distribution costs	49,534	42,970	46,855
Taxes other than income taxes	45,723	45,644	45,181
Total operating expenses	924,937	1,032,754	946,932
Operating income	214,897	61,068	145,033
Other Income and Deductions:
Interest income	14,469	14,303	13,089
Gains (losses) on investment securities	21,599	29,589	(17,176)
Other income	9,800	9,213	10,992
Other (deductions)	(14,279)	(11,813)	(11,128)
Net other income and (deductions)	31,589	41,292	(4,223)
Interest Charges	64,615	72,900	76,458
Earnings before Income Taxes	181,871	29,460	64,352
Income Taxes (Benefits)	21,857	(25,962)	(5,971)
Net Earnings	160,014	55,422	70,323
(Earnings) Attributable to Valencia Non-controlling Interest	(14,013)	(14,241)	(15,112)
Net earnings	146,001	41,181	55,211
Preferred Stock Dividends Requirements	(528)	(528)	(528)
Net Earnings Attributable to PNMR	145,473	40,653	54,683
Texas-New Mexico Power Company
Electric Operating Revenues
Contracts with customers	391,641	366,310	340,449
Alternative revenue programs	(8,463)	(2,529)	4,199
Other electric operating revenue	0	0	0
Total electric operating revenues	383,178	363,781	344,648
Operating Expenses:
Administrative and general	44,811	40,530	38,642
Regulatory disallowances and restructuring costs	0	496	(741)
Depreciation and amortization	87,799	84,259	66,189
Transmission and distribution costs	28,409	26,892	29,579
Taxes other than income taxes	31,632	30,703	28,792
Total operating expenses	294,725	277,967	248,151
Operating income	88,453	85,814	96,497
Other Income and Deductions:
Other income	8,546	5,559	5,487
Other (deductions)	(1,718)	(1,428)	(1,422)
Net other income and (deductions)	6,828	4,131	4,065
Interest Charges	30,388	29,100	32,091
Earnings before Income Taxes	64,893	60,845	68,471
Income Taxes (Benefits)	6,308	5,046	16,880
Net earnings	58,585	55,799	51,591
Electricity
Electric Operating Revenues
Total electric operating revenues	1,523,012	1,457,603	1,436,613
Operating Expenses:
Cost of energy and production costs	447,241	412,812	399,726
Electricity | Public Service Company of New Mexico
Operating Expenses:
Cost of energy and production costs	345,167	317,725	314,036
Electricity | Texas-New Mexico Power Company
Operating Expenses:
Cost of energy and production costs	102,074	95,087	85,690
Electricity, Generation
Operating Expenses:
Cost of energy and production costs	137,977	142,545	149,477
Electricity, Generation | Public Service Company of New Mexico
Operating Expenses:
Cost of energy and production costs	$ 137,977	$ 142,545	$ 149,477

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Earnings	$ 187,316	$ 92,131	$ 101,282
Unrealized Gains on Available-for-Sale Securities:
Unrealized holding gains (losses) arising during the period, net of income tax (expense) benefit	16,850	19,190	2,827
Reclassification adjustment for (gains) included in net earnings (loss), net of income tax expense	(7,085)	(10,491)	(2,849)
Pension Liability Adjustment:
Experience gain (loss), net of income tax (expense) benefit	4,587	(2,856)	(7,745)
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, net of income tax (expense) benefit	6,192	5,524	5,646
Fair Value Adjustment for Cash Flow Hedges:
Change in fair market value, net of income tax (expense) benefit	948	(2,607)
Change in fair market value, net of income tax (expense) benefit			425
Reclassification adjustment for losses included in net earnings, net of income tax (benefit)	(1,298)	547
Reclassification adjustment for losses included in net earnings, net of income tax (benefit)			160
Total Other Comprehensive Income (Loss)	20,194	9,307	(1,536)
Comprehensive Income	207,510	101,438	99,746
Comprehensive (Income) Attributable to Valencia Non-controlling Interest	(14,013)	(14,241)	(15,112)
Preferred Stock Dividends Requirements	(528)	(528)	(528)
Comprehensive Income Attributable to PNMR	192,969	86,669	84,106
Public Service Company of New Mexico
Net Earnings	160,014	55,422	70,323
Unrealized Gains on Available-for-Sale Securities:
Unrealized holding gains (losses) arising during the period, net of income tax (expense) benefit	16,850	19,190	2,827
Reclassification adjustment for (gains) included in net earnings (loss), net of income tax expense	(7,085)	(10,491)	(2,849)
Pension Liability Adjustment:
Experience gain (loss), net of income tax (expense) benefit	4,587	(2,856)	(7,745)
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, net of income tax (expense) benefit	6,192	5,524	5,646
Fair Value Adjustment for Cash Flow Hedges:
Total Other Comprehensive Income (Loss)	20,544	11,367	(2,121)
Comprehensive Income	180,558	66,789	68,202
Comprehensive (Income) Attributable to Valencia Non-controlling Interest	(14,013)	(14,241)	(15,112)
Comprehensive Income Attributable to PNMR	$ 166,545	$ 52,548	$ 53,090

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unrealized holding gains (losses) arising during the period, income tax (expense) benefit	$ (5,736)	$ (6,534)	$ (963)
Reclassification adjustment for (gains) losses included in net earnings, income tax expense (benefit)	2,412	3,572	970
Pension liability adjustment, income tax expense (benefit)	(1,562)	973	2,637
Reclassification adjustment for amortization of experience losses recognized as net periodic benefit cost, income tax expense	(2,108)	(1,880)	(1,922)
Change in fair market value, income tax (expense) benefit	(323)	888	(145)
Reclassification adjustment for losses included in net earnings, income tax expense (benefit)	442	(186)	(56)
Public Service Company of New Mexico
Unrealized holding gains (losses) arising during the period, income tax (expense) benefit	(5,736)	(6,534)	(963)
Reclassification adjustment for (gains) losses included in net earnings, income tax expense (benefit)	2,412	3,572	970
Pension liability adjustment, income tax expense (benefit)	(1,562)	973	2,637
Reclassification adjustment for amortization of experience losses recognized as net periodic benefit cost, income tax expense	$ (2,108)	$ (1,880)	$ (1,922)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities:
Net Earnings	$ 187,316,000	$ 92,131,000	$ 101,282,000
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	314,668,000	301,068,000	275,641,000
Deferred income tax expense (benefit)	20,405,000	(25,385,000)	8,019,000
(Gains) losses on investment securities	(21,599,000)	(29,589,000)	17,176,000
Stock based compensation expense	8,141,000	6,414,000	7,120,000
Regulatory disallowances and restructuring costs	1,098,000	151,095,000	65,598,000
Allowance for equity funds used during construction	(11,254,000)	(9,478,000)	(10,404,000)
Other, net	3,497,000	2,395,000	3,529,000
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(42,035,000)	3,796,000	(8,702,000)
Materials, supplies, and fuel stock	11,512,000	(6,095,000)	(5,331,000)
Other current assets	(8,135,000)	1,872,000	2,491,000
Other assets	29,923,000	42,803,000	(840,000)
Accounts payable	7,403,000	(272,000)	(20,714,000)
Accrued interest and taxes	(9,347,000)	14,691,000	1,713,000
Other current liabilities	23,740,000	(7,212,000)	2,614,000
Other liabilities	(29,633,000)	(35,071,000)	(10,966,000)
Net cash flows from operating activities	485,700,000	503,163,000	428,226,000
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(679,028,000)	(616,273,000)	(501,213,000)
Proceeds from sales of investment securities	590,998,000	494,528,000	984,533,000
Purchases of investment securities	(607,591,000)	(513,866,000)	(1,007,022,000)
Investments in NMRD	(23,250,000)	(38,250,000)	(9,000,000)
Principal repayments on Westmoreland Loan	0	0	56,640,000
Other, net	(14,928,000)	(37,000)	338,000
Net cash flows from investing activities	(733,799,000)	(673,898,000)	(475,724,000)
Cash Flows From Financing Activities:
Short-term loan borrowings (repayments)	0	(150,000,000)	50,000,000
Revolving credit facilities borrowings (repayments), net	(153,100,000)	99,200,000	(119,500,000)
Long-term borrowings	1,267,845,000	745,000,000	984,652,000
Repayment of long-term debt	(977,845,000)	(407,302,000)	(750,162,000)
Issuance of common stock	283,208,000	0	0
Proceeds from stock option exercise	24,000	943,000	963,000
Awards of common stock	(11,984,000)	(9,918,000)	(12,635,000)
Dividends paid	(98,502,000)	(92,926,000)	(84,961,000)
Valencia’s transactions with its owner	(18,056,000)	(15,401,000)	(17,095,000)
Amounts received under transmission interconnection arrangements	11,452,000	10,015,000	4,060,000
Refunds paid under transmission interconnection arrangements	(5,905,000)	(4,325,000)	(2,830,000)
Other, net	(4,943,000)	(2,840,000)	(6,846,000)
Net cash flows from financing activities	292,194,000	172,446,000	45,646,000
Change in Cash and Cash Equivalents	44,095,000	1,711,000	(1,852,000)
Cash and Cash Equivalents at Beginning of Year	3,833,000	2,122,000	3,974,000
Cash and Cash Equivalents at End of Year	47,928,000	3,833,000	2,122,000
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	106,575,000	115,476,000	119,308,000
Income taxes paid (refunded), net	969,000	(2,929,000)	842,000
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(58,796,000)	8,781,000	(11,502,000)
Contribution of utility plant to NMRD	801,000	0	578,000
Public Service Company of New Mexico
Cash Flows From Operating Activities:
Net Earnings	160,014,000	55,422,000	70,323,000
Net earnings	146,001,000	41,181,000	55,211,000
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	198,418,000	191,213,000	182,355,000
Deferred income tax expense (benefit)	22,442,000	(20,145,000)	3,334,000
(Gains) losses on investment securities	(21,599,000)	(29,589,000)	17,176,000
Regulatory disallowances and restructuring costs	1,098,000	150,599,000	66,339,000
Allowance for equity funds used during construction	(6,958,000)	(6,656,000)	(8,173,000)
Other, net	4,950,000	2,697,000	3,395,000
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(41,340,000)	5,877,000	(7,959,000)
Materials, supplies, and fuel stock	11,753,000	(5,128,000)	(6,238,000)
Other current assets	(2,718,000)	(1,453,000)	(468,000)
Other assets	24,882,000	31,409,000	6,894,000
Accounts payable	6,267,000	(3,617,000)	(14,290,000)
Accrued interest and taxes	(11,572,000)	5,579,000	(7,617,000)
Other current liabilities	16,682,000	18,002,000	(17,975,000)
Other liabilities	(36,556,000)	(39,087,000)	(3,761,000)
Net cash flows from operating activities	325,763,000	355,123,000	283,335,000
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(335,055,000)	(341,847,000)	(255,627,000)
Proceeds from sales of investment securities	590,998,000	494,528,000	984,533,000
Purchases of investment securities	(607,591,000)	(513,866,000)	(1,007,022,000)
Other, net	(14,942,000)	(87,000)	544,000
Net cash flows from investing activities	(366,590,000)	(361,272,000)	(277,572,000)
Cash Flows From Financing Activities:
Short-term loan borrowings (repayments)	(48,000,000)	15,600,000	2,600,000
Short-term borrowings (repayments) - affiliate, net	0	(19,800,000)	19,800,000
Long-term borrowings	852,845,000	290,000,000	450,000,000
Repayment of long-term debt	(902,845,000)	(200,000,000)	(450,025,000)
Equity contribution from parent	230,000,000	0	0
Dividends paid	(41,181,000)	(528,000)	(77,904,000)
Valencia’s transactions with its owner	(18,056,000)	(15,401,000)	(17,095,000)
Amounts received under transmission interconnection arrangements	4,050,000	10,015,000	72,260,000
Refunds paid under transmission interconnection arrangements	(5,905,000)	(72,525,000)	(2,830,000)
Other, net	364,000	(296,000)	(3,592,000)
Net cash flows from financing activities	71,272,000	7,065,000	(6,786,000)
Change in Cash and Cash Equivalents	30,445,000	916,000	(1,023,000)
Cash and Cash Equivalents at Beginning of Year	1,001,000	85,000	1,108,000
Cash and Cash Equivalents at End of Year	31,446,000	1,001,000	85,000
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	60,663,000	65,445,000	73,029,000
Income taxes paid (refunded), net	0	(3,544,000)	134,000
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(48,037,000)	4,751,000	(12,310,000)
Texas-New Mexico Power Company
Cash Flows From Operating Activities:
Net earnings	58,585,000	55,799,000	51,591,000
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	89,010,000	85,453,000	68,078,000
Deferred income tax expense (benefit)	(7,773,000)	(7,650,000)	1,780,000
Regulatory disallowances and restructuring costs	0	496,000	(741,000)
Allowance for equity funds used during construction	(4,300,000)	(2,800,000)	(2,200,000)
Allowance for equity funds used during construction and other, net	(4,305,000)	(2,808,000)	(2,048,000)
Other, net
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(695,000)	(2,081,000)	(744,000)
Materials, supplies, and fuel stock	(241,000)	(967,000)	907,000
Other current assets	(1,291,000)	(798,000)	1,929,000
Other assets	8,553,000	8,366,000	(7,174,000)
Accounts payable	1,607,000	1,829,000	(4,199,000)
Accrued interest and taxes	(530,000)	186,000	12,263,000
Other current liabilities	2,518,000	771,000	6,719,000
Other liabilities	2,135,000	(1,004,000)	(6,610,000)
Net cash flows from operating activities	147,573,000	137,592,000	121,751,000
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(321,505,000)	(254,006,000)	(223,448,000)
Net cash flows from investing activities	(321,505,000)	(254,006,000)	(223,448,000)
Cash Flows From Financing Activities:
Short-term loan borrowings (repayments)	(15,000,000)	(2,500,000)	17,500,000
Short-term borrowings (repayments) - affiliate, net	0	(100,000)	100,000
Long-term borrowings	185,000,000	305,000,000	95,000,000
Repayment of long-term debt	0	(207,302,000)	0
Equity contribution from parent	71,000,000	80,000,000	30,000,000
Dividends paid	(58,534,000)	(55,265,000)	(41,903,000)
Amounts received under transmission interconnection arrangements	7,402,000	0	0
Other, net	(2,136,000)	(2,419,000)	(700,000)
Net cash flows from financing activities	187,732,000	117,414,000	99,997,000
Change in Cash and Cash Equivalents	13,800,000	1,000,000	(1,700,000)
Cash and Cash Equivalents at Beginning of Year	1,000,000	0	1,700,000
Cash and Cash Equivalents at End of Year	14,800,000	1,000,000	0
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	28,114,000	28,055,000	28,629,000
Income taxes paid (refunded), net	16,790,000	13,611,000	4,266,000
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	$ (11,415,000)	$ 5,035,000	$ 1,810,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 47,928	$ 3,833
Accounts receivable, net of allowance for uncollectible accounts	113,410	85,889
Unbilled revenues	55,504	57,416
Other receivables	23,797	12,165
Materials, supplies, and fuel stock	66,417	77,929
Regulatory assets	202	7,373
Income taxes receivable	5,672	4,933
Other current assets	64,549	44,472
Total current assets	377,479	294,010
Other Property and Investments:
Investment securities	440,115	388,832
Equity investment in NMRD	90,655	65,159
Other investments	284	356
Non-utility property, including financing leases	24,075	12,459
Total other property and investments	555,129	466,806
Utility Plant:
Plant in service, held for future use, and to be abandoned	8,480,799	7,918,601
Less accumulated depreciation and amortization	2,835,170	2,713,503
Net plant in service and plant held for future use	5,645,629	5,205,098
Construction work in progress	218,719	161,106
Nuclear fuel, net of accumulated amortization of $41,367 and $42,354	100,801	99,805
Net utility plant	5,965,149	5,466,009
Deferred Charges and Other Assets:
Regulatory assets	557,790	556,930
Goodwill	278,297	278,297
Operating lease assets, net of amortization	105,133	131,212
Other deferred charges	100,877	105,510
Total deferred charges and other assets	1,042,097	1,071,949
Total assets	7,939,854	7,298,774
Current Liabilities:
Short-term debt	32,000	185,100
Current installments of long-term debt	575,518	490,268
Accounts payable	169,317	103,118
Customer deposits	6,606	10,585
Accrued interest and taxes	68,206	76,815
Regulatory liabilities	7,471	505
Operating lease liabilities	27,460	29,068
Dividends declared	28,243	24,625
Other current liabilities	62,841	47,397
Total current liabilities	977,662	967,481
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	2,719,632	2,517,449
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	694,512	626,058
Regulatory liabilities	850,228	866,243
Asset retirement obligations	183,421	181,962
Accrued pension liability and postretirement benefit cost	58,101	95,037
Operating lease liabilities	81,065	105,512
Other deferred credits	255,230	185,753
Total deferred credits and other liabilities	2,122,557	2,060,565
Total liabilities	5,819,851	5,545,495
Commitments and Contingencies (See Note 16)
Cumulative Preferred Stock of Subsidiary without mandatory redemption requirements ($100 stated value; 10,000,000 shares authorized; issued and outstanding 115,293 shares)	11,529	11,529
Company common stockholders’ equity:
Common stock	1,429,941	1,150,552
Accumulated other comprehensive income (loss), net of income taxes	(79,183)	(99,377)
Retained earnings	698,707	627,523
Total PNMR common stockholders’ equity	2,049,465	1,678,698
Non-controlling interest in Valencia	59,009	63,052
Total equity	2,108,474	1,741,750
Total liabilities and stockholders' equity	$ 7,939,854	$ 7,298,774
Common stock, shares issued (in shares)	85,834,874	85,834,874
Common stock, shares outstanding (in shares)	79,653,624	79,653,624
Public Service Company of New Mexico
Current Assets:
Cash and cash equivalents	$ 31,446	$ 1,001
Accounts receivable, net of allowance for uncollectible accounts	88,239	60,447
Unbilled revenues	43,724	46,602
Other receivables	21,814	11,039
Affiliate receivables	8,819	8,825
Materials, supplies, and fuel stock	60,472	72,225
Regulatory assets	0	7,373
Income taxes receivable	15,706	15,122
Other current assets	51,908	36,561
Total current assets	322,128	259,195
Other Property and Investments:
Investment securities	440,115	388,832
Other investments	120	178
Non-utility property, including financing leases	9,505	4,470
Total other property and investments	449,740	393,480
Utility Plant:
Plant in service, held for future use, and to be abandoned	6,022,753	5,753,267
Less accumulated depreciation and amortization	2,158,915	2,076,291
Net plant in service and plant held for future use	3,863,838	3,676,976
Construction work in progress	148,962	108,787
Nuclear fuel, net of accumulated amortization of $41,367 and $42,354	100,801	99,805
Net utility plant	4,113,601	3,885,568
Deferred Charges and Other Assets:
Regulatory assets	457,953	435,467
Goodwill	51,632	51,632
Operating lease assets, net of amortization	97,461	120,585
Other deferred charges	88,518	97,064
Total deferred charges and other assets	695,564	704,748
Total assets	5,581,033	5,242,991
Current Liabilities:
Short-term debt	10,000	58,000
Current installments of long-term debt	345,570	350,268
Accounts payable	121,050	66,746
Affiliate payables	14,058	12,524
Customer deposits	6,606	10,585
Accrued interest and taxes	32,630	43,617
Regulatory liabilities	5,419	371
Operating lease liabilities	25,130	25,927
Dividends declared	132	132
Other current liabilities	33,737	25,066
Total current liabilities	594,332	593,236
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	1,351,050	1,397,752
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	579,150	521,990
Regulatory liabilities	664,873	683,398
Asset retirement obligations	182,718	181,081
Accrued pension liability and postretirement benefit cost	56,273	87,838
Operating lease liabilities	75,941	97,992
Other deferred credits	201,415	155,744
Total deferred credits and other liabilities	1,760,370	1,728,043
Total liabilities	3,705,752	3,719,031
Commitments and Contingencies (See Note 16)
Cumulative Preferred Stock of Subsidiary without mandatory redemption requirements ($100 stated value; 10,000,000 shares authorized; issued and outstanding 115,293 shares)	11,529	11,529
Company common stockholders’ equity:
Common stock	1,494,918	1,264,918
Accumulated other comprehensive income (loss), net of income taxes	(78,511)	(99,055)
Retained earnings	388,336	283,516
Total PNMR common stockholders’ equity	1,804,743	1,449,379
Non-controlling interest in Valencia	59,009	63,052
Total equity	1,863,752	1,512,431
Total liabilities and stockholders' equity	$ 5,581,033	$ 5,242,991
Common stock, shares issued (in shares)	39,117,799	39,117,799
Common stock, shares outstanding (in shares)	39,117,799	39,117,799
Texas-New Mexico Power Company
Current Assets:
Cash and cash equivalents	$ 14,800	$ 1,000
Accounts receivable, net of allowance for uncollectible accounts	25,171	25,442
Unbilled revenues	11,780	10,814
Other receivables	3,703	2,713
Affiliate receivables	0	0
Materials, supplies, and fuel stock	5,945	5,704
Regulatory assets	202	0
Other current assets	1,738	1,280
Total current assets	63,339	46,953
Other Property and Investments:
Other investments	164	178
Non-utility property, including financing leases	13,298	6,684
Total other property and investments	13,462	6,862
Utility Plant:
Plant in service, held for future use, and to be abandoned	2,193,270	1,919,256
Less accumulated depreciation and amortization	537,707	516,795
Net plant in service and plant held for future use	1,655,563	1,402,461
Construction work in progress	61,359	42,554
Net utility plant	1,716,922	1,445,015
Deferred Charges and Other Assets:
Regulatory assets	99,837	121,463
Goodwill	226,665	226,665
Operating lease assets, net of amortization	7,206	9,954
Other deferred charges	5,149	3,527
Total deferred charges and other assets	338,857	361,609
Total assets	2,132,580	1,860,439
Current Liabilities:
Short-term debt	0	15,000
Accounts payable	33,620	20,598
Affiliate payables	5,883	5,419
Accrued interest and taxes	41,538	42,068
Regulatory liabilities	2,052	134
Operating lease liabilities	2,193	2,753
Other current liabilities	4,486	3,565
Total current liabilities	89,772	89,537
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	853,673	670,691
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	145,369	140,151
Regulatory liabilities	185,355	182,845
Asset retirement obligations	703	881
Accrued pension liability and postretirement benefit cost	1,828	7,199
Operating lease liabilities	4,779	7,039
Other deferred credits	25,423	7,469
Total deferred credits and other liabilities	363,457	345,584
Total liabilities	1,306,902	1,105,812
Commitments and Contingencies (See Note 16)
Company common stockholders’ equity:
Common stock	64	64
Paid-in-capital	685,166	614,166
Retained earnings	140,448	140,397
Total PNMR common stockholders’ equity	825,678	754,627
Total liabilities and stockholders' equity	$ 2,132,580	$ 1,860,439
Common stock, shares issued (in shares)	6,358	6,358
Common stock, shares outstanding (in shares)	6,358	6,358

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Allowance for uncollectible accounts	$ 8,333	$ 1,163
Utility Plant:
Accumulated depreciation, nuclear fuel	$ 41,367	$ 42,354
Deferred Credits and Other Liabilities:
Cumulative preferred stock of subsidiary, stated value (in dollars per share)	$ 100	$ 100
Cumulative preferred stock of subsidiary, shares authorized (in shares)	10,000,000	10,000,000
Cumulative preferred stock of subsidiary, shares issued (in shares)	115,293	115,293
Cumulative preferred stock of subsidiary, shares outstanding (in shares)	115,293	115,293
Company common stockholders’ equity:
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	85,834,874	85,834,874
Common stock, shares outstanding (in shares)	79,653,624	79,653,624
Public Service Company of New Mexico
Current Assets:
Allowance for uncollectible accounts	$ 8,333	$ 1,163
Utility Plant:
Accumulated depreciation, nuclear fuel	$ 41,367	$ 42,354
Deferred Credits and Other Liabilities:
Cumulative preferred stock of subsidiary, stated value (in dollars per share)	$ 100	$ 100
Cumulative preferred stock of subsidiary, shares authorized (in shares)	10,000,000	10,000,000
Cumulative preferred stock of subsidiary, shares issued (in shares)	115,293	115,293
Cumulative preferred stock of subsidiary, shares outstanding (in shares)	115,293	115,293
Company common stockholders’ equity:
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	39,117,799	39,117,799
Common stock, shares outstanding (in shares)	39,117,799	39,117,799
Texas-New Mexico Power Company
Deferred Credits and Other Liabilities:
Cumulative preferred stock of subsidiary, shares authorized (in shares)	1,000,000
Company common stockholders’ equity:
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized (in shares)	12,000,000	12,000,000
Common stock, shares issued (in shares)	6,358	6,358
Common stock, shares outstanding (in shares)	6,358	6,358

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Total Stockholders' Equity	Total Stockholders' EquityCumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common StockCumulative Effect, Period of Adoption, Adjusted Balance	AOCI	AOCICumulative Effect, Period of Adoption, Adjustment	AOCICumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Retained EarningsCumulative Effect, Period of Adoption, Adjusted Balance	Non- controlling Interest in Valencia	Non- controlling Interest in ValenciaCumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New Mexico	Public Service Company of New MexicoCumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New MexicoTotal Stockholders' Equity	Public Service Company of New MexicoTotal Stockholders' EquityCumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New MexicoCommon Stock	Public Service Company of New MexicoCommon StockCumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New MexicoAOCI	Public Service Company of New MexicoAOCICumulative Effect, Period of Adoption, Adjustment	Public Service Company of New MexicoAOCICumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New MexicoRetained Earnings	Public Service Company of New MexicoRetained EarningsCumulative Effect, Period of Adoption, Adjustment	Public Service Company of New MexicoRetained EarningsCumulative Effect, Period of Adoption, Adjusted Balance	Public Service Company of New MexicoNon- controlling Interest in Valencia	Public Service Company of New MexicoNon- controlling Interest in ValenciaCumulative Effect, Period of Adoption, Adjusted Balance	Texas-New Mexico Power Company	Texas-New Mexico Power CompanyCommon Stock	Texas-New Mexico Power CompanyPaid-in Capital	Texas-New Mexico Power CompanyRetained Earnings
Beginning Balance at Dec. 31, 2017	$ 1,761,448	$ 0	$ 1,761,448	$ 1,695,253	$ 1,695,253	$ 1,157,665	$ 1,157,665	$ (95,940)	$ (11,208)	$ (107,148)	$ 633,528	$ 11,208	$ 644,736	$ 66,195	$ 66,195	$ 1,488,369	$ 1,488,369	$ 1,422,174	$ 1,422,174	$ 1,264,918	$ 1,264,918	$ (97,093)	$ (11,208)	$ (108,301)	$ 254,349	$ 11,208	$ 265,557	$ 66,195	$ 66,195
Beginning Balance at Dec. 31, 2017																														$ 634,405	$ 64	$ 504,166	$ 130,175
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	101,282			86,170							86,170			15,112		70,323		55,211							55,211			15,112
Net earnings																55,211														51,591			51,591
Total other comprehensive income (loss)	(1,536)			(1,536)				(1,536)								(2,121)		(2,121)				(2,121)
Equity contribution from parent																														30,000		30,000
Subsidiary preferred stock dividends	(528)			(528)							(528)					(528)		(528)							(528)
Dividends declared on common stock	(86,425)			(86,425)							(86,425)					(77,377)		(77,377)							(77,377)					(41,903)			(41,903)
Proceeds from stock option exercise	963			963		963
Awards of common stock	(12,635)			(12,635)		(12,635)
Stock based compensation expense	7,120			7,120		7,120
Valencia’s transactions with its owner	(17,095)													(17,095)		(17,095)												(17,095)
Ending Balance at Dec. 31, 2018	1,752,594			1,688,382		1,153,113		(108,684)			643,953			64,212		1,461,571		1,397,359		1,264,918		(110,422)			242,863			64,212
Ending Balance at Dec. 31, 2018																														674,093	64	534,166	139,863
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	92,131			77,890							77,890			14,241		55,422		41,181							41,181			14,241
Net earnings																41,181														55,799			55,799
Total other comprehensive income (loss)	9,307			9,307				9,307								11,367		11,367				11,367
Equity contribution from parent																														80,000		80,000
Subsidiary preferred stock dividends	(528)			(528)							(528)					(528)		(528)							(528)
Dividends declared on common stock	(93,792)			(93,792)							(93,792)					0		0							0					(55,265)			(55,265)
Proceeds from stock option exercise	943			943		943
Awards of common stock	(9,918)			(9,918)		(9,918)
Stock based compensation expense	6,414			6,414		6,414
Valencia’s transactions with its owner	(15,401)													(15,401)		(15,401)												(15,401)
Ending Balance at Dec. 31, 2019	1,741,750			1,678,698		1,150,552		(99,377)			627,523			63,052		1,512,431		1,449,379		1,264,918		(99,055)			283,516			63,052
Ending Balance at Dec. 31, 2019	1,678,698															1,449,379														754,627	64	614,166	140,397
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	187,316			173,303							173,303			14,013		160,014		146,001							146,001			14,013
Net earnings																146,001														58,585			58,585
Total other comprehensive income (loss)	20,194			20,194				20,194			0					20,544		20,544				20,544
Equity contribution from parent	230,000			230,000		230,000																								71,000		71,000
Subsidiary preferred stock dividends	(528)			(528)							(528)					(528)		(528)							(528)
Dividends declared on common stock	(101,591)			(101,591)							(101,591)					(40,653)		(40,653)							(40,653)					(58,534)			(58,534)
Proceeds from stock option exercise	24			24		24
Awards of common stock	(11,984)			(11,984)		(11,984)
Issuance of common stock	283,208			283,208		283,208
Stock based compensation expense	8,141			8,141		8,141
Valencia’s transactions with its owner	(18,056)													(18,056)		(18,056)												(18,056)
Ending Balance at Dec. 31, 2020	2,108,474			$ 2,049,465		$ 1,429,941		$ (79,183)			$ 698,707			$ 59,009		1,863,752		$ 1,804,743		$ 1,494,918		$ (78,511)			$ 388,336			$ 59,009
Ending Balance at Dec. 31, 2020	$ 2,049,465															$ 1,804,743														$ 825,678	$ 64	$ 685,166	$ 140,448

Summary of the Business and Sig

Summary of the Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of the Business and Significant Accounting Policies	Summary of the Business and Significant Accounting Policies Nature of Business PNMR is an investor-owned holding company with two regulated utilities providing electricity and electric services in New Mexico and Texas. PNMR’s primary subsidiaries are PNM and TNMP. PNM is a public utility with regulated operations primarily engaged in the generation, transmission, and distribution of electricity. TNMP is a wholly-owned subsidiary of TNP, which is a holding company that is wholly-owned by PNMR. TNMP provides regulated transmission and distribution services in Texas. PNMR’s common stock trades on the New York Stock Exchange under the symbol PNM. On October 20, 2020, PNMR, Avangrid, and Merger Sub, entered into an Agreement and Plan of Merger (the “Merger Agreement”) pursuant to which Merger Sub will merge with and into PNMR (the “Merger”), with PNMR surviving the Merger as a wholly-owned subsidiary of Avangrid. See Note 22. Financial Statement Preparation and Presentation The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could ultimately differ from those estimated. The Notes to Consolidated Financial Statements include disclosures for PNMR, PNM, and TNMP. This report uses the term “Company” when discussing matters of common applicability to PNMR, PNM, and TNMP. Discussions regarding only PNMR, PNM, or TNMP are so indicated. Certain amounts in the 2019 and 2018 Consolidated Financial Statements and Notes thereto have been reclassified to conform to the 2020 financial statement presentation. GAAP defines subsequent events as events or transactions that occur after the balance sheet date but before financial statements are issued or are available to be issued. Based on their nature, magnitude, and timing, certain subsequent events may be required to be reflected at the balance sheet date and/or required to be disclosed in the financial statements. The Company has evaluated subsequent events as required by GAAP. Principles of Consolidation The Consolidated Financial Statements of each of PNMR, PNM, and TNMP include their accounts and those of subsidiaries in which that entity owns a majority voting interest. PNM also consolidates Valencia (Note 10). PNM owns undivided interests in several jointly-owned power plants and records its pro-rata share of the assets, liabilities, and expenses for those plants. The agreements for the jointly-owned plants provide that if an owner were to default on its payment obligations, the non-defaulting owners would be responsible for their proportionate share of the obligations of the defaulting owner. In exchange, the non-defaulting owners would be entitled to their proportionate share of the generating capacity of the defaulting owner. There have been no such payment defaults under any of the agreements for the jointly-owned plants. PNMR Services Company expenses, which represent costs that are primarily driven by corporate level activities, are charged to the business segments. These services are billed at cost and are reflected as general and administrative expenses in the business segments. Other significant intercompany transactions between PNMR, PNM, and TNMP include interest and income tax sharing payments, as well as equity transactions, and interconnection billings. All intercompany transactions and balances have been eliminated. See Note 20. Accounting for the Effects of Certain Types of Regulation The Company maintains its accounting records in accordance with the uniform system of accounts prescribed by FERC and adopted by the NMPRC and PUCT. Certain of the Company’s operations are regulated by the NMPRC, PUCT, and FERC and the provisions of GAAP for rate-regulated enterprises are applied to the regulated operations. Regulators may assign costs to accounting periods that differ from accounting methods applied by non-regulated utilities. When it is probable that regulators will permit recovery of costs through future rates, costs are deferred as regulatory assets that otherwise would be expensed. Likewise, regulatory liabilities are recognized when it is probable that regulators will require refunds through future rates or when revenue is collected for expenditures that have not yet been incurred. GAAP also provides for the recognition of revenue and regulatory assets and liabilities associated with “alternative revenue programs” authorized by regulators. Such programs allow the utility to adjust future rates in response to past activities or completed events, if certain criteria are met. Regulatory assets and liabilities are amortized into earnings over the authorized recovery period. Accordingly, the Company has deferred certain costs and recorded certain liabilities pursuant to the rate actions of the NMPRC, PUCT, and FERC. Information on regulatory assets and regulatory liabilities is contained in Note 13. In some circumstances, regulators allow a requested increase in rates to be implemented, subject to refund, before the regulatory process has been completed and a decision rendered by the regulator. When this occurs, the Company assesses the possible outcomes of the rate proceeding. The Company records a provision for refund to the extent the amounts being collected, subject to refund, exceed the amount the Company determines is probable of ultimately being allowed by the regulator. Cash and Restricted Cash Cash deposits received and held for a period of time that are restricted to a specific purpose, under the terms of their effective agreements, are considered restricted cash. Investments in highly liquid investments with original maturities of three months or less at the date of purchase are considered cash and cash equivalents. At December 31, 2020 and 2019 there was no restricted cash for PNMR, PNM, and TNMP. Utility Plant Utility plant is stated at original cost and includes capitalized payroll-related costs such as taxes, pension, other fringe benefits, administrative costs, and AFUDC, where authorized by rate regulation, or capitalized interest. Repairs, including major maintenance activities, and minor replacements of property are expensed when incurred, except as required by regulators for ratemaking purposes. Major replacements are charged to utility plant. Gains, losses, and costs to remove resulting from retirements or other dispositions of regulated property in the normal course of business are credited or charged to accumulated depreciation. PNM and TNMP may receive reimbursements, referred to as CIAC, from customers to pay for all or part of certain construction projects to the extent the project does not benefit regulated customers in general. PNM and TNMP account for these reimbursements as offsets to utility plant additions based on the requirements of the NMPRC, FERC, and PUCT. Due to the PUCT’s regulatory treatment of CIAC reimbursements, TNMP also receives a financing component that is recognized as other income on the Consolidated Statements of Earnings. Under the NMPRC regulatory treatment, PNM typically does not receive a financing component. Depreciation and Amortization PNM’s provision for depreciation and amortization of utility plant, other than nuclear fuel, is based upon straight-line rates approved by the NMPRC and FERC. Amortization of nuclear fuel is based on units-of-production. TNMP’s provision for depreciation and amortization of utility plant is based upon straight-line rates approved by the PUCT. Depreciation and amortization of non-utility property, including right-of-use assets for finance leases as discussed in Note 8, is computed based on the straight-line method. The provision for depreciation of certain equipment is allocated between operating expenses and construction projects based on the use of the equipment. Average straight-line rates used were as follows: Year ended December 31, 2020 2019 2018 PNM Electric plant 2.47 % 2.47 % 2.40 % Common, intangible, and general plant 7.65 % 7.91 % 8.18 % TNMP 3.95 % 4.04 % 3.49 % Allowance for Funds Used During Construction As provided by the FERC uniform systems of accounts, AFUDC is charged to regulated utility plant for construction projects. This allowance is designed to enable a utility to capitalize financing costs during periods of construction of property subject to rate regulation. It represents the cost of borrowed funds (allowance for borrowed funds used during construction or “debt AFUDC”) and a return on other funds (allowance for equity funds used during construction or “equity AFUDC”). The debt AFUDC is recorded in interest charges and the equity AFUDC is recorded in other income on the Consolidated Statements of Earnings. For the years ended December 31, 2020, 2019, and 2018, PNM recorded $3.0 million, $5.0 million, and $6.1 million of debt AFUDC at annual rates of 2.40%, 2.99%, and 3.19% and $7.0 million, $6.7 million, and $8.2 million of equity AFUDC at annual rates of 3.42%, 3.95%, and 4.25%. For the years ended December 31, 2020, 2019, and 2018, TNMP recorded $2.1 million, $2.4 million, and $2.3 million of debt AFUDC at rates of 2.20%, 3.23%, and 3.32% and $4.3 million, $2.8 million, and $2.2 million of equity AFUDC at rates of 4.42%, 3.78%, and 3.29%. Materials, Supplies, and Fuel Stock Materials and supplies relate to transmission, distribution, and generating assets. Materials and supplies are charged to inventory when purchased and are expensed or capitalized as appropriate when issued. Materials and supplies are valued using an average costing method. Coal is valued using a rolling weighted average costing method that is updated based on the current period cost per ton. Periodic aerial surveys are performed on the coal piles and adjustments are made. Average cost is equal to net realizable value under the ratemaking process. Inventories consisted of the following at December 31: PNMR PNM TNMP 2020 2019 2020 2019 2020 2019 (In thousands) Coal $ 12,012 $ 24,914 $ 12,012 $ 24,914 $ — $ — Materials and supplies 54,405 53,015 48,460 47,311 5,945 5,704 $ 66,417 $ 77,929 $ 60,472 $ 72,225 $ 5,945 $ 5,704 Investments PNM holds investment securities in the NDT for the purpose of funding its share of the decommissioning costs of PVNGS and trusts for PNM’s share of final reclamation costs related to the coal mines serving SJGS and Four Corners (Note 16). Since third party investment managers have sole discretion over the purchase and sale of the securities, PNM records a realized loss as an impairment for any available-for-sale debt security that has a market value that is less than cost at the end of each quarter. Effective January 1, 2018, the Company adopted Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10), which eliminates the requirement to classify investments in equity securities with readily determinable fair values into trading or available-for-sale categories and requires those equity securities to be measured at fair value with changes in fair value recognized in earnings rather than in OCI. On January 1, 2018, PNM recorded a cumulative effect adjustment to reclassify unrealized holding gains on equity securities held in the NDT and coal mine reclamation trusts from AOCI to retained earnings on the Consolidated Balance Sheets. For the years ended December 31, 2020, 2019 and 2018, PNM recorded impairment losses on the available-for-sale debt securities of $3.2 million, $5.7 million and $13.7 million. No gains or losses are deferred as regulatory assets or liabilities. See Notes 3 and 9. All investments are held in PNM’s name and are in the custody of major financial institutions. The specific identification method is used to determine the cost of securities disposed of, with realized gains and losses reflected in other income and deductions. On January 1, 2020, the Company adopted Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which changed the way entities recognize impairments of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining lives of the assets. The majority of the amendments made by the new standard were required to be applied using a modified retrospective approach. The amendments in ASU 2016-13 also required entities to separately measure and realize an impairment for credit losses on available-for-sale debt securities for which carrying value exceeded fair value, unless such securities have been determined to be other than temporarily impaired and the entire decrease in value had been realized as an impairment. The amendments relating to available-for-sale debt securities were required to be applied prospectively on the date of adoption. PNM records a realized loss as an impairment for any available-for-sale debt security that has a fair value that is less than its carrying value. As a result, the Company has no available-for-sale debt securities for which carrying value exceeds fair value and there are no impairments considered to be “other than temporary” that are included in AOCI and not recognized in earnings. Adoption of the standard did not result in the Company recording a cumulative effect adjustment or impact the Company's accounting for its available-for-sale debt securities. All gains and losses resulting from sales and changes in the fair value of equity securities are recognized immediately in earnings. Equity Method Investment PNMR accounts for its investment in NMRD using the equity method of accounting because PNMR’s ownership interest results in significant influence, but not control, over NMRD and its operations. PNMR records as income its percentage share of earnings or loss of NMRD and carries its investment at cost, adjusted for its share of undistributed earnings or losses. See Note 21. Goodwill The Company does not amortize goodwill. Goodwill is evaluated for impairment annually, or more frequently if events and circumstances indicate that the goodwill might be impaired. See Note 19. Asset Impairment Tangible long-lived assets and right-of-use assets associated with leases are evaluated in relation to the estimated future undiscounted cash flows to assess recoverability when events and circumstances indicate that the assets might be impaired. See Note 16. Revenue Recognition See Note 4 for a discussion of electric operating revenues. Accounts Receivable and Allowance for Credit Losses Accounts receivable consists primarily of trade receivables from customers. In the normal course of business, credit is extended to customers on a short-term basis. PNM estimates the allowance for credit losses on trade receivables based on historical experience and estimated default rates. Accounts receivable balances are reviewed monthly, adjustments to the allowance for credit losses are made as necessary, and amounts that are deemed uncollectible are written off. See Note 4. TNMP has a regulatory mechanism to recover uncollectible amounts from REPs as a regulatory asset and as a result has no allowance for credit losses on trade receivables . As discussed in Note 17, both PNM and TNMP suspended disconnecting certain customers for past due bills, waived late fees during the pandemic, and have been provided regulatory mechanisms to recover bad debt expense and other costs resulting from COVID-19. Amortization of Debt Acquisition Costs Discount, premium, and expense related to the issuance of long-term debt are amortized over the lives of the respective issues. Gains and losses incurred upon the early retirement of long-term debt are recognized in other income or other deductions, except for amounts recoverable through NMPRC, FERC, or PUCT regulation, which are recorded as regulatory assets or liabilities and amortized over the lives of the respective issues. Unamortized premium, discount, and expense related to long-term debt are reflected as part of the related liability on the Consolidated Balance Sheets. Derivatives The Company records derivative instruments, including energy contracts, on the balance sheet as either an asset or liability measured at their fair value. Changes in the derivatives’ fair value are recognized in earnings unless specific hedge accounting criteria are met. PNM also records certain commodity derivative transactions recoverable through NMPRC regulation as regulatory assets or liabilities. See Note 7 and Note 9. The Company treats all forward commodity purchases and sales contracts subject to unplanned netting or “book-out” by the transmission provider as derivative instruments subject to mark-to-market accounting. GAAP provides guidance on whether realized gains and losses on derivative contracts not held for trading purposes should be reported on a net or gross basis and concludes such classification is a matter of judgment that depends on the relevant facts and circumstances. See Note 4. Decommissioning and Reclamation Costs PNM is only required to recognize and measure decommissioning liabilities for tangible long-lived assets for which a legal obligation exists. Nuclear decommissioning costs and related accruals are based on periodic site-specific estimates of the costs for removing all radioactive and other structures at PVNGS and are dependent upon numerous assumptions, including estimates of future decommissioning costs at current price levels, inflation rates, and discount rates. PNM’s accruals for PVNGS Units 1, 2, and 3, including portions held under leases, have been made based on such estimates, the guidelines of the NRC, and the PVNGS license periods. See Note 17 for information concerning the treatment of nuclear decommissioning costs for certain purchased and leased portions of PVNGS in the NMPRC’s order in PNM’s NM 2015 Rate Case and the NM Supreme Court’s decision on PNM’s appeal of that order. In connection with both the SJGS and Four Corners coal supply agreements, the owners are required to reimburse the mining companies for the cost of contemporaneous reclamation, as well as the costs for final reclamation of the coal mines. The reclamation costs are based on periodic site-specific studies that estimate the costs to be incurred in the future and are dependent upon numerous assumptions, including estimates of future reclamation costs at current price levels, inflation rates, and discount rates. PNM considers the contemporaneous reclamation costs part of the cost of its delivered coal costs. See Note 16 for a discussion of reclamation costs. Environmental Costs The normal operations of the Company involve activities and substances that expose the Company to potential liabilities under laws and regulations protecting the environment. Liabilities under these laws and regulations can be material and may be imposed without regard to fault, or may be imposed for past acts, even though the past acts may have been lawful at the time they occurred. The Company records its environmental liabilities when site assessments or remedial actions are probable and a range of reasonably likely cleanup costs can be estimated. The Company reviews its sites and measures the liability by assessing a range of reasonably likely costs for each identified site using currently available information and the probable level of involvement and financial condition of other potentially responsible parties. These estimates are based on assumptions regarding the costs for site investigations, remediation, operations and maintenance, monitoring, and site closure. The ultimate cost to clean up the Company’s identified sites may vary from its recorded liability due to numerous uncertainties inherent in the estimation process. Amounts recorded for environmental expense in the years ended December 31, 2020, 2019, and 2018, as well as the amounts of environmental liabilities at December 31, 2020 and 2019 were insignificant. Pension and Other Postretirement Benefits See Note 11 for a discussion of pension and postretirement benefits expense, including a discussion of the actuarial assumptions. Stock-Based Compensation See Note 12 for a discussion of stock-based compensation expense. Income Taxes Income taxes are recognized using the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying value of existing assets and liabilities and their respective tax basis. All deferred taxes are reflected as non-current on the Consolidated Balance Sheets. Current NMPRC, FERC, and PUCT approved rates include the tax effects of the majority of these differences. Rate-regulated enterprises are required to record deferred income taxes for temporary differences accorded flow-through treatment at the direction of a regulatory commission. The resulting deferred tax assets and liabilities are recorded based on the expected cash flow to be reflected in future rates. Because the NMPRC, FERC, and the PUCT have consistently permitted the recovery of tax effects previously flowed-through earnings, the Company has established regulatory assets and liabilities offsetting such deferred tax assets and liabilities. The Company recognizes only the impact of tax positions that, based on their merits, are more likely than not to be sustained upon an IRS audit. The Company defers investment tax credits and amortizes them over the estimated useful lives of the assets. See Note 18 for additional information, including a discussion of the impacts of the Tax Act. The Company makes an estimate of its anticipated effective tax rate for the year as of the end of each quarterly period within its fiscal year. In interim periods, income tax expense is calculated by applying the anticipated annual effective tax rate to year-to-date earnings before taxes, which includes the earnings attributable to the Valencia non-controlling interest. Certain unusual or infrequently occurring items, as well as adjustments due to enactment of new tax laws, have been excluded from the estimated annual effective tax rate calculation. Lease Commitments See Note 8 for a discussion of lease commitments. New Accounting Pronouncements Information concerning recently issued accounting pronouncements that have not been adopted by the Company is presented below. The Company does not expect difficulty in adopting these standards by their required effective dates. Accounting Standards Update 2019-12 – Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12 as part of its initiative to reduce complexity in accounting standards. The amendments in ASU 2019-12 simplify accounting for income taxes by removing several accounting exceptions to accounting for income taxes. ASU 2019-12 also eliminates or simplifies other income tax accounting requirements, including a requirement that entities recognize franchise tax (or similar tax) that is partially based on income as an income-based tax. ASU 2019-12 is effective for the Company beginning on January 1, 2021 and allows for early adoption. ASU 2019-12 is to be applied prospectively or retrospectively in the period of adoption depending on the type of amendment. The Company is in the process of analyzing the impacts of this new standard.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information The following segment presentation is based on the methodology that management uses for making operating decisions and assessing performance of its various business activities. A reconciliation of the segment presentation to the GAAP financial statements is provided. PNM PNM includes the retail electric utility operations of PNM that are subject to traditional rate regulation by the NMPRC. PNM provides integrated electricity services that include the generation, transmission, and distribution of electricity for retail electric customers in New Mexico. PNM also includes the generation and sale of electricity into the wholesale market, as well as providing transmission services to third parties. The sale of electricity includes the asset optimization of PNM’s jurisdictional capacity as well as the capacity excluded from retail rates. FERC has jurisdiction over wholesale power and transmission rates. TNMP TNMP is an electric utility providing services in Texas under the TECA. TNMP’s operations are subject to traditional rate regulation by the PUCT. TNMP provides transmission and distribution services at regulated rates to various REPs that, in turn, provide retail electric service to consumers within TNMP’s service area. TNMP also provides transmission services at regulated rates to other utilities that interconnect with TNMP’s facilities. Corporate and Other The Corporate and Other segment includes PNMR holding company activities, primarily related to corporate level debt and PNMR Services Company. The activities of PNMR Development, NM Capital, and the equity method investment in NMRD are also included in Corporate and Other. Eliminations of intercompany income and expense transactions are reflected in the Corporate and Other segment. PNMR SEGMENT INFORMATION The following tables present summarized financial information for PNMR by segment. PNM and TNMP each operate in only one segment. Therefore, tabular segment information is not presented for PNM and TNMP. 2020 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,139,834 $ 383,178 $ — $ 1,523,012 Cost of energy 345,167 102,074 — 447,241 Utility margin 794,667 281,104 — 1,075,771 Other operating expenses 414,445 104,852 (4,419) 514,878 Depreciation and amortization 165,325 87,799 22,488 275,612 Operating income (loss) 214,897 88,453 (18,069) 285,281 Interest income 14,469 — (246) 14,223 Other income (deductions) 17,120 6,828 (1,108) 22,840 Interest charges (64,615) (30,388) (19,389) (114,392) Segment earnings (loss) before income taxes 181,871 64,893 (38,812) 207,952 Income taxes (benefit) 21,857 6,308 (7,529) 20,636 Segment earnings (loss) 160,014 58,585 (31,283) 187,316 Valencia non-controlling interest (14,013) — — (14,013) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 145,473 $ 58,585 $ (31,283) $ 172,775 At December 31, 2020: Total Assets $ 5,581,033 $ 2,132,580 $ 226,241 $ 7,939,854 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2019 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,093,822 $ 363,781 $ — $ 1,457,603 Cost of energy 317,725 95,087 — 412,812 Utility margin 776,097 268,694 — 1,044,791 Other operating expenses 554,661 98,621 (20,499) 632,783 Depreciation and amortization 160,368 84,259 23,181 267,808 Operating income 61,068 85,814 (2,682) 144,200 Interest income 14,303 — (281) 14,022 Other income (deductions) 26,989 4,131 (1,477) 29,643 Interest charges (72,900) (29,100) (19,016) (121,016) Segment earnings (loss) before income taxes 29,460 60,845 (23,456) 66,849 Income taxes (25,962) 5,046 (4,366) (25,282) Segment earnings (loss) 55,422 55,799 (19,090) 92,131 Valencia non-controlling interest (14,241) — — (14,241) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 40,653 $ 55,799 $ (19,090) $ 77,362 At December 31, 2019: Total Assets $ 5,242,991 $ 1,860,439 $ 195,344 $ 7,298,774 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2018 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,091,965 $ 344,648 $ — $ 1,436,613 Cost of energy 314,036 85,690 — 399,726 Utility margin 777,929 258,958 — 1,036,887 Other operating expenses 481,030 96,272 (17,650) 559,652 Depreciation and amortization 151,866 66,189 23,133 241,188 Operating income (loss) 145,033 96,497 (5,483) 236,047 Interest income 13,089 — 2,451 15,540 Other income (deductions) (17,312) 4,065 (2,039) (15,286) Interest charges (76,458) (32,091) (18,695) (127,244) Segment earnings (loss) before income taxes 64,352 68,471 (23,766) 109,057 Income taxes (benefit) (5,971) 16,880 (3,134) 7,775 Segment earnings (loss) 70,323 51,591 (20,632) 101,282 Valencia non-controlling interest (15,112) — — (15,112) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 54,683 $ 51,591 $ (20,632) $ 85,642 At December 31, 2018: Total Assets $ 5,035,883 $ 1,665,177 $ 164,491 $ 6,865,551 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 The Company defines utility margin as electric operating revenues less cost of energy. Cost of energy consists primarily of fuel and purchase power costs for PNM and costs charged by third-party transmission providers for TNMP. The Company believes that utility margin provides a more meaningful basis for evaluating operations than electric operating revenues since substantially all such costs are offset in revenues as fuel and purchase power costs are passed through to customers under PNM’s FPPAC and third-party transmission costs are passed on to customers through TNMP’s transmission cost recovery factor. Utility margin is not a financial measure required to be presented under GAAP and is considered a non-GAAP measure. Major Customers No individual customer accounted for more than 10% of the electric operating revenues of PNMR or PNM. Three REPs accounted for more than 10% of the electric operating revenues of TNMP, as follows: Year Ended December 31, 2020 2019 2018 REP A 21 % 22 % 21 % REP B 18 % 17 % 15 % REP C 11 % 12 % 12 %

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) AOCI reports a measure for accumulated changes in equity that result from transactions and other economic events other than transactions with shareholders. Information regarding AOCI is as follows: Accumulated Other Comprehensive Income (Loss) PNM PNMR Unrealized Gains on Available-for-Sale Securities Pension Total Fair Value Adjustment for Cash Flow Hedges Total (In thousands) Balance at December 31, 2017, as originally reported $ 13,169 $ (110,262) $ (97,093) $ 1,153 $ (95,940) Cumulative effect adjustment (Note 9) (11,208) — (11,208) — (11,208) Balance at January 1, 2018, as adjusted 1,961 (110,262) (108,301) 1,153 (107,148) Amounts reclassified from AOCI (pre-tax) (3,819) 7,568 3,749 216 3,965 Income tax impact of amounts reclassified 970 (1,922) (952) (56) (1,008) Other OCI changes (pre-tax) 3,790 (10,382) (6,592) 570 (6,022) Income tax impact of other OCI changes (963) 2,637 1,674 (145) 1,529 Net after-tax change (22) (2,099) (2,121) 585 (1,536) Balance at December 31, 2018 1,939 (112,361) (110,422) 1,738 (108,684) Amounts reclassified from AOCI (pre-tax) (14,063) 7,404 (6,659) 733 (5,926) Income tax impact of amounts reclassified 3,572 (1,880) 1,692 (186) 1,506 Other OCI changes (pre-tax) 25,724 (3,829) 21,895 (3,495) 18,400 Income tax impact of other OCI changes (6,534) 973 (5,561) 888 (4,673) Net after-tax change 8,699 2,668 11,367 (2,060) 9,307 Balance at December 31, 2019 10,638 (109,693) (99,055) (322) (99,377) Amounts reclassified from AOCI (pre-tax) (9,497) 8,300 (1,197) (1,740) (2,937) Income tax impact of amounts reclassified 2,412 (2,108) 304 442 746 Other OCI changes (pre-tax) 22,586 6,149 28,735 1,271 30,006 Income tax impact of other OCI changes (5,736) (1,562) (7,298) (323) (7,621) Net after-tax change 9,765 10,779 20,544 (350) 20,194 Balance at December 31, 2020 $ 20,403 $ (98,914) $ (78,511) $ (672) $ (79,183) The Consolidated Statements of Earnings include pre-tax amounts reclassified from AOCI related to Unrealized Gains on Available-for-Sale Debt Securities in gains (losses) on investment securities, related to Pension Liability Adjustment in other (deductions), and related to Fair Value Adjustment for Cash Flow Hedges in interest charges. The income tax impacts of all amounts reclassified from AOCI are included in income taxes in the Consolidated Statements of Earnings.

Electric Operating Revenues

Electric Operating Revenues	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Electric Operating Revenues	Electric Operating Revenues Revenue Recognition Electric operating revenues are recorded in the period of energy delivery, which includes estimated amounts for service rendered but unbilled at the end of each accounting period. The determination of the energy sales billed to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading and the corresponding unbilled revenue are estimated. Unbilled electric revenue is estimated based on daily generation volumes, estimated customer usage by class, line losses, historical trends and experience, applicable customer rates or by using AMS data where available. Amounts billed are generally due within the next month. The Company does not incur incremental costs to obtain contracts for its energy services. PNM’s wholesale electricity sales are recorded as electric operating revenues and wholesale electricity purchases are recorded as costs of energy sold. Derivative contracts that are subject to unplanned netting are recorded net in earnings. A “book-out” is the planned or unplanned netting of off-setting purchase and sale transactions. A book-out is a transmission mechanism to reduce congestion on the transmission system or administrative burden. For accounting purposes, a book-out is the recording of net revenues upon the settlement of a derivative contract. Unrealized gains and losses on derivative contracts that are not designated for hedge accounting are classified as economic hedges. Economic hedges are defined as derivative instruments, including long-term power and fuel supply agreements, used to hedge generation assets and purchased power costs. Changes in the fair value of economic hedges are reflected in results of operations, with changes related to economic hedges on sales included in operating revenues and changes related to economic hedges on purchases included in cost of energy sold. See Note 9. The Company adopted ASU 2014-09 – Revenue from Contracts with Customers (Topic 606) as of January 1, 2018, its required effective date, using the modified retrospective method of adoption. The adoption of ASU 2014-09 did not result in changes to the nature, amount, and timing of the Company’s existing revenue recognition processes or information technology infrastructure. Therefore, the adoption of ASU 2014-09 had no effect on the amount of revenue recorded in 2018 compared to the amount that would have been recorded under prior GAAP, no effect on total electric operating revenues or any other caption within the Company’s financial statements, and no cumulative effect adjustment was recorded. Additional disclosures to further disaggregate 2020, 2019 and 2018 revenues are presented below. The Company adopted ASU 2018-18 – Collaborative Arrangements (Topic 808) in 2019, ahead of its required effective date, using the retrospective method of adoption. The Company has collaborative arrangements related to its interest in SJGS, Four Corners, PVNGS, and Luna. The Company has determined that during the years ended December 31, 2020, 2019, and 2018 none of the joint owners in its collaborative arrangements were customers under Topic 606. Therefore, the adoption of this standard did not impact the financial statements. The Company will continue to evaluate transactions between collaborative arrangement participants in future periods under the requirements of the new standard. PNM and TNMP recognize revenue as they satisfy performance obligations, which typically occurs as the customer or end-user consumes the electric service provided. Electric services are typically for a bundle of services that are distinct and transferred to the end-user in one performance obligation measured by KWh or KW. Electric operating revenues are recorded in the period of energy delivery, including estimated unbilled amounts. The Company has elected to exclude all sales and similar taxes from revenue. Revenue from contracts with customers is recorded based upon the total authorized tariff price at the time electric service is rendered, including amounts billed under arrangements qualifying as an Alternative Revenue Program (“ARP”). ARP arrangements are agreements between PNM or TNMP and its regulator that allow PNM or TNMP to adjust future rates in response to past activities or completed events, if certain criteria are met. ARP revenues are required to be reported separately from contracts with customers. ARP revenues in a given period include the recognition of “originating” ARP revenues (i.e. when the regulator-specific conditions are met) in the period, offset by the reversal of ARP revenues when billed to customers. Sources of Revenue Additional information about the nature of revenues is provided below. Additional information about matters affecting PNM’s and TNMP’s regulated revenues is provided in Note 17. Revenue from Contracts with Customers PNM NMPRC Regulated Retail Electric Service – PNM provides electric generation, transmission, and distribution service to its rate-regulated customers in New Mexico. PNM’s retail electric service territory covers a large area of north central New Mexico, including the cities of Albuquerque, Rio Rancho, and Santa Fe, and certain areas of southern New Mexico. Customer rates for retail electric service are set by the NMPRC and revenue is recognized as energy is delivered to the customer. PNM invoices customers on a monthly basis for electric service and generally collects billed amounts within one month. Transmission Service to Third Parties – PNM owns transmission lines that are interconnected with other utilities in New Mexico, Texas, Arizona, Colorado, and Utah. Transmission customers receive service for the transmission of energy owned by the customer utilizing PNM’s transmission facilities. Customers generally receive transmission services, which are regulated by FERC, from PNM through PNM’s Open Access Transmission Tariff (“OATT”) or a specific contract. Customers are billed based on capacity and energy components on a monthly basis. Miscellaneous – Beginning on January 1, 2018, PNM acquired a 65 MW interest in SJGS Unit 4, which is held as merchant plant as ordered by the NMPRC (Note 16). PNM sells power from 36 MW of this capacity to a third party at a fixed price that is recorded as revenue from contracts with customers. PNM is obligated to deliver power under this arrangement only when SJGS Unit 4 is operating. Other market sales from this 65 MW interest are recorded in other electric operating revenues. TNMP PUCT Regulated Retail Electric Service – TNMP provides transmission and distribution services in Texas under the provisions of TECA and the Texas Public Utility Regulatory Act. TNMP is subject to traditional cost-of-service regulation with respect to rates and service under the jurisdiction of the PUCT and certain municipalities. TNMP’s transmission and distribution activities are solely within ERCOT and not subject to traditional rate regulation by FERC. TNMP provides transmission and distribution services at regulated rates to various REPs that, in turn, provide retail electric service to consumers within TNMP’s service territory. Revenue is recognized as energy is delivered to the consumer. TNMP invoices REPs on a monthly basis and is generally paid within a month. Transmission Cost of Service (“TCOS”) – TNMP is a transmission service provider that is allowed to recover its TCOS through a network transmission rate that is approved by the PUCT. TCOS customers are other utilities that receive service for the transmission of energy owned by the customer utilizing TNMP’s transmission facilities. Alternative Revenue Programs The Company defers certain costs and records certain liabilities pursuant to the rate actions of the NMPRC, PUCT, and FERC. ARP revenues, which are discussed above, include recovery or refund provisions under PNM’s renewable energy rider and true-ups to PNM’s formula transmission rates; TNMP’s AMS surcharge, transmission cost recovery factor, and the impacts of the PUCT’s January 25, 2018 order regarding the change in the federal corporate income tax rate; and the energy efficiency incentive bonus at both PNM and TNMP. Regulatory assets and liabilities are recognized for the difference between ARP revenues and amounts billed under those programs. Regulatory assets and liabilities are amortized into earnings as amounts are billed. As discussed in Note 17, TNMP’s 2018 Rate Case integrated AMS costs into base rates beginning January 1, 2019. These costs are being amortized into earnings as alternative revenues over a period of five years. Other Electric Operating Revenues Other electric operating revenues consist primarily of PNM’s sales for resale meeting the definition of a derivative. Derivatives are not considered revenue from contracts with customers. PNM engages in activities meeting the definition of derivatives to optimize its existing jurisdictional assets and long-term power agreements through spot market, hour-ahead, day-ahead, week-ahead, month-ahead, and other sales of excess generation not required to fulfill retail load and contractual commitments. Disaggregation of Revenues A disaggregation of revenues from contracts with customers by the type of customer is presented in the table below. The table also reflects ARP revenues and other revenues. PNM TNMP PNMR Consolidated Year Ended December 31, 2020 (In thousands) Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 482,852 $ 158,066 $ 640,918 Commercial 392,257 118,243 510,500 Industrial 90,845 27,367 118,212 Public authority 23,126 5,853 28,979 Economy energy service 15,911 — 15,911 Transmission 59,856 78,374 138,230 Miscellaneous 13,311 3,738 17,049 Total revenues from contracts with customers 1,078,158 391,641 1,469,799 Alternative revenue programs (3,531) (8,463) (11,994) Other electric operating revenues 65,207 — 65,207 Total Electric Operating Revenues $ 1,139,834 $ 383,178 $ 1,523,012 Year Ended December 31, 2019 Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 427,883 $ 150,742 $ 578,625 Commercial 396,987 116,953 513,940 Industrial 69,601 22,405 92,006 Public authority 20,322 5,694 26,016 Economy energy service 25,757 — 25,757 Transmission 57,214 66,948 124,162 Miscellaneous 13,134 3,568 16,702 Total revenues from contracts with customers 1,010,898 366,310 1,377,208 Alternative revenue programs 1,987 (2,529) (542) Other electric operating revenues 80,937 — 80,937 Total Electric Operating Revenues $ 1,093,822 $ 363,781 $ 1,457,603 Year Ended December 31, 2018 Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 433,009 $ 130,288 $ 563,297 Commercial 408,333 111,261 519,594 Industrial 61,119 17,317 78,436 Public authority 21,688 5,609 27,297 Economy energy service 26,764 — 26,764 Transmission 54,280 66,991 121,271 Miscellaneous 14,098 8,983 23,081 Total revenues from contracts with customers 1,019,291 340,449 1,359,740 Alternative revenue programs (2,443) 4,199 1,756 Other electric operating revenues 75,117 — 75,117 Total Electric Operating Revenues $ 1,091,965 $ 344,648 $ 1,436,613 Contract Balances Performance obligations related to contracts with customers are typically satisfied when the energy is delivered and the customer or end-user utilizes the energy. Accounts receivable from customers represent amounts billed, including amounts under ARP programs. For PNM, accounts receivable reflected on the Consolidated Balance Sheets, net of allowance for credit losses, includes $86.2 million and $59.3 million at December 31, 2020 and 2019 resulting from contracts with customers. All of TNMP’s accounts receivable results from contracts with customers. On January 1, 2020, the Company adopted Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. As a result of the adoption of the new standard and economic conditions resulting from the COVID-19 pandemic, PNM updated its allowance for accounts receivable balances and recorded incremental credit losses of $7.2 million in the year ended December 31, 2020. The NMPRC issued an order authorizing all public utilities to create a regulatory asset to defer incremental costs related to COVID-19, including increases in uncollectible accounts. See additional discussion of ASU 2016-13 in Note 9 and the related regulatory treatment in Note 17. Contract assets are an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer when that right is conditioned on something other than the passage of time (for example, the entity’s future performance). The Company has no contract assets as of December 31, 2020. Contract liabilities arise when consideration is received in advance from a customer before satisfying the performance obligations. Therefore, revenue is deferred and not recognized until the obligation is satisfied. Under its OATT, PNM accepts upfront consideration for capacity reservations requested by transmission customers, which requires PNM to defer the customer’s transmission capacity rights for a specific period of time. PNM recognizes the revenue of these capacity reservations over the period it defers the customer’s capacity rights. Other utilities pay PNM and TNMP in advance for the joint-use of their utility poles. These revenues are recognized over the period of time specified in the joint-use contract, typically for one calendar year. Deferred revenues on these arrangements are recorded as contract liabilities. PNMR’s, PNM’s, and TNMP’s contract liabilities and related revenues are insignificant for all periods presented. The Company has no other arrangements with remaining performance obligations to which a portion of the transaction price would be required to be allocated.

Earnings and Dividends Per Shar

Earnings and Dividends Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings and Dividends Per Share	Earnings and Dividends Per Share Dual presentation of basic and diluted earnings per share has been presented in the Consolidated Statements of Earnings of PNMR. Information regarding the computation of earnings per share and dividends per share is as follows: Year Ended December 31, 2020 2019 2018 (In thousands, except per share amounts) Net Earnings Attributable to PNMR $ 172,775 $ 77,362 $ 85,642 Average Number of Common Shares: Outstanding during year 79,941 79,654 79,654 Vested awards of restricted stock 216 277 236 Average Shares – Basic 80,157 79,931 79,890 Dilutive Effect of Common Stock Equivalents: PNMR 2020 Forward Equity Sale Agreements 106 — — Stock options and restricted stock 40 59 122 Average Shares – Diluted 80,303 79,990 80,012 Net Earnings Attributable to PNMR Per Share of Common Stock: Basic $ 2.16 $ 0.97 $ 1.07 Diluted $ 2.15 $ 0.97 $ 1.07 Dividends Declared per Common Share $ 1.2500 $ 1.1775 $ 1.0850

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock and Equity Contributions On December 15, 2020 PNMR physically settled all shares under the PNMR 2020 Forward Equity Sale Agreements by issuing 6.2 million shares to the forward purchasers at a price of $45.805 per share aggregating net proceeds of $283.1 million. In addition, PNMR recorded a net $0.1 million for equity issuance costs reimbursed by the lead underwriter. Following this settlement, no shares of PNMR’s common stock remain subject to future settlement under the PNMR 2020 Forward Equity Sale Agreements. See Note 7. Neither PNM nor TNMP issued any common stock during the year ended December 31, 2020. PNMR, PNM, and TNMP did not issue any common stock during the years ended December 31, 2019 and 2018. PNMR funded $230.0 million, zero, and zero of cash equity contributions to PNM in 2020, 2019, and 2018, respectively. PNMR also funded $71.0 million, $80.0 million, and $30.0 million of cash equity contributions to TNMP in 2020, 2019, and 2018, respectively. PNMR offered shares of PNMR common stock through the PNMR Direct Plan. As required by the Merger Agreement, effective November 2, 2020, PNMR entered into the Second Amendment to the Third Amended and Restated PNM Resources, Inc. Direct Plan (the “PNMR Direct Plan”), which among other matters, terminated the right to purchase shares of PNMR common stock under the PNMR Direct Plan with respect to any cash dividends and optional cash investments not received by noon Eastern Time on November 17, 2020. No purchases of shares of PNMR common stock under the PNMR Direct Plan may occur after November 18, 2020. The shares of PNMR common stock utilized in the PNMR Direct Plan were offered under a SEC shelf registration statement that expires in March 2021. Dividends on Common Stock The declaration of common dividends by PNMR is dependent upon a number of factors, including the ability of PNMR’s subsidiaries to pay dividends. PNMR’s primary sources of dividends are its operating subsidiaries. PNM declared and paid cash dividends to PNMR of $40.7 million, zero, and $77.4 million in 2020, 2019, and 2018. TNMP declared and paid cash dividends to PNMR of $58.5 million, $55.3 million, and $41.9 million in 2020, 2019, and 2018. The NMPRC has placed certain restrictions on the ability of PNM to pay dividends to PNMR, including the restriction that PNM cannot pay dividends that cause its debt rating to fall below investment grade. The NMPRC provisions allow PNM to pay dividends, without prior NMPRC approval, from current earnings, which is determined on a rolling four quarter basis, or from equity contributions previously made by PNMR. The Federal Power Act also imposes certain restrictions on dividends by public utilities, including that dividends cannot be paid from paid-in capital. Debt-to-capitalization ratio requirements, as discussed in Note 7, remain at less than or equal to 65% for PNM and TNMP. These debt-to-capitalization ratio requirements could limit the amounts of dividends that could be paid. PNM also has other financial covenants that limit the transfer of assets, through dividends or other means, including a requirement to obtain the approval of certain financial counterparties to transfer more than five percent of PNM’s assets. As of December 31, 2020, none of the numerical tests would restrict the payment of dividends from the retained earnings of PNM or TNMP, and the 70% debt-to-capitalization covenant would restrict the payment of dividends by PNMR to $423.7 million. In addition, the ability of PNMR to declare dividends is dependent upon the extent to which cash flows will support dividends, the availability of retained earnings, financial circumstances and performance, current and future regulatory decisions, Congressional and legislative acts, and economic conditions. Conditions imposed by the NMPRC or PUCT, future growth plans and related capital requirements, and business considerations may also affect PNMR’s ability to pay dividends. Preferred Stock PNM’s cumulative preferred shares outstanding bear dividends at 4.58% per annum. PNM preferred stock does not have a mandatory redemption requirement, but may be redeemed, at PNM’s option, at 102% of the stated value plus accrued dividends. The holders of the PNM preferred stock are entitled to payment before the holders of common stock in the event of any liquidation or dissolution or distribution of assets of PNM. In addition, PNM’s preferred stock is not entitled to a sinking fund and cannot be converted into any other class of stock of PNM. PNMR and TNMP have no preferred stock outstanding. The authorized shares of PNMR and TNMP preferred stock are 10 million shares and 1 million shares, respectively.

Financing

Financing	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Financing	FinancingThe Company’s financing strategy includes both short-term and long-term borrowings. The Company utilizes short-term revolving credit facilities, as well as cash flows from operations, to provide funds for both construction and operating expenditures. Depending on market and other conditions, the Company will periodically sell long-term debt or enter into term loan arrangements and use the proceeds to reduce borrowings under the revolving credit facilities or refinance other debt. Prior to July 2018, each of the Company’s revolving credit facilities and term loans contained a single financial covenant, which required the maintenance of a debt-to-capitalization ratio of less than or equal to 65%. In July 2018, the PNMR and the PNMR Development agreements were each amended such that each is now required to maintain a debt-to-capitalization ratio of less than or equal to 70%. The debt-to-capitalization ratio requirement remains at less than or equal to 65% for the PNM and TNMP agreements. The Company’s revolving credit facilities and term loans generally also contain customary covenants, events of default, cross-default provisions, and change-of-control provisions. PNM must obtain NMPRC approval for any financing transaction having a maturity of more than 18 months. In addition, PNM files its annual informational financing filing and short-term financing plan with the NMPRC. Financing Activities PNMR At January 1, 2018, PNMR had outstanding the $150.0 million PNMR 2015 Term Loan, which matured and was repaid on March 9, 2018. As discussed in Note 16, at January 1, 2018, NM Capital, a wholly-owned subsidiary of PNMR, had outstanding $50.1 million of the $125.0 million term loan agreement (the “BTMU Term Loan”) with BTMU. PNMR, as parent company of NM Capital, guaranteed NM Capital’s obligations to BTMU. NM Capital utilized the proceeds of the BTMU Term Loan to provide funding of $125.0 million (the “Westmoreland Loan”) to a ring-fenced, bankruptcy-remote, special-purpose entity subsidiary of Westmoreland to finance Westmoreland’s purchase of SJCC. The BTMU Term Loan agreement required that NM Capital utilize all amounts, less taxes and fees, it received under the Westmoreland Loan to repay the BTMU Term Loan. On May 22, 2018, the full principal balance outstanding under the Westmoreland Loan of $50.1 million was repaid. NM Capital used a portion of the proceeds to repay all remaining principal of $43.0 million owed under the BTMU Term Loan. These payments effectively terminated the loan agreements. In addition, PNMR’s guarantee of NM Capital’s obligations was also effectively terminated. See Note 10. At January 1, 2018, PNMR had outstanding letters of credit arrangements with JPMorgan Chase Bank N.A. (the “JPM LOC Facility”) under which letters of credit aggregating $30.3 million were issued to facilitate the posting of reclamation bonds, which SJCC was required to post in connection with permits relating to the operation of the San Juan mine. On March 15, 2019, WSJ LLC acquired the assets of SJCC following the bankruptcy of Westmoreland. WSJ LLC assumed all obligations of SJCC, including those under the letter of credit support agreements. See Note 16. In May 2020, JPMorgan Chase Bank N.A. gave notice that it would not extend the letters of credit beyond their October 21, 2020 expiration. In August 2020, PNMR entered into replacement letter of credit arrangements with Wells Fargo Bank, N.A. (the "WFB LOC Facility") to replace the JPM LOC Facility. Letters of credit were issued under the WFB LOC Facility and exchanged for the letters of credit outstanding under the JPM LOC Facility prior to the expiration of the JPM LOC Facility. On October 21, 2020, the JPM LOC Facility expired according to its terms. At January 1, 2018, PNMR had outstanding two term loan agreements: (1) a $100.0 million term loan agreement (the “PNMR 2016 One-Year Term Loan”) and (2) a $100.0 million term loan agreement (the “PNMR 2016 Two-Year Term Loan”) that matured in December 2018. In December 2018, both the PNMR 2016 One-Year Term Loan (as extended) and the PNMR 2016 Two-Year Term Loan were repaid. On March 9, 2018, PNMR issued $300.0 million aggregate principal amount of 3.25% SUNs (the “PNMR 2018 SUNs”), which mature on March 9, 2021. The proceeds from the offering were used to repay the $150.0 million PNMR 2015 Term Loan that was due on March 9, 2018 and to reduce borrowings under the PNMR Revolving Credit Facility. PNMR intends to utilize the remaining $220.0 million of capacity under the PNMR 2020 Delayed-Draw Term Loan, discussed below, to repay an equivalent amount of the PNMR 2018 SUNs. As PNMR can demonstrate the intent and ability to extend that portion of the $300.0 million SUNs through January 31, 2022, $220.0 million of the PNMR 2018 SUNs is reflected as long-term debt in the Consolidated Balance Sheet at December 31, 2020. On November 26, 2018, PNMR Development entered into a $90.0 million term loan agreement (the “PNMR Development Term Loan”), among PNMR Development and KeyBank, N.A., as administrative agent and sole lender. Proceeds from the PNMR Development Term Loan were used to repay short-term borrowings under the PNMR Development’s revolving credit facility and to repay borrowings under its intercompany loan from PNMR. On November 25, 2020 the PNMR Development Term Loan was amended to reduce the balance from $90.0 million to $65.0 million and the maturity was subsequently extended to January 31, 2022. The PNMR Development Term Loan bears interest at a variable rate, which was 1.52% on December 31, 2020. PNMR, as parent company of PNMR Development, continues to guarantee PNMR Development’s obligations under the loan. On December 14, 2018, PNMR entered into a $150.0 million term loan agreement (the “PNMR 2018 One-Year Term Loan”) among PNMR, the lenders identified therein, and MUFG Bank, Ltd., as administrative agent. The proceeds from the PNMR 2018 One-Year Term Loan were used to repay the PNMR 2016 One-Year Term Loan (as extended), a portion of the PNMR 2016 Two-Year Term Loan, and for general corporate purposes. On December 13, 2019, the PNMR 2018 One-Year Term Loan was extended to June 11, 2021 (as extended, the “PNMR 2019 Term Loan”). The PNMR 2019 Term Loan bears interest at a variable rate, which was 1.11% at December 31, 2020. On December 21, 2018, PNMR entered into a $50.0 million term loan agreement (the “PNMR 2018 Two-Year Term Loan”), between PNMR and Bank of America, N.A. as sole lender. Proceeds from the PNMR 2018 Two-Year Term Loan were used to repay the remaining amount owed under the PNMR 2016 Two-Year Term Loan and for general corporate purposes. On December 21, 2020, the PNMR 2018 Two-Year Term Loan was repaid and terminated in accordance with its terms. On January 7, 2020, PNMR entered into forward sale agreements with each of Citibank N.A., and Bank of America N.A., as forward purchasers and an underwriting agreement with Citigroup Global Markets Inc., and BofA Securities, Inc. as representatives of the underwriters named therein, relating to an aggregate of approximately 6.2 million shares of PNMR common stock (including 0.8 million shares of PNMR common stock pursuant to the underwriters’ option to purchase additional shares) (the “PNMR 2020 Forward Equity Sale Agreements”). On January 8, 2020, the underwriters exercised in full their option to purchase the additional 0.8 million shares of PNMR common stock and PNMR entered into separate forward sales agreements with respect to the additional shares. The initial forward sale price of $47.21 per share is subject to adjustments based on a net interest rate factor and by expected future dividends paid on PNMR common stock as specified in the forward sale agreements. PNMR did not initially receive any proceeds upon the execution of these agreements and, except in certain specified circumstances, had the option to elect physical, cash, or net share settlement on or before the date that is 12 months from their effective dates. On December 15, 2020 PNMR physically settled all shares under the PNMR 2020 Forward Equity Sale Agreements by issuing 6.2 million shares to the forward purchasers at a price of $45.805 per share aggregating net proceeds of $283.1 million. In addition, PNMR recorded a net $0.1 million for equity issuance costs reimbursed by the lead underwriter. Following this settlement, no shares of PNMR’s common stock remain subject to future settlement under the PNMR 2020 Forward Equity Sale Agreements. The PNMR 2020 Forward Equity Sale Agreements meet the derivative scope exception requirements for contracts involving an entity’s own equity. Until settlement of the forward sale agreements, PNMR’s EPS dilution resulting from the agreements, if any, was determined using the treasury stock method, which resulted in dilution during periods when the average market price of PNMR stock during the reporting period was higher than the applicable forward sales price as of the end of that period. See Note 5. On October 20, 2020, the execution of the Merger Agreement constituted a “Change of Control” under certain PNMR, TNMP and PNMR Development debt agreements. Under each of the specified debt agreements, a “Change of Control” constitutes an “Event of Default,” pursuant to which the lender parties thereto had the right to accelerate the indebtedness under the debt agreements. The definition of Change of Control under the PNM debt agreements and PNM note purchase agreements is not triggered by the execution of the Merger Agreement. To ensure sufficient liquidity pending lender consent to the signing of the Merger Agreement, on October 20, 2020, PNMR entered into backstop credit facilities related to the Merger between PNMR, the lenders party thereto, and MUFG Bank, Ltd., as administrative agent. The $300.0 million 364-day revolving credit facility ("Merger Backstop Revolving Facility") was available to provide liquidity to refinance the PNMR Revolving Credit Facility, if needed, and the $50.0 million, 364-day delayed-draw term loan ("Merger Backstop Term Loan") was available to provide liquidity to refinance any of the applicable PNMR term loans or TNMP and PNMR Development credit facilities, if needed, and to fund other corporate purposes. The Merger Backstop Revolving Facility expired upon the execution of the necessary waiver amendments (discussed below). Had PNMR made borrowings under the Merger Backstop Term Loan, those borrowings would have matured on the earliest of the closing of the Merger or October 19, 2021 and would have borne interest at a variable rate based on a pricing grid. As PNMR did not make any borrowings under the Merger Backstop Term Loan by the commitment termination date of December 18, 2020, the Merger Backstop Term Loan expired according to its terms. On October 26, 2020, PNMR, TNMP and PNMR Development entered into amendment agreements with the lender parties thereto to amend the definition of "Change of Control" such that the entry into the Merger Agreement would not constitute a Change of Control and to waive the Event of Default arising from entry into the Merger Agreement. The amended Change of Control definition under the PNMR, TNMP, and PNMR Development debt agreements will, however, be triggered again upon the closing of the merger transaction. Prior to the closing of the Merger, the Company intends to coordinate with the lenders and Avangrid to either amend the definition of Change of Control permitting Avangrid ownership of the Company; or to refinance or enter into new debt agreements that would include Avangrid as owners of the Company. The Change of Control provisions in the PNM debt agreements are not triggered by the close of the Merger. The documents governing TNMP's aggregate $750.0 million of outstanding First Mortgage Bonds ("TNMP FMBs") obligated TNMP to offer, within 30 business days following the signing of the Merger Agreement, to prepay all $750.0 million outstanding TNMP FMBs at 100% of the principal amount, plus accrued and unpaid interest thereon, but without any make-whole amount or other premium. TNMP made such offer to prepay the TNMP FMBs in accordance with the terms of the TNMP FMBs, and none of the holders of the TNMP FMBs accepted TNMP’s offer. The documents governing the TNMP FMBs require TNMP to make another offer, within 30 business days of closing of the Merger, to prepay all outstanding TNMP FMBs at par. TNMP will make such offer to prepay the TNMP FMBs in accordance with the terms of the TNMP FMBs; however, holders of the TNMP FMBs are not required to tender their TNMP FMBs and may accept or reject such offer to prepay. The information in this Annual Report on Form 10-K is for informational purposes only and is neither an offer to purchase, nor a solicitation of an offer to sell, subscribe for or buy any securities in any jurisdiction pursuant to the proposed transactions or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law. Similar to the offer to prepay made after signing the Merger Agreement, the post-Merger closing offer to prepay the TNMP FMBs will be made only pursuant to an offer to prepay, which will set forth the terms and conditions of the offer to prepay. On December 21, 2020, PNMR entered into a $150.0 million term loan agreement (the “PNMR 2020 Term Loan”), between PNMR and U.S. Bank National Association, as sole lender. Proceeds from the PNMR 2020 Term Loan were used to repay the $50.0 million PNMR 2018 Two On December 22, 2020, PNMR entered into a $300.0 million delayed-draw term loan agreement (the “PNMR 2020 Delayed-Draw Term Loan”), among PNMR, the lenders party thereto, and MUFG Bank, Ltd., as administrative agent. Initially PNMR drew $80.0 million to refinance existing indebtedness and for other corporate purposes. Draws on the PNMR 2020 Delayed-Draw Term Loan, aggregating $80.0 million, bear interest at a variable rate, which was 1.40% at December 31, 2020, and mature on January 31, 2022. PNMR expects to use the remaining $220.0 million of capacity from the PNMR 2020 Delayed-Draw Term Loan to repay an equivalent amount of the PNMR 2018 SUNs. PNMR has an automatic shelf registration that provides for the issuance of various types of debt and equity securities that expires in March 2021. PNM At January 1, 2018, PNM had a $200.0 million term loan agreement (the “PNM 2017 Term Loan”) between PNM and JPMorgan Chase Bank, N.A., as lender and administrative agent, and U.S. Bank National Association, as lender. The PNM 2017 Term Loan was repaid on January 18, 2019. On July 28, 2017, PNM entered into an agreement (the “PNM 2017 Senior Unsecured Note Agreement”) with institutional investors for the sale of $450.0 million aggregate principal amount of eight series of Senior Unsecured Notes (the “PNM 2018 SUNs”) offered in private placement transactions. On May 14, 2018, PNM issued $350.0 million of the PNM 2018 SUNs under that agreement (at fixed annual interest rates ranging from 3.15% to 4.50% for terms between 5 and 30 years) and used the proceeds to repay an equal amount of PNM’s 7.95% SUNs that matured on May 15, 2018. On July 31, 2018, PNM issued the remaining $100.0 million of the PNM 2018 SUNs (at fixed annual interest rates of 3.78% and 4.60% for terms of 10 and 30 years) and used the proceeds to repay an equal amount of PNM’s 7.50% SUNs on August 1, 2018. The PNM 2017 Senior Unsecured Note Agreement includes customary covenants, including a covenant that requires the maintenance of a debt-to-capitalization ratio of less than or equal to 65%, customary events of default, including a cross-default provision, and covenants regarding parity of financial covenants, liens and guarantees with respect to PNM’s material credit facilities. In the event of a change of control, PNM will be required to offer to prepay the PNM 2018 SUNs at par. As discussed above, the change of control provisions in the PNM debt agreements are not triggered by the close of the Merger. PNM has the right to redeem any or all of the PNM 2018 SUNs prior to their respective maturities, subject to payment of a customary make-whole premium. On April 9, 2018, PNMR Development deposited $68.2 million with PNM related to potential transmission network interconnections. PNM used the deposit to repay intercompany borrowings. PNM was required to pay interest to PNMR Development to the extent work under the interconnections has not been performed. The entire deposit of $68.2 million and accrued interest of $5.7 million was refunded in November 2019. The interconnection deposit and related refund is presented in financing activities and the interest payment is presented in operating activities on PNM’s Consolidated Statements of Cash Flows for the years ended December 31, 2019 and 2018. During the years ended December 31, 2019 and December 31, 2018, PNM recognized $3.3 million and $2.4 million of interest expense under the agreement. All intercompany transactions related to this deposit have been eliminated on PNMR’s Consolidated Financial Statements. On January 18, 2019, PNM entered into a $250.0 million term loan agreement (the “PNM 2019 $250.0 million Term Loan”) among PNM, the lenders identified therein, and U.S. Bank N.A., as administrative agent. PNM used the proceeds of the PNM 2019 $250.0 million Term Loan to repay the PNM 2017 Term Loan, to reduce short-term borrowings under the PNM Revolving Credit Facility, and for general corporate purposes. The PNM 2019 $250.0 million Term Loan was prepaid in April 2020 without penalty. On December 18, 2019, PNM entered into a $40.0 million term loan agreement (the “PNM 2019 $40.0 million Term Loan”), between PNM and Bank of America, N.A. as sole lender and administrative agent. PNM used the proceeds of the PNM 2019 $40.0 million Term Loan to reduce short-term borrowings under the PNM Revolving Credit Facility and for general corporate purposes. The PNM 2019 $40.0 million Term Loan bears interest at a variable rate, which was 0.80% at December 31, 2020, and must be repaid on or before June 18, 2021. On April 15, 2020, PNM entered into a $250.0 million term loan agreement (the "PNM 2020 Term Loan"), between PNM, the lenders party thereto, and U.S. Bank, as administrative agent. Proceeds from the PNM 2020 Term Loan were used to prepay the PNM 2019 $250.0 million Term Loan due July 2020, without penalty. As discussed below, on April 30, 2020, PNM used $100.0 million of proceeds from the PNM 2020 SUNs to prepay without penalty an equal amount of the PNM 2020 Term Loan. On December 21, 2020, PNM prepaid without penalty, the remaining $150.0 million balance of the PNM 2020 Term Loan. On April 30, 2020, PNM entered into an agreement (the "PNM 2020 Note Purchase Agreement") with institutional investors for the sale of $200.0 million aggregate principal amount of senior unsecured notes offered in private placement transactions. Under the agreement, PNM issued $150.0 million aggregate principal amount of its 3.21% senior unsecured notes, Series A, due April 30, 2030, and $50.0 million of its aggregate principal amount of its 3.57% senior unsecured notes, Series B, due April 29, 2039 (the "PNM 2020 SUNs"). The PNM 2020 SUNs were issued on April 30, 2020. PNM used $100.0 million of proceeds from the PNM 2020 SUNs to repay an equal amount of the PNM 2020 Term Loan. The remaining $100.0 million of the PNM 2020 SUNs were used to repay borrowings on the PNM Revolving Credit Facility and for other corporate purposes. The PNM 2020 Note Purchase Agreement includes customary covenants, including a covenant that requires PNM to maintain a debt-to-capitalization ratio of less than or equal to 65%, customary events of default, including a cross-default provision, and covenants regarding parity of financial covenants, liens and guarantees with respect to PNM’s material credit facilities. In the event of a change of control, PNM will be required to offer to prepay the PNM 2020 SUNs at par. As discussed above, the change of control provisions in the PNM debt agreements are not triggered by the close of the Merger. PNM has the right to redeem any or all of the PNM 2020 SUNs prior to their maturities, subject to payment of a customary make-whole premium. At December 31, 2019, PNM had $40.0 million of outstanding PCRBs, which have a final maturity of June 1, 2040 and two series of outstanding PCRBs of $39.3 million and $21.0 million, which have a final maturity of June 1, 2043. These PCRBs, aggregating $100.3 million, were subject to mandatory tender on June 1, 2020. On June 1, 2020, PNM purchased these PCRBs utilizing borrowings under the PNM Revolving Credit Facility and converted the PCRBs to the weekly mode. PNM held these PCRBs (without legally canceling them) until July 1, 2020, when they were remarketed in the weekly mode (the "PNM Floating Rate PCRBs") and PNM used the remarketing proceeds to repay the revolver borrowings. PNM Floating Rate PCRBs in the weekly mode bear interest at rates that are reset weekly, giving investors the option to return the PCRBs for remarketing to new investors upon 7 days' notice. At December 31, 2020, this rate was 0.19%. A corresponding portion of the borrowing capacity under the PNM Revolving Credit Facility is reserved to support the investors' option to return the PNM Floating Rate PCRBs upon 7 days' notice. At December 31, 2019, PNM had PCRBs outstanding of $36.0 million at 6.25% issued by the Maricopa County, Arizona Pollution Control Corporation as well as $255.0 million at 5.90% and $11.5 million at 6.25% issued by the City of Farmington, New Mexico. The $36.0 million PCRBs became callable at 101% of par on January 1, 2020 and the remaining $266.5 million PCRBs became callable at par on June 1, 2020. On June 22, 2020, PNM provided notice to the bondholders that it was calling the PCRBs aggregating $302.5 million. On July 22, 2020, PNM purchased the PCRBs in lieu of redemption and remarketed them to new investors (the "PNM 2020 Fixed Rate PCRBs"). Information concerning the funding dates, mandatory tender dates, and interest rates on the PNM 2020 Fixed Rate PCRBs are provided below. On April 1, 2020, the NMPRC approved PNM’s request to issue approximately $361 million of Securitized Bonds upon the retirement of SJGS in 2022. The NMPRC’s approval of the issuance of these Securitized Bonds is currently being appealed to the NM Supreme Court. See SJGS Abandonment Application in Note 17. PNM has a shelf registration statement, which will expire in May 2023, with capacity for the issuance of up to $650.0 million of senior unsecured notes. TNMP On June 28, 2018, TNMP entered into an agreement under which TNMP issued $60.0 million aggregate principal amount of 3.85% first mortgage bonds, due 2028. On July 25, 2018, TNMP entered into a $20.0 million term loan agreement. On December 17, 2018, the TNMP 2018 Term Loan agreement was amended to provide additional funding of $15.0 million, which results in a total committed amount of $35.0 million under the agreement (the “TNMP 2018 Term Loan”). TNMP used the proceeds from these issuances to repay short-term borrowings and for TNMP’s general corporate purposes. The TNMP 2018 Term Loan was repaid on December 30, 2019. On February 26, 2019, TNMP entered into the TNMP 2019 Bond Purchase Agreement with institutional investors for the sale of $305.0 million aggregate principal amount of four series of TNMP first mortgage bonds (the “TNMP 2019 Bonds”) offered in private placement transactions. TNMP issued $225.0 million of TNMP 2019 Bonds on March 29, 2019 and used the proceeds to repay TNMP’s $172.3 million 9.50% first mortgage bonds at their maturity on April 1, 2019, as well as to repay borrowing under the TNMP Revolving credit Facility and for general corporate purposes. TNMP issued the remaining $80.0 million of TNMP 2019 Bonds on July 1, 2019 and used the proceeds to repay borrowing under the TNMP Revolving Credit Facility and for general corporate purposes. The terms of the indenture governing the TNMP 2019 Bonds include customary covenants, including a covenant that requires TNMP to maintain a debt-to-capitalization ratio of less than or equal to 65%, customary events of default, a cross-default provision, and a change-of-control provision. TNMP has the right to redeem any or all of the TNMP 2019 Bonds prior to their respective maturities, subject to payment of a customary make-whole premium. On April 24, 2020, TNMP entered into the TNMP 2020 Bond Purchase Agreement with institutional investors for the sale of $185.0 million aggregate principal amount of four series of TNMP first mortgage bonds (the "TNMP 2020 Bonds") offered in private placement transactions. TNMP issued $110.0 million of TNMP 2020 Bonds on April 24, 2020 and used the proceeds to repay borrowings under the TNMP Revolving Credit Facility and for other corporate purposes. TNMP issued the remaining $75.0 million of TNMP 2020 Bonds on July 15, 2020 and used the proceeds from that issuance to repay borrowings under the TNMP Revolving Credit facility and for other corporate purposes. The TNMP 2020 Bonds are subject to continuing compliance with the representations, warranties and covenants set forth in the indenture governing the TNMP 2020 Bonds. The terms of the indenture governing the TNMP 2020 Bonds include customary covenants, including a covenant that requires TNMP to maintain a debt-to-capitalization ratio of less than or equal to 65%, customary events of default, a cross-default provision, and a change-of-control provision. TNMP has the right to redeem any or all of the TNMP 2020 Bonds prior to their respective maturities, subject to payment of a customary make-whole premium. Information concerning the funding dates, maturities and interest rates on the TNMP 2020 Bonds issued in April and July 2020 are provided below. Interest Rate Hedging Activities At January 1, 2018, PNMR had a hedging agreement that effectively established a fixed interest rate of 1.927% for borrowings under the PNMR 2015 Term Loan through its maturity on March 9, 2018. In 2017, PNMR entered into three separate four-year hedging agreements that effectively established fixed interest rates of 1.926%, 1.823%, and 1.629%, plus customary spreads over LIBOR, subject to change if there is a change in PNMR’s credit rating, for three separate tranches, each of $50.0 million, of its variable rate debt. These hedge agreements are accounted for as cash flow hedges and had fair values of $0.9 million and $0.4 million that are included in other current liabilities on the Consolidated Balance Sheets at December 31, 2020 and 2019. As discussed in Note 3, changes in the fair value of the cash flow hedges are deferred in AOCI and amounts reclassified to the Condensed Consolidated Statement of Earnings are recorded in interest charges. The fair values were determined using Level 2 inputs, including using forward LIBOR curves under the mid-market convention to discount cash flows over the remaining term of the agreement. Borrowing Arrangements Between PNMR and its Subsidiaries PNMR has intercompany loan agreements with its subsidiaries. Individual subsidiary loan agreements vary in amount up to $150.0 million and have either reciprocal or non-reciprocal terms. Interest charged to the subsidiaries is equivalent to interest paid by PNMR on its short-term borrowings or the money-market interest rate if PNMR does not have any short-term borrowings outstanding. PNM and TNMP had no borrowings from PNMR at December 31, 2020 and 2019, and no borrowings at February 19, 2021. PNMR Development had $0.3 million and zero in short-term borrowings outstanding from PNMR at December 31, 2020 and 2019 and $0.4 million at February 19, 2021. Short-term Debt and Liquidity Currently, the PNMR Revolving Credit Facility has a financing capacity of $300.0 million and the PNM Revolving Credit Facility has a financing capacity of $400.0 million. Both facilities currently expire on October 31, 2023 and contain options to be extended through October 2024, subject to approval by a majority of the lenders. PNM also has the $40.0 million PNM 2017 New Mexico Credit Facility that expires on December 12, 2022. The TNMP Revolving Credit Facility is a $75.0 million revolving credit facility secured by $75.0 million aggregate principal amount of TNMP first mortgage bonds and matures on September 23, 2022 and contains two one-year extension options, subject to approval by a majority of the lenders. PNMR Development has a $40.0 million revolving credit facility that was expected to expire on February 23, 2021. On February 22, 2021, PNMR Development extended the facility to January 31, 2022. PNMR Development has the option, subject to lender approval, to further increase the capacity of this facility to $50.0 million upon 15-days advance notice. The PNMR Development Revolving Credit Facility bears interest at a variable rate and contains terms similar to the PNMR Revolving Credit Facility. PNMR has guaranteed the obligations of PNMR Development under the facility. PNMR Development uses the facility to finance its participation in NMRD and for other activities. Variable interest rates under these facilities are based on LIBOR but contain provisions which allow for the replacement of LIBOR with other widely accepted interest rates. Short-term debt outstanding consists of: December 31, Short-term Debt 2020 2019 (In thousands) PNM: PNM Revolving Credit Facility $ — $ 48,000 PNM 2017 New Mexico Credit Facility 10,000 10,000 10,000 58,000 TNMP Revolving Credit Facility — 15,000 PNMR: PNMR Revolving Credit Facility 12,000 112,100 PNMR Development Revolving Credit Facility 10,000 — $ 32,000 $ 185,100 In addition to the above borrowings, PNMR, PNM, and TNMP had letters of credit outstanding of $4.7 million, $2.2 million, and zero at December 31, 2020 that reduce the available capacity under their respective revolving credit facilities. In addition, PNMR had $30.3 million of letters of credit outstanding under the WFB LOC Facility. At December 31, 2020, interest rates on outstanding borrowings were 1.66% for the PNMR Revolving Credit Facility, 1.41% for the PNM 2017 New Mexico Credit Facility, and 1.15% for the PNMR Development Revolving Credit Facility. There were no borrowings outstanding under the PNM and TNMP Revolving Credit Facilities at December 31, 2020. At February 19, 2021, PNMR, PNM, TNMP, and PNMR Development had $257.7 million, $397.8 million, $47.6 million, and $30.0 million of availability under their respective revolving credit facilities, including reductions of availability due to outstanding letters of credit. PNM had $40.0 million of availability under the PNM 2017 New Mexico Credit Facility. Total availability at February 19, 2021, on a consolidated basis, was $773.1 million for PNMR. Availability under PNM’s Revolving Credit Facility and total availability at PNMR, on a consolidated basis, does not reflect a reduction of $100.3 million that PNM has reserved to provide liquidity support for the PNM Floating Rate PCRBs. At February 19, 2021, PNMR, PNM, and TNMP had invested cash of $0.9 million, $32.6 million, and zero. Long-Term Debt As discussed above, in June 2020, PNM purchased an aggregate amount of $100.3 million PCRBs using borrowings under the PNM Revolving Credit Facility. In July 2020, PNM remarketed the PCRBs in the weekly mode and used the proceeds to repay the borrowings under the PNM Revolving Credit Facility. A corresponding amount of the PNM Revolving Credit Facility is reserved to support the investors’ option to return the PCRBs upon 7 days’ notice. As PNM can demonstrate the intent and ability to keep the PNM Floating Rate PCRBs outstanding through at least the October 31, 2023 maturity of the PNM Revolving Credit Facility, PNM Floating Rate PCRBs, aggregating $100.3 million, are reflected as long-term debt in the Consolidated Balance Sheets at December 31, 2020. Also discussed above, PNMR intends to use the remaining capacity of $220.0 million under the PNMR 2020 Delayed-Draw Term Loan to repay an equivalent amount of the PNMR 2018 SUNs. As PNMR can demonstrate the intent and ability to extend that portion of the $300.0 million SUNs through January 31, 2022, $220.0 million of the PNMR 2018 SUNs is reflected as long-term debt in the Consolidated Balance Sheet at December 31, 2020. Information concerning long-term debt outstanding and unamortized (premiums), discounts, and debt issuance costs is as follows: December 31, 2020 December 31, 2019 Principal Unamortized Discounts, (Premiums), and Issuance Costs, net Principal Unamortized Discount

Lease Commitments

Lease Commitments	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Commitments	Lease Commitments The Company enters into various lease agreements to meet its business needs and to satisfy the needs of its customers. Historically, the Company’s leases were classified as operating leases and included leases for generating capacity from PVNGS Units 1 and 2, certain rights-of-way agreements for transmission lines and facilities, vehicles and equipment necessary to construct and maintain the Company’s assets and building and office equipment. In February 2016, the FASB issued ASU 2016-02 – Leases (Topic 842) to provide guidance on the recognition, measurement, presentation, and disclosure of leases. Among other things, ASU 2016-02 requires that all leases be recorded on the Consolidated Balance Sheets by recognizing a present value liability for future cash flows of the lease agreement and a corresponding right-of-use asset. The Company adopted Topic 842 on January 1, 2019, its required effective date. The Company elected to use many of the practical expedients available upon adoption of the standard. As a result, the Company will continue to classify its leases existing as of December 31, 2018 as operating leases until they expire or are modified. In addition, the Company elected the practical expedient to not reevaluate the accounting for land easements and rights-of-way agreements existing at December 31, 2018. The Company also elected the use of the practical expedient to apply the requirements of the new standard on its effective date and has not restated prior periods to conform to the new guidance. Adoption of the lease standard has a material impact on the Company’s Consolidated Balance Sheets but does not have a material impact on the Consolidated Statements of Earnings or the Consolidated Statements of Cash Flows. Effective January 1, 2019, the Company accounts for contracts that convey the use and control of identified assets for a period of time as leases. The Company classifies leases as operating or financing by evaluating the terms of the lease agreement. Agreements under which the Company is likely to utilize substantially all of the economic value or life of the asset or that the Company is likely to own at the end of the lease term, either through purchase or transfer of ownership, are classified as financing leases. Leases not meeting these criteria are accounted for as operating leases. Agreements under which the Company is a lessor are insignificant. PNMR, PNM, and TNMP determine present value for their leases using their incremental borrowing rates at the commencement date of the lease or, when readily available, the rate implicit in the agreement. The Company leases office buildings, vehicles, and other equipment. In addition, PNM leases interests in PVNGS Units 1 and 2 and certain rights-of-way agreements that are classified as leases. All of the Company’s leases with terms in excess of one year are recorded on the Consolidated Balance Sheets by recording a present value lease liability and a corresponding right-of-use asset. Operating lease expense is recognized within operating expenses according to the use of the asset on a straight-line basis. Financing lease costs, which are comprised primarily of fleet and office equipment leases commencing after January 1, 2019, are recognized by amortizing the right-of-use asset on a straight-line basis and by recording interest expense on the lease liability. Financing lease right-of-use assets amortization is reflected in depreciation and amortization and interest on financing lease liabilities is reflected as interest charges on the Company’s Consolidated Statements of Earnings. PVNGS PNM leases interests in Units 1 and 2 of PVNGS. The PVNGS leases were entered into in 1985 and 1986 and initially were scheduled to expire on January 15, 2015 for the four Unit 1 leases and January 15, 2016 for the four Unit 2 leases. Following procedures set forth in the PVNGS leases, PNM notified four of the lessors under the Unit 1 leases and one lessor under the Unit 2 lease that it would elect to renew those leases on the expiration date of the original leases. The four Unit 1 leases now expire on January 15, 2023 and the one Unit 2 lease now expires on January 15, 2024. The annual lease payments during the renewal periods aggregate $16.5 million for PVNGS Unit 1 and $1.6 million for Unit 2. The terms of each of the extended leases do not provide for additional renewal options beyond their currently scheduled expiration dates. PNM had the option to purchase the assets underlying each of the extended leases at their fair market value or to return the lease interests to the lessors on the expiration dates. Under the terms of the extended leases, PNM had until January 15, 2020 for the Unit 1 leases and until January 15, 2021 for the Unit 2 lease to provide notices to the lessors of PNM’s intent to exercise the purchase options or to return the leased assets to the lessors. On January 3, 2020, PNM filed notice with the NMPRC of 60-day waivers of the deadline to provide notice to purchase or return the assets underlying the PVNGS Unit 1 leases. On March 3, 2020, and April 10, 2020, PNM filed additional notices of waivers of the deadlines. The waivers did not impact the PVNGS Unit 1 leases’ current January 15, 2023 expiration dates. PNM’s elections are independent for each lease and are irrevocable. On June 11, 2020, PNM provided notice to the lessors and the NMPRC of its intent to return the assets underlying in both the PVNGS Unit 1 and Unit 2 leases upon their expiration in January 2023 and 2024. Although PNM elected to return the assets underlying the extended leases, PNM retains certain obligations related to PVNGS, including costs to decommission the facility. PNM is depreciating its capital improvements related to the extended leases using NMPRC approved rates through the end of the NRC license period for each unit, which expire in June 2045 for Unit 1 and in June 2046 for Unit 2. Any transfer of the assets underlying the leases will be required to comply with NRC licensing requirements. For example, the NRC could limit the transfer of ownership of the assets underlying all or a portion of PNM’s currently leased interests in PVNGS. If a qualified buyer cannot be identified, PNM may be required to retain all or a portion of its currently leased capacity in PVNGS or be exposed to other claims for damages by the lessors. PNM will seek to recover its undepreciated investments, as well as any other obligations related to PVNGS from NM retail customers. PNM is exposed to loss under the PVNGS lease arrangements upon the occurrence of certain events that PNM does not consider reasonably likely to occur. Under certain circumstances (for example, the NRC issuing specified violation orders with respect to PVNGS or the occurrence of specified nuclear events), PNM would be required to make specified payments to the lessors and take title to the leased interests. If such an event had occurred as of December 31, 2020, amounts due to the lessors under the circumstances described above would be up to $154.5 million, payable on January 15, 2021 in addition to the scheduled lease payments due on that date. Land Easements and Rights-of-Ways Many of PNM’s electric transmission and distribution facilities are located on lands that require the grant of rights-of-way from governmental entities, Native American tribes, or private parties. PNM has completed several renewals of rights-of-way, the largest of which is a renewal with the Navajo Nation. PNM is obligated to pay the Navajo Nation annual payments of $6.0 million, subject to adjustment each year based on the Consumer Price Index, through 2029. PNM’s April 2020 payment for the amount due under the Navajo Nation right-of-way lease was $7.1 million, which included amounts due under the Consumer Price Index adjustment. Changes in the Consumer Price Index subsequent to January 1, 2019 are considered variable lease payments. PNM has other prepaid rights-of-way agreements that are not accounted for as leases or recognized as a component of plant in service. PNM reflects the unamortized balance of these prepayments in other deferred charges on the Consolidated Balance Sheets and recognizes amortization expense associated with these agreements in the Consolidated Statement of Earnings over their term. As of December 31, 2020 and 2019, the unamortized balance of these rights-of-ways was $55.8 million and $60.2 million. During the years ended December 31, 2020, 2019, and 2018, PNM recognized amortization expense associated with these agreements of $4.4 million, $3.7 million, and $3.8 million. Fleet Vehicles and Equipment Fleet vehicle and equipment leases commencing on or after January 1, 2019 are classified as financing leases. Fleet vehicle and equipment leases existing as of December 31, 2018 are classified as operating leases. The Company’s fleet vehicle and equipment lease agreements include non-lease components for insignificant administrative and other costs that are billed over the life of the agreement. At December 31, 2020, residual value guarantees on fleet vehicle and equipment leases are $0.9 million, $1.4 million, and $2.3 million for PNM, TNMP, and PNMR. Information related to the Company’s operating leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Operating leases: Operating lease assets, net of amortization $ 97,461 $ 7,206 $ 105,133 $ 120,585 $ 9,954 $ 131,212 Current portion of operating lease liabilities 25,130 2,193 27,460 25,927 2,753 29,068 Long-term portion of operating lease liabilities 75,941 4,779 81,065 97,992 7,039 105,512 As discussed above, the Company classifies its fleet vehicle and equipment leases and its office equipment leases commencing on or after January 1, 2019 as financing leases. Information related to the Company’s financing leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) (In thousands) Financing leases: Non-utility property $ 11,453 $ 13,299 $ 25,055 $ 4,857 $ 4,910 $ 10,028 Accumulated depreciation (2,044) (2,241) (4,383) (482) (466) (973) Non-utility property, net $ 9,409 $ 11,058 $ 20,672 $ 4,375 $ 4,444 $ 9,055 Other current liabilities $ 1,993 $ 2,397 $ 4,470 $ 722 $ 850 $ 1,637 Other deferred credits 7,176 8,669 15,972 3,333 3,597 7,102 Information concerning the weighted average remaining lease terms and the weighted average discount rates used to determine the Company’s lease liabilities is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated Weighted average remaining lease term (years): Operating leases 6.23 3.46 6.04 6.70 4.10 6.49 Financing leases 4.78 4.84 4.79 5.64 5.54 5.54 Weighted average discount rate: Operating leases 3.93 % 4.06 % 3.94 % 3.89 % 3.95 % 3.90 % Financing leases 2.76 % 2.84 % 2.80 % 3.68 % 3.65 % 3.64 % Information for the components of lease expense is as follows: Year Ended December 31, 2020 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 27,302 $ 2,870 $ 30,418 Amounts capitalized (1,020) (2,375) (3,395) Total operating lease expense 26,282 495 27,023 Financing lease cost: Amortization of right-of-use assets 1,563 1,775 3,412 Interest on lease liabilities 221 285 511 Amounts capitalized (1,056) (1,754) (2,810) Total financing lease expense 728 306 1,113 Variable lease expense 221 — 221 Short-term lease expense 288 5 295 Total lease expense for the period $ 27,519 $ 806 $ 28,652 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 28,254 $ 3,341 $ 31,963 Amounts capitalized (1,319) (2,594) (3,913) Total operating lease expense 26,935 747 28,050 Financing lease cost: Amortization of right-of-use assets 481 466 973 Interest on lease liabilities 92 100 194 Amounts capitalized (280) (423) (704) Total financing lease expense 293 143 463 Variable lease expense 96 — 96 Short-term lease expense 346 26 414 Total lease expense for the period $ 27,670 $ 916 $ 29,023 Supplemental cash flow information related to the Company’s leases is as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 26,007 $ 596 $ 27,121 $ 26,392 $ 935 $ 27,849 Operating cash flows from financing leases 82 48 136 44 25 71 Finance cash flows from financing leases 557 307 936 183 109 313 Non-cash information related to right-of-use assets obtained in exchange for lease obligations: Operating leases $ — $ — $ — $ 143,816 $ 12,942 $ 157,816 Financing leases 6,588 8,985 15,614 4,473 4,910 9,645 Capitalized costs excluded from the operating and financing cash paid for leases above for the year ended December 31, 2020 are $1.0 million and $1.1 million at PNM, $2.4 million and $1.8 million at TNMP, and $3.4 million and $2.8 million at PNMR. These capitalized costs are reflected as investing activities on the Company’s Consolidated Statements of Cash Flows for the twelve months ended December 31, 2020. For the year ended December 31, 2019, capitalized costs excluded are $1.3 million and $0.3 million at PNM, $2.6 million and $0.4 million at TNMP, and $3.9 million and $0.7 million at PNMR Future expected lease payments are shown below: As of December 31, 2020 PNM TNMP PNMR Consolidated Financing Operating Financing Operating Financing Operating (In thousands) 2021 $ 2,214 $ 26,572 $ 2,672 $ 2,426 $ 4,970 $ 29,290 2022 2,159 26,266 2,557 1,987 4,797 28,464 2023 2,095 17,735 2,372 1,481 4,511 19,395 2024 1,434 7,899 1,897 895 3,335 8,841 2025 854 6,946 1,190 690 2,044 7,673 Later years 1,030 27,530 1,120 75 2,150 27,827 Total minimum lease payments 9,786 112,948 11,808 7,554 21,807 121,490 Less: Imputed interest 617 11,877 742 582 1,365 12,965 Lease liabilities as of December 31, 2020 $ 9,169 $ 101,071 $ 11,066 $ 6,972 $ 20,442 $ 108,525
Lease Commitments	Lease Commitments The Company enters into various lease agreements to meet its business needs and to satisfy the needs of its customers. Historically, the Company’s leases were classified as operating leases and included leases for generating capacity from PVNGS Units 1 and 2, certain rights-of-way agreements for transmission lines and facilities, vehicles and equipment necessary to construct and maintain the Company’s assets and building and office equipment. In February 2016, the FASB issued ASU 2016-02 – Leases (Topic 842) to provide guidance on the recognition, measurement, presentation, and disclosure of leases. Among other things, ASU 2016-02 requires that all leases be recorded on the Consolidated Balance Sheets by recognizing a present value liability for future cash flows of the lease agreement and a corresponding right-of-use asset. The Company adopted Topic 842 on January 1, 2019, its required effective date. The Company elected to use many of the practical expedients available upon adoption of the standard. As a result, the Company will continue to classify its leases existing as of December 31, 2018 as operating leases until they expire or are modified. In addition, the Company elected the practical expedient to not reevaluate the accounting for land easements and rights-of-way agreements existing at December 31, 2018. The Company also elected the use of the practical expedient to apply the requirements of the new standard on its effective date and has not restated prior periods to conform to the new guidance. Adoption of the lease standard has a material impact on the Company’s Consolidated Balance Sheets but does not have a material impact on the Consolidated Statements of Earnings or the Consolidated Statements of Cash Flows. Effective January 1, 2019, the Company accounts for contracts that convey the use and control of identified assets for a period of time as leases. The Company classifies leases as operating or financing by evaluating the terms of the lease agreement. Agreements under which the Company is likely to utilize substantially all of the economic value or life of the asset or that the Company is likely to own at the end of the lease term, either through purchase or transfer of ownership, are classified as financing leases. Leases not meeting these criteria are accounted for as operating leases. Agreements under which the Company is a lessor are insignificant. PNMR, PNM, and TNMP determine present value for their leases using their incremental borrowing rates at the commencement date of the lease or, when readily available, the rate implicit in the agreement. The Company leases office buildings, vehicles, and other equipment. In addition, PNM leases interests in PVNGS Units 1 and 2 and certain rights-of-way agreements that are classified as leases. All of the Company’s leases with terms in excess of one year are recorded on the Consolidated Balance Sheets by recording a present value lease liability and a corresponding right-of-use asset. Operating lease expense is recognized within operating expenses according to the use of the asset on a straight-line basis. Financing lease costs, which are comprised primarily of fleet and office equipment leases commencing after January 1, 2019, are recognized by amortizing the right-of-use asset on a straight-line basis and by recording interest expense on the lease liability. Financing lease right-of-use assets amortization is reflected in depreciation and amortization and interest on financing lease liabilities is reflected as interest charges on the Company’s Consolidated Statements of Earnings. PVNGS PNM leases interests in Units 1 and 2 of PVNGS. The PVNGS leases were entered into in 1985 and 1986 and initially were scheduled to expire on January 15, 2015 for the four Unit 1 leases and January 15, 2016 for the four Unit 2 leases. Following procedures set forth in the PVNGS leases, PNM notified four of the lessors under the Unit 1 leases and one lessor under the Unit 2 lease that it would elect to renew those leases on the expiration date of the original leases. The four Unit 1 leases now expire on January 15, 2023 and the one Unit 2 lease now expires on January 15, 2024. The annual lease payments during the renewal periods aggregate $16.5 million for PVNGS Unit 1 and $1.6 million for Unit 2. The terms of each of the extended leases do not provide for additional renewal options beyond their currently scheduled expiration dates. PNM had the option to purchase the assets underlying each of the extended leases at their fair market value or to return the lease interests to the lessors on the expiration dates. Under the terms of the extended leases, PNM had until January 15, 2020 for the Unit 1 leases and until January 15, 2021 for the Unit 2 lease to provide notices to the lessors of PNM’s intent to exercise the purchase options or to return the leased assets to the lessors. On January 3, 2020, PNM filed notice with the NMPRC of 60-day waivers of the deadline to provide notice to purchase or return the assets underlying the PVNGS Unit 1 leases. On March 3, 2020, and April 10, 2020, PNM filed additional notices of waivers of the deadlines. The waivers did not impact the PVNGS Unit 1 leases’ current January 15, 2023 expiration dates. PNM’s elections are independent for each lease and are irrevocable. On June 11, 2020, PNM provided notice to the lessors and the NMPRC of its intent to return the assets underlying in both the PVNGS Unit 1 and Unit 2 leases upon their expiration in January 2023 and 2024. Although PNM elected to return the assets underlying the extended leases, PNM retains certain obligations related to PVNGS, including costs to decommission the facility. PNM is depreciating its capital improvements related to the extended leases using NMPRC approved rates through the end of the NRC license period for each unit, which expire in June 2045 for Unit 1 and in June 2046 for Unit 2. Any transfer of the assets underlying the leases will be required to comply with NRC licensing requirements. For example, the NRC could limit the transfer of ownership of the assets underlying all or a portion of PNM’s currently leased interests in PVNGS. If a qualified buyer cannot be identified, PNM may be required to retain all or a portion of its currently leased capacity in PVNGS or be exposed to other claims for damages by the lessors. PNM will seek to recover its undepreciated investments, as well as any other obligations related to PVNGS from NM retail customers. PNM is exposed to loss under the PVNGS lease arrangements upon the occurrence of certain events that PNM does not consider reasonably likely to occur. Under certain circumstances (for example, the NRC issuing specified violation orders with respect to PVNGS or the occurrence of specified nuclear events), PNM would be required to make specified payments to the lessors and take title to the leased interests. If such an event had occurred as of December 31, 2020, amounts due to the lessors under the circumstances described above would be up to $154.5 million, payable on January 15, 2021 in addition to the scheduled lease payments due on that date. Land Easements and Rights-of-Ways Many of PNM’s electric transmission and distribution facilities are located on lands that require the grant of rights-of-way from governmental entities, Native American tribes, or private parties. PNM has completed several renewals of rights-of-way, the largest of which is a renewal with the Navajo Nation. PNM is obligated to pay the Navajo Nation annual payments of $6.0 million, subject to adjustment each year based on the Consumer Price Index, through 2029. PNM’s April 2020 payment for the amount due under the Navajo Nation right-of-way lease was $7.1 million, which included amounts due under the Consumer Price Index adjustment. Changes in the Consumer Price Index subsequent to January 1, 2019 are considered variable lease payments. PNM has other prepaid rights-of-way agreements that are not accounted for as leases or recognized as a component of plant in service. PNM reflects the unamortized balance of these prepayments in other deferred charges on the Consolidated Balance Sheets and recognizes amortization expense associated with these agreements in the Consolidated Statement of Earnings over their term. As of December 31, 2020 and 2019, the unamortized balance of these rights-of-ways was $55.8 million and $60.2 million. During the years ended December 31, 2020, 2019, and 2018, PNM recognized amortization expense associated with these agreements of $4.4 million, $3.7 million, and $3.8 million. Fleet Vehicles and Equipment Fleet vehicle and equipment leases commencing on or after January 1, 2019 are classified as financing leases. Fleet vehicle and equipment leases existing as of December 31, 2018 are classified as operating leases. The Company’s fleet vehicle and equipment lease agreements include non-lease components for insignificant administrative and other costs that are billed over the life of the agreement. At December 31, 2020, residual value guarantees on fleet vehicle and equipment leases are $0.9 million, $1.4 million, and $2.3 million for PNM, TNMP, and PNMR. Information related to the Company’s operating leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Operating leases: Operating lease assets, net of amortization $ 97,461 $ 7,206 $ 105,133 $ 120,585 $ 9,954 $ 131,212 Current portion of operating lease liabilities 25,130 2,193 27,460 25,927 2,753 29,068 Long-term portion of operating lease liabilities 75,941 4,779 81,065 97,992 7,039 105,512 As discussed above, the Company classifies its fleet vehicle and equipment leases and its office equipment leases commencing on or after January 1, 2019 as financing leases. Information related to the Company’s financing leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) (In thousands) Financing leases: Non-utility property $ 11,453 $ 13,299 $ 25,055 $ 4,857 $ 4,910 $ 10,028 Accumulated depreciation (2,044) (2,241) (4,383) (482) (466) (973) Non-utility property, net $ 9,409 $ 11,058 $ 20,672 $ 4,375 $ 4,444 $ 9,055 Other current liabilities $ 1,993 $ 2,397 $ 4,470 $ 722 $ 850 $ 1,637 Other deferred credits 7,176 8,669 15,972 3,333 3,597 7,102 Information concerning the weighted average remaining lease terms and the weighted average discount rates used to determine the Company’s lease liabilities is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated Weighted average remaining lease term (years): Operating leases 6.23 3.46 6.04 6.70 4.10 6.49 Financing leases 4.78 4.84 4.79 5.64 5.54 5.54 Weighted average discount rate: Operating leases 3.93 % 4.06 % 3.94 % 3.89 % 3.95 % 3.90 % Financing leases 2.76 % 2.84 % 2.80 % 3.68 % 3.65 % 3.64 % Information for the components of lease expense is as follows: Year Ended December 31, 2020 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 27,302 $ 2,870 $ 30,418 Amounts capitalized (1,020) (2,375) (3,395) Total operating lease expense 26,282 495 27,023 Financing lease cost: Amortization of right-of-use assets 1,563 1,775 3,412 Interest on lease liabilities 221 285 511 Amounts capitalized (1,056) (1,754) (2,810) Total financing lease expense 728 306 1,113 Variable lease expense 221 — 221 Short-term lease expense 288 5 295 Total lease expense for the period $ 27,519 $ 806 $ 28,652 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 28,254 $ 3,341 $ 31,963 Amounts capitalized (1,319) (2,594) (3,913) Total operating lease expense 26,935 747 28,050 Financing lease cost: Amortization of right-of-use assets 481 466 973 Interest on lease liabilities 92 100 194 Amounts capitalized (280) (423) (704) Total financing lease expense 293 143 463 Variable lease expense 96 — 96 Short-term lease expense 346 26 414 Total lease expense for the period $ 27,670 $ 916 $ 29,023 Supplemental cash flow information related to the Company’s leases is as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 26,007 $ 596 $ 27,121 $ 26,392 $ 935 $ 27,849 Operating cash flows from financing leases 82 48 136 44 25 71 Finance cash flows from financing leases 557 307 936 183 109 313 Non-cash information related to right-of-use assets obtained in exchange for lease obligations: Operating leases $ — $ — $ — $ 143,816 $ 12,942 $ 157,816 Financing leases 6,588 8,985 15,614 4,473 4,910 9,645 Capitalized costs excluded from the operating and financing cash paid for leases above for the year ended December 31, 2020 are $1.0 million and $1.1 million at PNM, $2.4 million and $1.8 million at TNMP, and $3.4 million and $2.8 million at PNMR. These capitalized costs are reflected as investing activities on the Company’s Consolidated Statements of Cash Flows for the twelve months ended December 31, 2020. For the year ended December 31, 2019, capitalized costs excluded are $1.3 million and $0.3 million at PNM, $2.6 million and $0.4 million at TNMP, and $3.9 million and $0.7 million at PNMR Future expected lease payments are shown below: As of December 31, 2020 PNM TNMP PNMR Consolidated Financing Operating Financing Operating Financing Operating (In thousands) 2021 $ 2,214 $ 26,572 $ 2,672 $ 2,426 $ 4,970 $ 29,290 2022 2,159 26,266 2,557 1,987 4,797 28,464 2023 2,095 17,735 2,372 1,481 4,511 19,395 2024 1,434 7,899 1,897 895 3,335 8,841 2025 854 6,946 1,190 690 2,044 7,673 Later years 1,030 27,530 1,120 75 2,150 27,827 Total minimum lease payments 9,786 112,948 11,808 7,554 21,807 121,490 Less: Imputed interest 617 11,877 742 582 1,365 12,965 Lease liabilities as of December 31, 2020 $ 9,169 $ 101,071 $ 11,066 $ 6,972 $ 20,442 $ 108,525

Fair Value of Derivative and Ot

Fair Value of Derivative and Other Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Derivative and Other Financial Instruments	Fair Value of Derivative and Other Financial Instruments Fair value is defined as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair value is based on current market quotes as available and is supplemented by modeling techniques and assumptions made by the Company to the extent quoted market prices or volatilities are not available. External pricing input availability varies based on commodity location, market liquidity, and term of the agreement. Valuations of derivative assets and liabilities take into account nonperformance risk, including the effect of counterparties’ and the Company’s credit risk. The Company regularly assesses the validity and availability of pricing data for its derivative transactions. Although the Company uses its best judgment in estimating the fair value of these instruments, there are inherent limitations in any estimation technique. Energy Related Derivative Contracts Overview The primary objective for the use of commodity derivative instruments, including energy contracts, options, swaps, and futures, is to manage price risk associated with forecasted purchases of energy and fuel used to generate electricity, as well as managing anticipated generation capacity in excess of forecasted demand from existing customers. PNM’s energy related derivative contracts manage commodity risk. PNM is required to meet the demand and energy needs of its customers. PNM is exposed to market risk for the needs of its customers not covered under the FPPAC. Beginning January 1, 2018, PNM is exposed to market risk for its 65 MW interest in SJGS Unit 4, which is held as merchant plant as ordered by the NMPRC (Note 16). PNM has entered into agreements to sell power from 36 MW of that capacity to a third party at a fixed price for the period January 1, 2018 through May 31, 2022, subject to certain conditions. Under these agreements, PNM is obligated to deliver 36 MW of power only when SJGS Unit 4 is operating. These agreements are not considered derivatives because there is no notional amount due to the unit-contingent nature of the transactions. PNM and Tri-State have a hazard sharing agreement that expires in May 2022. Under this agreement, each party sells the other party 100 MW of capacity and energy from a designated generation resource on a unit contingent basis, subject to certain performance guarantees. Both the purchases and sales are made at the same market index price. This agreement serves to reduce the magnitude of each party’s single largest generating hazard and assists in enhancing the reliability and efficiency of their respective operations. PNM passes the sales and purchases through to customers under PNM’s FPPAC. PNM’s operations are managed primarily through a net asset-backed strategy, whereby PNM’s aggregate net open forward contract position is covered by its forecasted excess generation capabilities or market purchases. PNM could be exposed to market risk if its generation capabilities were to be disrupted or if its load requirements were to be greater than anticipated. If all or a portion of load requirements were required to be covered as a result of such unexpected situations, commitments would have to be met through market purchases. TNMP does not enter into energy related derivative contracts. Commodity Risk Marketing and procurement of energy often involve market risks associated with managing energy commodities and establishing positions in the energy markets, primarily on a short-term basis. PNM routinely enters into various derivative instruments such as forward contracts, option agreements, and price basis swap agreements to economically hedge price and volume risk on power commitments and fuel requirements and to minimize the effect of market fluctuations. PNM monitors the market risk of its commodity contracts in accordance with approved risk and credit policies. Accounting for Derivatives Under derivative accounting and related rules for energy contracts, PNM accounts for its various instruments for the purchase and sale of energy, which meet the definition of a derivative, based on PNM’s intent. During the years ended December 31, 2020, 2019, and 2018, PNM was not hedging its exposure to the variability in future cash flows from commodity derivatives through designated cash flow hedges. The derivative contracts recorded at fair value that do not qualify or are not designated for cash flow hedge accounting are classified as economic hedges. Economic hedges are defined as derivative instruments, including long-term power agreements, used to economically hedge generation assets, purchased power and fuel costs, and customer load requirements. Changes in the fair value of economic hedges are reflected in results of operations and are classified between operating revenues and cost of energy according to the intent of the hedge. PNM has no trading transactions. Commodity Derivatives PNM’s commodity derivative instruments that are recorded at fair value, all of which are accounted for as economic hedges and considered Level 2 fair value measurements, are presented in the following line items on the Consolidated Balance Sheets: Economic Hedges December 31, 2020 2019 (In thousands) Other current assets $ 1,096 $ 1,089 Other deferred charges 455 1,507 1,551 2,596 Other current liabilities (1,096) (1,089) Other deferred credits (455) (1,507) (1,551) (2,596) Net $ — $ — PNM’s commodity derivative instruments in the above table are subject to master netting agreements whereby assets and liabilities could be offset in the settlement process. PNM does not offset fair value and cash collateral for derivative instruments under master netting arrangements and the above table reflects the gross amounts of fair value assets and liabilities for commodity derivatives. All of the assets and liabilities in the table above at December 31, 2020 and December 31, 2019 result from PNM’s hazard sharing arrangements with Tri-State. The hazard sharing arrangements are net-settled upon delivery. At December 31, 2020 and 2019, PNM had no amounts recognized for the legal right to reclaim cash collateral. However, at December 31, 2020 and 2019, amounts posted as cash collateral under margin arrangements were $0.5 million and $0.5 million. At December 31, 2020 and 2019, obligations to return cash collateral were $0.9 million and $0.9 million. Cash collateral amounts are included in other current assets and other current liabilities on the Consolidated Balance Sheets. PNM has a NMPRC-approved hedging plan to manage fuel and purchased power costs related to customers covered by its FPPAC. There were no amounts hedged under this plan as of December 31, 2020 or 2019. The effects of mark-to-market commodity derivative instruments on PNM’s revenues and cost of energy during the years ended December 31, 2020 and 2019 were less than $0.1 million. Commodity derivatives had no impact on OCI for the periods presented. PNM has contingent requirements to provide collateral under commodity contracts having an objectively determinable collateral provision that are in net liability positions and are not fully collateralized with cash. In connection with managing its commodity risks, PNM enters into master agreements with certain counterparties. If PNM is in a net liability position under an agreement, some agreements provide that the counterparties can request collateral if PNM’s credit rating is downgraded; other agreements provide that the counterparty may request collateral to provide it with “adequate assurance” that PNM will perform; and others have no provision for collateral. At December 31, 2020 and 2019, PNM had no such contracts in a net liability position. Non-Derivative Financial Instruments The carrying amounts reflected on the Consolidated Balance Sheets approximate fair value for cash, receivables, and payables due to the short period of maturity. Investment securities are carried at fair value. Investment securities consist of PNM assets held in the NDT for its share of decommissioning costs of PVNGS and trusts for PNM’s share of final reclamation costs related to the coal mines serving SJGS and Four Corners. See Note 16. At December 31, 2020 and 2019, the fair value of investment securities included $379.2 million and $336.0 million for the NDT and $60.9 million and $52.8 million for the coal mine reclamation trusts. In June 2016, the FASB issued Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which changes the way entities recognize impairments of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining lives of the assets. The majority of the amendments made by the new standard are required to be applied using a modified retrospective approach. The amendments in ASU 2016-13 also require entities to separately measure and realize an impairment for credit losses on available-for-sale debt securities for which carrying value exceeds fair value, unless such securities have been determined to be other than temporarily impaired and the entire decrease in value has been realized as an impairment. The amendments relating to available-for-sale debt securities are required to be applied prospectively on the date of adoption. PNM records a realized loss as an impairment for any available-for-sale debt security that has a fair value that is less than its carrying value. As a result, the Company has no available-for-sale debt securities for which carrying value exceeds fair value and there are no impairments considered to be “other than temporary” that are included in AOCI and not recognized in earnings. The Company adopted ASU 2016-13 on January 1, 2020, its required effective date. Adoption of the standard did not result in the Company recording a cumulative effect adjustment or impact the Company's accounting for its available-for-sale debt securities. All gains and losses resulting from sales and changes in the fair value of equity securities are recognized immediately in earnings. Gains and losses recognized on the Consolidated Statements of Earnings related to investment securities in the NDT and reclamation trusts are presented in the following table: Year ended December 31, 2020 2019 2018 (In thousands) Equity securities: Net gains from equity securities sold $ 5,861 $ 5,698 $ 4,864 Net gains (losses) from equity securities still held 17,707 18,319 (10,523) Total net gains (losses) on equity securities 23,568 24,017 (5,659) Available-for-sale debt securities: Net gains (losses) on debt securities (1,969) 5,572 (11,517) Net gains (losses) on investment securities $ 21,599 $ 29,589 $ (17,176) The proceeds and gross realized gains and losses on the disposition of securities held in the NDT and coal mine reclamation trusts are shown in the following table. Realized gains and losses are determined by specific identification of costs of securities sold. Gross realized losses shown below exclude the (increase)/decrease in realized impairment losses of $(3.2) million, $3.0 million, and $(9.4) million for the years ended December 31, 2020, 2019 and 2018. Year Ended December 31, 2020 2019 2018 (In thousands) Proceeds from sales $ 590,998 $ 494,528 $ 984,533 Gross realized gains $ 35,904 $ 25,760 $ 19,358 Gross realized (losses) $ (28,817) $ (17,453) $ (16,624) At December 31, 2020, the available-for-sale debt securities held by PNM, had the following final maturities: Fair Value (In thousands) Within 1 year $ 33,301 After 1 year through 5 years 89,646 After 5 years through 10 years 89,130 After 10 years through 15 years 14,947 After 15 years through 20 years 9,256 After 20 years 43,730 $ 280,010 Fair Value Disclosures The Company determines the fair values of its derivative and other financial instruments based on the hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. For investment securities, Level 2 and Level 3 fair values are provided by fund managers utilizing a pricing service. For Level 2 fair values, the pricing provider predominantly uses the market approach using bid side market values based upon a hierarchy of information for specific securities or securities with similar characteristics. Fair values of Level 2 investments in mutual funds are equal to net asset value. For commodity derivatives, Level 2 fair values are determined based on market observable inputs, which are validated using multiple broker quotes, including forward price, volatility, and interest rate curves to establish expectations of future prices. Credit valuation adjustments are made for estimated credit losses based on the overall exposure to each counterparty. For the Company’s long-term debt, Level 2 fair values are provided by an external pricing service. The pricing service primarily utilizes quoted prices for similar debt in active markets when determining fair value. The valuation of Level 3 investments, when applicable, requires significant judgment by the pricing provider due to the absence of quoted market values, changes in market conditions, and the long-term nature of the assets. The Company has no Level 3 investments as of December 31, 2020 and 2019. Management of the Company independently verifies the information provided by pricing services. In August 2018, the FASB issued Accounting Standards Update 2018-13 – Fair Value Measurements (Topic 820) Disclosure Framework: Changes to the Disclosure Requirements for Fair Value Measurements, to improve fair value disclosures. ASU 2018-13 eliminates certain disclosure requirements related to transfers between Levels 1 and 2 of the fair value hierarchy and the requirement to disclose the valuation process for Level 3 fair value measurements. ASU 2018-13 also amends certain disclosure requirements for investments measured at net asset value and requires new disclosures for Level 3 investments, including a new requirement to disclose changes in unrealized gains or losses recorded in OCI related to Level 3 fair value measurements. The Company adopted ASU 2018-13 on January 1, 2020, its required effective date. The Company applied the requirements of the new standard using retrospective application, except for the new disclosures related to Level 3 investments, which are to be applied prospectively. Adoption of the standard did not have a material impact on the Company's disclosures. Items recorded at fair value by PNM on the Consolidated Balance Sheets are presented below by level of the fair value hierarchy along with gross unrealized gains on investments in available-for-sale securities. GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Unrealized Gains (In thousands) December 31, 2020 Cash and cash equivalents $ 6,107 $ 6,107 $ — Equity securities: Corporate stocks, common 85,271 85,271 — Corporate stocks, preferred 9,910 3,608 6,302 Mutual funds and other 58,817 58,762 55 Available-for-sale debt securities: U.S. government 55,839 29,579 26,260 $ 950 International government 16,032 — 16,032 2,537 Municipals 50,139 — 50,139 2,779 Corporate and other 158,000 3 157,997 21,121 $ 440,115 $ 183,330 $ 256,785 $ 27,387 December 31, 2019 Cash and cash equivalents $ 15,606 $ 15,606 $ — Equity securities: Corporate stocks, common 64,527 64,527 — Corporate stocks, preferred 9,033 2,212 6,821 Mutual funds and other 49,848 49,786 62 Available-for-sale debt securities: U.S. government 48,439 31,389 17,050 $ 535 International government 15,292 — 15,292 1,193 Municipals 46,642 — 46,642 1,768 Corporate and other 139,445 187 139,258 10,801 $ 388,832 $ 163,707 $ 225,125 $ 14,297 The carrying amounts and fair values of long-term debt, all of which are considered Level 2 fair value measurements and are not recorded at fair value on the Consolidated Balance Sheets are presented below: Carrying Fair Value December 31, 2020 (In thousands) PNMR $ 3,295,150 $ 3,355,761 PNM $ 1,696,620 $ 1,602,547 TNMP $ 853,673 $ 1,006,722 December 31, 2019 PNMR $ 3,007,717 $ 3,142,704 PNM $ 1,748,020 $ 1,795,149 TNMP $ 670,691 $ 753,317 The carrying amount and fair value of the Company’s other investments presented on the Consolidated Balance Sheets are not material and not shown in the above table. Investments Held by Employee Benefit Plans As discussed in Note 11, PNM and TNMP have trusts that hold investment assets for their pension and other postretirement benefit plans. The fair value of the assets held by the trusts impacts the determination of the funded status of each plan but the assets are not reflected on the Company’s Consolidated Balance Sheets. Both the PNM Pension Plan and the TNMP Pension Plan hold units of participation in the PNM Resources, Inc. Master Trust (the “PNMR Master Trust”), which was established for the investment of assets of the pension plans. The Company’s investment allocation targets in 2020 consist of 35% equities, 15% alternative investments (both of which are considered return generating), and 50% fixed income. GAAP provides a practical expedient that allows the net asset value per share to be used as fair value for investments in certain entities that do not have readily determinable fair values and are considered to be investment companies. Fair values for alternative investments held by the PNMR Master Trust are valued using this practical expedient. Investments for which fair value is measured using that practical expedient are not required to be categorized within the fair value hierarchy. Level 2 and Level 3 fair values are provided by fund managers utilizing a pricing service. For level 2 fair values, the pricing provider predominately uses the market approach using bid side market value based upon a hierarchy of information for specific securities or securities with similar characteristics. Fair values of Level 2 investments in mutual funds are equal to net asset value as of year-end. Fair value prices for Level 2 corporate term loans predominately use the market approach which uses bid side market values based upon hierarchy information for specific securities or securities with similar characteristics. Alternative investments include private equity funds, hedge funds, and real estate funds. The private equity funds are not voluntarily redeemable. These investments are realized through periodic distributions occurring over a 10 to 15 years term after the initial investment. The real estate funds and hedge funds may be voluntarily redeemed but are subject to redemption provisions that may result in the funds not being redeemable in the near term. Audited financial statements are received for each fund and are reviewed by the Company annually. The valuation of alternative investments requires significant judgment by the pricing provider due to the absence of quoted market values, changes in market conditions, and the long-term nature of the assets. The significant unobservable inputs include estimates of liquidation value, current operating performance, and future expectations of performance. Neither the employee benefit plans nor the PNMR Master Trust have any Level 3 investments as of December 31, 2020 or 2019. The fair values of investments held by the employee benefit plans are as follows: GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets Significant December 31, 2020 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 498,907 $ 241,445 $ 257,462 Uncategorized investments 88,984 Total Master Trust Investments $ 587,891 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 56,966 $ 28,732 $ 28,234 Uncategorized investments 9,230 Total Master Trust Investments $ 66,196 PNM OPEB Plan Cash and cash equivalents $ 1,310 $ 1,310 $ — Equity securities: Mutual funds 92,400 52,284 40,116 $ 93,710 $ 53,594 $ 40,116 TNMP OPEB Plan Cash and cash equivalents $ 18 $ 18 $ — Equity securities: Mutual funds 12,843 10,806 2,037 $ 12,861 $ 10,824 $ 2,037 GAAP Fair Value Hierarchy Total Quoted Prices in Active Significant December 31, 2019 PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 445,984 $ 152,158 $ 293,826 Uncategorized investments 86,675 Total Master Trust Investments $ 532,659 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 49,353 $ 17,335 $ 32,018 Uncategorized investments 9,974 Total Master Trust Investments $ 59,327 PNM OPEB Plan Cash and cash equivalents $ 1,022 $ 1,022 $ — Equity securities: Mutual funds 85,727 39,361 46,366 $ 86,749 $ 40,383 $ 46,366 TNMP OPEB Plan Cash and cash equivalents $ 275 $ 275 $ — Equity securities: Mutual funds 10,635 4,075 6,560 $ 10,910 $ 4,350 $ 6,560 The fair values of investments in the PNMR Master Trust are as follows: GAAP Fair Value Hierarchy Total Quoted Prices Significant December 31, 2020 (In thousands) PNMR Master Trust Cash and cash equivalents $ 20,812 $ 20,812 $ — Equity securities: Corporate stocks, common 114,983 114,983 — Corporate stocks, preferred 1,187 135 1,052 Mutual funds and other 173,931 47,418 126,513 Fixed income securities: U.S. government 97,460 86,829 10,631 International government 6,202 — 6,202 Municipals 6,277 — 6,277 Corporate and other 135,021 — 135,021 Total investments categorized within fair value hierarchy 555,873 $ 270,177 $ 285,696 Uncategorized investments: Private equity funds 12,552 Hedge funds 52,285 Real estate funds 33,377 $ 654,087 GAAP Fair Value Hierarchy Total Quoted Prices Significant December 31, 2019 (In thousands) PNMR Master Trust Cash and cash equivalents $ 19,982 $ 19,982 $ — Equity securities: Corporate stocks, common 68,497 68,497 — Corporate stocks, preferred 825 — 825 Mutual funds and other 172,326 — 172,326 Fixed income securities: U.S. government 90,970 81,014 9,956 International government 5,411 — 5,411 Municipals 6,980 — 6,980 Corporate and other 130,346 — 130,346 Total investments categorized within fair value hierarchy 495,337 $ 169,493 $ 325,844 Uncategorized investments: Private equity funds 15,827 Hedge funds 47,618 Real estate funds 33,204 $ 591,986

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2020
Variable Interest Entities [Abstract]
Variable Interest Entities	Variable Interest Entities How an enterprise evaluates and accounts for its involvement with variable interest entities, focuses primarily on whether the enterprise has the power to direct the activities that most significantly impact the economic performance of a variable interest entity (“VIE”). This evaluation requires continual reassessment of the primary beneficiary of a VIE. Valencia PNM has a PPA to purchase all of the electric capacity and energy from Valencia, a 155 MW natural gas-fired power plant near Belen, New Mexico, through May 2028. A third party built, owns, and operates the facility while PNM is the sole purchaser of the electricity generated. PNM is obligated to pay fixed operation and maintenance and capacity charges in addition to variable operation and maintenance charges under this PPA. For the years ended December 31, 2020, 2019, and 2018, PNM paid $20.0 million, $19.9 million, and $19.6 million for fixed charges and $1.4 million, $1.2 million, and $1.4 million for variable charges. PNM does not have any other financial obligations related to Valencia. The assets of Valencia can only be used to satisfy its obligations and creditors of Valencia do not have any recourse against PNM’s assets. During the term of the PPA, PNM has the option, under certain conditions, to purchase and own up to 50% of the plant or the VIE. The PPA specifies that the purchase price would be the greater of 50% of book value reduced by related indebtedness or 50% of fair market value. PNM sources fuel for the plant, controls when the facility operates through its dispatch, and receives the entire output of the plant, which factors directly and significantly impact the economic performance of Valencia. Therefore, PNM has concluded that the third-party entity that owns Valencia is a VIE and that PNM is the primary beneficiary of the entity since PNM has the power to direct the activities that most significantly impact the economic performance of Valencia and will absorb the majority of the variability in the cash flows of the plant. As the primary beneficiary, PNM consolidates Valencia in its financial statements. Accordingly, the assets, liabilities, operating expenses, and cash flows of Valencia are included in the Consolidated Financial Statements of PNM although PNM has no legal ownership interest or voting control of the VIE. The assets and liabilities of Valencia set forth below are immaterial to PNM and, therefore, not shown separately on the Consolidated Balance Sheets. The owner’s equity and net income of Valencia are considered attributable to non-controlling interest. Summarized financial information for Valencia is as follows: Results of Operations Year Ended December 31 2020 2019 2018 (In thousands) Operating revenues $ 21,297 $ 21,073 $ 21,025 Operating expenses 7,284 6,832 5,913 Earnings attributable to non-controlling interest $ 14,013 $ 14,241 $ 15,112 Financial Position December 31, 2020 2019 (In thousands) Current assets $ 3,911 $ 5,094 Net property, plant and equipment 55,744 58,581 Total assets 59,655 63,675 Current liabilities 646 623 Owners’ equity – non-controlling interest $ 59,009 $ 63,052 Westmoreland San Juan Mining, LLC As discussed in the subheading Coal Supply in Note 16, PNM purchases coal for SJGS under a coal supply agreement (“SJGS CSA”). That section includes information on the acquisition of SJCC by WSJ, a subsidiary of Westmoreland Coal Company (“Westmoreland”), as well as the announcement that it had filed voluntary petitions for relief under Chapter 11 of the U.S. Bankruptcy Code. On March 15, 2019, Westmoreland emerged from Chapter 11 bankruptcy as a privately held company owned and operated by a group of its former creditors. Under the reorganization, the assets of SJCC were sold to Westmoreland San Juan Mining, LLC (“WSJ LLC”), a subsidiary of Westmoreland Mining Holdings, LLC. As successor entity to SJCC, WSJ LLC assumed all rights and obligations of WSJ including obligations to PNM under the SJGS CSA and to PNMR under letter of credit support agreements. See Note 16. PNMR issued $30.3 million in letters of credit to facilitate the issuance of reclamation bonds required in order for SJCC to mine coal to be supplied to SJGS. As discussed above, WSJ LLC assumed the rights and obligations of SJCC, including obligations to PNMR for the letters of credit. The letters of credit support results in PNMR having a variable interest in WSJ LLC since PNMR is subject to possible loss in the event performance by PNMR is required under the letters of credit support. PNMR considers the possibility of loss under the letters of credit support to be remote since the purpose of posting the bonds is to provide assurance that WSJ LLC performs the required reclamation of the mine site in accordance with applicable regulations and all reclamation costs are reimbursable under the SJGS CSA. Also, much of the mine reclamation activities will not be performed until after the expiration of the SJGS CSA. In addition, each of the SJGS participants has established and actively fund trusts to meet future reclamation obligations. WSJ LLC is considered a VIE. PNMR’s analysis of its arrangements with WSJ LLC concluded that WSJ LLC has the ability to direct its mining operations, which is the factor that most significantly impacts the economic performance of WSJ LLC. Other than PNM being able to ensure that coal is supplied in adequate quantities and of sufficient quality to provide the fuel necessary to operate SJGS in a normal manner, the mining operations are solely under the control of WSJ LLC, including developing mining plans, hiring of personnel, and incurring operating and maintenance expenses. Neither PNMR nor PNM has any ability to direct or influence the mining operation. PNM’s involvement through the SJGS CSA is a protective right rather than a participating right and WSJ LLC has the power to direct the activities that most significantly impact the economic performance of WSJ LLC. The SJGS CSA requires WSJ LLC to deliver coal required to fuel SJGS in exchange for payment of a set price per ton, which is escalated over time for inflation. If WSJ LLC is able to mine more efficiently than anticipated, its economic performance will be improved. Conversely, if WSJ LLC cannot mine as efficiently as anticipated, its economic performance will be negatively impacted. Accordingly, PNMR believes WSJ LLC is the primary beneficiary and, therefore, WSJ LLC is not consolidated by either PNMR or PNM. The amounts outstanding under the letters of credit support constitute PNMR’s maximum exposure to loss from the VIE at December 31, 2020.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits PNMR and its subsidiaries maintain qualified defined benefit pension plans, postretirement benefit plans providing medical and dental benefits, and executive retirement programs (collectively, the “PNM Plans” and “TNMP Plans”). PNMR maintains the legal obligation for the benefits owed to participants under these plans. The periodic costs or income of the PNM Plans and TNMP Plans are included in regulated rates to the extent attributable to regulated operations. PNM and TNMP receive a regulated return on the amounts funded for pension and OPEB plans in excess of the periodic cost or income to the extent included in retail rates (a “prepaid pension asset”). Participants in the PNM Plans include eligible employees and retirees of PNMR and PNM. Participants in the TNMP Plans include eligible employees and retirees of TNMP. The PNM pension plan was frozen at the end of 1997 with regard to new participants, salary levels, and benefits. Through December 31, 2007, additional credited service could be accrued under the PNM pension plan up to a limit determined by age and service. The TNMP pension plan was frozen at December 31, 2005 with regard to new participants, salary levels, and benefits. A plan sponsor is required to (a) recognize in its statement of financial position an asset for a plan’s overfunded status or a liability for a plan’s underfunded status; (b) measure a plan’s assets and its obligations that determine its funded status as of the end of the employer’s fiscal year; and (c) recognize changes in the funded status of a defined benefit postretirement plan in the year in which the changes occur. Unrecognized prior service costs and unrecognized gains or losses are required to be recorded in AOCI and subsequently amortized. To the extent the amortization of these items will ultimately be recovered or returned through future rates, PNM and TNMP record the costs as a regulatory asset or regulatory liability. The amortization of these incurred costs is included as pension and postretirement benefit periodic cost or income in subsequent years. The Company maintains trust funds for the pension and OPEB plans from which benefits are paid to eligible employees and retirees. The Company’s funding policy is to make contributions to the trusts, as determined by an independent actuary, that comply with minimum guidelines of the Employee Retirement Income Security Act and the IRC. Information concerning the investments is contained in Note 9. The Company has in place a policy that defines the investment objectives, establishes performance goals of asset managers, and provides procedures for the manner in which investments are to be reviewed. The plans implement investment strategies to achieve the following objectives: • Implement investment strategies commensurate with the risk that the Corporate Investment Committee deems appropriate to meet the obligations of the pension plans and OPEB plans, minimize the volatility of expense, and account for contingencies • Transition asset mix over the long-term to a higher proportion of high-quality fixed income investments as the plans’ funded statuses improve Management is responsible for the determination of the asset target mix and the expected rate of return. The target asset allocations are determined based on consultations with external investment advisors. The expected long-term rate of return on pension and postretirement plan assets is calculated on the market-related value of assets. Actual gains and losses on pension and OPEB plan assets are recognized in the market-related value of assets equally over a period of not more than five years, which reduces year-to-year volatility. For the PNM Plans and TNMP Plans, the market-related value of assets is equal to the prior year’s market-related value of assets adjusted for contributions, benefit payments and investment gains and losses that are within a corridor of plus or minus 4.0% around the expected return on market value. Gains and losses that are outside the corridor are amortized over five years. In August 2018, the FASB issued Accounting Standards Update 2018-14 - Compensation Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) to improve benefit plan sponsors’ disclosures for defined benefit pension and other post-employment benefit plans. ASU 2018-14 removes the requirement to disclose the amounts in other comprehensive income expected to be recognized as benefit cost over the next fiscal year and the requirement to disclose the impact of a one-percentage-point change in the assumed heath care cost trend rate. ASU 2018-14 clarifies the disclosure requirements for plans with PBOs and ABOs that are in excess of plan assets and requires an explanation for significant gains and losses related to changes in the benefit obligation during the period be disclosed. The Company has adopted ASU 2018-14 for the period ended December 31, 2020, its required effective date by modifying the disclosures herein as appropriate. Pension Plans For defined benefit pension plans, including the executive retirement plans, the PBO represents the actuarial present value of all benefits attributed by the pension benefit formula to employee service rendered prior to that date using assumptions regarding future compensation levels. The ABO represents the PBO without considering future compensation levels. Since the pension plans are frozen, the PBO and ABO are equal. The following table presents information about the PBO, fair value of plan assets, and funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) PBO at beginning of year $ 605,745 $ 564,258 $ 65,574 $ 60,587 Service cost — — — — Interest cost 19,941 25,175 2,177 2,686 Actuarial (gain) loss 47,567 61,151 4,459 7,889 Benefits paid (42,349) (44,839) (4,820) (5,588) PBO at end of year 630,904 605,745 67,390 65,574 Fair value of plan assets at beginning of year 531,467 489,978 59,367 55,074 Actual return on plan assets 98,412 86,328 11,602 9,881 Employer contributions — — — — Benefits paid (42,349) (44,839) (4,820) (5,588) Fair value of plan assets at end of year 587,530 531,467 66,149 59,367 Funded status – asset (liability) for pension benefits $ (43,374) $ (74,278) $ (1,241) $ (6,207) Actuarial (gain) loss results from changes in: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (in thousands) Discount rates $ 44,960 $ 66,108 $ 4,756 $ 8,006 Demographic experience 2,607 (732) (54) 394 Mortality rate — (4,225) — (296) Other assumptions and experience — — (243) (215) $ 47,567 $ 61,151 $ 4,459 $ 7,889 The following table presents pre-tax information about net actuarial (gain) loss in AOCI as of December 31, 2020. PNM TNMP (In thousands) Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year $ 146,391 $ — Experience (gain) loss (21,393) 3,860 Regulatory asset (liability) adjustment 15,211 (3,860) 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 $ — The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ — $ — $ — Interest cost 19,941 25,175 24,270 Expected return on plan assets (29,453) (34,103) (34,686) Amortization of net (gain) loss 17,860 15,518 16,348 Amortization of prior service cost (554) (965) (965) Net periodic benefit cost $ 7,794 $ 5,625 $ 4,967 TNMP Service cost $ — $ — $ — Interest cost 2,177 2,686 2,625 Expected return on plan assets (3,284) (3,868) (3,963) Amortization of net (gain) loss 1,258 941 1,088 Amortization of prior service cost — — — Net periodic benefit cost (income) $ 151 $ (241) $ (250) The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost (income). Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost (income) would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 PBO 2.66 % 3.42 % 4.65 % Discount rate for determining net periodic benefit cost (income) 3.42 % 4.65 % 4.05 % Expected return on plan assets 5.90 % 6.86 % 6.54 % Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 PBO 2.69 % 3.46 % 4.63 % Discount rate for determining net periodic benefit cost (income) 3.46 % 4.63 % 4.01 % Expected return on plan assets 5.90 % 6.90 % 6.57 % Rate of compensation increase N/A N/A N/A The assumed discount rate for determining the PBO was determined based on a review of long-term high-grade bonds and management’s expectations. The expected long-term rate of return on plan assets reflects the average rate of earnings expected on the funds invested, or to be invested, to provide for the benefits included in the PBO. Factors that are considered include, but are not limited to, historic returns on plan assets, current market information on long-term returns (e.g., long-term bond rates) and current and target asset allocations between asset categories. If all other factors were to remain unchanged, a 1% decrease in the expected long-term rate of return would cause PNM’s and TNMP’s 2021 net periodic benefit cost to increase $5.2 million and $0.6 million (analogous changes would result from a 1% increase). The actual rate of return for the PNM and TNMP pension plans was 19.3% and 20.4% for the year ended December 31, 2020. The Company’s long-term pension investment strategy is to invest in assets whose interest rate sensitivity is correlated with the pension liability. The Company uses an investment strategy, known as Liability Driven Investing, that increases the liability matching investments as the funded status of the pension plans improve. The Company’s investment allocation targets consist of 35% equities, 15% alternative investments (both of which are considered return generating), and 50% liability matching securities that are primarily bonds and other fixed income investments. Equity investments are primarily in domestic securities that include large-, mid-, and small-capitalization companies. The pension plans have a 13% targeted allocation to equities of companies domiciled primarily in developed countries outside of the U.S. The equity investments category includes actively managed domestic equity securities that are benchmarked against a variety of style indices. Fixed income investments are primarily corporate bonds of companies from diversified industries and government securities. Alternative investments include investments in hedge funds, real estate funds, and private equity funds. The hedge funds and private equity funds are structured as multi-manager multi-strategy fund of funds to achieve a diversified position in these asset classes. The hedge funds pursue various absolute return strategies such as relative value, long-short equity, and event driven. Private equity fund strategies include mezzanine financing, buy-outs, and venture capital. The real estate investments are commingled real estate portfolios that invest in a diversified portfolio of assets including commercial property and multi-family housing. See Note 9 for fair value information concerning assets held by the pension plans. The following pension benefit payments are expected to be paid: PNM TNMP (In thousands) 2021 $ 46,312 $ 5,301 2022 45,583 5,193 2023 44,299 4,936 2024 43,066 4,702 2025 41,869 4,589 2026 - 2030 188,950 19,829 Based on current law, funding requirements, and estimates of portfolio performance, the Company does not expect to make any cash contributions to the pension plans in 2021 or 2022. PNM and TNMP expect to contribute $10.8 million and zero in 2023, $11.5 million and zero in 2024, and $10.6 million and zero in 2025. The funding assumptions were developed using discount a rate of 2.9%. Actual amounts to be funded in the future will be dependent on the actuarial assumptions at that time, including the appropriate discount rates. PNM and TNMP may make additional contributions at their discretion. Other Postretirement Benefit Plans For postretirement benefit plans, the APBO is the actuarial present value of all future benefits attributed under the terms of the postretirement benefit plan to employee service rendered to date. The following table presents information about the APBO, the fair value of plan assets, and the funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) APBO at beginning of year $ 75,121 $ 75,305 $ 11,235 $ 10,064 Service cost 38 53 46 50 Interest cost 2,453 3,316 373 451 Participant contributions 1,714 2,131 243 316 Actuarial (gain) loss 3,261 2,587 747 1,004 Benefits paid (7,391) (8,271) (706) (650) APBO at end of year 75,196 75,121 11,938 11,235 Fair value of plan assets at beginning of year 86,400 69,703 10,844 8,744 Actual return on plan assets 9,423 19,257 2,505 2,434 Employer contributions 3,256 3,580 — — Participant contributions 1,714 2,131 243 316 Benefits paid (7,391) (8,271) (707) (650) Fair value of plan assets at end of year 93,402 86,400 12,885 10,844 Funded status – asset (liability) $ 18,206 $ 11,279 $ 947 $ (391) As of December 31, 2020, the fair value of plan assets exceeds the APBO for both PNM’s and TNMP’s OPEB Plans and the resulting net asset is presented in other deferred charges on the Consolidated Balance Sheets. Actuarial (gain) loss results from changes in: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (in thousands) Discount rates $ 4,959 $ 7,236 $ 1,008 $ 1,375 Claims, contributions, and demographic experience (1,698) (4,022) (261) (311) Assumed participation rate — — — — Mortality rate — (627) — (60) $ 3,261 $ 2,587 $ 747 $ 1,004 In the year ended December 31, 2020, actuarial gains of $0.6 million were recorded as adjustments to regulatory assets for the PNM OPEB plan. For the TNMP OPEB plan, actuarial gains of $1.2 million were recorded as adjustments to regulatory liabilities. The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ 38 $ 53 $ 83 Interest cost 2,453 3,316 3,439 Expected return on plan assets (5,548) (5,278) (5,414) Amortization of net (gain) loss 348 675 2,354 Amortization of prior service credit — (397) (1,664) Net periodic benefit cost (income) $ (2,709) $ (1,631) $ (1,202) TNMP Service cost $ 46 $ 50 $ 134 Interest cost 373 451 477 Expected return on plan assets (538) (517) (542) Amortization of net (gain) loss (323) (444) (227) Amortization of prior service cost — — — Net periodic benefit cost (income) $ (442) $ (460) $ (158) The following significant weighted-average assumptions were used to determine the APBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the APBO and net periodic benefit cost would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 APBO 2.65 % 3.42 % 4.63 % Discount rate for determining net periodic benefit cost 3.42 % 4.63 % 4.00 % Expected return on plan assets 7.00 % 7.20 % 7.42 % Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 APBO 2.65 % 3.42 % 4.63 % Discount rate for determining net periodic benefit cost 3.42 % 4.63 % 4.00 % Expected return on plan assets 5.60 % 5.80 % 5.86 % Rate of compensation increase N/A N/A N/A The assumed discount rate for determining the APBO was determined based on a review of long-term high-grade bonds and management’s expectations. The expected long-term rate of return on plan assets reflects the average rate of earnings expected on the funds invested, or to be invested, to provide for the benefits included in the APBO. Factors that are considered include, but are not limited to, historic returns on plan assets, current market information on long-term returns (e.g., long-term bond rates), and current and target asset allocations between asset categories. If all other factors were to remain unchanged, a 1% decrease in the expected long-term rate of return would cause PNM’s and TNMP’s 2021 net periodic benefit cost to increase $0.9 million and $0.1 million (analogous changes would result from a 1% increase). The actual rate of return for the PNM and TNMP OPEB plans was 11.1% and 23.6% for the year ended December 31, 2020. The following table shows the assumed health care cost trend rates for the PNM OPEB plan: PNM December 31, 2020 2019 Health care cost trend rate assumed for next year 6.25 % 6.50 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate 2026 2026 TNMP’s exposure to cost increases in the OPEB plan is minimized by a provision that limits TNMP’s share of costs under the plan. Costs of the plan in excess of the limit, which was reached at the end of 2001, are wholly borne by the participants. As a result, a one-percentage-point change in assumed health care cost trend rates would have no effect on either the net periodic expense or the year-end APBO. Effective January 1, 2018, the PNM OPEB plan was amended to limit the annual increase in the Company’s costs to 5%. Increases in excess of the limit are born by the PNM OPEB plan participants. The Company’s OPEB plans invest in a portfolio that is diversified by asset class and style strategies. The OPEB plans generally use the same pension fixed income and equity investment managers and utilize the same overall investment strategy as described above for the pension plans, except there is no allocation to alternative investments. The OPEB plans have a target asset allocation of 30% equities and 70% fixed income. See Note 9 for fair value information concerning assets held by the other postretirement benefit plans. The following OPEB payments, which reflect expected future service and are net of participant contributions, are expected to be paid: PNM TNMP (In thousands) 2021 $ 6,455 $ 649 2022 6,132 678 2023 5,960 698 2024 5,711 709 2025 5,357 713 2026 - 2030 22,474 3,400 PNM and TNMP made no cash contributions to the OPEB trusts in 2020 or 2019 and PNM and TNMP do not expect to make cash contributions to the OPEB trusts in 2021-2025. However, a portion of the disbursements attributable to the OPEB trust are paid by PNM and are therefore considered to be contributions to the PNM OPEB plan. Payments by PNM on behalf of the PNM OPEB plan are expected to be $3.7 million in 2021 and $13.1 million in 2022-2025. Executive Retirement Programs For the executive retirement programs, the following table presents information about the PBO and funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) PBO at beginning of year $ 14,994 $ 14,726 $ 692 $ 702 Service cost — — — — Interest cost 491 651 22 30 Actuarial (gain) loss 78 1,053 58 54 Benefits paid (1,341) (1,436) (94) (94) PBO at end of year – funded status 14,222 14,994 678 692 Less current liability 1,323 1,434 91 91 Non-current liability $ 12,899 $ 13,560 $ 587 $ 601 The following table presents pre-tax information about net actuarial loss in AOCI as of December 31, 2020. December 31, 2020 PNM TNMP (In thousands) Amount in AOCI not yet recognized in net periodic benefit cost at beginning of year $ 2,395 $ — Experience (gain) loss 78 58 Regulatory asset (liability) adjustment (45) (58) Amortization recognized in net periodic benefit cost (income) (169) — Amount in AOCI not yet recognized in net periodic benefit cost at end of year $ 2,259 $ — The following table presents the components of net periodic benefit cost: Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ — $ — $ — Interest cost 491 651 622 Amortization of net (gain) loss 403 318 359 Amortization of prior service cost — — — Net periodic benefit cost $ 894 $ 969 $ 981 TNMP Service cost $ — $ — $ — Interest cost 22 30 29 Amortization of net (gain) loss 24 15 15 Amortization of prior service cost — — — Net periodic benefit cost $ 46 $ 45 $ 44 The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 PBO 2.68 % 3.44 % 4.66 % Discount rate for determining net periodic benefit cost 3.44 % 4.66 % 4.05 % Long-term rate of return on plan assets N/A N/A N/A Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 PBO 2.69 % 3.46 % 4.63 % Discount rate for determining net periodic benefit cost 3.46 % 4.63 % 4.01 % Long-term rate of return on plan assets N/A N/A N/A Rate of compensation increase N/A N/A N/A The assumed discount rate for determining the PBO was determined based on a review of long-term high-grade bonds and management’s expectations. The impacts of changes in assumptions or experience were not significant. Disbursements under the executive retirement program, funded by PNM and TNMP, which are considered to be contributions to the plan were $1.4 million and $0.1 million in the year ended December 31, 2020 and $1.4 million and $0.1 million for the year ended December 31, 2019. The following executive retirement plan payments, which reflect expected future service, are expected: PNM TNMP (In thousands) 2021 $ 1,341 $ 93 2022 1,303 90 2023 1,259 85 2024 1,210 80 2025 1,156 73 2026 - 2030 4,856 252 Other Retirement Plans PNMR sponsors a 401(k) defined contribution plan for eligible employees, including those of its subsidiaries. PNMR’s contributions to the 401(k) plan consist of a discretionary matching contribution equal to 75% of the first 6% of eligible compensation contributed by the employee on a before-tax basis. PNMR also makes a non-matching contribution ranging from 3% to 10% of eligible compensation based on the eligible employee’s age. PNMR also provides executive deferred compensation benefits through an unfunded, non-qualified plan. The purpose of this plan is to permit certain key employees of PNMR who participate in the 401(k) defined contribution plan to defer compensation and receive credits without reference to the certain limitations on contributions. A summary of expenses for these other retirement plans is as follows: Year Ended December 31, 2020 2019 2018 (In thousands) PNMR 401(k) plan $ 16,247 $ 16,097 $ 16,677 Non-qualified plan $ 2,090 $ 4,551 $ 865 PNM 401(k) plan $ 11,676 $ 11,587 $ 12,052 Non-qualified plan $ 1,544 $ 3,384 $ 621 TNMP 401(k) plan $ 4,572 $ 4,511 $ 4,625 Non-qualified plan $ 547 $ 1,167 $ 244

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation PNMR has various stock-based compensation programs, including stock options, restricted stock, and performance shares granted under the Performance Equity Plan (“PEP”). Although certain PNM and TNMP employees participate in the PNMR plans, PNM and TNMP do not have separate employee stock-based compensation plans. The Company has not awarded stock options since 2010 and all employee stock options expired or were exercised in February 2020. Certain restricted stock awards are subject to achieving performance or market targets. Other awards of restricted stock are only subject to time vesting requirements. Performance Equity Plan The PEP provides for the granting of non-qualified stock options, restricted stock rights, performance shares, performance units, and stock appreciation rights to officers, key employees, and non-employee members of the Board. Restricted stock under the PEP refers to awards of stock subject to vesting, performance, or market conditions rather than to shares with contractual post-vesting restrictions. Generally, the awards vest ratably over three years from the grant date of the award. However, awards with performance or market conditions vest upon satisfaction of those conditions. In addition, plan provisions provide that upon retirement, participants become 100% vested in certain stock awards. The vesting period for awards of restricted stock to non-employee members of the Board is one year. The total number of shares of PNMR common stock subject to all awards under the PEP, as approved by PNMR’s shareholders in May 2014, may not exceed 13.5 million shares, subject to adjustment and certain share counting rules set forth in the PEP. This current share pool is charged five shares for each share subject to restricted stock or other full value award. Source of Shares The source of shares for exercised stock options and vested restricted stock is shares acquired on the open market by an independent agent, rather than newly issued shares. Accounting for Stock Awards The stock-based compensation expense related to restricted stock awards without performance or market conditions to participants that are retirement eligible on the grant date is recognized immediately at the grant date and is not amortized. Compensation expense for other such awards is amortized to compensation expense over the shorter of the requisite vesting period or the period until the participant becomes retirement eligible. Compensation expense for performance-based shares is recognized ratably over the performance period as required service is provided and is adjusted periodically to reflect the level of achievement expected to be attained. Compensation expense related to market-based shares is recognized ratably over the measurement period, regardless of the actual level of achievement, provided the employees meet their service requirements. Total compensation expense for stock-based payment arrangements recognized by PNMR for the years ended December 31, 2020, 2019, and 2018 was $8.1 million, $6.4 million, and $7.1 million. Stock compensation expense of $5.5 million, $4.2 million, and $4.9 million was charged to PNM and $2.6 million, $2.2 million, and $2.2 million was charged to TNMP. At December 31, 2020, PNMR had unrecognized compensation expense related to stock awards of $4.0 million, which is expected to be recognized over an average of 1.52 years. PNMR receives a tax deduction for certain stock option exercises during the period the options are exercised, generally for the excess of the price at which the options are sold over the exercise prices of the options, and a tax deduction for the value of restricted stock at the vesting date. All excess tax benefits and deficiencies are recorded to tax expense and classified as operating cash flows when used to reduce taxes payable. Year Ended December 31, Excess Tax Benefits 2020 2019 2018 (In thousands) PNM $ 279 $ 559 $ 1,007 TNMP 112 236 377 PNMR 391 795 1,384 TNMP used excess tax benefits to reduce income taxes payable and the benefit was reflected in cash flows from operating activities. The benefit of excess tax benefits at PNM and PNMR will be reflected in operating cash flows when they reduce income taxes payable. The grant date fair value for restricted stock and stock awards with Company internal performance targets is determined based on the market price of PNMR common stock on the date of the agreements reduced by the present value of future dividends that will not be received prior to vesting. The grant date fair value is applied to the total number of shares that are anticipated to vest, although the number of performance shares that ultimately vest cannot be determined until after the performance periods end. The grant date fair value of stock awards with market targets is determined using Monte Carlo simulation models, which provide grant date fair values that include an expectation of the number of shares to vest at the end of the measurement period. The following table summarizes the weighted-average assumptions used to determine the awards grant date fair value: Year Ended December 31, Restricted Shares and Performance-Based Shares 2020 2019 2018 Expected quarterly dividends per share $ 0.3075 $ 0.2900 $ 0.2650 Risk-free interest rate 0.72 % 2.47 % 2.38 % Market-Based Shares Dividend yield 2.51 % 2.59 % 2.96 % Expected volatility 19.41 % 19.55 % 19.12 % Risk-free interest rate 0.72 % 2.51 % 2.36 % The following table summarizes activity in restricted stock awards, including performance-based and market-based shares, and stock options: Restricted Stock Stock Options Shares Weighted-Average Grant Date Fair Value Shares Weighted Outstanding at December 31, 2019 161,542 $ 38.21 2,000 $ 12.22 Granted 246,029 36.73 — — Exercised (238,054) 34.86 (2,000) 12.22 Forfeited (1,456) 41.32 — — Outstanding at December 31, 2020 168,061 $ 40.77 — $ — PNMR’s current stock-based compensation program provides for performance and market targets through 2022. In February 2019, the Board approved amendments to exclude certain impacts of the Tax Act on performance metrics for the performance periods ending in 2018 and 2019. These amendments did not impact the Company’s calculation of grant date fair values under the plans but did increase actual achievement levels for the performance period ending in 2018 from below “threshold” levels to below “target” levels and anticipated achievement levels for the performance period ending in 2019 from below “target” levels to the “maximum” levels. As a result of these amendments for the year ended December 31, 2018, the Company recorded additional pre-tax expense of $1.0 million, of which $0.7 million was allocated to PNM and $0.3 million was allocated to TNMP. Included as granted and exercised in the table above are 47,279 previously awarded shares that were earned for the 2016 - 2018 performance measurement period and ratified by the Board in February 2019 (based upon achieving market targets at below “threshold” levels, weighted at 40%, and performance targets at above “target” levels, together weighted at 60%). Excluded from the above table are 122,277 previously awarded shares that were earned for the 2017 - 2019 performance measurement period and ratified by the Board in February 2020 (based upon achieving market and performance targets at near “maximum” levels). Also excluded from the table above are 150,543 and 142,080 shares for the three-year performance periods ending in 2020 and 2021 that will be awarded if all performance and market criteria are achieved at maximum levels and all executives remain eligible. Effective as of January 1, 2015, the Company entered into a retention award agreement with its then Executive Vice President and Chief Financial Officer under which he would receive awards of restricted stock if PNMR met specified performance targets at the end of 2016 and 2017 and he remained an employee of the Company. The retention award was made under the PEP and was approved by the Board on December 9, 2014. The specified performance target was achieved at the end of 2016 and the Board ratified him receiving $100,000 of PNMR common stock in February 2017 based on a market per share value of $36.30 on the grant date of March 3, 2017, or 2,754 shares. Similarly, if PNMR achieved the specified performance target for the period from January 1, 2015 through December 31, 2017, he was to receive $275,000 of PNMR common stock based on the market value per share on the grant date in early 2018. The specified performance target was achieved at the end of 2017 and the Board ratified him receiving $275,000 of PNMR common stock in February 2018 based on a market value per share of $35.85 on the grant date of March 2, 2018, or 7,670 shares. In 2015, the Company entered into an additional retention award agreement with its Chairman, President, and Chief Executive Officer under which she would receive a total 53,859 shares of PNMR’s common stock if PNMR meets certain performance targets at the end of 2017 and 2019 and she remains an employee of the Company. The retention award was made under the PEP and was approved by the Board on February 26, 2015. The specified performance target was achieved at the end of 2017 and the Board ratified her receiving 17,953 shares in February 2018. The second portion of the 2015 agreement of 35,906 shares was achieved at the end of 2019 and the Board ratified her receiving the shares in February 2020. The above table does not include any restricted stock shares that remain unvested under this retention award agreement. At December 31, 2019, the aggregate intrinsic value of stock options outstanding, all of which were exercisable, was less than $0.1 million. All the options were exercised or expired in February 2020. The following table provides additional information concerning restricted stock activity, including performance-based and market-based shares, and stock options: Year Ended December 31, Restricted Stock 2020 2019 2018 Weighted-average grant date fair value $ 36.73 $ 37.92 $ 29.65 Total fair value of restricted shares that vested (in thousands) $ 8,299 $ 6,246 $ 8,558 Stock Options Total intrinsic value of options exercised (in thousands) $ 84 $ 2,617 $ 3,117

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The operations of PNM and TNMP are regulated by the NMPRC, PUCT, and FERC and the provisions of GAAP for rate-regulated enterprises are applied to its regulated operations. Regulatory assets represent probable future recovery of previously incurred costs that will be collected from customers through the ratemaking process. Regulatory liabilities represent probable future reductions in revenues associated with amounts that are to be credited to customers through the ratemaking process. Regulatory assets and liabilities reflected in the Consolidated Balance Sheets are presented below. PNM TNMP December 31, December 31, 2020 2019 2020 2019 Assets: (In thousands) Current: FPPAC $ — $ 7,373 $ — $ — Energy efficiency costs — — 202 — — 7,373 202 — Non-Current: CTC, including carrying charges — — 324 7,412 Coal mine reclamation costs (3) 9,980 13,995 — — Deferred income taxes 65,564 66,296 9,817 8,997 Loss on reacquired debt 19,748 19,426 28,914 30,212 Pension and OPEB (1) 190,147 214,771 22,863 27,947 Shutdown of SJGS Units 2 and 3 107,231 113,508 — — Hurricane recovery costs (2) — — 480 1,041 AMS surcharge — — 18,761 25,015 AMS retirement and other costs — — 13,915 15,542 Renewable energy costs — 643 — — Deferred cost under the ETA 42,703 — — — Deferred COVID-19 costs 8,761 — 676 — SJGS replacement resources 8,282 — — — Other 5,537 6,828 4,087 5,297 457,953 435,467 99,837 121,463 Total regulatory assets $ 457,953 $ 442,840 $ 100,039 $ 121,463 PNM TNMP December 31, December 31, 2020 2019 2020 2019 Liabilities: Current: FPPAC $ (2,274) $ — $ — $ — Renewable energy rider (2,044) — — — Other (1,101) (371) (2,052) (134) (5,419) (371) (2,052) (134) Non-Current: Cost of removal (284,695) (271,025) (59,613) (46,091) Deferred income taxes (343,844) (374,122) (119,695) (131,871) PVNGS ARO (5,394) (11,341) — — Renewable energy tax benefits (17,912) (19,069) — — Accelerated depreciation SNCRs (4) (12,045) (7,758) — — Pension and OPEB — — (5,535) (4,775) COVID-19 cost savings (900) — — — Other (83) (83) (512) (108) (664,873) (683,398) (185,355) (182,845) Total regulatory liabilities $ (670,292) $ (683,769) $ (187,407) $ (182,979) (1) Includes $1.6 million for certain PNM pension costs as described in Note 11 (2) Amount shown is net of amounts owed under the PUCT’s January 25, 2018 order as described in Note 17 (3) Includes $9.3 million in coal mine reclamation costs related to PNM’s planned retirement of SJGS in 2022 and recoverable under the ETA as described in Note 16 (4) Amounts to be refunded under the ETA The Company’s regulatory assets and regulatory liabilities are reflected in rates charged to customers or have been addressed in a regulatory proceeding. The Company does not receive or pay a rate of return on the following regulatory assets and regulatory liabilities (and their remaining amortization periods): coal mine reclamation costs (through 2020); deferred income taxes (over the remaining life of the taxable item, up to the remaining life of utility plant); pension and OPEB costs (through 2033); PVNGS ARO (to be determined in a future regulatory proceeding); costs recoverable under the ETA (over the securitization period); deferred COVID-19 costs (to be determined in a future regulatory proceeding); and SJGS replacement resources (to be determined in a future regulatory proceeding). The Company is permitted, under rate regulation, to accrue and record a regulatory liability for the estimated cost of removal and salvage associated with certain of its assets through depreciation expense. Actuarial losses and prior service costs for pension plans are required to be recorded in AOCI; however, to the extent authorized for recovery through the regulatory process these amounts are recorded as regulatory assets or liabilities. Based on prior regulatory approvals, the amortization of these amounts will be included in the Company’s rates. Based on a current evaluation of the various factors and conditions that are expected to impact future cost recovery, the Company believes that future recovery of its regulatory assets is probable.

Construction Program and Jointl

Construction Program and Jointly-Owned Electric Generating Plants	12 Months Ended
	Dec. 31, 2020
Construction Program and Jointly-Owned Electric Generating Plants [Abstract]
Construction Program and Jointly-Owned Electric Generating Plants	Construction Program and Jointly-Owned Electric Generating Plants PNM is a participant in several jointly-owned power plant projects. The primary operating or participation agreements for the joint projects expire in July 2022 for SJGS, July 2041 for Four Corners, December 2046 for Luna, and November 2047 for PVNGS. PNM’s expenditures for additions to utility plant were $335.1 million in 2020, including expenditures on jointly-owned projects. TNMP does not participate in the ownership or operation of any generating plants, but incurred expenditures for additions to utility plant of $321.5 million during 2020. On a consolidated basis, PNMR’s expenditures for additions to utility plant were $679.0 million in 2020. Joint Projects Under the agreements for the jointly-owned projects, PNM has an undivided interest in each asset and liability of the project and records its pro-rata share of each item in the corresponding asset and liability account on PNM’s Consolidated Balance Sheets. Likewise, PNM records its pro-rata share of each item of operating and maintenance expenses for its jointly-owned plants within the corresponding operating expense account in its Consolidated Statements of Earnings. PNM is responsible for financing its share of the capital and operating costs of the joint projects. At December 31, 2020, PNM’s interests and investments in jointly-owned generating facilities are: Station (Fuel Type) Plant in Accumulated Depreciation (1) Construction Composite (In thousands) SJGS (Coal) $ 780,544 $ (448,213) $ 659 66.35 % PVNGS (Nuclear) (2) $ 828,191 $ (387,436) $ 37,235 10.20 % Four Corners Units 4 and 5 (Coal) $ 301,867 $ (100,187) $ 7,820 13.00 % Luna (Gas) $ 76,917 $ (29,758) $ 57 33.33 % (1) Includes cost of removal. (2) Includes interest in PVNGS Unit 3, interest in common facilities for all PVNGS units, and owned interests in PVNGS Units 1 and 2, including improvements. San Juan Generating Station PNM operates and jointly owns SJGS. Effective January 1, 2018, SJGS Unit 1 is owned 50% by PNM and 50% by Tucson and SJGS Unit 4 is owned 77.297% by PNM, including a 12.8% interest held as merchant plant, 8.475% by Farmington, 7.2% by Los Alamos, and 7.028% by UAMPS. See Notes 16 and 17 for additional information about SJGS, including the shutdown of SJGS Units 2 and 3 in December 2017 and the restructuring of SJGS ownership as well as information on PNM’s SJGS Abandonment Application. Palo Verde Nuclear Generating Station PNM is a participant in the three units of PVNGS with APS (the operating agent), SRP, EPE, SCE, SCPPA, and The Department of Water and Power of the City of Los Angeles. PNM has a 10.2% undivided interest in PVNGS, with portions of its interests in Units 1 and 2 held under leases. See Note 8 for additional information concerning the PVNGS leases, including PNM’s purchase of the assets underlying certain of the leases in January 2016, PNM’s option to purchase or return certain lease interests that have been extended through 2023 and 2024, and Note 17 for the outcome of PNM’s appeal to the NM Supreme Court regarding the NMPRC’s treatment of those purchases and lease extensions in the NM 2015 Rate Case. Operation of each of the three PVNGS units requires an operating license from the NRC. The NRC issued full power operating licenses for Unit 1 in June 1985, Unit 2 in April 1986, and Unit 3 in November 1987. The full power operating licenses were originally for a period of 40 years and authorize APS, as operating agent for PVNGS, to operate the three PVNGS units. In April 2011, the NRC approved extensions in the operating licenses for the plants for 20 years through June 2045 for Unit 1, April 2046 for Unit 2, and November 2047 for Unit 3. Four Corners Power Plant PNM is a participant in two units of Four Corners with APS (the operating agent), an affiliate of APS, SRP, and Tucson. PNM has a 13.0% undivided interest in Units 4 and 5 of Four Corners. The Four Corners plant site is located on land within the Navajo Nation and is subject to an easement from the federal government. APS, on behalf of the Four Corners participants, negotiated amendments to an existing agreement with the Navajo Nation, which extends the owners’ right to operate the plant on the site to July 2041. See Note 16 and 17 for additional information about Four Corners. Luna Energy Facility Luna is a combined-cycle power plant near Deming, New Mexico. Luna is owned equally by PNM, Tucson, and Samchully Power & Utilities 1, LLC. The operation and maintenance of the facility has been contracted to North American Energy Services. Construction Program The Company anticipates making substantial capital expenditures for the construction and acquisition of utility plant and other property and equipment. An unaudited summary of the budgeted construction expenditures, including expenditures for jointly-owned projects, and nuclear fuel, is as follows: 2021 2022 2023 2024 2025 Total (In millions) PNM $ 661.9 $ 396.6 $ 382.0 $ 388.5 $ 379.9 $ 2,208.9 TNMP 320.1 342.0 348.0 298.0 299.0 1,607.1 Corporate and Other 34.5 26.5 31.2 26.5 26.5 145.2 Total PNMR $ 1,016.5 $ 765.1 $ 761.2 $ 713.0 $ 705.4 $ 3,961.2

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations AROs are recorded based on studies to estimate the amount and timing of future ARO expenditures and reflect underlying assumptions, such as discount rates, estimates of the future costs for decommissioning, and the timing of the removal activities to be performed. Approximately 76% of PNM’s total ARO liabilities are related to nuclear decommissioning of PVNGS. PNM is responsible for all decommissioning obligations related to its entire interest in PVNGS, including portions under lease both during and after termination of the leases. Studies of the decommissioning costs of PVNGS, SJGS, Four Corners, and other facilities are performed periodically and revisions to the ARO liabilities are recorded. Changes in the assumptions underlying the calculations may also require revisions to the estimated AROs when identified. A reconciliation of the ARO liabilities is as follows: PNMR PNM TNMP (In thousands) Liability at December 31, 2017 $ 146,679 $ 145,707 $ 793 Liabilities incurred — — — Liabilities settled (192) — — Accretion expense 11,482 11,402 67 Revisions to estimated cash flows 705 705 — Liability at December 31, 2018 158,674 157,814 860 Liabilities incurred — — — Liabilities settled (987) (935) (52) Accretion expense 12,635 12,562 73 Revisions to estimated cash flows (1) 11,640 11,640 — Liability at December 31, 2019 181,962 181,081 881 Liabilities incurred — — — Liabilities settled (1,444) (1,192) (252) Accretion expense 11,310 11,235 75 Revisions to estimated cash flows (2) (8,407) (8,407) — Liability at December 31, 2020 $ 183,421 $ 182,717 $ 704 (1) Reflects the impacts of an updated SJGS decommissioning study that assumes PNM will retire its share of SJGS in 2022. (2)

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Overview There are various claims and lawsuits pending against the Company. In addition, the Company is subject to federal, state, and local environmental laws and regulations and periodically participates in the investigation and remediation of various sites. In addition, the Company periodically enters into financial commitments in connection with its business operations. Also, the Company is involved in various legal and regulatory proceedings in the normal course of its business. See Note 17. It is not possible at this time for the Company to determine fully the effect of all litigation and other legal and regulatory proceedings on its financial position, results of operations, or cash flows. With respect to some of the items listed below, the Company has determined that a loss is not probable or that, to the extent probable, cannot be reasonably estimated. In some cases, the Company is not able to predict with any degree of certainty the range of possible loss that could be incurred. The Company assesses legal and regulatory matters based on current information and makes judgments concerning their potential outcome, giving due consideration to the nature of the claim, the amount and nature of any damages sought, and the probability of success. Such judgments are made with the understanding that the outcome of any litigation, investigation, or other legal proceeding is inherently uncertain. The Company records liabilities for matters where it is probable a loss has been incurred and the amount of loss is reasonably estimable. The actual outcomes of the items listed below could ultimately differ from the judgments made and the differences could be material. The Company cannot make any assurances that the amount of reserves or potential insurance coverage will be sufficient to cover the cash obligations that might be incurred as a result of litigation or regulatory proceedings. Except as otherwise disclosed, the Company does not expect that any known lawsuits, environmental costs, and commitments will have a material effect on its financial condition, results of operations, or cash flows. Commitments and Contingencies Related to the Environment PVNGS Decommissioning Funding The costs of decommissioning a nuclear power plant are substantial. PNM is responsible for all decommissioning obligations related to its entire interest in PVNGS, including portions under lease both during and after termination of the leases. PNM has a program for funding its share of decommissioning costs for PVNGS, including portions held under leases. The nuclear decommissioning funding program is invested in equities and fixed income instruments in qualified and non-qualified trusts. PNM funded $1.3 million for each of the years ended December 31, 2020, 2019, and 2018 into the qualified trust funds. The market value of the trusts at December 31, 2020 and 2019 was $379.2 million and $336.0 million. See Note 17 for additional discussion of the NM Supreme Court’s decisions in PNM’s appeal of the NMPRC’s decisions in the NM 2015 Rate Case. Nuclear Spent Fuel and Waste Disposal Nuclear power plant operators are required to enter into spent fuel disposal contracts with the DOE that require the DOE to accept and dispose of all spent nuclear fuel and other high-level radioactive wastes generated by domestic power reactors. Although the Nuclear Waste Policy Act required the DOE to develop a permanent repository for the storage and disposal of spent nuclear fuel by 1998, the DOE announced that it would not be able to open the repository by 1998 and sought to excuse its performance of these requirements. In November 1997, the DC Circuit issued a decision preventing the DOE from excusing its own delay but refused to order the DOE to begin accepting spent nuclear fuel. Based on this decision and the DOE’s delay, a number of utilities, including APS (on behalf of itself and the other PVNGS owners, including PNM), filed damages actions against the DOE in the Court of Federal Claims. The lawsuits filed by APS alleged that damages were incurred due to DOE’s continuing failure to remove spent nuclear fuel and high-level waste from PVNGS. In August 2014, APS and the DOE entered into a settlement agreement that establishes a process for the payment of claims for costs incurred through December 31, 2019. In July 2020, APS accepted the DOE’s extension of the settlement agreement for recovery of costs incurred through December 31, 2022. Under the settlement agreement, APS must submit claims annually for payment of allowable costs. PNM records estimated claims on a quarterly basis. The benefit from the claims is passed through to customers under the FPPAC to the extent applicable to NMPRC regulated operations. PNM estimates that it will incur approximately $59.6 million (in 2019 dollars) for its share of the costs related to the on-site interim storage of spent nuclear fuel at PVNGS during the term of the operating licenses. PNM accrues these costs as a component of fuel expense as the nuclear fuel is consumed. At December 31, 2020 and 2019, PNM had a liability for interim storage costs of $12.8 million and $12.7 million, which is included in other deferred credits. PVNGS has sufficient capacity at its on-site Independent Spent Fuel Storage Installation (“ISFSI”) to store all of the nuclear fuel that will be irradiated during the initial operating license period, which ends in December 2027. Additionally, PVNGS has sufficient capacity at its on-site ISFSI to store a portion of the fuel that will be irradiated during the period of extended operation, which ends in November 2047. If uncertainties regarding the U.S. government’s obligation to accept and store spent fuel are not favorably resolved, APS will evaluate alternative storage solutions that may obviate the need to expand the ISFSI to accommodate all of the fuel that will be irradiated during the period of extended operation. The Energy Transition Act On March 22, 2019, the Governor signed into New Mexico state law Senate Bill 489, known as the Energy Transition Act (“ETA”). The ETA became effective as of June 14, 2019 and sets a statewide standard that requires investor-owned electric utilities to have specified percentages of their electric-generating portfolios be from renewable and zero-carbon generating resources. The ETA amends the REA and requires utilities operating in New Mexico to have renewable portfolios equal to 20% by 2020, 40% by 2025, 50% by 2030, 80% by 2040, and 100% zero-carbon energy by 2045. The ETA also amends sections of the REA to allow for the recovery of undepreciated investments and decommissioning costs related to qualifying EGUs that the NMPRC has required be removed from retail jurisdictional rates, provided replacement resources to be included in retail rates have lower or zero-carbon emissions. The ETA requires the NMPRC to review and approve utilities’ annual renewable portfolio plans to ensure compliance with the RPS. The ETA also directs the New Mexico Environmental Improvement Board to adopt standards of performance that limit CO 2 emissions to no more than 1,100 lbs. per MWh beginning January 1, 2023 for new or existing coal-fired EGUs with original installed capacities exceeding 300 MW. The ETA provides for a transition from fossil-fuel generation resources to renewable and other carbon-free resources through certain provisions relating to the abandonment of coal-fired generating facilities. These provisions include the use of energy transition bonds, which are designed to be highly rated bonds that can be issued to finance certain costs of abandoning coal-fired facilities that are retired prior to January 1, 2023 for facilities operated by a “qualifying utility,” or prior to January 1, 2032 for facilities that are not operated by the qualifying utility. The amount of energy transition bonds that can be issued to recover abandonment costs is limited to the lesser of $375.0 million or 150% of the undepreciated investment of the facility as of the abandonment date. Proceeds provided by energy transition bonds must be used only for purposes related to providing utility service to customers and to pay energy transition costs (as defined by the ETA). These costs may include plant decommissioning and coal mine reclamation costs provided those costs have not previously been recovered from customers or disallowed by the NMPRC or by a court order. See Note 17 for a discussion of the NM Supreme Court’s decision to affirm the NMPRC’s disallowance of certain costs, including the cost of BDT at SJGS, in PNM’s NM 2015 Rate Case. Proceeds from energy transition bonds may also be used to fund severances for employees of the retired facility and related coal mine and to promote economic development, education and job training in areas impacted by the retirement of the coal-fired facilities. Energy transition bonds must be issued under a NMPRC approved financing order, are secured by “energy transition property,” are non-recourse to the issuing utility, and must be repaid by a non-bypassable charge paid by all customers of the issuing utility. These customer charges are subject to an adjustment mechanism designed to provide for timely and complete payment of principal and interest due under the energy transition bonds. The ETA also provides that utilities must obtain NMPRC approval of competitively procured replacement resources that shall be evaluated based on their cost, economic development opportunity, ability to provide jobs with comparable pay and benefits to those lost upon retirement of the facility, and that do not exceed emissions thresholds specified in the ETA. In determining whether to approve replacement resources, the NMPRC must give preference to resources with the least environmental impacts, those with higher ratios of capital costs to fuel costs, and those located in the school district of the abandoned facility. The ETA also provides for the procurement of energy storage facilities and gives utilities discretion to maintain, control, and operate these systems to ensure reliable and efficient service. PNM expects the ETA will have a significant impact on PNM’s future generation portfolio, including PNM’s planned retirements of SJGS in 2022 and the planned Four Corners exit in 2024. PNM cannot predict the full impact of the ETA or the outcome of its pending and potential future generating resource abandonment and replacement resource filings with the NMPRC. See additional discussion in Note 17 of PNM’s SJGS and Four Corners Abandonment Applications. The Clean Air Act Regional Haze In 1999, EPA developed a regional haze program and regional haze rules under the CAA. The rule directs each of the 50 states to address regional haze. Pursuant to the CAA, states are required to establish goals for improving visibility in national parks and wilderness areas (also known as Class I areas) and to develop long-term strategies for reducing emissions of air pollutants that cause visibility impairment in their own states and for preventing degradation in other states. States must establish a series of interim goals to ensure continued progress by adopting a new SIP every ten years. In the first SIP planning period, states were required to conduct BART determinations for certain covered facilities, including utility boilers, built between 1962 and 1977 that have the potential to emit more than 250 tons per year of visibility impairing pollution. If it was demonstrated that the emissions from these sources caused or contributed to visibility impairment in any Class I area, BART must have been installed by the beginning of 2018. For all future SIP planning periods, states must evaluate whether additional emissions reduction measures may be needed to continue making reasonable progress toward natural visibility conditions. In 2017, EPA published in the Federal Register revisions to the regional haze rule. EPA also provided a companion draft guidance document for public comment. The new rule delayed the due date for the next cycle of SIPs from 2019 to 2021, altered the planning process that states must employ in determining whether to impose “reasonable progress” emission reduction measures, and gave new authority to federal land managers to seek additional emission reduction measures outside of the states’ planning process. Finally, the rule made several procedural changes to the regional haze program, including changes to the schedule and process for states to file 5-year progress reports. EPA’s new rule was challenged by numerous parties. On January 19, 2018, EPA filed a motion to hold the case in abeyance in light of several letters issued by EPA on January 17, 2018 to grant various petitions for reconsideration of the 2017 rule revisions. EPA’s decision to revisit the 2017 rule is not a determination on the merits of the issues raised in the petitions. On December 20, 2018, EPA released a new guidance document on tracking visibility progress for the second planning period. EPA is allowing states discretion to develop SIPs that may differ from EPA’s guidance as long as they are consistent with the CAA and other applicable regulations. On August 20, 2019, EPA finalized the draft guidance that was released in 2016 as a companion to the regional haze rule revisions. The final guidance differs from the draft in several ways, but is likely to be reconsidered by the Biden Administration. SIPs for the second planning period are due in July 2021. NMED is currently preparing its SIP for the second compliance period and has notified PNM that it will not be required to submit a regional haze four-factor analysis for SJGS since PNM will retire its share of SJGS in 2022. PNM cannot predict the outcome of these matters with respect to Four Corners. SJGS December 2018 Compliance Filing – In December 2015 PNM received NMPRC approval for a plan to comply with EPA’s regional haze rule at SJGS. Among other things, the NMPRC’s December 2015 order required that, no later than December 31, 2018, PNM make a filing with the NMPRC to determine the extent to which SJGS should continue serving PNM’s customers’ needs after June 30, 2022 (the “December 2018 Compliance Filing”). The December 2018 Compliance Filing was required to be made before PNM entered into a binding commitment for post-2022 coal supply but after PNM received firm pricing and other terms for the supply of coal at SJGS, unless PNM did not intend to pursue an agreement for post-2022 coal supply at SJGS. The NMPRC’s December 2015 order also indicated that, if SJGS Unit 4 is abandoned with undepreciated investment on PNM’s books, PNM is prohibited from recovering the undepreciated investment of its 132 MW interest and required that PNM’s 65 MW interest in SJGS Unit 4 be treated as excluded merchant plant. PNM submitted the December 2018 Compliance Filing to the NMPRC on December 31, 2018 indicating that, consistent with the conclusions reached in PNM’s 2017 IRP, PNM’s customers would benefit from the retirement of PNM’s share of SJGS after the current SJGS CSA expires in mid-2022. The December 2018 Compliance Filing also indicated that, pursuant to the terms of the agreements governing SJGS, all of the SJGS owners except for Farmington provided written notice that they do not intend to extend the SJGS operating agreements beyond their June 30, 2022 expiration dates, and that PNM has provided written notice to the San Juan mine operator that PNM does not intend to extend the SJGS CSA beyond June 30, 2022. On January 30, 2019, the NMPRC issued an order initiating a proceeding and requiring PNM to submit an application for the abandonment of PNM’s share of SJGS by March 1, 2019. On February 27, 2019, PNM filed a petition with the NM Supreme Court stating that the requirements of the January 30, 2019 order exceed the NMPRC’s authority by, among other things, mandating PNM to make a filing that is legally voluntary, and that the order is contrary to NMPRC precedent which requires abandonment applications to also include identified replacement resources and other information that would not be available to PNM by March 1, 2019. On March 1, 2019, the NM Supreme Court granted a temporary stay of the NMPRC’s order. Various parties intervened in the petition. On June 26, 2019, and after the effective date of the ETA, the NM Supreme Court lifted the stay and denied PNM’s petition without discussion. On July 1, 2019, PNM filed its SJGS Abandonment Application. See Note 17. Long-lived assets are required to be tested for impairment when events or changes in circumstances indicate that their carrying value may not be recoverable. As of December 31, 2018, PNM evaluated the events surrounding its future participation in SJGS and determined that it was more likely than not that PNM’s share of SJGS will be retired in 2022. As a result, PNM performed an impairment analysis that assumed SJGS would not continue to operate through 2053, as previously approved by the NMPRC. PNM’s impairment analysis indicated that PNM’s undepreciated 132 MW interest in SJGS Unit 4 at June 30, 2022 will not be recovered from customers; that the estimated future cash flows expected to result from the operation of SJGS Unit 4 through June 30, 2022 are not sufficient to provide for recovery of PNM’s 65 MW merchant interest in the facility; and that it is unlikely PNM will be able to sell or transfer its interests in SJGS to third parties at amounts sufficient to provide for their recovery. As a result, as of December 31, 2018, PNM recorded a pre-tax impairment of its investment in SJGS of approximately $35.0 million, which is reflected as regulatory disallowances and restructuring costs on the Consolidated Statements of Earnings. This amount includes the entire $11.9 million carrying value of PNM’s 65 MW interest in SJGS Unit 4 as of December 31, 2018 and $23.1 million of estimated undepreciated investments in PNM’s 132 MW jurisdictional interest as of June 30, 2022 that will not be recovered from customers. See additional discussion below regarding the increase in PNM’s estimated liability for coal mine reclamation. NEE Complaint – On March 31, 2016, NEE filed a complaint with the NMPRC alleging that PNM failed to comply with its discovery obligation in the case authorizing the shutdown of SJGS Units 2 and 3 and requesting the NMPRC investigate whether financing provided by NM Capital to the former owner of SJCC (the “Westmoreland Loan”) could adversely affect PNM’s ability to provide electric service to its retail customers. On January 31, 2018, NEE filed a motion asking the NMPRC to investigate whether PNM’s relationship with the former owner of SJCC could be harmful to PNM’s customers. On May 23, 2018, PNM filed its response to the NMPRC staff’s comments noting that the Westmoreland Loan was paid in full on May 22, 2018. On October 11, 2018, PNM notified the NMPRC that the former owner of SJCC, Westmoreland, had filed voluntary petitions for relief under Chapter 11 of the U.S. Bankruptcy Code. As discussed in Note 10, on March 15, 2019, Westmoreland announced that it had emerged from Chapter 11 bankruptcy as a privately held company owned and operated by a group of its former creditors. Under the reorganization, all the assets of SJCC were sold to WSJ LLC. As successor entity to SJCC, WSJ LLC assumed all rights and obligations of Westmoreland including obligations to PNM under the SJGS CSA. The NMPRC has taken no further action on NEE’s complaint. PNM is not able to predict the potential outcome of this matter but does not anticipate the NMPRC will take any further action. Four Corners On August 6, 2012, EPA issued its Four Corners FIP with a final BART determination for Four Corners. The rule included two compliance alternatives. On December 30, 2013, APS notified EPA that the Four Corners participants selected the alternative that required APS to permanently close Units 1, 2, and 3 by January 1, 2014 and install SCR post-combustion NOx control technology on each of Units 4 and 5 by July 31, 2018. Installation of SCRs on Four Corners Unit 5 was completed in March 2018 and the installation on Unit 4 was completed in June 2018. PNM owns a 13% interest in Units 4 and 5, but had no ownership interest in Units 1, 2, and 3, which were shut down by APS on December 30, 2013. For particulate matter emissions, EPA is requiring Units 4 and 5 to meet an emission limit of 0.015 lbs./MMBTU and the plant to meet a 20% opacity limit, both of which are achievable through operation of the existing baghouses. Although unrelated to BART, the final BART rule also imposes a 20% opacity limitation on certain fugitive dust emissions from Four Corners’ coal and material handling operations. PNM share of costs for post-combustion controls at Four Corners Units 4 and 5 through December 31, 2018 was $88.7 million, including PNM’s AFUDC. See Note 17 for information on the NMPRC’s treatment of these costs in PNM’s NM 2016 Rate Case and the Four Corners Abandonment Application. Four Corners Federal Agency Lawsuit – On April 20, 2016, several environmental groups filed a lawsuit against OSM and other federal agencies in the U.S. District Court for the District of Arizona in connection with their issuance of the approvals that extended the life of Four Corners and the adjacent mine. The lawsuit alleges that these federal agencies violated both the ESA and NEPA in providing the federal approvals necessary to extend operations at Four Corners and the adjacent mine past July 6, 2016. The court granted an APS motion to intervene in the litigation. NTEC, the current owner of the mine providing coal to Four Corners, filed a motion to intervene for the limited purpose of seeking dismissal of the lawsuit based on NTEC’s tribal sovereign immunity. The court granted NTEC’s motion and dismissed the case with prejudice, terminating the proceedings. In November 2017, the environmental group plaintiffs filed a Notice of Appeal of the dismissal in the U.S. Court of Appeals for the Ninth Circuit, and the court granted their subsequent motion to expedite the appeal. The Ninth Circuit issued a decision affirming the District Court’s dismissal of the case. In September 2019, the environmental groups filed a motion for reconsideration, which was denied in December 2019. On March 24, 2020, the environmental groups filed a petition for writ of certiorari in the U.S. Supreme Court seeking review of the Ninth Circuit’s decision. The U.S. Supreme Court denied the petition on June 29, 2020, making the decision of the Ninth Circuit to affirm the District Courts dismissal of the case final. This matter is now complete. Carbon Dioxide Emissions On August 3, 2015, EPA established standards to limit CO 2 emissions from power plants. EPA took three separate but related actions in which it: (1) established the Carbon Pollution Standards for new, modified, and reconstructed power plants; (2) established the Clean Power Plan to set standards for carbon emission reductions from existing power plants; and (3) released a proposed federal plan associated with the final Clean Power Plan. The Clean Power Plan was published on October 23, 2015. Multiple states, utilities, and trade groups filed petitions for review in the DC Circuit to challenge both the Carbon Pollution Standards for new sources and the Clean Power Plan for existing sources and challengers successfully petitioned the US Supreme Court for a stay of the Clean Power Plan. However, before the DC Circuit could issue an opinion regarding either the Carbon Pollution Standards or the Clean Power Plan, the Trump Administration asked that the case be held in abeyance while the rule was being re-evaluated, which was granted. On June 19, 2019, EPA repealed the Clean Power Plan; promulgated the ACE Rule; and revised the implementing regulations for all emission guidelines. EPA set the Best System of Emissions Reduction (“BSER”) for existing coal-fired power plants as heat rate efficiency improvements based on a range of “candidate technologies” that can be applied inside the fence-line. Rather than setting a specific numerical standard of performance, EPA’s rule directed states to determine which of the candidate technologies to apply to each coal-fired unit and establish standards of performance based on the degree of emission reduction achievable based on the application of BSER. On September 17, 2019, the DC Circuit issued an order that granted motions by various petitioners, including industry groups and EPA, to dismiss the cases challenging the Clean Power Plan as moot due to EPA’s issuance of the ACE Rule. However, on January 19, 2021, the U.S. Court of Appeals for the District of Columbia Circuit issued an opinion in American Lung Association and American Public Health Association v. EPA, et al. regarding challenges to the ACE Rule. The D.C. Circuit vacated the ACE Rule and remanded the record back to the EPA for further consideration consistent with its opinion, finding that EPA misinterpreted the CAA when it determined that the language of section 111 unambiguously barred consideration of emissions reductions options that were not applied at the source. Unless the court issues a stay of its mandate, the mandate for its decision will issue in March 2021 after the deadline passes for petitions for rehearing or rehearing en banc, although an appeal via petitions for certiorari to the US Supreme Court will remain available until June 2021. EPA has filed a motions seeking a partial stay of the mandate as to the repeal of the Clean Power Plan, to ensure the court’s order will not render effective the now out-of-date Clean Power Plan, but the court has not yet acted on that motion. The litigation over the Carbon Pollution Standards remains held in abeyance but could be reactivated by the parties upon a determination by the court that the Biden Administration is unlikely to finalize the revisions proposed in 2018 and that reconsideration of the rule has concluded. While corresponding NSR reform regulations were proposed as part of the proposed ACE Rule, the final rule did not include such reform measures. Unrelated to the ACE Rule, EPA issued a proposed rule on August 1, 2019 to clarify one aspect of the pre-construction review process for evaluating whether the NSR permitting program would apply to a proposed project at an existing source of emissions. The final rule on NSR Project Emissions Accounting became effective on December 24, 2020 clarifying that both emissions increases and decreases resulting from a project are to be considered in determining whether the proposed project will result in an increase in air emissions, but the rule may be reconsidered by the Biden Administration. On January 27, 2021, President Biden signed an extensive Executive Order aimed at addressing climate change concerns domestically and internationally. The order is intended build on the initial climate-related actions the Biden Administration took on January 20, 2021. It addresses a wide range of issues, including establishing climate change concerns as an essential element of U.S. foreign and security policy, identifying a process to determine the U.S. INDC under the Paris Agreement, and establishing a Special Presidential Envoy for Climate that will sit on the National Security Council. PNM’s review of the GHG emission reductions standards that may occur as a result of legislation or regulation under the new Biden Administration and in response to the court’s ruling on the ACE Rule is ongoing. PNM cannot predict the impact these standards may have on its operations or a range of the potential costs of compliance, if any. National Ambient Air Quality Standards (“NAAQS”) The CAA requires EPA to set NAAQS for pollutants reasonably anticipated to endanger public health or welfare. EPA has set NAAQS for certain pollutants, including NOx, SO 2 , ozone, and particulate matter. NO X Standard – On April 18, 2018, EPA published the final rule to retain the current primary health-based NOx standards of which NO 2 is the constituent of greatest concern and is the indicator for the primary NAAQS. EPA concluded that the current 1-hour and annual primary NO 2 standards are requisite to protect public health with an adequate margin of safety. The rule became effective on May 18, 2018. SO 2 Standard – On May 13, 2014, EPA released the draft data requirements rule for the 1-hour SO 2 NAAQS, which directs state and tribal air agencies to characterize current air quality in areas with large SO 2 sources to identify maximum 1-hour SO 2 concentrations. This characterization requires areas be designated as attainment, nonattainment, or unclassifiable for compliance with the 1-hour SO 2 NAAQS. On August 11, 2015, EPA released the Data Requirements Rule for SO 2 , telling states how to model or monitor to determine attainment or nonattainment with the new 1-hour SO 2 NAAQS. NMED submitted the first annual report for SJGS as required by the Data Requirements Rule in June 2018. That report recommended that no further modeling was warranted due to decreased SO 2 emissions. NMED submitted the second and third annual modeling report to EPA in July 2019 and July 2020. Those reports retained the recommendation that no further modeling is needed at this time and is subject to EPA review. On February 25, 2019, EPA announced its final decision to retain without changes the primary health-based NAAQS for SO 2 . Specifically, EPA will retain the current 1-hour standard for SO 2 , which is 75 parts per billion, based on the 3-year average of the 99th percentile of daily maximum 1-hour SO 2 concentrations. Ozone Standard – On October 1, 2015, EPA finalized the new ozone NAAQS and lowered both the primary and secondary 8-hour standard from 75 to 70 parts per billion. With ozone standards becoming more stringent, fossil-fueled generation units will come under increasing pressure to reduce emissions of NOx and volatile organic compounds since these are the pollutants that form ground level ozone. On July 13, 2020, EPA proposed to retain the existing ozone NAAQS based on a review of the full body of currently available scientific evidence and exposure/risk information. EPA finalized its decision to retain the ozone NAAQS in a notice published on December 31, 2020 making it immediately effective. On November 10, 2015, EPA proposed a rule revising its Exceptional Events Rule, which outlines the requirements for excluding air quality data (including ozone data) from regulatory decisions if the data is affected by events outside an area’s control. The proposed rule is important in light of the more stringent ozone NAAQS final rule since western states like New Mexico and Arizona are subject to elevated background ozone transport from natural local sources, such as wildfires and stratospheric inversions, and transported via winds from distant sources in other regions or countries. EPA finalized the rule on October 3, 2016 and released related guidance in 2018 and 2019 to help implement its new exceptional events policy. During 2017 and 2018, EPA released rules establishing area designations for ozone. In those rules, San Juan County, New Mexico, where SJGS and Four Corners are located, is designated as attainment/unclassifiable and only a small area in Doña Ana County, New Mexico is designated as marginal non-attainment. Although Afton is located in Doña Ana County, it is not located within the small area designated as nonattainment for the 2015 ozone standard. The rule became effective May 8, 2018. Attainment plans for nonattainment areas are due in August 2021. NMED has responsibility for bringing the small area in Doña Ana County designated as marginal/non-attainment for ozone into compliance and will look at all sources of NOx and volatile organic compounds. On November 22, 2019, EPA issued findings that several states, including New Mexico, had failed to submit SIPs for the 8-hour ozone NAAQS. In response, in December 2019, NMED published the Public Review Draft of the New Mexico 2013 NAAQS Good Neighbor SIP that outlines the strategies and emissions control measures that are expected to improve air quality in the area by May 8, 2021. These strategies and measures would aim to reduce the amount of NOx and volatile organic compounds emitted to the atmosphere and will rely upon current or upcoming federal rules, new or revised state rules, and other programs. Comments or requests for a public hearing were required by January 21, 2020. PNM does not believe there will be material impacts to its facilities as a result of NMED’s non-attainment designat

Regulatory and Rate Matters

Regulatory and Rate Matters	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Regulatory and Rate Matters	Regulatory and Rate Matters The Company is involved in various regulatory matters, some of which contain contingencies that are subject to the same uncertainties as those described in Note 16. PNM New Mexico General Rate Cases New Mexico 2015 General Rate Case (“NM 2015 Rate Case”) In 2015, PNM filed an application with the NMPRC for a general increase in retail electric rates. The application proposed a revenue increase of $123.5 million, including base non-fuel revenues of $121.7 million. The NMPRC ordered PNM to file additional testimony regarding PNM’s interests in PVNGS, including the 64.1 MW of PVNGS Unit 2 that PNM repurchased in January 2016 pursuant to the terms of the initial sales-leaseback transactions. In August 2016, the Hearing Examiner in the case issued a recommended decision (the “August 2016 RD”). The August 2016 RD, among other things, recommended that the NMPRC find PNM was imprudent in the actions taken to purchase the previously leased 64.1 MW of capacity in PVNGS Unit 2, extending the leases for 114.6 MW of capacity of PVNGS Units 1 and 2, and installing the BDT equipment on SJGS Units 1 and 4. As a result, the August 2016 RD recommended the NMPRC disallow recovery of the entire $163.3 million purchase price for the January 15, 2016 purchases of the assets underlying three leases aggregating 64.1 MW of PVNGS Unit 2, the undepreciated capital improvements made during the period the 64.1 MW of purchased capacity was leased, rent expense aggregating $18.1 million annually for leases aggregating 114.6 MW of capacity that were extended through January 2023 and 2024 (Note 8), and recovery of the costs of converting SJGS Units 1 and 4 to BDT. On September 28, 2016, the NMPRC issued an order that authorized PNM to implement an increase in non-fuel rates of $61.2 million, effective for bills sent to customers after September 30, 2016. The order generally approved the August 2016 RD, but with certain significant modifications. The modifications to the August 2016 RD included: • Inclusion of the January 2016 purchase of the assets underlying three leases of capacity, aggregating 64.1 MW, of PVNGS Unit 2 at an initial rate base value of $83.7 million; and disallowance of the recovery of the undepreciated costs of capitalized improvements made during the period the 64.1 MW was being leased by PNM, which aggregated $43.8 million when the order was issued • Recovery of annual rent expenses associated with the 114.6 MW of capacity under the extended leases • Disallowance of the recovery of any future contributions for PVNGS decommissioning costs related to the 64.1 MW of capacity purchased in January 2016 and the 114.6 MW of capacity under the extended leases On September 30, 2016, PNM filed a notice of appeal with the NM Supreme Court regarding the order in the NM 2015 Rate Case. Specifically, PNM appealed the NMPRC’s determination that PNM was imprudent in certain matters in the case, including the NMPRC’s disallowance of the full purchase price of the 64.1 MW of capacity in PVNGS Unit 2, the undepreciated costs of capitalized improvements made during the period the 64.1 MW of capacity was leased by PNM, the cost of converting SJGS Units 1 and 4 to BDT, and future contributions for PVNGS decommissioning attributable to the 64.1 MW of purchased capacity and the 114.6 MW of capacity under the extended leases. NEE, NM AREA, and ABCWUA filed notices of cross-appeal to PNM’s appeal. The issues appealed by the various cross-appellants included, among other things, the NMPRC allowing PNM to recover any of the costs of the lease extensions for the 114.6 MW of PVNGS Units 1 and 2 and the purchase price for the 64.1 MW in PVNGS Unit 2, the costs incurred under the Four Corners CSA, and the inclusion of the “prepaid pension asset” in rate base. During the pendency of the appeal, PNM evaluated the consequences of the order in the NM 2015 Rate Case and the related appeals to the NM Supreme Court. These evaluations indicated that it was reasonably possible that PNM would be successful on the issues it was appealing but would not be provided capital costs recovery until the NMPRC acted on a decision of the NM Supreme Court. PNM also evaluated the accounting consequences of the issues being appealed by the cross-appellants and concluded that the issues raised in the cross-appeals did not have substantial merit. PNM periodically updated its estimate of the amount of time necessary for the NM Supreme Court to render a decision and for the NMPRC to take action on any remanded issues. As a result of those evaluations, through December 31, 2018, PNM recorded accumulated pre-tax impairments of its capital investments subject to the appeal in the amount of $18.4 million, of which $4.0 million was recorded during the year ended December 31, 2018, and $3.1 million was recorded during the year ended December 31, 2017. On May 16, 2019, the NM Supreme Court issued its decision on the matters that had been appealed in the NM 2015 Rate Case. The NM Supreme Court rejected the matters appealed by the cross-appellants and affirmed the NMPRC’s disallowance of a portion of the purchase price of the 64.1 MW of capacity in PVNGS Unit 2; the undepreciated costs of capital improvements made during the time the 64.1 MW capacity was leased by PNM; and the costs to install BDT at SJGS Units 1 and 4. The NM Supreme Court also ruled that the NMPRC’s decision to permanently disallow recovery of future decommissioning costs related to the 64.1 MW of PVNGS Unit 2 and the 114.6 MW of PVNGS Units 1 and 2 deprived PNM of its rights to due process of law and remanded the case to the NMPRC for further proceedings consistent with the court’s findings. On July 17, 2019, the NMPRC heard oral argument from parties in the case on how to best proceed with the NM Supreme Court’s remand. At oral argument, parties presented various positions ranging from re-litigating the value of PVNGS resources determined by the NMPRC and affirmed by the NM Supreme Court to re-affirming the NMPRC’s final order with a single modification to address recovery of future PVNGS decommissioning costs in a future case. On January 8, 2020, the NMPRC issued its order on remand, which reaffirmed its September 2016 order except for the decision to permanently disallow recovery of certain future decommissioning costs related to PVNGS Units 1 and 2. The NMPRC indicated that PNM’s ability to recover these costs will be addressed in a future proceeding and closed the NM 2015 Rate Case docket. As a result of the NM Supreme Court’s ruling, during the year ended December 31, 2019, PNM recorded pre-tax impairments of $150.6 million, which includes $73.2 million for a portion of the purchase price for 64.1 MW in PVNGS Unit 2, $39.7 million of undepreciated capitalized improvements made during the period the 64.1 MW was being leased by PNM, and $37.7 million for BDT on SJGS Units 1 and 4 and is reflected as regulatory disallowances and restructuring costs in the Consolidated Statements of Earnings. The impairment was offset by tax impacts of $45.7 million, which are reflected as income taxes on the Consolidated Statements of Earnings. New Mexico 2016 General Rate Case (“NM 2016 Rate Case”) In 2016, PNM filed an application with the NMPRC for a general increase in retail electric rates. PNM’s application used a FTY beginning January 1, 2018 and requested an increase in base non-fuel revenues of $99.2 million based on a ROE of 10.125%. The primary drivers of PNM’s revenue deficiency included implementation of modifications to PNM’s resource portfolio, which were approved by the NMPRC in December 2015 as part of the SJGS regional haze compliance plan, infrastructure investments, including environmental upgrades at Four Corners, declines in forecasted energy sales due to successful energy efficiency programs and other economic factors, and updates to FERC/retail jurisdictional allocations. After extensive settlement negotiations and public proceedings, the NMPRC issued a Revised Order Partially Adopting Certification of Stipulation dated January 10, 2018 (the “Revised Order”). The key terms of the Revised Order include: • An increase in base non-fuel revenues totaling $10.3 million, which includes a reduction to reflect the impact of the decrease in the federal corporate income tax rate and updates to PNM’s cost of debt (aggregating an estimated $47.6 million annually) • A ROE of 9.575% • Returning to customers over a three-year period the benefit of the reduction in the New Mexico corporate income tax rate to the extent attributable to PNM’s retail operations (Note 18) • Disallowing PNM’s ability to collect an equity return on certain investments aggregating $148.1 million at Four Corners, but allowing recovery with a debt-only return • An agreement to not implement non-fuel base rate changes, other than changes related to PNM’s rate riders, with an effective date prior to January 1, 2020 • A requirement to consider the prudency of PNM’s decision to continue its participation in Four Corners in PNM’s next general rate case filing In accordance with the settlement agreement and the NMPRC’s final order, PNM implemented 50% of the approved increase for service rendered beginning February 1, 2018 and implemented the rest of the increase for service rendered beginning January 1, 2019. On December 29, 2020, Sierra Club filed a motion asking the NMPRC to re-open the NM 2016 Rate Case for the limited purpose of conducting a prudence review of certain Four Corners investments that were deferred at the conclusion of the case. In the alternative, Sierra Club requested that the NMPRC order that the deferred prudence review be conducted in the Four Corners Abandonment Application, filed on January 8, 2021. On February 10, 2021, the NMPRC rejected Sierra Club’s motion to re-open the NM 2016 Rate Case and stated that issues on whether the terms of the ETA provide an opportunity for consideration of prudence for Four Corners undepreciated investments included in a financing order or what effects the rates approved in the NM 2016 Rate Case may have on determining energy transition cost should be considered in the Four Corners Abandonment Application. See discussion regarding PNM’s Four Corners Abandonment Application discussed below. Renewable Portfolio Standard As discussed in Note 16, the ETA, enacted on June 14, 2019 amends the REA including removal of diversity requirements and certain customer caps and exemptions relating to the application of the RPS under the REA. The REA provides for streamlined proceedings for approval of utilities’ renewable energy procurement plans, assures that utilities recover costs incurred consistent with approved procurement plans, and requires the NMPRC to establish a RCT for the procurement of renewable resources to prevent excessive costs being added to rates. The ETA sets a RCT of $60 per MWh using an average annual levelized resource cost basis. PNM makes renewable procurements consistent with the NMPRC approved plans and recovers certain renewable procurement costs from customers through a rate rider. See Renewable Energy Rider below. Included in PNM’s approved procurement plans are the following renewable energy resources: • 158 MW of PNM-owned solar-PV facilities • A PPA through 2044 for the output of New Mexico Wind, having a current aggregate capacity of 200 MW, and a PPA through 2035 for the output of Red Mesa Wind, having an aggregate capacity of 102 MW • A PPA through 2040 for 140 MW of output from La Joya Wind II • A PPA through 2042 for the output of the Lightning Dock Geothermal facility with a current capacity of 11 MW • Solar distributed generation, aggregating 161.0 MW at December 31, 2020, owned by customers or third parties from whom PNM purchases any net excess output and RECs On June 1, 2017, PNM filed its 2018 renewable energy procurement plan. PNM requested approval to procure an additional 80 GWh in 2019 and 105 GWh in 2020 from a re-powering of New Mexico Wind; approval to procure an additional 55 GWh in 2019 and 77 GWh in 2020 from a re-powering of Lightning Dock Geothermal; approval to procure 50 MW of new PNM-owned solar facilities to be constructed beginning in 2018, and continuation of customer REC purchase programs and other purchases of RECs to ensure annual compliance with the RPS. The plan also sought a variance from the “other” diversity category in 2018 due to a revised production forecast of the Lightning Dock Geothermal facility in 2018. On October 17, 2017, the Hearing Examiner issued a recommended decision that PNM’s 2018 renewable energy procurement plan be approved by the NMPRC, except for the re-powering of Lightning Dock Geothermal and PNM’s request to procure 50 MW of new PNM-owned solar facilities. On November 15, 2017, the NMPRC issued an order approving PNM’s plan and rejecting the Hearing Examiner’s recommendations. On November 29, 2017, NM AREA filed an appeal with the NM Supreme Court objecting to the fuel allocation methodology and requested a partial stay of the NMPRC order, which was denied. NEE subsequently filed a motion to intervene and cross-appeal objecting to the approval of the 50 MW of new PNM-owned solar facilities. On July 5, 2019, the NM Supreme Court approved a motion filed by NM AREA to dismiss its appeal. On August 8, 2019, the NM Supreme Court issued an opinion affirming the NMPRC’s approval of PNM’s 2018 renewable energy procurement plan and denying NEE’s cross appeal. This matter is now concluded. On June 1, 2018, PNM filed its 2019 renewable energy procurement plan. The plan met RPS and diversity requirements for 2019 and 2020 using resources already approved by the NMPRC and did not propose any significant new procurements. PNM projected the plan would be within the RCT in 2019 and will slightly exceed the current RCT in 2020. The NMPRC approved PNM’s 2019 renewable energy procurement plan on November 28, 2018. On June 3, 2019, PNM filed its 2020 renewable energy procurement plan. The plan requested approval of a 20-year PPA to purchase 140 MW of renewable energy and RECs from La Joya Wind II. PNM intends to utilize the BB2 line to deliver power from the PPA. See additional discussion below under Application for a New 345-kV Transmission Line . PNM’s 2020 renewable energy procurement plan requested a variance from the RPS for 2020 and proposes the shortfall be met with excess RECs that will be available under the La Joya Wind II PPA in 2021. PNM also submitted proposed adjustments to the current FPPAC methodology for non-renewable fuel allocations to reflect the ETA’s removal of certain customer cost caps associated with the RPS and requested that the fuel clause year be reset to correspond to the January 1 reset date under the renewable energy rider. On December 2, 2019, the Hearing Examiner issued a recommended decision in the case recommending approval of PNM’s 2020 renewable energy procurement plan including La Joya Wind II. On January 29, 2020, the NMPRC accepted the Hearing Examiners recommended decision and approved PNM’s 2020 renewable energy procurement plan. On June 1, 2020, PNM filed its 2021 renewable energy procurement plan. In the plan, PNM proposed to collect a revenue requirement of approximately $67.8 million through the renewable energy rider, including recovery of a regulatory asset of $2.3 million for costs of administering PNM's Sky Blue voluntary renewable energy program that PNM has not been able to collect from Sky Blue participants. The Sky Blue regulatory asset of $2.3 million included carrying charges of 8.64% totaling approximately $0.7 million. PNM did not propose any new procurements in the plan. On November 18, 2020 the NMPRC issued a final order approving the 2021 renewable energy procurement plan with the exception of PNM’s request to recover the Sky Blue regulatory asset. The NMPRC denied PNM’s request to recover the regulatory asset, in part, because PNM did not adequately account for the renewable energy certificates associated with the regulatory asset. The NMPRC indicated that it will initiate a separate proceeding on the subject of whether the Sky Blue program should continue in its current form, be modified, or be terminated. The NMPRC also placed conditions on PNM’s ability to recover the Sky Blue regulatory asset from all customers, rather than from program participants, in a future proceeding, including that the carrying charge associated with the regulatory asset be reduced from 8.64% to 4% and that PNM be prohibited from collecting carrying charges from the date of the final order. However, PNM is permitted to seek recovery of carrying charges for the full 8.64% through the current Sky Blue program. Renewable Energy Rider The NMPRC has authorized PNM to recover certain renewable procurement costs through a rate rider billed on a per KWh basis. PNM recorded revenues from the rider of $56.4 million, $52.0 million, and $41.4 million in 2020, 2019, and 2018. The 2020 renewable energy procurement plan became effective on February 1, 2020. In its 2021 renewable energy procurement plan case, PNM proposed to collect $67.8 million through a revised rate rider beginning in 2021. The NMPRC approved recovery of $65.5 million through the rider in 2021, which reflected the NMPRC’s rejection of PNM’s request to recover the $2.3 million Sky Blue regulatory asset in 2021. The revised rate rider became effective on January 1, 2021. Under the renewable rider, if PNM’s earned rate of return on jurisdictional equity in a calendar year, adjusted for items not representative of normal operations, exceeds the NMPRC-approved rate by 0.5%, PNM is required to refund the excess to customers during May through December of the following year. PNM did not exceed such limitation in 2019 and does not expect to exceed the limitation in 2020. Energy Efficiency and Load Management Program Costs and Incentives/Disincentives The New Mexico Efficient Use of Energy Act (“EUEA”) requires public utilities to achieve specified levels of energy savings and to obtain NMPRC approval to implement energy efficiency and load management programs. The EUEA requires the NMPRC to remove utility disincentives to implementing energy efficiency and load management programs and to provide incentives for such programs. The NMPRC has adopted a rule to implement this act. PNM’s costs to implement approved programs and incentives are recovered through a rate rider. During the 2019 New Mexico legislative session, the EUEA was amended to, among other things, include a decoupling mechanism for disincentives, preclude a reduction to a utility’s ROE based on approval of disincentive or incentive mechanisms, establish energy savings targets for the period 2021 through 2025, and require that annual program funding be 3% to 5% of an electric utility’s annual customer bills excluding gross receipt taxes, franchise and right-of-way access fees, provided that a customer’s annual cost not exceed seventy-five thousand dollars. On July 26, 2017, PNM, NMPRC staff, and other parties filed a stipulation in PNM’s energy efficiency and load management application, providing for all of PNM’s proposed energy efficiency and load management programs to be approved with limited modifications and PNM’s base level incentive would be $1.7 million and could earn an incentive of up to $1.9 million based on savings of 69 GWh in 2018. The settlement also established a base level incentive for PNM of $1.8 million with the opportunity to earn up to $2.7 million in 2019 and required PNM to make a filing in 2019 to address incentives to be earned in 2020. On November 8, 2017, the Hearing Examiner recommended approval of the stipulation with various modifications, including adoption of a discount rate equal to the tax-adjusted WACC of 9.59% rather than the 7.71% proposed in the stipulation and modifying the program budgets to $23.6 million for 2018 and $24.9 million for 2019. On January 31, 2018, the NMPRC issued an order that largely accepted the certification with certain exceptions concerning the measurement and verification of the approved load management programs. In 2019, PNM submitted a filing to address incentives to be earned in 2020. PNM’s proposed incentive mechanism was similar to that approved for 2018 and 2019 with minor modifications to reflect input from interested parties. The proposed incentive mechanism includes a base incentive of 7.1% of program costs, or approximately $1.8 million, based on savings of 59 GWh in 2020 with a sliding scale that provides for additional incentive if savings exceed 68 GWh. No hearings were considered necessary and PNM’s 2020 energy efficiency rider reflecting the 2020 incentive became effective beginning December 30, 2019. On April 15, 2020, PNM filed an application for energy efficiency and load management programs to be offered in 2021, 2022, and 2023. The proposed program portfolio consists of twelve programs with a total annual budget of $31.4 million in 2021, $31.0 million in 2022, and $29.6 million in 2023. The application also sought approval of an annual base incentive of 7.1% of the portfolio budget if PNM were to achieve energy savings of at least 80 GWh in a year. The proposed incentive would increase if PNM is able to achieve savings greater than 80 GWh in a year. The application also proposed an advanced metering infrastructure (“AMI”) pilot program, which included the installation of 5,000 AMI meters at a cost of $2.9 million. PNM proposed the pilot program to comply with an NMPRC order denying PNM’s February 2016 application to replace its existing customer metering equipment with AMI. PNM did not recommend the AMI pilot program due to the limited benefits that are cost-effective under a pilot structure. On September 17, 2020 the Hearing Examiner in the case issued a recommended decision recommending that PNM's proposed energy efficiency and load management program be approved, with the exception of the proposed AMI pilot program. On October 28, 2020 the NMPRC issued an order adopting the recommended decision in its entirety. 2020 Decoupling Petition As discussed above, the legislature amended the EUEA to, among other things, include a decoupling mechanism for disincentives. On May 28, 2020, PNM filed a petition for approval of a rate adjustment mechanism that would decouple the rates of its residential and small power rate classes. Decoupling is a rate design principle that severs the link between the recovery of fixed costs of the utility through volumetric charges. PNM proposed to record the difference between the annual revenue per customer derived from the cost of service approved in the NM 2015 Rate Case and the annual revenue per customer actually recovered from the rate classes beginning on January 1, 2021. If approved, on January 1, 2022, PNM would begin to collect the difference from customers if the revenue per customer from the NM 2015 Rate Case exceeds the actual revenue recovered in 2021, or return the difference to customers if the actual revenue per customer recovered in 2021 exceeds the revenue per customer from the NM 2015 Rate Case. On July 13, 2020, NEE, ABCWUA, the City of Albuquerque, and Bernalillo County filed motions to dismiss the petition on the grounds that approving PNM’s proposed rate adjustment mechanism outside of a general rate case would result in retroactive ratemaking and piecemeal ratemaking. The motions to dismiss also allege that PNM’s proposed rate adjustment mechanism is inconsistent with the EUEA. Responses to the motions to dismiss were filed on August 7, 2020. On September 16, 2020 ABCWUA, Bernalillo County, CCAE, the City of Albuquerque, NEE, NMAG, Staff and WRA filed testimony. CCAE and WRA support PNM's petition, but recommend that the rate adjustment mechanism not take effect until new rates are approved in PNM's next general rate case. The other parties filing testimony oppose PNM's petition. On October 2, 2020, PNM requested an order to vacate the public hearing, scheduled to begin October 13, 2020, and staying the proceeding until the NMPRC decides whether to entertain a petition to issue a declaratory order resolving the issues raised in the motions to dismiss. On October 7, 2020, the Hearing Examiner approved PNM's request to stay the proceeding and vacate the public hearing and required PNM to file a petition for declaratory order by October 30, 2020. On October 30, 2020 PNM filed a petition for declaratory order asking the NMPRC to issue an order finding that full revenue decoupling is authorized by the EUEA. On November 4, 2020, ABCWUA and Bernalillo County jointly filed a competing petition asking the NMPRC to issue a declaratory order on the EUEA’s requirements related to disincentives. On November 24, 2020, the NMAG requested that the NMPRC deny both petitions for declaratory orders and instead address disincentives under the EUEA in a rulemaking. PNM cannot predict the outcome of this matter. Integrated Resource Plans NMPRC rules require that investor owned utilities file an IRP every three years. The IRP is required to cover a 20-year planning period and contain an action plan covering the first four years of that period. 2017 IRP PNM filed its 2017 IRP on July 3, 2017 addressing the 20-year planning period, from 2017 through 2036. Key findings of the 2017 IRP included, among other things, that retiring PNM’s share of SJGS in 2022 and existing ownership in Four Corners in 2031 would provide long-term cost savings for PNM’s customers and that the best mix of new resources to replace the retired coal generation would include solar energy and flexible natural gas-fired peaking capacity as well as energy storage, if the economics support it, and wind energy provided additional transmission capacity becomes available. The 2017 IRP also indicated that PNM should retain the currently leased capacity in PVNGS. See additional discussion of PNM’s leased capacity in PVNGS below and in Note 8. PNM’s 2017 IRP was subject to extensive hearings and legal challenges and was accepted as compliant with the applicable statute and rules by the NMPRC on December 19, 2018, with further consideration being denied. 2020 IRP NMPRC rules required PNM to file its 2020 IRP in July 2020. On March 16, 2020, PNM filed a motion to extend the deadline to file its 2020 IRP to six months after the NMPRC issues a final order approving a replacement resource portfolio and closes the docket in the bifurcated SJGS Abandonment Application and replacement resource proceedings. On April 8, 2020, the NMPRC approved PNM’s motion to extend the deadline to file its 2020 IRP as requested. On January 29, 2021 PNM filed its 2020 IRP addressing the 20-year planning period, from 2020 through 2040. The plan focuses on a carbon-free electricity portfolio by 2040 that would eliminate coal at the end of 2024. This includes replacing the power from San Juan with a mix of approved carbon-free resources and the plan to exit Four Corners at the end of 2024. The plan highlights the need for additional investments in a diverse set of resources, including renewables to supply carbon-free power, energy storage to balance supply and demand, and efficiency and other demand-side resources to mitigate load growth. Abandonment Applications made under the ETA As discussed in Note 16, the ETA sets a statewide standard that requires investor-owned electric utilities to have specified percentages of their electric-generating portfolios be from renewable and zero-carbon generating resources. The ETA also provides for a transition from fossil-fuel generation resources to renewable and other carbon-free resources through certain provisions relating to the abandonment of coal-fired generating facilities. These provisions include the use of energy transition bonds, which are designed to be highly rated bonds that can be issued to finance certain costs of abandoning coal-fired facilities that are retired prior to January 1, 2023 for facilities operated by a “qualifying utility,” or prior to January 1, 2032 for facilities that are not operated by the qualifying utility. SJGS Abandonment Application On July 1, 2019, PNM filed a Consolidated Application for the Abandonment and Replacement of SJGS and Related Securitized Financing Pursuant to the ETA (the “SJGS Abandonment Application”). The SJGS Abandonment Application sought NMPRC approval to retire PNM’s share of SJGS after the existing coal supply and participation agreements end in June 2022, for approval of replacement resources, and for the issuance of energy transition bonds. PNM’s application proposed several replacement resource scenarios including PNM’s recommended replacement scenario, which would have provided cost savings to customers compared to continued operation of SJGS, preserved system reliability, and is consistent with PNM’s plan to have an emissions-free generation portfolio by 2040. This plan would have provided PNM authority to construct and own a 280 MW natural gas-fired peaking plant, to be located on the existing SJGS facility site, and 70 MW of battery storage facilities. In addition, PNM’s recommended replacement resource scenario would have allowed PNM to execute PPAs to procure renewable energy from a total of 350 MW of solar-PV generating facilities and for energy from a total of 60 MW of battery storage facilities. PNM’s application included three other replacement resource scenarios that would have placed a greater amount of resources in the San Juan area, or resulted in no new fossil-fueled generating facilities, or no battery storage facilities being added to PNM’s portfolio. When compared to PNM’s recommended replacement resource scenario, the three alternative resource scenarios were expected to result in increased costs to customers and the two alternative resource scenarios that result in no new fossil-fueled generating facilities were expected to not provide adequate system reliability. The SJGS Abandonment Application also included a request to issue approximately $361 million of energy transition bonds (the “Securitized Bonds”). PNM’s request for the issuance of Securitized Bonds included approximately $283 million of forecasted undepreciated investments in SJGS at June 30, 2022, an estimated $28.6 million for plant decommissioning and coal mine reclamation costs, approximately $9.6 million in upfront financing costs, and approximately $20.0 million for job training and severance costs for affected employees. Proceeds from the Securitization Bonds would also be used to fund approximately $19.8 million for economic development in the four corners area. As discussed in Note 16, the NM Supreme Court granted a request by PNM to stay a January 30, 2019 NMPRC order requiring PNM to file an abandonment application for SJGS by March 1, 2019. On June 26, 2019, and after the effective date of the ETA, the NM Supreme Court lifted the stay and denied PNM’s petition without discussion. On July 10, 2019, the NMPRC issued an order requiring the SJGS Abandonment Application be considered in two proceedings: one addressing SJGS abandonment and related financing, and the other addressing replacement resources. The NMPRC indicated that PNM’s July 1, 2019 filing is responsive to the January 30, 2019 order but did not definitively indicate if the abandonment and financing proceedings would be evaluated under the requirements of the ETA. The NMPRC’s July 10, 2019 order also extended the deadline to issue the abandonment and financing order to nine months and to issue the replacement resources order to 15 months. On July 22, 2019, Western Resource Advocates filed a motion requesting the NMPRC clarify whether it intends to evaluate the abandonment and financing proceeding under the requirements of the ETA and, in the event the abandonment and financing proceeding would not be evaluated under the ETA, to reconsider its decision and provide parties an opportunity to present oral argument on the matter. The NMPRC chair responded on July 24, 2019, indicating that the Hearing Examiners assigned to the proceeding would address the issue of law applicable to the approvals sought by PNM in the scheduling orders. On July 25, 2019, the Hearing Examiners issued procedural orders that set public hearings on SJGS abandonment and related financing to begin on December 10, 2019, on PNM’s proposed PPA replacement resources to begin on December 2, 2019, and on PNM-owned replacement resources to begin on March 2, 2020. These procedural orders were subsequently amended to allow public hearings for both the PPA and PNM-owned replacement resources to begin in January 2020. The procedural

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Federal Income Tax Reform In 2017, comprehensive changes in U.S. federal income taxes were enacted through legislation commonly known as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act made many significant modifications to the tax laws, including reducing the federal corporate income tax rate from 35% to 21% effective January 1, 2018. The Tax Act also eliminated federal bonus depreciation for utilities, limited interest deductibility for non-utility businesses and limited the deductibility of officer compensation. During 2020, the IRS issued final regulations related to certain officer compensation and, in January 2021, issued final regulations on interest deductibility that provide a 10% “de minimis” exception that allows entities with predominantly regulated activities to fully deduct interest expenses. In addition, in 2019, the IRS issued proposed regulations interpreting Tax Act amendments to depreciation provisions of the IRC that allow the Company to claim a bonus depreciation deduction on certain construction projects placed in service subsequent to the third quarter of 2017. As a result of the change in the federal income tax rate, the Company re-measured and adjusted its deferred tax assets and liabilities as of December 31, 2017. The portion of that adjustment not related to PNM’s and TNMP’s regulated activities was recorded as a reduction in net deferred tax assets and an increase in income tax expense. The portion related to PNM’s and TNMP’s regulated activities was recorded as a reduction in net deferred tax liabilities and an increase in regulatory liabilities. Beginning February 2018, PNM’s NM 2016 Rate Case reflects the reduction in the federal corporate income tax rate, including amortization of excess deferred federal and state income taxes. In accordance with the order in that case, PNM is returning the protected portion of excess deferred federal income taxes to customers over the average remaining life of plant in service as of December 31, 2017, the unprotected portion of excess deferred federal income taxes to customers over a period of approximately twenty-three years, and excess deferred state income taxes to customers over a period of three years. The approved settlement in the TNMP 2018 Rate Case includes a reduction in customer rates to reflect the impacts of the Tax Act beginning on January 1, 2019. See additional discussion of PNM’s NM 2016 Rate Case and TNMP’s 2018 Rate Case in Note 17. In December 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”), which provided guidance to address the application of GAAP to reflect the Tax Act in circumstances where all information and analysis was not yet available or complete. This bulletin provided for a one-year period in which to complete the required analyses and accounting for the impacts of the Tax Act. In accordance with SAB 118, the Company completed its analysis of the impacts of the Tax Act in 2018. The adjustments to deferred income taxes resulting from completion of the Company’s analysis, which resulted primarily from differences between the estimated amounts recorded as of December 31, 2017 and the actual amounts reflected in the Company’s 2017 tax return filing, including adjustments resulting from additional guidance and interpretations to the Tax Act issued in 2018 related to bonus depreciation, certain incentive compensation, and other items are presented below: PNM TNMP Corporate and Other Consolidated (In thousands) Net increase (decrease) in regulatory liabilities $ 11,244 $ (4,069) $ — $ 7,175 Net decrease in deferred income tax liabilities (deferred income tax assets) (2,175) (9,784) 13,869 1,910 Net increase in affiliate receivables 12,300 4,042 (16,342) — Net deferred income tax expense $ 1,119 $ 1,673 $ 2,473 $ 5,265 As discussed in Note 17, the NM Supreme Court issued a decision in May 2019 on the appeal of the NM 2015 Rate Case resulting in pre-tax impairments of $150.6 million in the year ending December 31, 2019. The impairments were recognized as discrete items within regulatory disallowances and restructuring costs resulting in tax benefits of $45.7 million, which is reflected in income taxes on the Company’s Consolidated Statements of Earnings for the year ended December 31, 2019. PNMR PNMR’s income taxes (benefits) consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ — $ 60 $ — Current state income tax 231 43 (244) Deferred federal income tax 17,574 (20,372) 7,716 Deferred state income tax 3,721 (4,491) 648 Amortization of accumulated investment tax credits (890) (522) (345) Total income taxes (benefits) $ 20,636 $ (25,282) $ 7,775 PNMR’s provision for income taxes (benefits) differed from the federal income tax computed at the statutory rate for each of the years shown. The differences are attributable to the following factors: Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 43,670 $ 14,038 $ 22,902 Amortization of accumulated investment tax credits (890) (522) (345) Amortization of excess deferred income tax (Note 17) (30,723) (37,799) (19,779) Flow-through of depreciation items 1,368 1,136 712 Earnings attributable to non-controlling interest in Valencia (2,943) (2,991) (3,173) State income tax, net of federal benefit 6,961 298 1,358 Impairment of state net operating loss carryforwards — — — Allowance for equity funds used during construction (2,363) (1,990) (2,185) Impairment of charitable contribution carryforward — — — Regulatory recovery of prior year impairments of state net operating loss carryforward, including amortization 1,367 1,367 1,367 Federal income tax rate change — — 2,914 Tax expense (benefit) related to stock compensation awards (392) (795) 4,647 Non-deductible compensation 2,630 1,156 891 Other 1,951 820 (1,534) Total income taxes (benefits) $ 20,636 $ (25,282) $ 7,775 Effective tax rate 9.92 % (37.82) % 7.13 % The components of PNMR’s net accumulated deferred income tax liability were: December 31, 2020 2019 (In thousands) Deferred tax assets: Net operating loss $ 41,419 $ 59,488 Regulatory liabilities related to income taxes 148,961 145,087 Federal tax credit carryforwards 121,354 101,231 Regulatory disallowances 38,531 34,639 Other 42,885 54,199 Total deferred tax assets 393,150 394,644 Deferred tax liabilities: Depreciation and plant related (738,342) (787,928) Investment tax credit (98,669) (81,186) Regulatory assets related to income taxes (61,330) (58,495) CTC — (1,466) Pension (37,099) (35,029) Regulatory asset for shutdown of SJGS Units 2 and 3 (27,237) (28,831) Other (124,985) (27,767) Total deferred tax liabilities (1,087,662) (1,020,702) Net accumulated deferred income tax liabilities $ (694,512) $ (626,058) The following table reconciles the change in PNMR’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 68,454 Change in tax effects of income tax related regulatory assets and liabilities (11,602) Amortization of excess deferred income tax (30,723) Tax effect of mark-to-market adjustments (3,206) Tax effect of excess pension liability (3,670) Adjustment for uncertain income tax positions 2,459 Reclassification of unrecognized tax benefits (2,459) Amortization of state net operating loss recovered in prior years 1,367 Refundable alternative minimum tax credit carryforward reclassified to receivable — Other (215) Deferred income taxes (benefits) $ 20,405 PNM PNM’s income taxes (benefit) consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ — $ (6,266) $ (6,644) Current state income tax (585) 449 (2,661) Deferred federal income tax 20,125 (12,308) 5,661 Deferred state income tax 2,560 (7,590) (2,080) Amortization of accumulated investment tax credits (243) (247) (247) Total income taxes (benefit) $ 21,857 $ (25,962) $ (5,971) PNM’s provision for income taxes (benefit) differed from the federal income tax computed at the statutory rate for each of the years shown. The differences are attributable to the following factors: Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 38,193 $ 6,187 $ 13,514 Amortization of accumulated investment tax credits (243) (247) (247) Amortization of excess deferred income tax (Note 17) (21,609) (28,923) (19,779) Flow-through of depreciation items 1,279 1,077 674 Earnings attributable to non-controlling interest in Valencia (2,943) (2,991) (3,173) State income tax, net of federal benefit 7,111 92 1,323 Impairment of state net operating loss carryforwards — — — Allowance for equity funds used during construction (1,461) (1,398) (1,716) Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization 1,367 1,367 1,367 Federal income tax rate change — — (683) Allocation of tax expense (benefit) related to stock compensation awards (279) (559) 3,967 Non-deductible compensation 1,554 683 612 Other (1,112) (1,250) (1,830) Total income taxes (benefit) $ 21,857 $ (25,962) $ (5,971) Effective tax rate 12.02 % (88.13) % (9.28) % The components of PNM’s net accumulated deferred income tax liability were: December 31, 2020 2019 (In thousands) Deferred tax assets: Net operating loss $ — $ 25,889 Regulatory liabilities related to income taxes 121,569 114,849 Federal tax credit carryforwards 84,719 82,983 Shutdown of SJGS Units 2 and 3 — — Regulatory disallowance 38,531 34,639 Other 46,444 38,735 Total deferred tax assets 291,263 297,095 Deferred tax liabilities: Depreciation and plant related (576,079) (630,293) Investment tax credit (74,424) (74,667) Regulatory assets related to income taxes (51,493) (49,479) Pension (32,413) (30,609) Regulatory asset for shutdown of SJGS Units 2 and 3 (27,237) (28,831) Other (108,767) (5,206) Total deferred tax liabilities (870,413) (819,085) Net accumulated deferred income tax liabilities $ (579,150) $ (521,990) The following table reconciles the change in PNM’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 57,160 Change in tax effects of income tax related regulatory assets and liabilities (7,936) Amortization of excess deferred income tax (21,609) Tax effect of mark-to-market adjustments (3,325) Tax effect of excess pension liability (3,670) Adjustment for uncertain income tax positions 2,454 Reclassification of unrecognized tax benefits (1,999) Amortization of state net operating loss recovered in prior years 1,367 Other — Deferred income taxes (benefits) $ 22,442 TNMP TNMP’s income taxes consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ 12,048 $ 10,792 $ 13,347 Current state income tax 2,033 1,904 1,753 Deferred federal income tax (7,744) (7,621) (540) Deferred state income tax (29) (29) 2,320 Total income taxes $ 6,308 $ 5,046 $ 16,880 TNMP’s provision for income taxes differed from the federal income tax computed at the statutory rate for each of the periods shown. The differences are attributable to the following factors: Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 13,628 $ 12,778 $ 14,379 Amortization of excess deferred income tax (9,113) (8,876) — State income tax, net of federal benefit 1,625 1,532 1,454 Allocation of tax expense (benefit) related to stock compensation awards (112) (236) 735 Officer compensation 1,071 471 277 Other (791) (623) 35 Total income taxes $ 6,308 $ 5,046 $ 16,880 Effective tax rate 9.71 % 8.29 % 24.65 % The components of TNMP’s net accumulated deferred income tax liability at December 31, were: December 31, 2020 2019 (In thousands) Deferred tax assets: Regulatory liabilities related to income taxes $ 27,392 $ 30,238 Other 4,548 3,788 Total deferred tax assets 31,940 34,026 Deferred tax liabilities: Depreciation and plant related (148,279) (142,791) CTC — (1,466) Regulatory assets related to income taxes (9,836) (9,016) Loss on reacquired debt (6,072) (6,345) Pension (4,685) (4,420) AMS (6,915) (8,473) Other (1,522) (1,666) Total deferred tax liabilities (177,309) (174,177) Net accumulated deferred income tax liabilities $ (145,369) $ (140,151) The following table reconciles the change in TNMP’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 5,218 Change in tax effects of income tax related regulatory assets and liabilities (3,666) Amortization of excess deferred income tax (9,113) Other (212) Deferred income taxes (benefits) $ (7,773) Other Disclosures The Company is required to recognize only the impact of tax positions that, based on their technical merits, are more likely than not to be sustained upon an audit by the taxing authority. A reconciliation of unrecognized tax benefits is as follows: PNMR PNM TNMP (In thousands) Balance at December 31, 2017 $ 9,429 $ 6,563 $ 63 Additions based on tax positions related to 2018 543 543 — Additions (reductions) for tax positions of prior years 222 182 40 Settlement payments — — — Balance at December 31, 2018 10,194 7,288 103 Additions based on tax positions related to 2019 329 329 — Additions (reductions) for tax positions of prior years 170 159 11 Settlement payments — — — Balance at December 31, 2019 10,693 7,776 114 Additions based on tax positions related to 2020 2,286 2,286 — Additions (reductions) for tax positions of prior years 173 168 5 Settlement payments — — — Balance at December 31, 2020 $ 13,152 $ 10,230 $ 119 Included in the balance of unrecognized tax benefits at December 31, 2020 are $10.7 million, $7.8 million, and $0.1 million that, if recognized, would affect the effective tax rate for PNMR, PNM, and TNMP. The Company does not anticipate that any unrecognized tax expenses or unrecognized tax benefits will be reduced or settled in 2021. PNMR, PNM, and TNMP had no estimated interest income or expense for the years ended December 31, 2020, 2019, and 2018. There was no accumulated accrued interest receivable or payable related to income taxes as of December 31, 2020 and 2019. The Company files a federal consolidated and several consolidated and separate state income tax returns. The tax years prior to 2017 are closed to examination by either federal or state taxing authorities other than Arizona. The tax years prior to 2016 are closed to examination by Arizona taxing authorities. Other tax years are open to examination by federal and state taxing authorities and net operating loss carryforwards are open to examination for the years in which the carryforwards are utilized. At December 31, 2020, the Company has $222.1 million of federal net operating loss carryforwards that expire beginning in 2031 and $121.4 million of federal tax credit carryforwards that expire beginning in 2023. State net operating losses expire beginning in 2035 and vary from federal due to differences between state and federal tax law. The proposed Merger may impact the Company’s ability to utilize its federal net operating loss and tax credit carryforwards. In 2008, fifty percent bonus tax depreciation was enacted as a temporary two-year stimulus measure as part of the Economic Stimulus Act of 2008. Bonus tax depreciation in various forms has been extended since that time, including by the Protecting Americans from Tax Hikes Act of 2015. The 2015 act extended and phased-out bonus tax depreciation through 2019. As discussed above the Tax Act eliminated bonus depreciation for utilities effective September 28, 2017. However, in 2018 the IRS issued proposed regulations interpreting Tax Act amendments to depreciation provisions of the IRC which allowed the Company to claim a bonus depreciation deduction on certain construction projects placed in service after the third quarter of 2017. As a result of the net operating loss carryforwards for income tax purposes created by bonus depreciation, certain tax carryforwards were not expected to be utilized before their expiration. In addition, as a result of Tax Act changes to the deductibility of officer compensation, certain deferred tax benefits related to compensation are not expected to be realized. The Company has impaired the deferred tax assets for tax carryforwards which are not expected to be utilized and for compensation that is not expected to be deductible. The Company earns investment tax credits for construction or purchase of eligible property. The Company uses the deferral method of accounting for these investment tax credits. The impairments after reflecting the expiration of carryforwards under applicable tax laws, net of federal tax benefit, for 2018 through 2020 are as follows: PNMR PNM TNMP (In thousands) December 31, 2020: State tax credit carryforwards $ (425) $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 96 $ 61 $ 35 December 31, 2019: State tax credit carryforwards $ 425 $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ (99) $ (100) $ 2 December 31, 2018: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 410 $ 298 $ 111 The impairments of unexpired state tax credits, state net operating loss, and charitable contribution carryforwards are reflected as a valuation allowance against deferred tax assets. The reserve balances, after reflecting expiration of carryforwards under applicable tax laws, at December 31, 2020 and 2019 are as follows: PNMR PNM TNMP (In thousands) December 31, 2020: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 407 $ 259 $ 148 December 31, 2019: State tax credit carryforwards $ 425 $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 311 $ 198 $ 113

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The excess purchase price over the fair value of the assets acquired and the liabilities assumed by PNMR for its 2005 acquisition of TNP was recorded as goodwill and was pushed down to the businesses acquired. In 2007, the TNMP assets that were included in its New Mexico operations, including goodwill, were transferred to PNM. PNMR’s reporting units that currently have goodwill are PNM and TNMP. The Company evaluates its goodwill for impairment annually at the reporting unit level or more frequently if circumstances indicate that the goodwill may be impaired. Application of the impairment test requires judgment, including the identification of reporting units, assignment of assets and liabilities to reporting units, and determination of the fair value of each reporting unit. In certain circumstances an entity may perform a qualitative analysis to conclude that the goodwill of a reporting unit is not impaired. Under a qualitative assessment an entity considers macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant entity-specific events affecting a reporting unit, as well as whether a sustained decrease (both absolute and relative to its peers) in share price has occurred. An entity considers the extent to which each of the adverse events and circumstances identified could affect the comparison of a reporting unit’s fair value with its carrying amount. An entity places more weight on the events and circumstances that most affect a reporting unit’s fair value or the carrying amount of its net assets. An entity also considers positive and mitigating events and circumstances that may affect its determination of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. An entity evaluates, on the basis of the weight of evidence, the significance of all identified events and circumstances in the context of determining whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative analysis is not required if, after assessing events and circumstances, an entity determines that it is not more likely than not that the fair value of a reporting unit is less than its carrying amount. In other circumstances, an entity may perform a quantitative analysis to reach the conclusion regarding impairment with respect to a reporting unit. An entity may choose to perform a quantitative analysis without performing a qualitative analysis and may perform a qualitative analysis for certain reporting units, but a quantitative analysis for others. The first step of the quantitative impairment test requires an entity to compare the fair value of the reporting unit with its carrying value, including goodwill. If as a result of this analysis, the entity concludes there is an indication of impairment in a reporting unit having goodwill, the amount of goodwill impairment to be recorded in the amount by which the carrying amount exceeds the reporting unit’s fair value. PNMR periodically updates its quantitative analysis for both PNM and TNMP. The use of a quantitative approach in a given period is not necessarily an indication that a potential impairment has been identified under a qualitative approach. When PNMR performs a quantitative analysis for PNM or TNMP, a discounted cash flow methodology is primarily used to estimate the fair value of the reporting unit. This analysis requires significant judgments, including estimations of future cash flows, which is dependent on internal forecasts, estimations of long-term growth rates for the business, and determination of appropriate weighted average cost of capital for the reporting unit. Changes in these estimates and assumptions could materially affect the determination of fair value and the conclusion of impairment. When PNMR performs a qualitative or quantitative analysis for PNM or TNMP, PNMR considers market and macroeconomic factors including changes in growth rates, changes in the WACC, and changes in discount rates. PNMR also evaluates its stock price relative to historical performance, industry peers, and to major market indices, including an evaluation of PNMR’s market capitalization relative to the carrying value of its reporting units. For the annual evaluations performed as of April 1, 2018, PNMR utilized a quantitative analysis for the PNM reporting unit and a qualitative analysis for the TNMP reporting unit. The April 1, 2018 quantitative evaluations indicated the fair value of the PNM reporting unit, which has goodwill of $51.6 million, exceeded its carrying value by approximately 19%. The 2018 qualitative analysis for the TNMP reporting unit was performed by considering changes in expectations of future financial performance since the April 1, 2016 quantitative analysis that indicated the fair value of the TNMP reporting unit, which has goodwill of $226.7 million, exceeded its carrying value by approximately 32%. The 2018 analysis considered events specific to TNMP such as the potential impacts of legal and regulatory matters discussed in Note 16 and Note 17, including potential adverse outcomes in the then pending TNMP 2018 Rate Case. Based on an evaluation of these and other factors, the Company determined it is not more likely than not that the April 1, 2018 carrying values of PNM or TNMP exceeded their fair values. For its annual evaluations performed as of April 1, 2019, PNMR performed qualitative analyses for both the PNM and TNMP reporting units. In addition to the typical considerations discussed above, the qualitative analysis considered changes in the Company’s expectations of future financial performance since the April 1, 2018 quantitative analysis performed for PNM, as well as the quantitative analysis performed for TNMP at April 1, 2016 and the previous qualitative analyses through April 1, 2018. This analysis considered Company specific events such as the potential impacts of legal and regulatory matters discussed in Note 16 and Note 17, including potential outcomes in PNM’s SJGS Abandonment Application, the impacts of the NM Supreme Court’s decision in the appeal of the NM 2015 Rate Case, and other potential impacts of changes in PNM’s resource needs based on PNM’s 2017 IRP. Based on an evaluation of these and other factors, the Company determined it was not more likely than not that the April 1, 2019 carrying values of PNM or TNMP exceeded their fair values.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions PNMR, PNM, TNMP, and NMRD are considered related parties, as is PNMR Services Company, a wholly-owned subsidiary of PNMR that provides corporate services to PNMR and its subsidiaries in accordance with shared services agreements. These services are billed at cost on a monthly basis to the business units. In addition, PNMR provides construction and operations and maintenance services to NMRD, a 50% owned subsidiary of PNMR Development (Note 21), and PNM purchases renewable energy from certain NMRD-owned facilities at a fixed price per MWh of energy produced. PNM also provides interconnection services to PNMR Development (Note 7) and NMRD. PNMR files a consolidated federal income tax return with its affiliated companies. A tax allocation agreement exists between PNMR and each of its affiliated companies. These agreements provide that the subsidiary company will compute its taxable income on a stand-alone basis. If the result is a net tax liability, such amount shall be paid to PNMR. If there are net operating losses and/or tax credits, the subsidiary shall receive payment for the tax savings from PNMR to the extent that PNMR is able to utilize those benefits. See Note 7 for information on intercompany borrowing arrangements. The table below summarizes the nature and amount of related party transactions of PNMR, PNM and TNMP: Year Ended December 31, 2020 2019 2018 (In thousands) Services billings: PNMR to PNM $ 100,872 $ 96,327 $ 95,637 PNMR to TNMP 39,053 36,554 33,493 PNM to TNMP 383 375 367 TNMP to PNMR 141 141 140 TNMP to PNM — — — PNMR to NMRD 260 238 183 Renewable energy purchases: PNM from NMRD 9,638 3,124 2,924 Interconnection and facility study billings: PNM to NMRD 350 650 2,108 PNM to PNMR — — 68,820 PNMR to PNM — 68,820 — Interest billings: PNMR to PNM 6 3,365 2,585 PNM to PNMR 255 299 289 PNMR to TNMP 2 42 136 Income tax sharing payments: PNMR to TNMP — — — PNMR to PNM — — — PNM to PNMR — — 134 TNMP to PNMR 15,820 12,996 3,424

Equity Method Investment

Equity Method Investment	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investment In September 2017, PNMR Development and AEP OnSite Partners created NMRD to pursue the acquisition, development, and ownership of renewable energy generation projects, primarily in the state of New Mexico. PNMR Development and AEP OnSite Partners each have a 50% ownership interest in NMRD. In December 2017, PNMR Development made a contribution to NMRD of its interest in three 10 MW solar facilities it was constructing and assigned its interests in several agreements related to those facilities to NMRD. The facilities had a book value of $24.8 million, which approximated fair value at that time. AEP OnSite Partners made a cash contribution to NMRD equal to 50% of the value of the 30 MW solar capacity, amounting to $12.4 million, which cash was then distributed from NMRD to PNMR Development. During 2020, 2019, and 2018 PNMR Development and AEP OnSite Partners each made cash contributions of $23.3 million, $38.3 million, and $9.0 million to NMRD for its construction activities. At December 31, 2020, NMRD’s renewable energy capacity in operation is 135.1 MW, which includes 130 MW of solar-PV facilities to supply energy to the Facebook data center located within PNM’s service territory, 1.9 MW to supply energy to Columbus Electric Cooperative located in southwest New Mexico, 2.0 MW to supply energy to the Central New Mexico Electric Cooperative, and 1.2 MW of solar-PV facilities to supply energy to the City of Rio Rancho, New Mexico. PNMR accounts for its investment in NMRD using the equity method of accounting because PNMR’s ownership interest results in significant influence, but not control, over NMRD and its operations. PNMR records as income its percentage share of earnings or loss of NMRD and carries its investment at cost, adjusted for its share of undistributed earnings or losses. PNMR presents its share of net earnings from NMRD in other income on the Consolidated Statements of Earnings. Summarized financial information for NMRD is as follows: December 31, 2020 2019 2018 (In thousands) Operating revenues $ 10,366 $ 3,662 $ 3,147 Operating expenses 7,476 2,971 2,136 Net earnings $ 2,890 $ 691 $ 1,011 Financial Position December 31, 2020 2019 (In thousands) Current assets $ 8,046 $ 7,187 Net property, plant, and equipment 172,585 132,772 Non-current assets 1,900 — Total assets 182,531 139,959 Current liabilities 841 9,640 Non-current liabilities $ 380 $ — Owners’ equity $ 181,310 $ 130,319

Merger

Merger	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Merger	Merger On October 20, 2020, PNMR, Avangrid, and Merger Sub, entered into the Merger Agreement pursuant to which Merger Sub will merge with and into PNMR, with PNMR surviving the Merger as a wholly-owned subsidiary of Avangrid. Pursuant to the Merger Agreement, each issued and outstanding share of the common stock of PNMR (other than (i) the issued shares of PNMR common stock that are owned by Avangrid, Merger Sub, PNMR or any wholly-owned subsidiary of Avangrid or PNMR, which will be automatically cancelled at the time the Merger is consummated (the "Effective Time") and (ii) shares of PNMR common stock outstanding immediately prior to the Effective Time and held by a holder who has not voted in favor of, or consented in writing to, the Merger who is entitled to, and who has demanded, payment for fair value of such shares) will be converted into the right to receive $50.30 in cash. The proposed Merger has been unanimously approved by the Boards of Directors of PNMR, Avangrid and Merger Sub and approved by PNMR shareholders at the Special Meeting of Shareholders held on February 12, 2021. On January 20, 2021, the FTC notified PNMR and Avangrid that early termination of the waiting period under the HSR Act in connection with the Merger was granted. CFIUS completed its review of the Merger on February 2, 2021, and has concluded that there are no unresolved national security concerns with respect to the Merger. The early termination of the waiting period under the HSR Act and clearance by CFIUS satisfies two of the conditions to the closing of the transactions contemplated by the Merger Agreement. Consummation of the Merger remains subject to the satisfaction or waiver of certain customary closing conditions, including, without limitation, the absence of any material adverse effect on PNMR, the receipt of required regulatory approvals (including the PUCT, the NMPRC, FERC, the FCC, and the NRC) and the agreements relating to the divestiture of Four Corners being in full force and effect and all applicable regulatory filings associated therewith being made. The Merger is currently expected to close in the second half of 2021. In connection with the Merger, Iberdrola, S.A. a corporation organized under the laws of the Kingdom of Spain, which owns 81.5% of the outstanding common stock of Avangrid (“Iberdrola”), has provided Avangrid a commitment letter (the "Iberdrola Funding Commitment Letter"), pursuant to which Iberdrola has unilaterally agreed to provide to Avangrid, or arrange the provision to Avangrid of, funds to the extent necessary for Avangrid to consummate the Merger, including the payment of the aggregate Merger consideration. To the extent Avangrid wishes to effect a funding transaction under the Iberdrola Funding Commitment Letter in order to pay the Merger consideration, the specific terms of any such transaction will be negotiated between Iberdrola and Avangrid on an arm's length basis and must be approved by both (i) a majority of the members of the unaffiliated committee of the board of directors of Avangrid, and (ii) the entire board of directors of Avangrid. Under the terms of such commitment letter, Iberdrola has agreed to negotiate with Avangrid the specific terms of any transaction effecting such funding commitment promptly and in good faith, with the objective that such terms shall be commercially reasonable and approved by Avangrid. Avangrid’s and Merger Sub’s obligations under the Merger Agreement are not conditioned upon Avangrid obtaining financing. The Merger Agreement provides for certain customary termination rights including the right of either party to terminate the Merger Agreement if the Merger is not completed on or before January 20, 2022 (subject to a three-month extension by either party if all of the conditions to the closing, other than the conditions related to obtaining regulatory approvals, have been satisfied or waived). The Merger Agreement further provides that, upon termination of the Merger Agreement under certain specified circumstances (including if Avangrid terminates the Merger Agreement due to a change in recommendation of the Board or if PNMR terminates the Merger Agreement to accept a superior proposal (as defined in the Merger Agreement)), PNMR will be required to pay Avangrid a termination fee of $130.0 million. In addition, the Merger Agreement provides that (i) if the Merger Agreement is terminated by either party due to a failure of a regulatory closing condition and such failure is the result of Avangrid’s breach of its regulatory covenants, or (ii) Avangrid fails to effect the closing when all closing conditions have been satisfied and it is otherwise obligated to do so under the Merger Agreement, then, in either such case, upon termination of the Merger Agreement, Avangrid will be required to pay PNMR a termination fee of $184.0 million as the sole

Quarterly Operating Results (Un

Quarterly Operating Results (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Data [Abstract]
Quarterly Operating Results (Unaudited)	Quarterly Operating Results (Unaudited) Unaudited operating results by quarters for 2020 and 2019 are presented below. In the opinion of management of the Company, all adjustments (consisting of normal recurring accruals) necessary for a fair statement of the results of operations for such periods have been included. The annual results of basic and diluted earnings per share shown below may be impacted by rounding. Quarter Ended March 31 June 30 September 30 December 31 (In thousands, except per share amounts) PNMR 2020 Operating revenues $ 333,622 $ 357,649 $ 472,465 $ 359,276 Operating income 47,738 71,150 147,805 18,588 Net earnings (loss) (11,399) 61,561 125,453 11,701 Net earnings (loss) attributable to PNMR (15,260) 57,489 121,768 8,778 Net earnings (loss) attributable to PNMR per common share: Basic (0.19) 0.72 1.52 0.11 Diluted (0.19) 0.72 1.52 0.10 2019 (1) Operating revenues $ 349,645 $ 330,228 $ 433,586 $ 344,144 Operating income (loss) 36,723 (93,615) 140,540 60,552 Net earnings (loss) 21,662 (72,283) 106,763 35,989 Net earnings (loss) attributable to PNMR 18,700 (75,914) 102,771 31,805 Net earnings attributable to PNMR per common share: Basic 0.23 (0.95) 1.29 0.40 Diluted 0.23 (0.95) 1.28 0.40 PNM 2020 Operating revenues $ 248,133 $ 260,788 $ 364,504 $ 266,409 Operating income 33,605 49,584 116,540 15,168 Net earnings (loss) (12,196) 49,612 103,004 19,594 Net earnings (loss) attributable to PNM (15,925) 45,672 99,451 16,803 2019 (1) Operating revenues $ 269,318 $ 238,219 $ 331,113 $ 255,172 Operating income (loss) 24,293 (115,977) 108,453 44,299 Net earnings (loss) 21,974 (83,313) 84,721 32,040 Net earnings (loss) attributable to PNM 19,144 (86,812) 80,861 27,988 TNMP 2020 Operating revenues $ 85,489 $ 96,861 $ 107,961 $ 92,867 Operating income 14,345 23,175 31,779 19,154 Net earnings 7,092 16,174 23,921 11,398 2019 Operating revenues $ 80,327 $ 92,009 $ 102,473 $ 88,972 Operating income 12,585 22,578 32,596 18,055 Net earnings 4,098 15,267 25,087 11,347 (1) 2019 reflects pre-tax impairments of $150.6 million offset by $45.7 million of related tax impacts resulting from the NM Supreme Court’s ruling on the appeals in the NM 2015 Rate Case. See Note 17.

Schedule I - Condensed Financia

Schedule I - Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Schedule I - Condensed Financial Information of Parent Company	SCHEDULE I PNM RESOURCES, INC. CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY STATEMENTS OF EARNINGS Year ended December 31, 2020 2019 2018 (In thousands) Operating Revenues $ — $ — $ — Operating Expenses 28,299 3,983 7,475 Operating income (loss) (28,299) (3,983) (7,475) Other Income and Deductions: Equity in earnings of subsidiaries 211,291 96,324 109,995 Other income (269) 731 2,048 Net other income and deductions 211,022 97,055 112,043 Interest Charges 19,078 19,581 19,453 Earnings Before Income Taxes 163,645 73,491 85,115 Income Tax Expense (Benefit) (9,130) (3,872) (527) Net Earnings $ 172,775 $ 77,363 $ 85,642 SCHEDULE I PNM RESOURCES, INC. CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY STATEMENTS OF CASH FLOWS Year Ended December 31, 2020 2019 2018 (In thousands) Cash Flows From Operating Activities: Net Cash Flows From Operating Activities $ (17,646) $ 2,001 $ (2,566) Cash Flows From Investing Activities: Utility plant additions 1,122 1,100 826 Investments in subsidiaries (301,000) (80,000) (30,000) Cash dividends from subsidiaries 99,187 54,465 129,379 Net cash flows from investing activities (200,691) (24,435) 100,205 Cash Flows From Financing Activities: Short-term loan borrowings (repayments) — (150,000) 50,000 Revolving credit facility borrowings (repayments), net (131,900) 123,900 (148,700) Long-term borrowings 230,000 150,000 349,652 Repayment of long-term debt (50,000) — (250,000) Issuance of common stock 283,208 — — Proceeds from stock option exercise 24 943 963 Awards of common stock (11,984) (9,918) (12,635) Dividends paid (97,974) (92,398) (84,433) Other, net (3,064) (107) (2,414) Net cash flows from financing activities 218,310 22,420 (97,567) Change in Cash and Cash Equivalents (27) (14) 72 Cash and Cash Equivalents at Beginning of Period 79 93 21 Cash and Cash Equivalents at End of Period $ 52 $ 79 $ 93 Supplemental Cash Flow Disclosures: Interest paid, net of amounts capitalized $ 16,869 $ 18,702 $ 15,450 Income taxes paid (refunded), net $ — $ — $ — SCHEDULE I PNM RESOURCES, INC. CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY BALANCE SHEETS December 31, 2020 2019 (In thousands) Assets Cash and cash equivalents $ 52 $ 79 Intercompany receivables 71,567 79,059 Income taxes receivable — 4,635 Other, net 5,545 2,876 Total current assets 77,164 86,649 Property, plant and equipment, net of accumulated depreciation of $15,706 and $14,583 23,191 24,313 Investment in subsidiaries 2,631,567 2,197,918 Other long-term assets 58,695 55,077 Total long-term assets 2,713,453 2,277,308 $ 2,790,617 $ 2,363,957 Liabilities and Stockholders’ Equity Short-term debt $ 12,000 $ 112,100 Short-term debt-affiliate 8,819 40,619 Current maturities of long-term debt 229,948 50,000 Accrued interest and taxes 8,124 5,239 Other current liabilities 29,549 25,450 Total current liabilities 288,440 233,408 Long-term debt 449,909 449,048 Other long-term liabilities 2,803 2,803 Total liabilities 741,152 685,259 Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 85,834,874 shares) 1,429,941 1,150,552 Accumulated other comprehensive income (loss), net of tax (79,183) (99,377) Retained earnings 698,707 627,523 Total common stockholders’ equity 2,049,465 1,678,698 $ 2,790,617 $ 2,363,957 See Notes 7, 8, 14, and 16 for information regarding commitments, contingencies, and maturities of long-term debt.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	SCHEDULE II PNM RESOURCES, INC. AND SUBSIDIARIES VALUATION AND QUALIFYING ACCOUNTS Additions Deductions Description Balance at Charged to Charged to Write-offs and other Balance at (In thousands) Allowance for doubtful accounts, year ended December 31: 2018 $ 1,081 $ 3,360 $ — $ 3,035 $ 1,406 2019 $ 1,406 $ 2,835 $ — $ 3,078 $ 1,163 2020 $ 1,163 $ 3,527 $ 6,070 $ 2,427 $ 8,333 SCHEDULE II PUBLIC SERVICE COMPANY OF NEW MEXICO AND SUBSIDIARY A WHOLLY-OWNED SUBSIDIARY OF PNM RESOURCES, INC. VALUATION AND QUALIFYING ACCOUNTS Additions Deductions Description Balance at Charged to Charged to Write-offs and other Balance at (In thousands) Allowance for doubtful accounts, year ended December 31: 2018 $ 1,081 $ 3,338 $ — $ 3,013 $ 1,406 2019 $ 1,406 $ 2,790 $ — $ 3,033 $ 1,163 2020 $ 1,163 $ 3,482 $ 6,070 $ 2,382 $ 8,333 SCHEDULE II TEXAS-NEW MEXICO POWER COMPANY AND SUBSIDIARIES A WHOLLY-OWNED SUBSIDIARY OF PNM RESOURCES, INC. VALUATION AND QUALIFYING ACCOUNTS Additions Deductions Description Balance at Charged to Charged to Write-offs and other Balance at (In thousands) Allowance for doubtful accounts, year ended December 31: 2018 $ — $ 22 $ — $ 22 $ — 2019 $ — $ 44 $ — $ 44 $ — 2020 $ — $ 45 $ — $ 45 $ —

Summary of the Business and S_2

Summary of the Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Financial Statement Preparation and Presentation	Financial Statement Preparation and Presentation The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could ultimately differ from those estimated.
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements of each of PNMR, PNM, and TNMP include their accounts and those of subsidiaries in which that entity owns a majority voting interest. PNM also consolidates Valencia (Note 10). PNM owns undivided interests in several jointly-owned power plants and records its pro-rata share of the assets, liabilities, and expenses for those plants. The agreements for the jointly-owned plants provide that if an owner were to default on its payment obligations, the non-defaulting owners would be responsible for their proportionate share of the obligations of the defaulting owner. In exchange, the non-defaulting owners would be entitled to their proportionate share of the generating capacity of the defaulting owner. There have been no such payment defaults under any of the agreements for the jointly-owned plants.
Accounting for the Effects of Certain Types of Regulation	Accounting for the Effects of Certain Types of Regulation The Company maintains its accounting records in accordance with the uniform system of accounts prescribed by FERC and adopted by the NMPRC and PUCT. Certain of the Company’s operations are regulated by the NMPRC, PUCT, and FERC and the provisions of GAAP for rate-regulated enterprises are applied to the regulated operations. Regulators may assign costs to accounting periods that differ from accounting methods applied by non-regulated utilities. When it is probable that regulators will permit recovery of costs through future rates, costs are deferred as regulatory assets that otherwise would be expensed. Likewise, regulatory liabilities are recognized when it is probable that regulators will require refunds through future rates or when revenue is collected for expenditures that have not yet been incurred. GAAP also provides for the recognition of revenue and regulatory assets and liabilities associated with “alternative revenue programs” authorized by regulators. Such programs allow the utility to adjust future rates in response to past activities or completed events, if certain criteria are met. Regulatory assets and liabilities are amortized into earnings over the authorized recovery period. Accordingly, the Company has deferred certain costs and recorded certain liabilities pursuant to the rate actions of the NMPRC, PUCT, and FERC. Information on regulatory assets and regulatory liabilities is contained in Note 13. In some circumstances, regulators allow a requested increase in rates to be implemented, subject to refund, before the regulatory process has been completed and a decision rendered by the regulator. When this occurs, the Company assesses the possible outcomes of the rate proceeding. The Company records a provision for refund to the extent the amounts being collected, subject to refund, exceed the amount the Company determines is probable of ultimately being allowed by the regulator.
Cash and Restricted Cash	Cash and Restricted Cash Cash deposits received and held for a period of time that are restricted to a specific purpose, under the terms of their effective agreements, are considered restricted cash. Investments in highly liquid investments with original maturities of three months or less at the date of purchase are considered cash and cash equivalents. At December 31, 2020 and 2019 there was no restricted cash for PNMR, PNM, and TNMP.
Utility Plant	Utility Plant Utility plant is stated at original cost and includes capitalized payroll-related costs such as taxes, pension, other fringe benefits, administrative costs, and AFUDC, where authorized by rate regulation, or capitalized interest. Repairs, including major maintenance activities, and minor replacements of property are expensed when incurred, except as required by regulators for ratemaking purposes. Major replacements are charged to utility plant. Gains, losses, and costs to remove resulting from retirements or other dispositions of regulated property in the normal course of business are credited or charged to accumulated depreciation. PNM and TNMP may receive reimbursements, referred to as CIAC, from customers to pay for all or part of certain construction projects to the extent the project does not benefit regulated customers in general. PNM and TNMP account for these reimbursements as offsets to utility plant additions based on the requirements of the NMPRC, FERC, and PUCT. Due to the PUCT’s regulatory treatment of CIAC reimbursements, TNMP also receives a financing component that is recognized as other income on the Consolidated Statements of Earnings. Under the NMPRC regulatory treatment, PNM typically does not receive a financing component.
Depreciation and Amortization	Depreciation and AmortizationPNM’s provision for depreciation and amortization of utility plant, other than nuclear fuel, is based upon straight-line rates approved by the NMPRC and FERC. Amortization of nuclear fuel is based on units-of-production. TNMP’s provision for depreciation and amortization of utility plant is based upon straight-line rates approved by the PUCT. Depreciation and amortization of non-utility property, including right-of-use assets for finance leases as discussed in Note 8, is computed based on the straight-line method. The provision for depreciation of certain equipment is allocated between operating expenses and construction projects based on the use of the equipment.
Allowance for Funds Used During Construction	Allowance for Funds Used During Construction As provided by the FERC uniform systems of accounts, AFUDC is charged to regulated utility plant for construction projects. This allowance is designed to enable a utility to capitalize financing costs during periods of construction of property subject to rate regulation. It represents the cost of borrowed funds (allowance for borrowed funds used during construction or
Materials, Supplies, and Fuel Stock	Materials, Supplies, and Fuel Stock Materials and supplies relate to transmission, distribution, and generating assets. Materials and supplies are charged to inventory when purchased and are expensed or capitalized as appropriate when issued. Materials and supplies are valued using an average costing method. Coal is valued using a rolling weighted average costing method that is updated based on the current period cost per ton. Periodic aerial surveys are performed on the coal piles and adjustments are made. Average cost is equal to net realizable value under the ratemaking process.
Investments	Investments PNM holds investment securities in the NDT for the purpose of funding its share of the decommissioning costs of PVNGS and trusts for PNM’s share of final reclamation costs related to the coal mines serving SJGS and Four Corners (Note 16). Since third party investment managers have sole discretion over the purchase and sale of the securities, PNM records a realized loss as an impairment for any available-for-sale debt security that has a market value that is less than cost at the end of each quarter. Effective January 1, 2018, the Company adopted Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10), which eliminates the requirement to classify investments in equity securities with readily determinable fair values into trading or available-for-sale categories and requires those equity securities to be measured at fair value with changes in fair value recognized in earnings rather than in OCI. On January 1, 2018, PNM recorded a cumulative effect adjustment to reclassify unrealized holding gains on equity securities held in the NDT and coal mine reclamation trusts from AOCI to retained earnings on the Consolidated Balance Sheets. For the years ended December 31, 2020, 2019 and 2018, PNM recorded impairment losses on the available-for-sale debt securities of $3.2 million, $5.7 million and $13.7 million. No gains or losses are deferred as regulatory assets or liabilities. See Notes 3 and 9. All investments are held in PNM’s name and are in the custody of major financial institutions. The specific identification method is used to determine the cost of securities disposed of, with realized gains and losses reflected in other income and deductions. On January 1, 2020, the Company adopted Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which changed the way entities recognize impairments of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining lives of the assets. The majority of the amendments made by the new standard were required to be applied using a modified retrospective approach. The amendments in ASU 2016-13 also required entities to separately measure and realize an impairment for credit losses on available-for-sale debt securities for which carrying value exceeded fair value, unless such securities have been determined to be other than temporarily impaired and the entire decrease in value had been realized as an impairment. The amendments relating to available-for-sale debt securities were required to be applied prospectively on the date of adoption. PNM records a realized loss as an impairment for any available-for-sale debt security that has a fair value that is less than its carrying value. As a result, the Company has no available-for-sale debt securities for which carrying value exceeds fair value and there are no impairments considered to be “other than temporary” that are included in AOCI and not recognized in earnings. Adoption of the standard did not result in the Company recording a cumulative effect adjustment or impact the Company's accounting for its available-for-sale debt securities. All gains and losses resulting from sales and changes in the fair value of equity securities are recognized immediately in earnings.
Equity Method Investment	Equity Method InvestmentPNMR accounts for its investment in NMRD using the equity method of accounting because PNMR’s ownership interest results in significant influence, but not control, over NMRD and its operations.  PNMR records as income its percentage share of earnings or loss of NMRD and carries its investment at cost, adjusted for its share of undistributed earnings or losses.
Goodwill	Goodwill The Company does not amortize goodwill. Goodwill is evaluated for impairment annually, or more frequently if events and circumstances indicate that the goodwill might be impaired.
Asset Impairment	Asset ImpairmentTangible long-lived assets and right-of-use assets associated with leases are evaluated in relation to the estimated future undiscounted cash flows to assess recoverability when events and circumstances indicate that the assets might be impaired.
Accounts Receivable and Allowance for Credit Losses	Accounts Receivable and Allowance for Credit Losses Accounts receivable consists primarily of trade receivables from customers. In the normal course of business, credit is extended to customers on a short-term basis. PNM estimates the allowance for credit losses on trade receivables based on historical experience and estimated default rates. Accounts receivable balances are reviewed monthly, adjustments to the allowance for credit losses are made as necessary, and amounts that are deemed uncollectible are written off. See Note 4. TNMP has a regulatory mechanism to recover uncollectible amounts from REPs as a regulatory asset and as a result has no allowance for credit losses on trade receivables .
Amortization of Debt Acquisition Costs	Amortization of Debt Acquisition Costs Discount, premium, and expense related to the issuance of long-term debt are amortized over the lives of the respective issues. Gains and losses incurred upon the early retirement of long-term debt are recognized in other income or other deductions, except for amounts recoverable through NMPRC, FERC, or PUCT regulation, which are recorded as regulatory assets or liabilities and amortized over the lives of the respective issues. Unamortized premium, discount, and expense related to long-term debt are reflected as part of the related liability on the Consolidated Balance Sheets.
Derivatives	Derivatives The Company records derivative instruments, including energy contracts, on the balance sheet as either an asset or liability measured at their fair value. Changes in the derivatives’ fair value are recognized in earnings unless specific hedge accounting criteria are met. PNM also records certain commodity derivative transactions recoverable through NMPRC regulation as regulatory assets or liabilities. See Note 7 and Note 9. Accounting for Derivatives Under derivative accounting and related rules for energy contracts, PNM accounts for its various instruments for the purchase and sale of energy, which meet the definition of a derivative, based on PNM’s intent. During the years ended December 31, 2020, 2019, and 2018, PNM was not hedging its exposure to the variability in future cash flows from commodity derivatives through designated cash flow hedges. The derivative contracts recorded at fair value that do not qualify or are not designated for cash flow hedge accounting are classified as economic hedges. Economic hedges are defined as derivative instruments, including long-term power agreements, used to economically hedge generation assets, purchased power and fuel costs, and customer load requirements. Changes in the fair value of economic hedges are reflected in results of operations and are classified between operating revenues and cost of energy according to the intent of the hedge. PNM has no trading transactions.
Decommissioning and Reclamation Costs	Decommissioning and Reclamation Costs PNM is only required to recognize and measure decommissioning liabilities for tangible long-lived assets for which a legal obligation exists. Nuclear decommissioning costs and related accruals are based on periodic site-specific estimates of the costs for removing all radioactive and other structures at PVNGS and are dependent upon numerous assumptions, including
Environmental Costs	Environmental Costs The normal operations of the Company involve activities and substances that expose the Company to potential liabilities under laws and regulations protecting the environment. Liabilities under these laws and regulations can be material and may be imposed without regard to fault, or may be imposed for past acts, even though the past acts may have been lawful at the time they occurred.
Income Taxes	Income Taxes Income taxes are recognized using the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying value of existing assets and liabilities and their respective tax basis. All deferred taxes are reflected as non-current on the Consolidated Balance Sheets. Current NMPRC, FERC, and PUCT approved rates include the tax effects of the majority of these differences. Rate-regulated enterprises are required to record deferred income taxes for temporary differences accorded flow-through treatment at the direction of a regulatory commission. The resulting deferred tax assets and liabilities are recorded based on the expected cash flow to be reflected in future rates. Because the NMPRC, FERC, and the PUCT have consistently permitted the recovery of tax effects previously flowed-through earnings, the Company has established regulatory assets and liabilities offsetting such deferred tax assets and liabilities. The Company recognizes only the impact of tax positions that, based on their merits, are more likely than not to be sustained upon an IRS audit. The Company defers investment tax credits and amortizes them over the estimated useful lives of the assets. See Note 18 for additional information, including a discussion of the impacts of the Tax Act. The Company makes an estimate of its anticipated effective tax rate for the year as of the end of each quarterly period within its fiscal year. In interim periods, income tax expense is calculated by applying the anticipated annual effective tax rate to year-to-date earnings before taxes, which includes the earnings attributable to the Valencia non-controlling interest. Certain unusual or infrequently occurring items, as well as adjustments due to enactment of new tax laws, have been excluded from the estimated annual effective tax rate calculation.
New Accounting Pronouncements	New Accounting Pronouncements Information concerning recently issued accounting pronouncements that have not been adopted by the Company is presented below. The Company does not expect difficulty in adopting these standards by their required effective dates. Accounting Standards Update 2019-12 – Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12 as part of its initiative to reduce complexity in accounting standards. The amendments in ASU 2019-12 simplify accounting for income taxes by removing several accounting exceptions to accounting for income taxes. ASU 2019-12 also eliminates or simplifies other income tax accounting requirements, including a requirement that entities recognize franchise tax (or similar tax) that is partially based on income as an income-based tax. ASU 2019-12 is effective for the Company beginning on January 1, 2021 and allows for early adoption. ASU 2019-12 is to be applied prospectively or retrospectively in the period of adoption depending on the type of amendment. The Company is in the process of analyzing the impacts of this new standard.
Segment Information	The following segment presentation is based on the methodology that management uses for making operating decisions and assessing performance of its various business activities. A reconciliation of the segment presentation to the GAAP financial statements is provided.
Revenue Recognition	Electric operating revenues are recorded in the period of energy delivery, which includes estimated amounts for service rendered but unbilled at the end of each accounting period. The determination of the energy sales billed to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading and the corresponding unbilled revenue are estimated. Unbilled electric revenue is estimated based on daily generation volumes, estimated customer usage by class, line losses, historical trends and experience, applicable customer rates or by using AMS data where available. Amounts billed are generally due within the next month. The Company does not incur incremental costs to obtain contracts for its energy services. PNM’s wholesale electricity sales are recorded as electric operating revenues and wholesale electricity purchases are recorded as costs of energy sold. Derivative contracts that are subject to unplanned netting are recorded net in earnings. A “book-out” is the planned or unplanned netting of off-setting purchase and sale transactions. A book-out is a transmission mechanism to reduce congestion on the transmission system or administrative burden. For accounting purposes, a book-out is the recording of net revenues upon the settlement of a derivative contract. Unrealized gains and losses on derivative contracts that are not designated for hedge accounting are classified as economic hedges. Economic hedges are defined as derivative instruments, including long-term power and fuel supply agreements, used to hedge generation assets and purchased power costs. Changes in the fair value of economic hedges are reflected in results of operations, with changes related to economic hedges on sales included in operating revenues and changes related to economic hedges on purchases included in cost of energy sold. See Note 9. The Company adopted ASU 2014-09 – Revenue from Contracts with Customers (Topic 606) as of January 1, 2018, its required effective date, using the modified retrospective method of adoption. The adoption of ASU 2014-09 did not result in changes to the nature, amount, and timing of the Company’s existing revenue recognition processes or information technology infrastructure. Therefore, the adoption of ASU 2014-09 had no effect on the amount of revenue recorded in 2018 compared to the amount that would have been recorded under prior GAAP, no effect on total electric operating revenues or any other caption within the Company’s financial statements, and no cumulative effect adjustment was recorded. Additional disclosures to further disaggregate 2020, 2019 and 2018 revenues are presented below. The Company adopted ASU 2018-18 – Collaborative Arrangements (Topic 808) in 2019, ahead of its required effective date, using the retrospective method of adoption. The Company has collaborative arrangements related to its interest in SJGS, Four Corners, PVNGS, and Luna. The Company has determined that during the years ended December 31, 2020, 2019, and 2018 none of the joint owners in its collaborative arrangements were customers under Topic 606. Therefore, the adoption of this standard did not impact the financial statements. The Company will continue to evaluate transactions between collaborative arrangement participants in future periods under the requirements of the new standard. PNM and TNMP recognize revenue as they satisfy performance obligations, which typically occurs as the customer or end-user consumes the electric service provided. Electric services are typically for a bundle of services that are distinct and transferred to the end-user in one performance obligation measured by KWh or KW. Electric operating revenues are recorded in the period of energy delivery, including estimated unbilled amounts. The Company has elected to exclude all sales and similar taxes from revenue. Revenue from contracts with customers is recorded based upon the total authorized tariff price at the time electric service is rendered, including amounts billed under arrangements qualifying as an Alternative Revenue Program (“ARP”). ARP arrangements are agreements between PNM or TNMP and its regulator that allow PNM or TNMP to adjust future rates in response to past activities or completed events, if certain criteria are met. ARP revenues are required to be reported separately from contracts with customers. ARP revenues in a given period include the recognition of “originating” ARP revenues (i.e. when the regulator-specific conditions are met) in the period, offset by the reversal of ARP revenues when billed to customers. Sources of Revenue Additional information about the nature of revenues is provided below. Additional information about matters affecting PNM’s and TNMP’s regulated revenues is provided in Note 17. Revenue from Contracts with Customers PNM NMPRC Regulated Retail Electric Service – PNM provides electric generation, transmission, and distribution service to its rate-regulated customers in New Mexico. PNM’s retail electric service territory covers a large area of north central New Mexico, including the cities of Albuquerque, Rio Rancho, and Santa Fe, and certain areas of southern New Mexico. Customer rates for retail electric service are set by the NMPRC and revenue is recognized as energy is delivered to the customer. PNM invoices customers on a monthly basis for electric service and generally collects billed amounts within one month. Transmission Service to Third Parties – PNM owns transmission lines that are interconnected with other utilities in New Mexico, Texas, Arizona, Colorado, and Utah. Transmission customers receive service for the transmission of energy owned by the customer utilizing PNM’s transmission facilities. Customers generally receive transmission services, which are regulated by FERC, from PNM through PNM’s Open Access Transmission Tariff (“OATT”) or a specific contract. Customers are billed based on capacity and energy components on a monthly basis. Miscellaneous – Beginning on January 1, 2018, PNM acquired a 65 MW interest in SJGS Unit 4, which is held as merchant plant as ordered by the NMPRC (Note 16). PNM sells power from 36 MW of this capacity to a third party at a fixed price that is recorded as revenue from contracts with customers. PNM is obligated to deliver power under this arrangement only when SJGS Unit 4 is operating. Other market sales from this 65 MW interest are recorded in other electric operating revenues. TNMP PUCT Regulated Retail Electric Service – TNMP provides transmission and distribution services in Texas under the provisions of TECA and the Texas Public Utility Regulatory Act. TNMP is subject to traditional cost-of-service regulation with respect to rates and service under the jurisdiction of the PUCT and certain municipalities. TNMP’s transmission and distribution activities are solely within ERCOT and not subject to traditional rate regulation by FERC. TNMP provides transmission and distribution services at regulated rates to various REPs that, in turn, provide retail electric service to consumers within TNMP’s service territory. Revenue is recognized as energy is delivered to the consumer. TNMP invoices REPs on a monthly basis and is generally paid within a month. Transmission Cost of Service (“TCOS”) – TNMP is a transmission service provider that is allowed to recover its TCOS through a network transmission rate that is approved by the PUCT. TCOS customers are other utilities that receive service for the transmission of energy owned by the customer utilizing TNMP’s transmission facilities. Alternative Revenue Programs The Company defers certain costs and records certain liabilities pursuant to the rate actions of the NMPRC, PUCT, and FERC. ARP revenues, which are discussed above, include recovery or refund provisions under PNM’s renewable energy rider and true-ups to PNM’s formula transmission rates; TNMP’s AMS surcharge, transmission cost recovery factor, and the impacts of the PUCT’s January 25, 2018 order regarding the change in the federal corporate income tax rate; and the energy efficiency incentive bonus at both PNM and TNMP. Regulatory assets and liabilities are recognized for the difference between ARP revenues and amounts billed under those programs. Regulatory assets and liabilities are amortized into earnings as amounts are billed. As discussed in Note 17, TNMP’s 2018 Rate Case integrated AMS costs into base rates beginning January 1, 2019. These costs are being amortized into earnings as alternative revenues over a period of five years. Other Electric Operating Revenues Other electric operating revenues consist primarily of PNM’s sales for resale meeting the definition of a derivative. Derivatives are not considered revenue from contracts with customers. PNM engages in activities meeting the definition of derivatives to optimize its existing jurisdictional assets and long-term power agreements through spot market, hour-ahead, day-ahead, week-ahead, month-ahead, and other sales of excess generation not required to fulfill retail load and contractual commitments.
Fair Value of Derivatives	The Company determines the fair values of its derivative and other financial instruments based on the hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. For investment securities, Level 2 and Level 3 fair values are provided by fund managers utilizing a pricing service. For Level 2 fair values, the pricing provider predominantly uses the market approach using bid side market values based upon a hierarchy of information for specific securities or securities with similar characteristics. Fair values of Level 2 investments in mutual funds are equal to net asset value. For commodity derivatives, Level 2 fair values are determined based on market observable inputs, which are validated using multiple broker quotes, including forward price, volatility, and interest rate curves to establish expectations of future prices. Credit valuation adjustments are made for estimated credit losses based on the overall exposure to each counterparty. For the Company’s long-term debt, Level 2 fair values are provided by an external pricing service. The pricing service primarily utilizes quoted prices for similar debt in active markets when determining fair value. The valuation of Level 3 investments, when applicable, requires significant judgment by the pricing provider due to the absence of quoted market values, changes in market conditions, and the long-term nature of the assets. The Company has no Level 3 investments as of December 31, 2020 and 2019. Management of the Company independently verifies the information provided by pricing services. In August 2018, the FASB issued Accounting Standards Update 2018-13 – Fair Value Measurements (Topic 820) Disclosure Framework: Changes to the Disclosure Requirements for Fair Value Measurements, to improve fair value disclosures. ASU 2018-13 eliminates certain disclosure requirements related to transfers between Levels 1 and 2 of the fair value hierarchy and the requirement to disclose the valuation process for Level 3 fair value measurements. ASU 2018-13 also amends certain disclosure requirements for investments measured at net asset value and requires new disclosures for Level 3 investments, including a new requirement to disclose changes in unrealized gains or losses recorded in OCI related to Level 3 fair value measurements. The Company adopted ASU 2018-13 on January 1, 2020, its required effective date. The Company applied the requirements of the new standard using retrospective application, except for the new disclosures related to Level 3 investments, which are to be applied prospectively. Adoption of the standard did not have a material impact on the Company's disclosures.
Variable Interest Entities	How an enterprise evaluates and accounts for its involvement with variable interest entities, focuses primarily on whether the enterprise has the power to direct the activities that most significantly impact the economic performance of a variable interest entity (“VIE”). This evaluation requires continual reassessment of the primary beneficiary of a VIE.
Pension and Other Postretirement Benefits	A plan sponsor is required to (a) recognize in its statement of financial position an asset for a plan’s overfunded status or a liability for a plan’s underfunded status; (b) measure a plan’s assets and its obligations that determine its funded status as of the end of the employer’s fiscal year; and (c) recognize changes in the funded status of a defined benefit postretirement plan in the year in which the changes occur. Unrecognized prior service costs and unrecognized gains or losses are required to be recorded in AOCI and subsequently amortized. To the extent the amortization of these items will ultimately be recovered or returned through future rates, PNM and TNMP record the costs as a regulatory asset or regulatory liability. The amortization of these incurred costs is included as pension and postretirement benefit periodic cost or income in subsequent years. The Company maintains trust funds for the pension and OPEB plans from which benefits are paid to eligible employees and retirees. The Company’s funding policy is to make contributions to the trusts, as determined by an independent actuary, that comply with minimum guidelines of the Employee Retirement Income Security Act and the IRC. Information concerning the investments is contained in Note 9. The Company has in place a policy that defines the investment objectives, establishes performance goals of asset managers, and provides procedures for the manner in which investments are to be reviewed. The plans implement investment strategies to achieve the following objectives: • Implement investment strategies commensurate with the risk that the Corporate Investment Committee deems appropriate to meet the obligations of the pension plans and OPEB plans, minimize the volatility of expense, and account for contingencies • Transition asset mix over the long-term to a higher proportion of high-quality fixed income investments as the plans’ funded statuses improve Management is responsible for the determination of the asset target mix and the expected rate of return. The target asset allocations are determined based on consultations with external investment advisors. The expected long-term rate of return on pension and postretirement plan assets is calculated on the market-related value of assets. Actual gains and losses on pension and OPEB plan assets are recognized in the market-related value of assets equally over a period of not more than five years, which reduces year-to-year volatility. For the PNM Plans and TNMP Plans, the market-related value of assets is equal to the prior year’s market-related value of assets adjusted for contributions, benefit payments and investment gains and losses that are within a corridor of plus or minus 4.0% around the expected return on market value. Gains and losses that are outside the corridor are amortized over five years. In August 2018, the FASB issued Accounting Standards Update 2018-14 - Compensation Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) to improve benefit plan sponsors’ disclosures for defined benefit pension and other post-employment benefit plans. ASU 2018-14 removes the requirement to disclose the amounts in other comprehensive income expected to be recognized as benefit cost over the next fiscal year and the requirement to disclose the impact of a one-percentage-point change in the assumed heath care cost trend rate. ASU 2018-14 clarifies the disclosure requirements for plans with PBOs and ABOs that are in excess of plan assets and requires an explanation for significant gains and losses related to changes in the benefit obligation during the period be disclosed. The Company has adopted ASU 2018-14 for the period ended December 31, 2020, its required effective date by modifying the disclosures herein as appropriate.
Commitments and Contingencies	There are various claims and lawsuits pending against the Company. In addition, the Company is subject to federal, state, and local environmental laws and regulations and periodically participates in the investigation and remediation of various sites. In addition, the Company periodically enters into financial commitments in connection with its business operations. Also, the Company is involved in various legal and regulatory proceedings in the normal course of its business. See Note 17. It is not possible at this time for the Company to determine fully the effect of all litigation and other legal and regulatory proceedings on its financial position, results of operations, or cash flows. With respect to some of the items listed below, the Company has determined that a loss is not probable or that, to the extent probable, cannot be reasonably estimated. In some cases, the Company is not able to predict with any degree of certainty the range of possible loss that could be incurred. The Company assesses legal and regulatory matters based on current information and makes judgments concerning their potential outcome, giving due consideration to the nature of the claim, the amount and nature of any damages sought, and the probability of success. Such judgments are made with the understanding that the outcome of any litigation, investigation, or other legal proceeding is inherently uncertain. The Company records liabilities for matters where it is probable a loss has been incurred and the amount of loss is reasonably estimable. The actual outcomes of the items listed below could ultimately differ from the judgments made and the differences could be material. The Company cannot make any assurances that the amount of reserves or potential insurance coverage will be sufficient to cover the cash obligations that might be incurred as a result of litigation or regulatory proceedings. Except as otherwise disclosed, the Company does not expect that any known lawsuits, environmental costs, and commitments will have a material effect on its financial condition, results of operations, or cash flows.

Summary of the Business and S_3

Summary of the Business and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Average Rates Used Allocated Between Depreciation Expense and Construction Expense Projects Based on Use of Equipment	Average straight-line rates used were as follows: Year ended December 31, 2020 2019 2018 PNM Electric plant 2.47 % 2.47 % 2.40 % Common, intangible, and general plant 7.65 % 7.91 % 8.18 % TNMP 3.95 % 4.04 % 3.49 %
Schedule of Inventory	Inventories consisted of the following at December 31: PNMR PNM TNMP 2020 2019 2020 2019 2020 2019 (In thousands) Coal $ 12,012 $ 24,914 $ 12,012 $ 24,914 $ — $ — Materials and supplies 54,405 53,015 48,460 47,311 5,945 5,704 $ 66,417 $ 77,929 $ 60,472 $ 72,225 $ 5,945 $ 5,704

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Summary of Segments	The following tables present summarized financial information for PNMR by segment. PNM and TNMP each operate in only one segment. Therefore, tabular segment information is not presented for PNM and TNMP. 2020 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,139,834 $ 383,178 $ — $ 1,523,012 Cost of energy 345,167 102,074 — 447,241 Utility margin 794,667 281,104 — 1,075,771 Other operating expenses 414,445 104,852 (4,419) 514,878 Depreciation and amortization 165,325 87,799 22,488 275,612 Operating income (loss) 214,897 88,453 (18,069) 285,281 Interest income 14,469 — (246) 14,223 Other income (deductions) 17,120 6,828 (1,108) 22,840 Interest charges (64,615) (30,388) (19,389) (114,392) Segment earnings (loss) before income taxes 181,871 64,893 (38,812) 207,952 Income taxes (benefit) 21,857 6,308 (7,529) 20,636 Segment earnings (loss) 160,014 58,585 (31,283) 187,316 Valencia non-controlling interest (14,013) — — (14,013) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 145,473 $ 58,585 $ (31,283) $ 172,775 At December 31, 2020: Total Assets $ 5,581,033 $ 2,132,580 $ 226,241 $ 7,939,854 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2019 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,093,822 $ 363,781 $ — $ 1,457,603 Cost of energy 317,725 95,087 — 412,812 Utility margin 776,097 268,694 — 1,044,791 Other operating expenses 554,661 98,621 (20,499) 632,783 Depreciation and amortization 160,368 84,259 23,181 267,808 Operating income 61,068 85,814 (2,682) 144,200 Interest income 14,303 — (281) 14,022 Other income (deductions) 26,989 4,131 (1,477) 29,643 Interest charges (72,900) (29,100) (19,016) (121,016) Segment earnings (loss) before income taxes 29,460 60,845 (23,456) 66,849 Income taxes (25,962) 5,046 (4,366) (25,282) Segment earnings (loss) 55,422 55,799 (19,090) 92,131 Valencia non-controlling interest (14,241) — — (14,241) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 40,653 $ 55,799 $ (19,090) $ 77,362 At December 31, 2019: Total Assets $ 5,242,991 $ 1,860,439 $ 195,344 $ 7,298,774 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2018 PNM TNMP Corporate PNMR Consolidated (In thousands) Electric operating revenues $ 1,091,965 $ 344,648 $ — $ 1,436,613 Cost of energy 314,036 85,690 — 399,726 Utility margin 777,929 258,958 — 1,036,887 Other operating expenses 481,030 96,272 (17,650) 559,652 Depreciation and amortization 151,866 66,189 23,133 241,188 Operating income (loss) 145,033 96,497 (5,483) 236,047 Interest income 13,089 — 2,451 15,540 Other income (deductions) (17,312) 4,065 (2,039) (15,286) Interest charges (76,458) (32,091) (18,695) (127,244) Segment earnings (loss) before income taxes 64,352 68,471 (23,766) 109,057 Income taxes (benefit) (5,971) 16,880 (3,134) 7,775 Segment earnings (loss) 70,323 51,591 (20,632) 101,282 Valencia non-controlling interest (15,112) — — (15,112) Subsidiary preferred stock dividends (528) — — (528) Segment earnings (loss) attributable to PNMR $ 54,683 $ 51,591 $ (20,632) $ 85,642 At December 31, 2018: Total Assets $ 5,035,883 $ 1,665,177 $ 164,491 $ 6,865,551 Goodwill $ 51,632 $ 226,665 $ — $ 278,297
Schedule of Major Customers	Three REPs accounted for more than 10% of the electric operating revenues of TNMP, as follows: Year Ended December 31, 2020 2019 2018 REP A 21 % 22 % 21 % REP B 18 % 17 % 15 % REP C 11 % 12 % 12 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Information regarding AOCI is as follows: Accumulated Other Comprehensive Income (Loss) PNM PNMR Unrealized Gains on Available-for-Sale Securities Pension Total Fair Value Adjustment for Cash Flow Hedges Total (In thousands) Balance at December 31, 2017, as originally reported $ 13,169 $ (110,262) $ (97,093) $ 1,153 $ (95,940) Cumulative effect adjustment (Note 9) (11,208) — (11,208) — (11,208) Balance at January 1, 2018, as adjusted 1,961 (110,262) (108,301) 1,153 (107,148) Amounts reclassified from AOCI (pre-tax) (3,819) 7,568 3,749 216 3,965 Income tax impact of amounts reclassified 970 (1,922) (952) (56) (1,008) Other OCI changes (pre-tax) 3,790 (10,382) (6,592) 570 (6,022) Income tax impact of other OCI changes (963) 2,637 1,674 (145) 1,529 Net after-tax change (22) (2,099) (2,121) 585 (1,536) Balance at December 31, 2018 1,939 (112,361) (110,422) 1,738 (108,684) Amounts reclassified from AOCI (pre-tax) (14,063) 7,404 (6,659) 733 (5,926) Income tax impact of amounts reclassified 3,572 (1,880) 1,692 (186) 1,506 Other OCI changes (pre-tax) 25,724 (3,829) 21,895 (3,495) 18,400 Income tax impact of other OCI changes (6,534) 973 (5,561) 888 (4,673) Net after-tax change 8,699 2,668 11,367 (2,060) 9,307 Balance at December 31, 2019 10,638 (109,693) (99,055) (322) (99,377) Amounts reclassified from AOCI (pre-tax) (9,497) 8,300 (1,197) (1,740) (2,937) Income tax impact of amounts reclassified 2,412 (2,108) 304 442 746 Other OCI changes (pre-tax) 22,586 6,149 28,735 1,271 30,006 Income tax impact of other OCI changes (5,736) (1,562) (7,298) (323) (7,621) Net after-tax change 9,765 10,779 20,544 (350) 20,194 Balance at December 31, 2020 $ 20,403 $ (98,914) $ (78,511) $ (672) $ (79,183)

Electric Operating Revenues (Ta

Electric Operating Revenues (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	A disaggregation of revenues from contracts with customers by the type of customer is presented in the table below. The table also reflects ARP revenues and other revenues. PNM TNMP PNMR Consolidated Year Ended December 31, 2020 (In thousands) Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 482,852 $ 158,066 $ 640,918 Commercial 392,257 118,243 510,500 Industrial 90,845 27,367 118,212 Public authority 23,126 5,853 28,979 Economy energy service 15,911 — 15,911 Transmission 59,856 78,374 138,230 Miscellaneous 13,311 3,738 17,049 Total revenues from contracts with customers 1,078,158 391,641 1,469,799 Alternative revenue programs (3,531) (8,463) (11,994) Other electric operating revenues 65,207 — 65,207 Total Electric Operating Revenues $ 1,139,834 $ 383,178 $ 1,523,012 Year Ended December 31, 2019 Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 427,883 $ 150,742 $ 578,625 Commercial 396,987 116,953 513,940 Industrial 69,601 22,405 92,006 Public authority 20,322 5,694 26,016 Economy energy service 25,757 — 25,757 Transmission 57,214 66,948 124,162 Miscellaneous 13,134 3,568 16,702 Total revenues from contracts with customers 1,010,898 366,310 1,377,208 Alternative revenue programs 1,987 (2,529) (542) Other electric operating revenues 80,937 — 80,937 Total Electric Operating Revenues $ 1,093,822 $ 363,781 $ 1,457,603 Year Ended December 31, 2018 Electric Operating Revenues: Contracts with customers: Retail electric revenue Residential $ 433,009 $ 130,288 $ 563,297 Commercial 408,333 111,261 519,594 Industrial 61,119 17,317 78,436 Public authority 21,688 5,609 27,297 Economy energy service 26,764 — 26,764 Transmission 54,280 66,991 121,271 Miscellaneous 14,098 8,983 23,081 Total revenues from contracts with customers 1,019,291 340,449 1,359,740 Alternative revenue programs (2,443) 4,199 1,756 Other electric operating revenues 75,117 — 75,117 Total Electric Operating Revenues $ 1,091,965 $ 344,648 $ 1,436,613

Earnings and Dividends Per Sh_2

Earnings and Dividends Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Computation of Earnings per Share and Dividends per Share	Information regarding the computation of earnings per share and dividends per share is as follows: Year Ended December 31, 2020 2019 2018 (In thousands, except per share amounts) Net Earnings Attributable to PNMR $ 172,775 $ 77,362 $ 85,642 Average Number of Common Shares: Outstanding during year 79,941 79,654 79,654 Vested awards of restricted stock 216 277 236 Average Shares – Basic 80,157 79,931 79,890 Dilutive Effect of Common Stock Equivalents: PNMR 2020 Forward Equity Sale Agreements 106 — — Stock options and restricted stock 40 59 122 Average Shares – Diluted 80,303 79,990 80,012 Net Earnings Attributable to PNMR Per Share of Common Stock: Basic $ 2.16 $ 0.97 $ 1.07 Diluted $ 2.15 $ 0.97 $ 1.07 Dividends Declared per Common Share $ 1.2500 $ 1.1775 $ 1.0850

Financing (Tables)

Financing (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Information concerning long-term debt outstanding and unamortized (premiums), discounts, and debt issuance costs is as follows: December 31, 2020 December 31, 2019 Principal Unamortized Discounts, (Premiums), and Issuance Costs, net Principal Unamortized Discounts, (Premiums), and Issuance Costs, net (In thousands) PNM Debt Senior Unsecured Notes, Pollution Control Revenue Bonds: 1.875% due April 2033, mandatory tender - October 1, 2021 $ 146,000 $ 301 $ 146,000 $ 662 6.25% due January 2038 — — 36,000 205 2.125% due June 2040, mandatory tender - June 1, 2022 37,000 135 37,000 224 5.20% due June 2040, mandatory tender - June 1, 2020 — — 40,045 17 5.90% due June 2040 — — 255,000 1,857 6.25% due June 2040 — — 11,500 84 2.45% due September 2042, mandatory tender - June 1, 2022 20,000 50 20,000 85 2.40% due June 2043, mandatory tender - June 1, 2020 — — 39,300 50 5.20% due June 2043, mandatory tender - June 1, 2020 — — 21,000 10 Floating rate, weekly-mode 100,345 798 — — 1.05% due January 2038, mandatory tender - June 1, 2022 36,000 226 — — 1.20% due June 2040, mandatory tender - June 1, 2022 11,500 72 — — 1.10% due June 2040, mandatory tender June 1, 2023 130,000 892 — — 1.15% due June 2040, mandatory tender - June 1, 2024 125,000 894 — — Senior Unsecured Notes: 5.35% due October 2021 160,000 129 160,000 292 3.15% due May 2023 55,000 184 55,000 261 3.45% due May 2025 104,000 457 104,000 562 3.85% due August 2025 250,000 1,375 250,000 1,675 3.68% due May 2028 88,000 457 88,000 518 3.78% due August 2028 15,000 80 15,000 91 3.93% due May 2033 38,000 221 38,000 238 4.22% due May 2038 45,000 275 45,000 291 4.50% due May 2048 20,000 128 20,000 133 4.60% due August 2048 85,000 550 85,000 570 3.21% due April 2030 150,000 1,490 — — 3.57% due April 2039 50,000 511 — — PNM 2019 $250.0 Million Term Loan due July 2020 — — 250,000 — PNM 2019 $40.0 Million Term Loan due June 2021 40,000 — 40,000 — 1,705,845 9,225 1,755,845 7,825 Less current maturities 346,000 430 350,345 77 1,359,845 8,795 1,405,500 7,748 December 31, 2020 December 31, 2019 Principal Unamortized Discounts, (Premiums), and Issuance Costs, net Principal Unamortized Discounts, (Premiums), and Issuance Costs, net (In thousands) TNMP Debt First Mortgage Bonds: 6.95% due April 2043 93,198 (15,917) 93,198 (16,632) 4.03% due July 2024 80,000 369 80,000 475 3.53% due February 2026 60,000 420 60,000 502 3.22% due August 2027 60,000 380 60,000 437 3.85% due June 2028 60,000 469 60,000 531 3.79% due March 2034 75,000 497 75,000 535 3.92% due March 2039 75,000 514 75,000 542 4.06% due March 2044 75,000 524 75,000 546 3.60% due July 2029 80,000 511 80,000 571 2.73% due April 24, 2030 85,000 784 — — 3.36% due April 24, 2050 25,000 243 — — 2.93% due July 15, 2035 25,000 241 — — 3.36% due July 15, 2050 50,000 490 — — 843,198 (10,475) 658,198 (12,493) Less current maturities — — — — 843,198 (10,475) 658,198 (12,493) PNMR Debt PNMR 3.25% 2018 SUNs due March 2021 300,000 137 300,000 917 PNMR Development Term Loan due January 2022 65,000 — 90,000 42 PNMR 2018 Two — — 50,000 — PNMR 2019 Term Loan due June 2021 150,000 6 150,000 35 PNMR 2020 Term Loan due January 2022 150,000 — — — PNMR 2020 Delayed-Draw Term Loan due January 2022 80,000 — — — 745,000 143 590,000 994 Less current maturities 230,000 52 140,000 — 515,000 91 450,000 994 Total Consolidated PNMR Debt 3,294,043 (1,107) 3,004,043 (3,674) Less current maturities 576,000 482 490,345 77 $ 2,718,043 $ (1,589) $ 2,513,698 $ (3,751)
Schedule of Short-term Debt	Short-term debt outstanding consists of: December 31, Short-term Debt 2020 2019 (In thousands) PNM: PNM Revolving Credit Facility $ — $ 48,000 PNM 2017 New Mexico Credit Facility 10,000 10,000 10,000 58,000 TNMP Revolving Credit Facility — 15,000 PNMR: PNMR Revolving Credit Facility 12,000 112,100 PNMR Development Revolving Credit Facility 10,000 — $ 32,000 $ 185,100
Schedule of Maturities of Long-term Debt	Reflecting mandatory tender dates, long-term debt maturities as of December 31, 2020 are follows: PNMR PNM TNMP PNMR Consolidated (In thousands) 2021 $ 230,000 $ 346,000 $ — $ 576,000 2022 515,000 104,500 — 619,500 2023 — 285,345 — 285,345 2024 — 125,000 80,000 205,000 2025 — 354,000 — 354,000 Thereafter — 491,000 763,198 1,254,198 Total $ 745,000 $ 1,705,845 $ 843,198 $ 3,294,043

Lease Commitments (Tables)

Lease Commitments (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Assets and Liabilities, Lessee	Information related to the Company’s operating leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Operating leases: Operating lease assets, net of amortization $ 97,461 $ 7,206 $ 105,133 $ 120,585 $ 9,954 $ 131,212 Current portion of operating lease liabilities 25,130 2,193 27,460 25,927 2,753 29,068 Long-term portion of operating lease liabilities 75,941 4,779 81,065 97,992 7,039 105,512 As discussed above, the Company classifies its fleet vehicle and equipment leases and its office equipment leases commencing on or after January 1, 2019 as financing leases. Information related to the Company’s financing leases recorded on the Consolidated Balance Sheets is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) (In thousands) Financing leases: Non-utility property $ 11,453 $ 13,299 $ 25,055 $ 4,857 $ 4,910 $ 10,028 Accumulated depreciation (2,044) (2,241) (4,383) (482) (466) (973) Non-utility property, net $ 9,409 $ 11,058 $ 20,672 $ 4,375 $ 4,444 $ 9,055 Other current liabilities $ 1,993 $ 2,397 $ 4,470 $ 722 $ 850 $ 1,637 Other deferred credits 7,176 8,669 15,972 3,333 3,597 7,102
Lease, Cost	Information concerning the weighted average remaining lease terms and the weighted average discount rates used to determine the Company’s lease liabilities is presented below: December 31, 2020 December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated Weighted average remaining lease term (years): Operating leases 6.23 3.46 6.04 6.70 4.10 6.49 Financing leases 4.78 4.84 4.79 5.64 5.54 5.54 Weighted average discount rate: Operating leases 3.93 % 4.06 % 3.94 % 3.89 % 3.95 % 3.90 % Financing leases 2.76 % 2.84 % 2.80 % 3.68 % 3.65 % 3.64 % Information for the components of lease expense is as follows: Year Ended December 31, 2020 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 27,302 $ 2,870 $ 30,418 Amounts capitalized (1,020) (2,375) (3,395) Total operating lease expense 26,282 495 27,023 Financing lease cost: Amortization of right-of-use assets 1,563 1,775 3,412 Interest on lease liabilities 221 285 511 Amounts capitalized (1,056) (1,754) (2,810) Total financing lease expense 728 306 1,113 Variable lease expense 221 — 221 Short-term lease expense 288 5 295 Total lease expense for the period $ 27,519 $ 806 $ 28,652 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated (In thousands) Operating lease cost $ 28,254 $ 3,341 $ 31,963 Amounts capitalized (1,319) (2,594) (3,913) Total operating lease expense 26,935 747 28,050 Financing lease cost: Amortization of right-of-use assets 481 466 973 Interest on lease liabilities 92 100 194 Amounts capitalized (280) (423) (704) Total financing lease expense 293 143 463 Variable lease expense 96 — 96 Short-term lease expense 346 26 414 Total lease expense for the period $ 27,670 $ 916 $ 29,023 Supplemental cash flow information related to the Company’s leases is as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 PNM TNMP PNMR Consolidated PNM TNMP PNMR Consolidated (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 26,007 $ 596 $ 27,121 $ 26,392 $ 935 $ 27,849 Operating cash flows from financing leases 82 48 136 44 25 71 Finance cash flows from financing leases 557 307 936 183 109 313 Non-cash information related to right-of-use assets obtained in exchange for lease obligations: Operating leases $ — $ — $ — $ 143,816 $ 12,942 $ 157,816 Financing leases 6,588 8,985 15,614 4,473 4,910 9,645
Finance Lease, Liability, Maturity	Future expected lease payments are shown below: As of December 31, 2020 PNM TNMP PNMR Consolidated Financing Operating Financing Operating Financing Operating (In thousands) 2021 $ 2,214 $ 26,572 $ 2,672 $ 2,426 $ 4,970 $ 29,290 2022 2,159 26,266 2,557 1,987 4,797 28,464 2023 2,095 17,735 2,372 1,481 4,511 19,395 2024 1,434 7,899 1,897 895 3,335 8,841 2025 854 6,946 1,190 690 2,044 7,673 Later years 1,030 27,530 1,120 75 2,150 27,827 Total minimum lease payments 9,786 112,948 11,808 7,554 21,807 121,490 Less: Imputed interest 617 11,877 742 582 1,365 12,965 Lease liabilities as of December 31, 2020 $ 9,169 $ 101,071 $ 11,066 $ 6,972 $ 20,442 $ 108,525
Lessee, Operating Lease, Liability, Maturity	Future expected lease payments are shown below: As of December 31, 2020 PNM TNMP PNMR Consolidated Financing Operating Financing Operating Financing Operating (In thousands) 2021 $ 2,214 $ 26,572 $ 2,672 $ 2,426 $ 4,970 $ 29,290 2022 2,159 26,266 2,557 1,987 4,797 28,464 2023 2,095 17,735 2,372 1,481 4,511 19,395 2024 1,434 7,899 1,897 895 3,335 8,841 2025 854 6,946 1,190 690 2,044 7,673 Later years 1,030 27,530 1,120 75 2,150 27,827 Total minimum lease payments 9,786 112,948 11,808 7,554 21,807 121,490 Less: Imputed interest 617 11,877 742 582 1,365 12,965 Lease liabilities as of December 31, 2020 $ 9,169 $ 101,071 $ 11,066 $ 6,972 $ 20,442 $ 108,525

Fair Value of Derivative and _2

Fair Value of Derivative and Other Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Commodity Derivatives	PNM’s commodity derivative instruments that are recorded at fair value, all of which are accounted for as economic hedges and considered Level 2 fair value measurements, are presented in the following line items on the Consolidated Balance Sheets: Economic Hedges December 31, 2020 2019 (In thousands) Other current assets $ 1,096 $ 1,089 Other deferred charges 455 1,507 1,551 2,596 Other current liabilities (1,096) (1,089) Other deferred credits (455) (1,507) (1,551) (2,596) Net $ — $ —
Schedule of Realized Gain (Loss)	Gains and losses recognized on the Consolidated Statements of Earnings related to investment securities in the NDT and reclamation trusts are presented in the following table: Year ended December 31, 2020 2019 2018 (In thousands) Equity securities: Net gains from equity securities sold $ 5,861 $ 5,698 $ 4,864 Net gains (losses) from equity securities still held 17,707 18,319 (10,523) Total net gains (losses) on equity securities 23,568 24,017 (5,659) Available-for-sale debt securities: Net gains (losses) on debt securities (1,969) 5,572 (11,517) Net gains (losses) on investment securities $ 21,599 $ 29,589 $ (17,176) Year Ended December 31, 2020 2019 2018 (In thousands) Proceeds from sales $ 590,998 $ 494,528 $ 984,533 Gross realized gains $ 35,904 $ 25,760 $ 19,358 Gross realized (losses) $ (28,817) $ (17,453) $ (16,624)
Investments Classified by Contractual Maturity Date	At December 31, 2020, the available-for-sale debt securities held by PNM, had the following final maturities: Fair Value (In thousands) Within 1 year $ 33,301 After 1 year through 5 years 89,646 After 5 years through 10 years 89,130 After 10 years through 15 years 14,947 After 15 years through 20 years 9,256 After 20 years 43,730 $ 280,010
Schedule of Instruments Presented by Level of Hierarchy	Items recorded at fair value by PNM on the Consolidated Balance Sheets are presented below by level of the fair value hierarchy along with gross unrealized gains on investments in available-for-sale securities. GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Unrealized Gains (In thousands) December 31, 2020 Cash and cash equivalents $ 6,107 $ 6,107 $ — Equity securities: Corporate stocks, common 85,271 85,271 — Corporate stocks, preferred 9,910 3,608 6,302 Mutual funds and other 58,817 58,762 55 Available-for-sale debt securities: U.S. government 55,839 29,579 26,260 $ 950 International government 16,032 — 16,032 2,537 Municipals 50,139 — 50,139 2,779 Corporate and other 158,000 3 157,997 21,121 $ 440,115 $ 183,330 $ 256,785 $ 27,387 December 31, 2019 Cash and cash equivalents $ 15,606 $ 15,606 $ — Equity securities: Corporate stocks, common 64,527 64,527 — Corporate stocks, preferred 9,033 2,212 6,821 Mutual funds and other 49,848 49,786 62 Available-for-sale debt securities: U.S. government 48,439 31,389 17,050 $ 535 International government 15,292 — 15,292 1,193 Municipals 46,642 — 46,642 1,768 Corporate and other 139,445 187 139,258 10,801 $ 388,832 $ 163,707 $ 225,125 $ 14,297
Summary of Carrying Amounts and Fair Value of Instruments	The carrying amounts and fair values of long-term debt, all of which are considered Level 2 fair value measurements and are not recorded at fair value on the Consolidated Balance Sheets are presented below: Carrying Fair Value December 31, 2020 (In thousands) PNMR $ 3,295,150 $ 3,355,761 PNM $ 1,696,620 $ 1,602,547 TNMP $ 853,673 $ 1,006,722 December 31, 2019 PNMR $ 3,007,717 $ 3,142,704 PNM $ 1,748,020 $ 1,795,149 TNMP $ 670,691 $ 753,317
Schedule of Investments Held by the Employee Benefit Plans	The fair values of investments held by the employee benefit plans are as follows: GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets Significant December 31, 2020 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 498,907 $ 241,445 $ 257,462 Uncategorized investments 88,984 Total Master Trust Investments $ 587,891 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 56,966 $ 28,732 $ 28,234 Uncategorized investments 9,230 Total Master Trust Investments $ 66,196 PNM OPEB Plan Cash and cash equivalents $ 1,310 $ 1,310 $ — Equity securities: Mutual funds 92,400 52,284 40,116 $ 93,710 $ 53,594 $ 40,116 TNMP OPEB Plan Cash and cash equivalents $ 18 $ 18 $ — Equity securities: Mutual funds 12,843 10,806 2,037 $ 12,861 $ 10,824 $ 2,037 GAAP Fair Value Hierarchy Total Quoted Prices in Active Significant December 31, 2019 PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 445,984 $ 152,158 $ 293,826 Uncategorized investments 86,675 Total Master Trust Investments $ 532,659 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 49,353 $ 17,335 $ 32,018 Uncategorized investments 9,974 Total Master Trust Investments $ 59,327 PNM OPEB Plan Cash and cash equivalents $ 1,022 $ 1,022 $ — Equity securities: Mutual funds 85,727 39,361 46,366 $ 86,749 $ 40,383 $ 46,366 TNMP OPEB Plan Cash and cash equivalents $ 275 $ 275 $ — Equity securities: Mutual funds 10,635 4,075 6,560 $ 10,910 $ 4,350 $ 6,560 The fair values of investments in the PNMR Master Trust are as follows: GAAP Fair Value Hierarchy Total Quoted Prices Significant December 31, 2020 (In thousands) PNMR Master Trust Cash and cash equivalents $ 20,812 $ 20,812 $ — Equity securities: Corporate stocks, common 114,983 114,983 — Corporate stocks, preferred 1,187 135 1,052 Mutual funds and other 173,931 47,418 126,513 Fixed income securities: U.S. government 97,460 86,829 10,631 International government 6,202 — 6,202 Municipals 6,277 — 6,277 Corporate and other 135,021 — 135,021 Total investments categorized within fair value hierarchy 555,873 $ 270,177 $ 285,696 Uncategorized investments: Private equity funds 12,552 Hedge funds 52,285 Real estate funds 33,377 $ 654,087 GAAP Fair Value Hierarchy Total Quoted Prices Significant December 31, 2019 (In thousands) PNMR Master Trust Cash and cash equivalents $ 19,982 $ 19,982 $ — Equity securities: Corporate stocks, common 68,497 68,497 — Corporate stocks, preferred 825 — 825 Mutual funds and other 172,326 — 172,326 Fixed income securities: U.S. government 90,970 81,014 9,956 International government 5,411 — 5,411 Municipals 6,980 — 6,980 Corporate and other 130,346 — 130,346 Total investments categorized within fair value hierarchy 495,337 $ 169,493 $ 325,844 Uncategorized investments: Private equity funds 15,827 Hedge funds 47,618 Real estate funds 33,204 $ 591,986

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2020
Variable Interest Entities [Abstract]
Summarized Financial Information for Noncontrolling Interest	Summarized financial information for Valencia is as follows: Results of Operations Year Ended December 31 2020 2019 2018 (In thousands) Operating revenues $ 21,297 $ 21,073 $ 21,025 Operating expenses 7,284 6,832 5,913 Earnings attributable to non-controlling interest $ 14,013 $ 14,241 $ 15,112 Financial Position December 31, 2020 2019 (In thousands) Current assets $ 3,911 $ 5,094 Net property, plant and equipment 55,744 58,581 Total assets 59,655 63,675 Current liabilities 646 623 Owners’ equity – non-controlling interest $ 59,009 $ 63,052

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following table presents information about the PBO, fair value of plan assets, and funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) PBO at beginning of year $ 605,745 $ 564,258 $ 65,574 $ 60,587 Service cost — — — — Interest cost 19,941 25,175 2,177 2,686 Actuarial (gain) loss 47,567 61,151 4,459 7,889 Benefits paid (42,349) (44,839) (4,820) (5,588) PBO at end of year 630,904 605,745 67,390 65,574 Fair value of plan assets at beginning of year 531,467 489,978 59,367 55,074 Actual return on plan assets 98,412 86,328 11,602 9,881 Employer contributions — — — — Benefits paid (42,349) (44,839) (4,820) (5,588) Fair value of plan assets at end of year 587,530 531,467 66,149 59,367 Funded status – asset (liability) for pension benefits $ (43,374) $ (74,278) $ (1,241) $ (6,207) The following table presents information about the APBO, the fair value of plan assets, and the funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) APBO at beginning of year $ 75,121 $ 75,305 $ 11,235 $ 10,064 Service cost 38 53 46 50 Interest cost 2,453 3,316 373 451 Participant contributions 1,714 2,131 243 316 Actuarial (gain) loss 3,261 2,587 747 1,004 Benefits paid (7,391) (8,271) (706) (650) APBO at end of year 75,196 75,121 11,938 11,235 Fair value of plan assets at beginning of year 86,400 69,703 10,844 8,744 Actual return on plan assets 9,423 19,257 2,505 2,434 Employer contributions 3,256 3,580 — — Participant contributions 1,714 2,131 243 316 Benefits paid (7,391) (8,271) (707) (650) Fair value of plan assets at end of year 93,402 86,400 12,885 10,844 Funded status – asset (liability) $ 18,206 $ 11,279 $ 947 $ (391)
Schedule of Assumptions Used	Actuarial (gain) loss results from changes in: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (in thousands) Discount rates $ 44,960 $ 66,108 $ 4,756 $ 8,006 Demographic experience 2,607 (732) (54) 394 Mortality rate — (4,225) — (296) Other assumptions and experience — — (243) (215) $ 47,567 $ 61,151 $ 4,459 $ 7,889 The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost (income). Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost (income) would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 PBO 2.66 % 3.42 % 4.65 % Discount rate for determining net periodic benefit cost (income) 3.42 % 4.65 % 4.05 % Expected return on plan assets 5.90 % 6.86 % 6.54 % Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 PBO 2.69 % 3.46 % 4.63 % Discount rate for determining net periodic benefit cost (income) 3.46 % 4.63 % 4.01 % Expected return on plan assets 5.90 % 6.90 % 6.57 % Rate of compensation increase N/A N/A N/A Actuarial (gain) loss results from changes in: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (in thousands) Discount rates $ 4,959 $ 7,236 $ 1,008 $ 1,375 Claims, contributions, and demographic experience (1,698) (4,022) (261) (311) Assumed participation rate — — — — Mortality rate — (627) — (60) $ 3,261 $ 2,587 $ 747 $ 1,004 The following significant weighted-average assumptions were used to determine the APBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the APBO and net periodic benefit cost would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 APBO 2.65 % 3.42 % 4.63 % Discount rate for determining net periodic benefit cost 3.42 % 4.63 % 4.00 % Expected return on plan assets 7.00 % 7.20 % 7.42 % Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 APBO 2.65 % 3.42 % 4.63 % Discount rate for determining net periodic benefit cost 3.42 % 4.63 % 4.00 % Expected return on plan assets 5.60 % 5.80 % 5.86 % Rate of compensation increase N/A N/A N/A The following significant weighted-average assumptions were used to determine the PBO and net periodic benefit cost. Should actual experience differ from actuarial assumptions, the PBO and net periodic benefit cost would be affected. Year Ended December 31, PNM 2020 2019 2018 Discount rate for determining December 31 PBO 2.68 % 3.44 % 4.66 % Discount rate for determining net periodic benefit cost 3.44 % 4.66 % 4.05 % Long-term rate of return on plan assets N/A N/A N/A Rate of compensation increase N/A N/A N/A TNMP Discount rate for determining December 31 PBO 2.69 % 3.46 % 4.63 % Discount rate for determining net periodic benefit cost 3.46 % 4.63 % 4.01 % Long-term rate of return on plan assets N/A N/A N/A Rate of compensation increase N/A N/A N/A
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	The following table presents pre-tax information about net actuarial (gain) loss in AOCI as of December 31, 2020. PNM TNMP (In thousands) Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year $ 146,391 $ — Experience (gain) loss (21,393) 3,860 Regulatory asset (liability) adjustment 15,211 (3,860) 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 $ — The following table presents pre-tax information about net actuarial loss in AOCI as of December 31, 2020. December 31, 2020 PNM TNMP (In thousands) Amount in AOCI not yet recognized in net periodic benefit cost at beginning of year $ 2,395 $ — Experience (gain) loss 78 58 Regulatory asset (liability) adjustment (45) (58) Amortization recognized in net periodic benefit cost (income) (169) — Amount in AOCI not yet recognized in net periodic benefit cost at end of year $ 2,259 $ —
Schedule of Net Benefit Costs	The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ — $ — $ — Interest cost 19,941 25,175 24,270 Expected return on plan assets (29,453) (34,103) (34,686) Amortization of net (gain) loss 17,860 15,518 16,348 Amortization of prior service cost (554) (965) (965) Net periodic benefit cost $ 7,794 $ 5,625 $ 4,967 TNMP Service cost $ — $ — $ — Interest cost 2,177 2,686 2,625 Expected return on plan assets (3,284) (3,868) (3,963) Amortization of net (gain) loss 1,258 941 1,088 Amortization of prior service cost — — — Net periodic benefit cost (income) $ 151 $ (241) $ (250) The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ 38 $ 53 $ 83 Interest cost 2,453 3,316 3,439 Expected return on plan assets (5,548) (5,278) (5,414) Amortization of net (gain) loss 348 675 2,354 Amortization of prior service credit — (397) (1,664) Net periodic benefit cost (income) $ (2,709) $ (1,631) $ (1,202) TNMP Service cost $ 46 $ 50 $ 134 Interest cost 373 451 477 Expected return on plan assets (538) (517) (542) Amortization of net (gain) loss (323) (444) (227) Amortization of prior service cost — — — Net periodic benefit cost (income) $ (442) $ (460) $ (158) The following table presents the components of net periodic benefit cost: Year Ended December 31, 2020 2019 2018 (In thousands) PNM Service cost $ — $ — $ — Interest cost 491 651 622 Amortization of net (gain) loss 403 318 359 Amortization of prior service cost — — — Net periodic benefit cost $ 894 $ 969 $ 981 TNMP Service cost $ — $ — $ — Interest cost 22 30 29 Amortization of net (gain) loss 24 15 15 Amortization of prior service cost — — — Net periodic benefit cost $ 46 $ 45 $ 44
Schedule of Expected Benefit Payments	The following pension benefit payments are expected to be paid: PNM TNMP (In thousands) 2021 $ 46,312 $ 5,301 2022 45,583 5,193 2023 44,299 4,936 2024 43,066 4,702 2025 41,869 4,589 2026 - 2030 188,950 19,829 The following OPEB payments, which reflect expected future service and are net of participant contributions, are expected to be paid: PNM TNMP (In thousands) 2021 $ 6,455 $ 649 2022 6,132 678 2023 5,960 698 2024 5,711 709 2025 5,357 713 2026 - 2030 22,474 3,400 PNM TNMP (In thousands) 2021 $ 1,341 $ 93 2022 1,303 90 2023 1,259 85 2024 1,210 80 2025 1,156 73 2026 - 2030 4,856 252
Schedule of Health Care Cost Trend Rates	The following table shows the assumed health care cost trend rates for the PNM OPEB plan: PNM December 31, 2020 2019 Health care cost trend rate assumed for next year 6.25 % 6.50 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate 2026 2026
Schedule of Net Funded Status	For the executive retirement programs, the following table presents information about the PBO and funded status of the plans: PNM TNMP Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 (In thousands) PBO at beginning of year $ 14,994 $ 14,726 $ 692 $ 702 Service cost — — — — Interest cost 491 651 22 30 Actuarial (gain) loss 78 1,053 58 54 Benefits paid (1,341) (1,436) (94) (94) PBO at end of year – funded status 14,222 14,994 678 692 Less current liability 1,323 1,434 91 91 Non-current liability $ 12,899 $ 13,560 $ 587 $ 601
Summary of Expenses for Other Retirement Plans	A summary of expenses for these other retirement plans is as follows: Year Ended December 31, 2020 2019 2018 (In thousands) PNMR 401(k) plan $ 16,247 $ 16,097 $ 16,677 Non-qualified plan $ 2,090 $ 4,551 $ 865 PNM 401(k) plan $ 11,676 $ 11,587 $ 12,052 Non-qualified plan $ 1,544 $ 3,384 $ 621 TNMP 401(k) plan $ 4,572 $ 4,511 $ 4,625 Non-qualified plan $ 547 $ 1,167 $ 244

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Cash Proceeds Received and Tax Benefit from Share-based Payment Awards	Year Ended December 31, Excess Tax Benefits 2020 2019 2018 (In thousands) PNM $ 279 $ 559 $ 1,007 TNMP 112 236 377 PNMR 391 795 1,384
Summary of Awards	The following table summarizes the weighted-average assumptions used to determine the awards grant date fair value: Year Ended December 31, Restricted Shares and Performance-Based Shares 2020 2019 2018 Expected quarterly dividends per share $ 0.3075 $ 0.2900 $ 0.2650 Risk-free interest rate 0.72 % 2.47 % 2.38 % Market-Based Shares Dividend yield 2.51 % 2.59 % 2.96 % Expected volatility 19.41 % 19.55 % 19.12 % Risk-free interest rate 0.72 % 2.51 % 2.36 % The following table summarizes activity in restricted stock awards, including performance-based and market-based shares, and stock options: Restricted Stock Stock Options Shares Weighted-Average Grant Date Fair Value Shares Weighted Outstanding at December 31, 2019 161,542 $ 38.21 2,000 $ 12.22 Granted 246,029 36.73 — — Exercised (238,054) 34.86 (2,000) 12.22 Forfeited (1,456) 41.32 — — Outstanding at December 31, 2020 168,061 $ 40.77 — $ — The following table provides additional information concerning restricted stock activity, including performance-based and market-based shares, and stock options: Year Ended December 31, Restricted Stock 2020 2019 2018 Weighted-average grant date fair value $ 36.73 $ 37.92 $ 29.65 Total fair value of restricted shares that vested (in thousands) $ 8,299 $ 6,246 $ 8,558 Stock Options Total intrinsic value of options exercised (in thousands) $ 84 $ 2,617 $ 3,117

Regulatory Assets and Liabili_2

Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Schedule of Regulatory Assets and Liabilities	Regulatory assets and liabilities reflected in the Consolidated Balance Sheets are presented below. PNM TNMP December 31, December 31, 2020 2019 2020 2019 Assets: (In thousands) Current: FPPAC $ — $ 7,373 $ — $ — Energy efficiency costs — — 202 — — 7,373 202 — Non-Current: CTC, including carrying charges — — 324 7,412 Coal mine reclamation costs (3) 9,980 13,995 — — Deferred income taxes 65,564 66,296 9,817 8,997 Loss on reacquired debt 19,748 19,426 28,914 30,212 Pension and OPEB (1) 190,147 214,771 22,863 27,947 Shutdown of SJGS Units 2 and 3 107,231 113,508 — — Hurricane recovery costs (2) — — 480 1,041 AMS surcharge — — 18,761 25,015 AMS retirement and other costs — — 13,915 15,542 Renewable energy costs — 643 — — Deferred cost under the ETA 42,703 — — — Deferred COVID-19 costs 8,761 — 676 — SJGS replacement resources 8,282 — — — Other 5,537 6,828 4,087 5,297 457,953 435,467 99,837 121,463 Total regulatory assets $ 457,953 $ 442,840 $ 100,039 $ 121,463 PNM TNMP December 31, December 31, 2020 2019 2020 2019 Liabilities: Current: FPPAC $ (2,274) $ — $ — $ — Renewable energy rider (2,044) — — — Other (1,101) (371) (2,052) (134) (5,419) (371) (2,052) (134) Non-Current: Cost of removal (284,695) (271,025) (59,613) (46,091) Deferred income taxes (343,844) (374,122) (119,695) (131,871) PVNGS ARO (5,394) (11,341) — — Renewable energy tax benefits (17,912) (19,069) — — Accelerated depreciation SNCRs (4) (12,045) (7,758) — — Pension and OPEB — — (5,535) (4,775) COVID-19 cost savings (900) — — — Other (83) (83) (512) (108) (664,873) (683,398) (185,355) (182,845) Total regulatory liabilities $ (670,292) $ (683,769) $ (187,407) $ (182,979) (1) Includes $1.6 million for certain PNM pension costs as described in Note 11 (2) Amount shown is net of amounts owed under the PUCT’s January 25, 2018 order as described in Note 17 (3) Includes $9.3 million in coal mine reclamation costs related to PNM’s planned retirement of SJGS in 2022 and recoverable under the ETA as described in Note 16 (4) Amounts to be refunded under the ETA

Construction Program and Join_2

Construction Program and Jointly-Owned Electric Generating Plants (Tables)	12 Months Ended
	Dec. 31, 2020
Construction Program and Jointly-Owned Electric Generating Plants [Abstract]
Summary of Interests and Investments in Jointly-Owned Generating Facilities	At December 31, 2020, PNM’s interests and investments in jointly-owned generating facilities are: Station (Fuel Type) Plant in Accumulated Depreciation (1) Construction Composite (In thousands) SJGS (Coal) $ 780,544 $ (448,213) $ 659 66.35 % PVNGS (Nuclear) (2) $ 828,191 $ (387,436) $ 37,235 10.20 % Four Corners Units 4 and 5 (Coal) $ 301,867 $ (100,187) $ 7,820 13.00 % Luna (Gas) $ 76,917 $ (29,758) $ 57 33.33 % (1) Includes cost of removal. (2) Includes interest in PVNGS Unit 3, interest in common facilities for all PVNGS units, and owned interests in PVNGS Units 1 and 2, including improvements.
Summary of Budgeted Construction Expenditures	An unaudited summary of the budgeted construction expenditures, including expenditures for jointly-owned projects, and nuclear fuel, is as follows: 2021 2022 2023 2024 2025 Total (In millions) PNM $ 661.9 $ 396.6 $ 382.0 $ 388.5 $ 379.9 $ 2,208.9 TNMP 320.1 342.0 348.0 298.0 299.0 1,607.1 Corporate and Other 34.5 26.5 31.2 26.5 26.5 145.2 Total PNMR $ 1,016.5 $ 765.1 $ 761.2 $ 713.0 $ 705.4 $ 3,961.2

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Reconciliation of Asset Retirement Obligations	A reconciliation of the ARO liabilities is as follows: PNMR PNM TNMP (In thousands) Liability at December 31, 2017 $ 146,679 $ 145,707 $ 793 Liabilities incurred — — — Liabilities settled (192) — — Accretion expense 11,482 11,402 67 Revisions to estimated cash flows 705 705 — Liability at December 31, 2018 158,674 157,814 860 Liabilities incurred — — — Liabilities settled (987) (935) (52) Accretion expense 12,635 12,562 73 Revisions to estimated cash flows (1) 11,640 11,640 — Liability at December 31, 2019 181,962 181,081 881 Liabilities incurred — — — Liabilities settled (1,444) (1,192) (252) Accretion expense 11,310 11,235 75 Revisions to estimated cash flows (2) (8,407) (8,407) — Liability at December 31, 2020 $ 183,421 $ 182,717 $ 704 (1) Reflects the impacts of an updated SJGS decommissioning study that assumes PNM will retire its share of SJGS in 2022. (2)

Regulatory and Rate Matters Reg

Regulatory and Rate Matters Regulatory and Rate Matters (Tables)	12 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Schedule of Rate Increases for Transmission Costs	The following sets forth TNMP’s approved EECRF increases: Effective Date Aggregate Collection Amount Performance Bonus (In millions) March 1, 2018 $ 6.0 $ 1.1 March 1, 2019 5.6 0.8 March 1, 2020 5.9 0.8 The following sets forth TNMP’s recent interim transmission cost rate increases: Effective Date Approved Increase in Rate Base Annual Increase in Revenue (In millions) March 27, 2018 $ 32 $ 0.6 March 21, 2019 111.8 14.3 September 19, 2019 21.9 3.3 March 27, 2020 59.2 7.8 October 7, 2020 10.8 2.0

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Tax Reform Adjustments	The adjustments to deferred income taxes resulting from completion of the Company’s analysis, which resulted primarily from differences between the estimated amounts recorded as of December 31, 2017 and the actual amounts reflected in the Company’s 2017 tax return filing, including adjustments resulting from additional guidance and interpretations to the Tax Act issued in 2018 related to bonus depreciation, certain incentive compensation, and other items are presented below: PNM TNMP Corporate and Other Consolidated (In thousands) Net increase (decrease) in regulatory liabilities $ 11,244 $ (4,069) $ — $ 7,175 Net decrease in deferred income tax liabilities (deferred income tax assets) (2,175) (9,784) 13,869 1,910 Net increase in affiliate receivables 12,300 4,042 (16,342) — Net deferred income tax expense $ 1,119 $ 1,673 $ 2,473 $ 5,265
Schedule of Components of Income Tax Expense (Benefit)	PNMR’s income taxes (benefits) consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ — $ 60 $ — Current state income tax 231 43 (244) Deferred federal income tax 17,574 (20,372) 7,716 Deferred state income tax 3,721 (4,491) 648 Amortization of accumulated investment tax credits (890) (522) (345) Total income taxes (benefits) $ 20,636 $ (25,282) $ 7,775 PNM’s income taxes (benefit) consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ — $ (6,266) $ (6,644) Current state income tax (585) 449 (2,661) Deferred federal income tax 20,125 (12,308) 5,661 Deferred state income tax 2,560 (7,590) (2,080) Amortization of accumulated investment tax credits (243) (247) (247) Total income taxes (benefit) $ 21,857 $ (25,962) $ (5,971) TNMP’s income taxes consist of the following components: Year Ended December 31, 2020 2019 2018 (In thousands) Current federal income tax $ 12,048 $ 10,792 $ 13,347 Current state income tax 2,033 1,904 1,753 Deferred federal income tax (7,744) (7,621) (540) Deferred state income tax (29) (29) 2,320 Total income taxes $ 6,308 $ 5,046 $ 16,880
Schedule of Effective Income Tax Rate Reconciliation	PNMR’s provision for income taxes (benefits) differed from the federal income tax computed at the statutory rate for each of the years shown. The differences are attributable to the following factors: Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 43,670 $ 14,038 $ 22,902 Amortization of accumulated investment tax credits (890) (522) (345) Amortization of excess deferred income tax (Note 17) (30,723) (37,799) (19,779) Flow-through of depreciation items 1,368 1,136 712 Earnings attributable to non-controlling interest in Valencia (2,943) (2,991) (3,173) State income tax, net of federal benefit 6,961 298 1,358 Impairment of state net operating loss carryforwards — — — Allowance for equity funds used during construction (2,363) (1,990) (2,185) Impairment of charitable contribution carryforward — — — Regulatory recovery of prior year impairments of state net operating loss carryforward, including amortization 1,367 1,367 1,367 Federal income tax rate change — — 2,914 Tax expense (benefit) related to stock compensation awards (392) (795) 4,647 Non-deductible compensation 2,630 1,156 891 Other 1,951 820 (1,534) Total income taxes (benefits) $ 20,636 $ (25,282) $ 7,775 Effective tax rate 9.92 % (37.82) % 7.13 % Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 38,193 $ 6,187 $ 13,514 Amortization of accumulated investment tax credits (243) (247) (247) Amortization of excess deferred income tax (Note 17) (21,609) (28,923) (19,779) Flow-through of depreciation items 1,279 1,077 674 Earnings attributable to non-controlling interest in Valencia (2,943) (2,991) (3,173) State income tax, net of federal benefit 7,111 92 1,323 Impairment of state net operating loss carryforwards — — — Allowance for equity funds used during construction (1,461) (1,398) (1,716) Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization 1,367 1,367 1,367 Federal income tax rate change — — (683) Allocation of tax expense (benefit) related to stock compensation awards (279) (559) 3,967 Non-deductible compensation 1,554 683 612 Other (1,112) (1,250) (1,830) Total income taxes (benefit) $ 21,857 $ (25,962) $ (5,971) Effective tax rate 12.02 % (88.13) % (9.28) % Year Ended December 31, 2020 2019 2018 (In thousands) Federal income tax at statutory rates $ 13,628 $ 12,778 $ 14,379 Amortization of excess deferred income tax (9,113) (8,876) — State income tax, net of federal benefit 1,625 1,532 1,454 Allocation of tax expense (benefit) related to stock compensation awards (112) (236) 735 Officer compensation 1,071 471 277 Other (791) (623) 35 Total income taxes $ 6,308 $ 5,046 $ 16,880 Effective tax rate 9.71 % 8.29 % 24.65 %
Components of Deferred Tax Assets and Liabilities	The components of PNMR’s net accumulated deferred income tax liability were: December 31, 2020 2019 (In thousands) Deferred tax assets: Net operating loss $ 41,419 $ 59,488 Regulatory liabilities related to income taxes 148,961 145,087 Federal tax credit carryforwards 121,354 101,231 Regulatory disallowances 38,531 34,639 Other 42,885 54,199 Total deferred tax assets 393,150 394,644 Deferred tax liabilities: Depreciation and plant related (738,342) (787,928) Investment tax credit (98,669) (81,186) Regulatory assets related to income taxes (61,330) (58,495) CTC — (1,466) Pension (37,099) (35,029) Regulatory asset for shutdown of SJGS Units 2 and 3 (27,237) (28,831) Other (124,985) (27,767) Total deferred tax liabilities (1,087,662) (1,020,702) Net accumulated deferred income tax liabilities $ (694,512) $ (626,058) The components of PNM’s net accumulated deferred income tax liability were: December 31, 2020 2019 (In thousands) Deferred tax assets: Net operating loss $ — $ 25,889 Regulatory liabilities related to income taxes 121,569 114,849 Federal tax credit carryforwards 84,719 82,983 Shutdown of SJGS Units 2 and 3 — — Regulatory disallowance 38,531 34,639 Other 46,444 38,735 Total deferred tax assets 291,263 297,095 Deferred tax liabilities: Depreciation and plant related (576,079) (630,293) Investment tax credit (74,424) (74,667) Regulatory assets related to income taxes (51,493) (49,479) Pension (32,413) (30,609) Regulatory asset for shutdown of SJGS Units 2 and 3 (27,237) (28,831) Other (108,767) (5,206) Total deferred tax liabilities (870,413) (819,085) Net accumulated deferred income tax liabilities $ (579,150) $ (521,990) The components of TNMP’s net accumulated deferred income tax liability at December 31, were: December 31, 2020 2019 (In thousands) Deferred tax assets: Regulatory liabilities related to income taxes $ 27,392 $ 30,238 Other 4,548 3,788 Total deferred tax assets 31,940 34,026 Deferred tax liabilities: Depreciation and plant related (148,279) (142,791) CTC — (1,466) Regulatory assets related to income taxes (9,836) (9,016) Loss on reacquired debt (6,072) (6,345) Pension (4,685) (4,420) AMS (6,915) (8,473) Other (1,522) (1,666) Total deferred tax liabilities (177,309) (174,177) Net accumulated deferred income tax liabilities $ (145,369) $ (140,151)
Reconciliation of Accumulated Deferred Income Tax Liability to Deferred Income Tax Benefit	The following table reconciles the change in PNMR’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 68,454 Change in tax effects of income tax related regulatory assets and liabilities (11,602) Amortization of excess deferred income tax (30,723) Tax effect of mark-to-market adjustments (3,206) Tax effect of excess pension liability (3,670) Adjustment for uncertain income tax positions 2,459 Reclassification of unrecognized tax benefits (2,459) Amortization of state net operating loss recovered in prior years 1,367 Refundable alternative minimum tax credit carryforward reclassified to receivable — Other (215) Deferred income taxes (benefits) $ 20,405 The following table reconciles the change in PNM’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 57,160 Change in tax effects of income tax related regulatory assets and liabilities (7,936) Amortization of excess deferred income tax (21,609) Tax effect of mark-to-market adjustments (3,325) Tax effect of excess pension liability (3,670) Adjustment for uncertain income tax positions 2,454 Reclassification of unrecognized tax benefits (1,999) Amortization of state net operating loss recovered in prior years 1,367 Other — Deferred income taxes (benefits) $ 22,442 The following table reconciles the change in TNMP’s net accumulated deferred income tax liability to the deferred income tax (benefit) included in the Consolidated Statement of Earnings: Year Ended December 31, 2020 (In thousands) Net change in deferred income tax liability per above table $ 5,218 Change in tax effects of income tax related regulatory assets and liabilities (3,666) Amortization of excess deferred income tax (9,113) Other (212) Deferred income taxes (benefits) $ (7,773)
Reconciliation of Unrecognized Tax Benefits (Expenses)	A reconciliation of unrecognized tax benefits is as follows: PNMR PNM TNMP (In thousands) Balance at December 31, 2017 $ 9,429 $ 6,563 $ 63 Additions based on tax positions related to 2018 543 543 — Additions (reductions) for tax positions of prior years 222 182 40 Settlement payments — — — Balance at December 31, 2018 10,194 7,288 103 Additions based on tax positions related to 2019 329 329 — Additions (reductions) for tax positions of prior years 170 159 11 Settlement payments — — — Balance at December 31, 2019 10,693 7,776 114 Additions based on tax positions related to 2020 2,286 2,286 — Additions (reductions) for tax positions of prior years 173 168 5 Settlement payments — — — Balance at December 31, 2020 $ 13,152 $ 10,230 $ 119
Tax Carryforward, Impairments, net of Federal Tax Benefit	The impairments after reflecting the expiration of carryforwards under applicable tax laws, net of federal tax benefit, for 2018 through 2020 are as follows: PNMR PNM TNMP (In thousands) December 31, 2020: State tax credit carryforwards $ (425) $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 96 $ 61 $ 35 December 31, 2019: State tax credit carryforwards $ 425 $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ (99) $ (100) $ 2 December 31, 2018: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 410 $ 298 $ 111
Summary of Tax Credit Carryforwards	The reserve balances, after reflecting expiration of carryforwards under applicable tax laws, at December 31, 2020 and 2019 are as follows: PNMR PNM TNMP (In thousands) December 31, 2020: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 407 $ 259 $ 148 December 31, 2019: State tax credit carryforwards $ 425 $ — $ — State net operating loss carryforwards $ — $ — $ — Charitable contribution carryforwards $ — $ — $ — Compensation expense $ 311 $ 198 $ 113

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The table below summarizes the nature and amount of related party transactions of PNMR, PNM and TNMP: Year Ended December 31, 2020 2019 2018 (In thousands) Services billings: PNMR to PNM $ 100,872 $ 96,327 $ 95,637 PNMR to TNMP 39,053 36,554 33,493 PNM to TNMP 383 375 367 TNMP to PNMR 141 141 140 TNMP to PNM — — — PNMR to NMRD 260 238 183 Renewable energy purchases: PNM from NMRD 9,638 3,124 2,924 Interconnection and facility study billings: PNM to NMRD 350 650 2,108 PNM to PNMR — — 68,820 PNMR to PNM — 68,820 — Interest billings: PNMR to PNM 6 3,365 2,585 PNM to PNMR 255 299 289 PNMR to TNMP 2 42 136 Income tax sharing payments: PNMR to TNMP — — — PNMR to PNM — — — PNM to PNMR — — 134 TNMP to PNMR 15,820 12,996 3,424

Equity Method Investment (Table

Equity Method Investment (Tables)	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Marketable Securities	PNMR presents its share of net earnings from NMRD in other income on the Consolidated Statements of Earnings. Summarized financial information for NMRD is as follows: December 31, 2020 2019 2018 (In thousands) Operating revenues $ 10,366 $ 3,662 $ 3,147 Operating expenses 7,476 2,971 2,136 Net earnings $ 2,890 $ 691 $ 1,011 Financial Position December 31, 2020 2019 (In thousands) Current assets $ 8,046 $ 7,187 Net property, plant, and equipment 172,585 132,772 Non-current assets 1,900 — Total assets 182,531 139,959 Current liabilities 841 9,640 Non-current liabilities $ 380 $ — Owners’ equity $ 181,310 $ 130,319

Quarterly Operating Results (_2

Quarterly Operating Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Data [Abstract]
Schedule of Quarterly Financial Information	Unaudited operating results by quarters for 2020 and 2019 are presented below. In the opinion of management of the Company, all adjustments (consisting of normal recurring accruals) necessary for a fair statement of the results of operations for such periods have been included. The annual results of basic and diluted earnings per share shown below may be impacted by rounding. Quarter Ended March 31 June 30 September 30 December 31 (In thousands, except per share amounts) PNMR 2020 Operating revenues $ 333,622 $ 357,649 $ 472,465 $ 359,276 Operating income 47,738 71,150 147,805 18,588 Net earnings (loss) (11,399) 61,561 125,453 11,701 Net earnings (loss) attributable to PNMR (15,260) 57,489 121,768 8,778 Net earnings (loss) attributable to PNMR per common share: Basic (0.19) 0.72 1.52 0.11 Diluted (0.19) 0.72 1.52 0.10 2019 (1) Operating revenues $ 349,645 $ 330,228 $ 433,586 $ 344,144 Operating income (loss) 36,723 (93,615) 140,540 60,552 Net earnings (loss) 21,662 (72,283) 106,763 35,989 Net earnings (loss) attributable to PNMR 18,700 (75,914) 102,771 31,805 Net earnings attributable to PNMR per common share: Basic 0.23 (0.95) 1.29 0.40 Diluted 0.23 (0.95) 1.28 0.40 PNM 2020 Operating revenues $ 248,133 $ 260,788 $ 364,504 $ 266,409 Operating income 33,605 49,584 116,540 15,168 Net earnings (loss) (12,196) 49,612 103,004 19,594 Net earnings (loss) attributable to PNM (15,925) 45,672 99,451 16,803 2019 (1) Operating revenues $ 269,318 $ 238,219 $ 331,113 $ 255,172 Operating income (loss) 24,293 (115,977) 108,453 44,299 Net earnings (loss) 21,974 (83,313) 84,721 32,040 Net earnings (loss) attributable to PNM 19,144 (86,812) 80,861 27,988 TNMP 2020 Operating revenues $ 85,489 $ 96,861 $ 107,961 $ 92,867 Operating income 14,345 23,175 31,779 19,154 Net earnings 7,092 16,174 23,921 11,398 2019 Operating revenues $ 80,327 $ 92,009 $ 102,473 $ 88,972 Operating income 12,585 22,578 32,596 18,055 Net earnings 4,098 15,267 25,087 11,347 (1) 2019 reflects pre-tax impairments of $150.6 million offset by $45.7 million of related tax impacts resulting from the NM Supreme Court’s ruling on the appeals in the NM 2015 Rate Case. See Note 17.

Summary of the Business and S_4

Summary of the Business and Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)utility	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Accounting Policies Disclosures [Line Items]
Payment defaults	$ 0
Allowance for equity funds used during construction	$ 11,254,000	$ 9,478,000	$ 10,404,000
PNMR
Accounting Policies Disclosures [Line Items]
Number of regulated utilities | utility	2
Restricted cash	$ 0	0
Public Service Company of New Mexico
Accounting Policies Disclosures [Line Items]
Restricted cash	0	0
Allowance for funds used during construction, capitalized interest	$ 3,000,000	$ 5,000,000	$ 6,100,000
Allowance for funds used during construction, capitalized interest rate	2.40%	2.99%	3.19%
Allowance for equity funds used during construction	$ 6,958,000	$ 6,656,000	$ 8,173,000
Allowance for funds used during construction, capitalized cost of equity rate	3.42%	3.95%	4.25%
Impairment losses on securities held in the NDT	$ 3,200,000	$ 5,700,000	$ 13,700,000
Texas-New Mexico Power Company
Accounting Policies Disclosures [Line Items]
Restricted cash	0	0
Allowance for funds used during construction, capitalized interest	$ 2,100,000	$ 2,400,000	$ 2,300,000
Allowance for funds used during construction, capitalized interest rate	2.20%	3.23%	3.32%
Allowance for equity funds used during construction	$ 4,300,000	$ 2,800,000	$ 2,200,000
Allowance for funds used during construction, capitalized cost of equity rate	4.42%	3.78%	3.29%

Summary of the Business and S_5

Summary of the Business and Significant Accounting Policies - Inventories/Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Inventory	$ 66,417	$ 77,929
Coal
Public Utilities, Inventory [Line Items]
Inventory	12,012	24,914
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	54,405	53,015
Public Service Company of New Mexico
Public Utilities, Inventory [Line Items]
Inventory	60,472	72,225
Public Service Company of New Mexico | Coal
Public Utilities, Inventory [Line Items]
Inventory	12,012	24,914
Public Service Company of New Mexico | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 48,460	$ 47,311
Public Service Company of New Mexico | Electric plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	2.47%	2.47%	2.40%
Public Service Company of New Mexico | Common, intangible, and general plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	7.65%	7.91%	8.18%
Texas-New Mexico Power Company
Public Utilities, Inventory [Line Items]
Depreciation average rates used	3.95%	4.04%	3.49%
Inventory	$ 5,945	$ 5,704
Texas-New Mexico Power Company | Coal
Public Utilities, Inventory [Line Items]
Inventory	0	0
Texas-New Mexico Power Company | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 5,945	$ 5,704

Segment Information - Schedule

Segment Information - Schedule (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Operating Revenues	$ 359,276	$ 472,465	$ 357,649	$ 333,622	$ 344,144	$ 433,586	$ 330,228	$ 349,645	$ 1,523,012	$ 1,457,603	$ 1,436,613
Other operating expenses									514,878	632,783	559,652
Depreciation and amortization									275,612	267,808	241,188
Operating income	18,588	147,805	71,150	47,738	60,552	140,540	(93,615)	36,723	285,281	144,200	236,047
Interest income									14,223	14,022	15,540
Other income (deductions)									22,840	29,643	(15,286)
Interest charges									(114,392)	(121,016)	(127,244)
Earnings before Income Taxes									207,952	66,849	109,057
Income taxes (benefit)									20,636	(25,282)	7,775
Net Earnings	11,701	$ 125,453	$ 61,561	$ (11,399)	35,989	$ 106,763	$ (72,283)	$ 21,662	187,316	92,131	101,282
Valencia non-controlling interest									(14,013)	(14,241)	(15,112)
Subsidiary preferred stock dividends									(528)	(528)	(528)
Net Earnings Attributable to PNMR									172,775	77,362	85,642
Total Assets	7,939,854				7,298,774				7,939,854	7,298,774	6,865,551
Goodwill	278,297				278,297				$ 278,297	278,297	278,297
PNM
Segment Reporting Information [Line Items]
Number of operating segments | segment									1
Other operating expenses									$ 414,445	554,661	481,030
Depreciation and amortization									165,325	160,368	151,866
Operating income									214,897	61,068	145,033
Interest income									14,469	14,303	13,089
Other income (deductions)									17,120	26,989	(17,312)
Interest charges									(64,615)	(72,900)	(76,458)
Earnings before Income Taxes									181,871	29,460	64,352
Income taxes (benefit)									21,857	(25,962)	(5,971)
Net Earnings									160,014	55,422	70,323
Valencia non-controlling interest									(14,013)	(14,241)	(15,112)
Subsidiary preferred stock dividends									(528)	(528)	(528)
Net Earnings Attributable to PNMR									145,473	40,653	54,683
Total Assets	5,581,033				5,242,991				5,581,033	5,242,991	5,035,883
Goodwill	51,632				51,632				$ 51,632	51,632	51,632
TNMP
Segment Reporting Information [Line Items]
Number of operating segments | segment									1
Other operating expenses									$ 104,852	98,621	96,272
Depreciation and amortization									87,799	84,259	66,189
Operating income									88,453	85,814	96,497
Interest income									0	0	0
Other income (deductions)									6,828	4,131	4,065
Interest charges									(30,388)	(29,100)	(32,091)
Earnings before Income Taxes									64,893	60,845	68,471
Income taxes (benefit)									6,308	5,046	16,880
Net Earnings									58,585	55,799	51,591
Valencia non-controlling interest									0	0	0
Subsidiary preferred stock dividends									0	0	0
Net Earnings Attributable to PNMR									58,585	55,799	51,591
Total Assets	2,132,580				1,860,439				2,132,580	1,860,439	1,665,177
Goodwill	226,665				226,665				226,665	226,665	226,665
Corporate and Other
Segment Reporting Information [Line Items]
Other operating expenses									(4,419)	(20,499)	(17,650)
Depreciation and amortization									22,488	23,181	23,133
Operating income									(18,069)	(2,682)	(5,483)
Interest income									(246)	(281)	2,451
Other income (deductions)									(1,108)	(1,477)	(2,039)
Interest charges									(19,389)	(19,016)	(18,695)
Earnings before Income Taxes									(38,812)	(23,456)	(23,766)
Income taxes (benefit)									(7,529)	(4,366)	(3,134)
Net Earnings									(31,283)	(19,090)	(20,632)
Valencia non-controlling interest									0	0	0
Subsidiary preferred stock dividends									0	0	0
Net Earnings Attributable to PNMR									(31,283)	(19,090)	(20,632)
Total Assets	226,241				195,344				226,241	195,344	164,491
Goodwill	$ 0				$ 0				0	0	0
Electricity
Segment Reporting Information [Line Items]
Operating Revenues									1,523,012	1,457,603	1,436,613
Cost of energy									447,241	412,812	399,726
Utility margin									1,075,771	1,044,791	1,036,887
Electricity | PNM
Segment Reporting Information [Line Items]
Operating Revenues									1,139,834	1,093,822	1,091,965
Cost of energy									345,167	317,725	314,036
Utility margin									794,667	776,097	777,929
Electricity | TNMP
Segment Reporting Information [Line Items]
Operating Revenues									383,178	363,781	344,648
Cost of energy									102,074	95,087	85,690
Utility margin									281,104	268,694	258,958
Electricity | Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenues									0	0	0
Cost of energy									0	0	0
Utility margin									$ 0	$ 0	$ 0

Segment Information - Major Cus

Segment Information - Major Customers (Details) - Customer Concentration Risk - Texas-New Mexico Power Company - Electric operating revenues	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REP A
Concentration Risk [Line Items]
Operating revenues from continuing operations	21.00%	22.00%	21.00%
REP B
Concentration Risk [Line Items]
Operating revenues from continuing operations	18.00%	17.00%	15.00%
REP C
Concentration Risk [Line Items]
Operating revenues from continuing operations	11.00%	12.00%	12.00%

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 1,741,750	$ 1,752,594	$ 1,761,448
Total Other Comprehensive Income (Loss)	20,194	9,307	(1,536)
Ending Balance	2,108,474	1,741,750	1,752,594
Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			0
Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			1,761,448
Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	1,512,431	1,461,571	1,488,369
Total Other Comprehensive Income (Loss)	20,544	11,367	(2,121)
Ending Balance	1,863,752	1,512,431	1,461,571
Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			1,488,369
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(99,377)	(108,684)	(95,940)
Amounts reclassified from AOCI (pre-tax)	(2,937)	(5,926)	3,965
Income tax impact of amounts reclassified	746	1,506	(1,008)
Other OCI changes (pre-tax)	30,006	18,400	(6,022)
Income tax impact of other OCI changes	(7,621)	(4,673)	1,529
Total Other Comprehensive Income (Loss)	20,194	9,307	(1,536)
Ending Balance	(79,183)	(99,377)	(108,684)
Total | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(11,208)
Total | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(107,148)
Total | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(99,055)	(110,422)	(97,093)
Amounts reclassified from AOCI (pre-tax)	(1,197)	(6,659)	3,749
Income tax impact of amounts reclassified	304	1,692	(952)
Other OCI changes (pre-tax)	28,735	21,895	(6,592)
Income tax impact of other OCI changes	(7,298)	(5,561)	1,674
Total Other Comprehensive Income (Loss)	20,544	11,367	(2,121)
Ending Balance	(78,511)	(99,055)	(110,422)
Total | Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(11,208)
Total | Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(108,301)
Unrealized Gains on Available-for-Sale Securities | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	10,638	1,939	13,169
Amounts reclassified from AOCI (pre-tax)	(9,497)	(14,063)	(3,819)
Income tax impact of amounts reclassified	2,412	3,572	970
Other OCI changes (pre-tax)	22,586	25,724	3,790
Income tax impact of other OCI changes	(5,736)	(6,534)	(963)
Total Other Comprehensive Income (Loss)	9,765	8,699	(22)
Ending Balance	20,403	10,638	1,939
Unrealized Gains on Available-for-Sale Securities | Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(11,208)
Unrealized Gains on Available-for-Sale Securities | Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			1,961
Pension Liability Adjustment | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(109,693)	(112,361)	(110,262)
Amounts reclassified from AOCI (pre-tax)	8,300	7,404	7,568
Income tax impact of amounts reclassified	(2,108)	(1,880)	(1,922)
Other OCI changes (pre-tax)	6,149	(3,829)	(10,382)
Income tax impact of other OCI changes	(1,562)	973	2,637
Total Other Comprehensive Income (Loss)	10,779	2,668	(2,099)
Ending Balance	(98,914)	(109,693)	(112,361)
Pension Liability Adjustment | Public Service Company of New Mexico | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(110,262)
Fair Value Adjustment for Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			1,153
Amounts reclassified from AOCI (pre-tax)			216
Income tax impact of amounts reclassified			(56)
Other OCI changes (pre-tax)			570
Income tax impact of other OCI changes			(145)
Total Other Comprehensive Income (Loss)			585
Fair Value Adjustment for Cash Flow Hedges | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			1,153
Fair Value Adjustment for Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(322)	1,738
Amounts reclassified from AOCI (pre-tax)	(1,740)	733
Income tax impact of amounts reclassified	442	(186)
Other OCI changes (pre-tax)	1,271	(3,495)
Income tax impact of other OCI changes	(323)	888
Total Other Comprehensive Income (Loss)	(350)	(2,060)
Ending Balance	$ (672)	$ (322)	$ 1,738

Electric Operating Revenues - N

Electric Operating Revenues - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)MW	Dec. 31, 2019USD ($)	Dec. 31, 2017MW
Contract with Customers, Asset and Liability [Roll Forward]
Capitalized contract cost, amortization period (in years)	5 years
Contract assets	$ 0
Public Service Company of New Mexico
Contract with Customers, Asset and Liability [Roll Forward]
Expected exposure to market risk (in megawatts) | MW	65		65
Power to be sold to third party (in megawatts) | MW	36		36
Contract with customers, net	$ 86,200,000	$ 59,300,000
Accounts receivable, credit loss expense (reversal)	$ 7,200,000

Electric Operating Revenues - D

Electric Operating Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contracts with customers									$ 1,469,799	$ 1,377,208	$ 1,359,740
Alternative revenue programs									(11,994)	(542)	1,756
Other electric operating revenue									65,207	80,937	75,117
Total electric operating revenues	$ 359,276	$ 472,465	$ 357,649	$ 333,622	$ 344,144	$ 433,586	$ 330,228	$ 349,645	1,523,012	1,457,603	1,436,613
Electricity
Disaggregation of Revenue [Line Items]
Total electric operating revenues									1,523,012	1,457,603	1,436,613
Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers									138,230	124,162	121,271
Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers									17,049	16,702	23,081
Public Service Company of New Mexico
Disaggregation of Revenue [Line Items]
Contracts with customers									1,078,158	1,010,898	1,019,291
Alternative revenue programs									(3,531)	1,987	(2,443)
Other electric operating revenue									65,207	80,937	75,117
Total electric operating revenues	266,409	364,504	260,788	248,133	255,172	331,113	238,219	269,318	1,139,834	1,093,822	1,091,965
Public Service Company of New Mexico | Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers									59,856	57,214	54,280
Public Service Company of New Mexico | Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers									13,311	13,134	14,098
Texas-New Mexico Power Company
Disaggregation of Revenue [Line Items]
Contracts with customers									391,641	366,310	340,449
Alternative revenue programs									(8,463)	(2,529)	4,199
Other electric operating revenue									0	0	0
Total electric operating revenues	$ 92,867	$ 107,961	$ 96,861	$ 85,489	$ 88,972	$ 102,473	$ 92,009	$ 80,327	383,178	363,781	344,648
Texas-New Mexico Power Company | Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers									78,374	66,948	66,991
Texas-New Mexico Power Company | Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers									3,738	3,568	8,983
Residential | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									640,918	578,625	563,297
Residential | Public Service Company of New Mexico | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									482,852	427,883	433,009
Residential | Texas-New Mexico Power Company | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									158,066	150,742	130,288
Commercial | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									510,500	513,940	519,594
Commercial | Public Service Company of New Mexico | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									392,257	396,987	408,333
Commercial | Texas-New Mexico Power Company | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									118,243	116,953	111,261
Industrial | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									118,212	92,006	78,436
Industrial | Public Service Company of New Mexico | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									90,845	69,601	61,119
Industrial | Texas-New Mexico Power Company | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									27,367	22,405	17,317
Public authority | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									28,979	26,016	27,297
Public authority | Public Service Company of New Mexico | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									23,126	20,322	21,688
Public authority | Texas-New Mexico Power Company | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									5,853	5,694	5,609
Economy energy service | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									15,911	25,757	26,764
Economy energy service | Public Service Company of New Mexico | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									15,911	25,757	26,764
Economy energy service | Texas-New Mexico Power Company | Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers									$ 0	$ 0	$ 0

Earnings and Dividends Per Sh_3

Earnings and Dividends Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Earnings Attributable to PNMR									$ 172,775	$ 77,362	$ 85,642
Average Number of Common Shares:
Outstanding during year (in shares)									79,941	79,654	79,654
Vested awards of restricted stock (in shares)									216	277	236
Average Shares – Basic (in shares)									80,157	79,931	79,890
Dilutive Effect of Common Stock Equivalents:
PNMR 2020 Forward Equity Sale Agreements (in shares)									106	0	0
Stock options and restricted stock (in shares)									40	59	122
Average Shares – Diluted (in shares)									80,303	79,990	80,012
Net Earnings Attributable to PNMR Per Share of Common Stock:
Basic (in dollars per share)	$ 0.11	$ 1.52	$ 0.72	$ (0.19)	$ 0.40	$ 1.29	$ (0.95)	$ 0.23	$ 2.16	$ 0.97	$ 1.07
Diluted (in dollars per share)	$ 0.10	$ 1.52	$ 0.72	$ (0.19)	$ 0.40	$ 1.28	$ (0.95)	$ 0.23	2.15	0.97	1.07
Dividends Declared per Common Share (in dollars per share)									$ 1.2500	$ 1.1775	$ 1.0850

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($)	Dec. 15, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 07, 2020
Class of Stock [Line Items]
Payment of dividends		$ 423,700,000
PNMR 2020 Forward Equity Sales Agreement
Class of Stock [Line Items]
Number of shares issued in transaction (in shares)	6,200,000
Sale of stock, price per share (in dollars per share)	$ 45.805				$ 47.21
Sale of stock, consideration received on transaction	$ 283,100,000
Payments of stock issuance costs	$ 100,000
Line of Credit
Class of Stock [Line Items]
Debt-to-capital ratio (not more than)		70.00%
Public Service Company of New Mexico
Class of Stock [Line Items]
Equity contribution from parent		$ 230,000,000	$ 0	$ 0
Preferred stock, dividend rate		4.58%
Preferred stock, redemption percent		102.00%
Preferred stock outstanding (in shares)		115,293	115,293
Preferred stock, cumulative shares authorized (in shares)		10,000,000	10,000,000
Public Service Company of New Mexico | Maximum
Class of Stock [Line Items]
Requirement to obtain approval to transfer more than a percentage of PNM's assets		5.00%
Public Service Company of New Mexico | Line of Credit
Class of Stock [Line Items]
Debt-to-capital ratio (not more than)		65.00%
Public Service Company of New Mexico | Affiliated Entity
Class of Stock [Line Items]
Cash dividends paid to parent company by consolidated subsidiaries		$ 40,700,000	$ 0	77,400,000
Texas-New Mexico Power Company
Class of Stock [Line Items]
Equity contribution from parent		$ 71,000,000	80,000,000	30,000,000
Preferred stock, cumulative shares authorized (in shares)		1,000,000
Texas-New Mexico Power Company | Affiliated Entity
Class of Stock [Line Items]
Cash dividends paid to parent company by consolidated subsidiaries		$ 58,500,000	$ 55,300,000	$ 41,900,000
PNMR and TNMP
Class of Stock [Line Items]
Preferred stock outstanding (in shares)		0

Financing - Financing Activitie

Financing - Financing Activities (Details)

Dec. 21, 2020USD ($)

Dec. 15, 2020USD ($)$ / sharesshares

Oct. 20, 2020USD ($)

Jun. 22, 2020USD ($)

Apr. 30, 2020USD ($)

Apr. 24, 2020USD ($)bond_series

Apr. 15, 2020USD ($)

Apr. 01, 2020USD ($)

Jan. 08, 2020shares

Jan. 07, 2020$ / sharesshares

Jan. 01, 2020

Dec. 13, 2019

Jul. 01, 2019USD ($)

Apr. 01, 2019USD ($)

Feb. 26, 2019USD ($)

Dec. 21, 2018USD ($)

Dec. 14, 2018USD ($)

Jul. 31, 2018USD ($)

May 14, 2018USD ($)

Apr. 09, 2018USD ($)

Mar. 09, 2018USD ($)

Jan. 01, 2018USD ($)loan

Jul. 28, 2017USD ($)bond_series

Dec. 31, 2018USD ($)derivative

Dec. 31, 2020USD ($)shares

Dec. 31, 2019USD ($)shares

Dec. 31, 2018USD ($)derivative

Feb. 19, 2021USD ($)

Dec. 22, 2020USD ($)

Nov. 26, 2020USD ($)

Nov. 25, 2020USD ($)

Jul. 15, 2020USD ($)

Jun. 30, 2020USD ($)

Jun. 01, 2020USD ($)

Dec. 18, 2019USD ($)

Jul. 22, 2019USD ($)

Mar. 29, 2019USD ($)

Jan. 18, 2019USD ($)

Dec. 17, 2018USD ($)

Nov. 26, 2018USD ($)

Jul. 25, 2018USD ($)

Jun. 28, 2018USD ($)

May 22, 2018USD ($)

Debt Instrument [Line Items]

Short-term debt

$ 32,000,000

$ 185,100,000

Common stock, shares issued (in shares) | shares

85,834,874

85,834,874

Financing capacity

$ 40,000,000

$ 50,000,000

Interest expenses

114,392,000

$ 121,016,000

$ 127,244,000

Fixed interest rate

1.927%

Cash Flow Hedge | Significant Other Observable Inputs (Level 2)

Debt Instrument [Line Items]

Fair value gain (loss, less than)

900,000

400,000

Interest rate contract

Debt Instrument [Line Items]

Number of derivatives | derivative

3

3

Revolving Credit Facility | Subsequent Event

Debt Instrument [Line Items]

Available borrowing capacity

$ 773,100,000

PNMR 2020 Forward Equity Sales Agreement

Debt Instrument [Line Items]

Common stock, shares issued (in shares) | shares

6,200,000

Number of shares issued in transaction (in shares) | shares

6,200,000

Sale of stock, price per share (in dollars per share) | $ / shares

$ 45.805

$ 47.21

Sale of stock, consideration received on transaction

$ 283,100,000

Payments of stock issuance costs

$ 100,000

Over-Allotment Option

Debt Instrument [Line Items]

Number of shares issued in transaction (in shares) | shares

800,000

800,000

PNMR 2015 Term Loan

Debt Instrument [Line Items]

Term loans

$ 150,000,000

$ 150,000,000

PNMR 2016 One-Year Term Loan and PNMR 2016 Two-Year Term Loan

Debt Instrument [Line Items]

Number of loan agreements (in loans) | loan

2

PNMR 2016 One Year Term Loan

Debt Instrument [Line Items]

Short-term debt

$ 100,000,000

Debt instrument, term

1 year

1 year

1 year

PNMR 2016 Two-Year Term Loan

Debt Instrument [Line Items]

Term loans

$ 100,000,000

Debt instrument, term

2 years

2 years

2 years

2 years

PNMR 2020 Delayed-Draw Term Loan

Debt Instrument [Line Items]

Term loans

$ 80,000,000

$ 300,000,000

Variable interest rate

1.40%

PNMR Development Term Loan due January 2022

Debt Instrument [Line Items]

Variable interest rate

1.52%

PNMR 2018 One Year Term Loan

Debt Instrument [Line Items]

Aggregate principal amount

$ 150,000,000

Debt instrument, term

1 year

1 year

Variable interest rate

1.11%

PNMR 2018 Two-Year Term Loan due December 2020

Debt Instrument [Line Items]

Term loans

$ 50,000,000

Aggregate principal amount

$ 50,000,000

Debt instrument, term

2 years

2 years

PNMR 2020 Term Loan

Debt Instrument [Line Items]

Term loans

$ 150,000,000

Variable interest rate

1.25%

TNMP 2018 Term Loan due July 2020

Debt Instrument [Line Items]

Term loan restatement to provide additional funding

$ 15,000,000

Term loan restatement committed amount

$ 35,000,000

Variable Rate Short-Term Debt

Debt Instrument [Line Items]

Aggregate principal amount

$ 50,000,000

$ 50,000,000

Term of derivatives

4 years

Variable Rate Short-Term Debt | Interest rate 1

Debt Instrument [Line Items]

Fixed interest rate

1.926%

1.926%

Variable Rate Short-Term Debt | Interest rate 2

Debt Instrument [Line Items]

Fixed interest rate

1.823%

1.823%

Variable Rate Short-Term Debt | Interest rate 3

Debt Instrument [Line Items]

Fixed interest rate

1.629%

1.629%

Maximum

Debt Instrument [Line Items]

Short-term debt - affiliate

$ 150,000,000

PNM and TNMP

Debt Instrument [Line Items]

Short-term debt - affiliate

0

0

PNM and TNMP | Subsequent Event

Debt Instrument [Line Items]

Short-term debt - affiliate

0

PNM

Debt Instrument [Line Items]

Short-term debt

$ 10,000,000

$ 58,000,000

Common stock, shares issued (in shares) | shares

39,117,799

39,117,799

Interest expenses

$ 64,615,000

$ 72,900,000

$ 76,458,000

PNM | PNM 2019 $250.0 Million Term Loan due July 2020

Debt Instrument [Line Items]

Aggregate principal amount

$ 250,000,000

PNM | PNM 2019 $40.0 Million Term Loan due June 2021

Debt Instrument [Line Items]

Aggregate principal amount

$ 40,000,000

PNM | Maximum

Debt Instrument [Line Items]

Maturity term over which financings require regulator approval (more than)

18 months

NM Capital | BTMU Term Loan

Debt Instrument [Line Items]

Term loans

$ 125,000,000

Estimated principal payments

$ 43,000,000

PNMR | PNMR 3.25% 2018 SUNs due March 2021

Debt Instrument [Line Items]

Term loans

$ 300,000,000

300,000,000

Stated percentage

3.25%

PNMR | PNMR 2020 Delayed-Draw Term Loan

Debt Instrument [Line Items]

Term loans

$ 80,000,000

0

Available borrowing capacity

220,000,000

Repayments of debt

220,000,000

PNMR | PNMR Development Term Loan due January 2022

Debt Instrument [Line Items]

Term loans

65,000,000

90,000,000

PNMR | PNMR 2018 Two-Year Term Loan due December 2020

Debt Instrument [Line Items]

Term loans

0

50,000,000

PNMR | Merger Backstop Facilities | Term Loan

Debt Instrument [Line Items]

Debt instrument, term

364 days

Financing capacity

$ 50,000,000

PNMR | Merger Backstop Facilities | Revolving Credit Facility | Line of Credit

Debt Instrument [Line Items]

Debt instrument, term

364 days

Financing capacity

$ 300,000,000

PNMR | PNMR 2020 Term Loan

Debt Instrument [Line Items]

Term loans

150,000,000

0

PNMR | PNM 2019 Term Loan

Debt Instrument [Line Items]

Term loans

150,000,000

150,000,000

Texas-New Mexico Power Company

Debt Instrument [Line Items]

Short-term debt

$ 0

$ 15,000,000

Common stock, shares issued (in shares) | shares

6,358

6,358

Interest expenses

$ 30,388,000

$ 29,100,000

32,091,000

PNMR Development

Debt Instrument [Line Items]

Short-term debt - affiliate

$ 300,000

0

PNMR Development | Deposit Related to Potential Transmission Interconnections

Debt Instrument [Line Items]

Amount of related party transaction

$ 68,200,000

Accrued interest

$ 5,700,000

Interest expenses

3,300,000

$ 2,400,000

PNMR Development | Subsequent Event

Debt Instrument [Line Items]

Short-term debt - affiliate

$ 400,000

Line of Credit

Debt Instrument [Line Items]

Ratio of debt to capital (less than or equal to)

65.00%

Line of Credit | PNMR and PNMR Development

Debt Instrument [Line Items]

Ratio of debt to capital (less than or equal to)

70.00%

Line of Credit | PNM and TNMP

Debt Instrument [Line Items]

Ratio of debt to capital (less than or equal to)

65.00%

Line of Credit | PNM | PNM Revolving Credit Facility

Debt Instrument [Line Items]

Repayments of debt

$ 100,000,000

Letter of Credit | PNMR | Letter or credit, 30 mil JP Morgan

Debt Instrument [Line Items]

Aggregate principal amount

30,300,000

Senior Unsecured Notes | PNMR 3.25% 2018 SUNs due March 2021

Debt Instrument [Line Items]

Term loans

220,000,000

Aggregate principal amount

$ 300,000,000

Stated percentage

3.25%

Senior Unsecured Notes | PNM

Debt Instrument [Line Items]

Shelf registration statement, capacity of issuance (up to)

$ 650,000,000

Senior Unsecured Notes | PNM | Senior Unsecured Note Agreement (SUNs), Private Placement Transactions with Institutional Investors

Debt Instrument [Line Items]

Aggregate principal amount

$ 450,000,000

Series of bond issuance | bond_series

8

Debt to capital ratio

65.00%

Senior Unsecured Notes | PNM | SUNs, Private Placement Transaction with Institutional Investors, Issuance in May 2018

Debt Instrument [Line Items]

Aggregate principal amount

$ 350,000,000

Senior Unsecured Notes | PNM | SUNs at 7.95% due 2018

Debt Instrument [Line Items]

Stated percentage

7.95%

Senior Unsecured Notes | PNM | SUN's, Private Placement Transaction with Institutional Investors, Issuance in July 2018

Debt Instrument [Line Items]

Aggregate principal amount

$ 100,000,000

Senior Unsecured Notes | PNM | SUNs at 7.50% due August 2018

Debt Instrument [Line Items]

Stated percentage

7.50%

Senior Unsecured Notes | PNM | PNM 2019 $250.0 Million Term Loan due July 2020

Debt Instrument [Line Items]

Term loans

0

250,000,000

Senior Unsecured Notes | PNM | PNM 2019 $40.0 Million Term Loan due June 2021

Debt Instrument [Line Items]

Term loans

$ 40,000,000

40,000,000

Senior Unsecured Notes | PNM | Minimum | SUNs, Private Placement Transaction with Institutional Investors, Issuance in May 2018

Debt Instrument [Line Items]

Debt instrument, term

5 years

Stated percentage

3.15%

Senior Unsecured Notes | PNM | Minimum | SUN's, Private Placement Transaction with Institutional Investors, Issuance in July 2018

Debt Instrument [Line Items]

Debt instrument, term

10 years

Stated percentage

3.78%

Senior Unsecured Notes | PNM | Maximum | SUNs, Private Placement Transaction with Institutional Investors, Issuance in May 2018

Debt Instrument [Line Items]

Debt instrument, term

30 years

Stated percentage

4.50%

Senior Unsecured Notes | PNM | Maximum | SUN's, Private Placement Transaction with Institutional Investors, Issuance in July 2018

Debt Instrument [Line Items]

Debt instrument, term

30 years

Stated percentage

4.60%

Senior Unsecured Notes | Texas-New Mexico Power Company | First Mortgage Bonds at 9.50% due 2019

Debt Instrument [Line Items]

Stated percentage

9.50%

Extinguishment of debt

$ 172,300,000

Medium-term Notes | PNMR Development Term Loan due January 2022

Debt Instrument [Line Items]

Aggregate principal amount

$ 65,000,000

$ 90,000,000

$ 90,000,000

Medium-term Notes | PNM | PNM 2020 $250.0 Million Term Loan

Debt Instrument [Line Items]

Aggregate principal amount

$ 150,000,000

$ 250,000,000

Medium-term Notes | PNM | PNM 2019 Term Loan

Debt Instrument [Line Items]

Repayments of debt

$ 250,000,000

Notes Payable to Banks | PNM | PNM 2017 Term Loan Agreement | JPMorgan Chase Bank, N.A. and U.S. Bank National Association

Debt Instrument [Line Items]

Aggregate principal amount

200,000,000

Notes Payable to Banks | PNM | PNM 2019 $40.0 Million Term Loan due June 2021 | JPMorgan Chase Bank, N.A. and U.S. Bank National Association

Debt Instrument [Line Items]

Stated percentage

0.80%

Secured Debt | Texas-New Mexico Power Company | TNMP First Mortgage Bonds

Debt Instrument [Line Items]

Aggregate principal amount

$ 750,000,000

Debt instrument, prepayment period

30 days

Debt instrument, redemption price, percentage of principal amount redeemed

100.00%

Secured Debt | Texas-New Mexico Power Company | TNMP Term Loan Agreement

Debt Instrument [Line Items]

Aggregate principal amount

$ 20,000,000

Secured Debt | Texas-New Mexico Power Company | TNMP 2020 Bond Purchase Agreement

Debt Instrument [Line Items]

Ratio of debt to capital (less than or equal to)

65.00%

Aggregate principal amount

$ 185,000,000

Series of bond issuance | bond_series

4

Secured Debt | Texas-New Mexico Power Company | TNMP 2020 Bond Purchase Agreement, Bond Series 1 and 2

Debt Instrument [Line Items]

Aggregate principal amount

$ 110,000,000

Secured Debt | Texas-New Mexico Power Company | TNMP 2020 Bond Purchase Agreement, Bond Series 3 and 4

Debt Instrument [Line Items]

Aggregate principal amount

$ 75,000,000

Senior Notes | Senior Unsecured Notes, 3.21% Series A, due April 2030

Debt Instrument [Line Items]

Aggregate principal amount

$ 150,000,000

Stated percentage

3.21%

Senior Notes | Senior Unsecured Notes, 3.57% Series B, due April 2039

Debt Instrument [Line Items]

Aggregate principal amount

$ 50,000,000

Stated percentage

3.57%

Senior Notes | PNM

Debt Instrument [Line Items]

Ratio of debt to capital (less than or equal to)

65.00%

Aggregate principal amount

$ 200,000,000

Senior Notes | PNM | PNM 2020 $250.0 Million Term Loan

Debt Instrument [Line Items]

Repayments of debt

$ 100,000,000

Bonds

Debt Instrument [Line Items]

Repayments of debt

$ 302,500,000

Bonds | City of Farmington, New Mexico

Debt Instrument [Line Items]

Aggregate principal amount

$ 266,500,000

Bonds | Pollution Control Revenue Bonds

Debt Instrument [Line Items]

Term loans

100,300,000

Aggregate principal amount

$ 100,300,000

Stated percentage

0.19%

Bonds | Pollution Control Revenue Bonds, Due 2040

Debt Instrument [Line Items]

Term loans

40,000,000

Bonds | Pollution Control Revenue Bonds, Due 2043, Series 1

Debt Instrument [Line Items]

Term loans

39,300,000

Bonds | Pollution Control Revenue Bonds, Due 2043, Series 2

Debt Instrument [Line Items]

Term loans

21,000,000

Bonds | Pollution Control Revenue Bonds, 6.25%, Callable | Maricopa County, Arizona Pollution Control Corporation

Debt Instrument [Line Items]

Aggregate principal amount

$ 36,000,000

Stated percentage

6.25%

Debt instrument, redemption price, percentage

101.00%

Bonds | Pollution Control Revenue Bonds, 6.25%, Callable | City of Farmington, New Mexico

Debt Instrument [Line Items]

Aggregate principal amount

$ 11,500,000

Stated percentage

6.25%

Bonds | Pollution Control Revenue Bonds, 5.90%, Callable | City of Farmington, New Mexico

Debt Instrument [Line Items]

Aggregate principal amount

$ 255,000,000

Stated percentage

5.90%

Mortgages | Texas-New Mexico Power Company | First Mortgage Bonds

Debt Instrument [Line Items]

Aggregate principal amount

$ 60,000,000

Stated percentage

3.85%

Mortgages | Texas-New Mexico Power Company | TNMP 2019 Bond Purchase Agreement

Debt Instrument [Line Items]

Aggregate principal amount

$ 305,000,000

$ 225,000,000

Stated percentage

400.00%

Debt to capital ratio

65.00%

Mortgages | Texas-New Mexico Power Company | First Mortgage Bonds at 3.60% due 2029

Debt Instrument [Line Items]

Aggregate principal amount

$ 80,000,000

San Juan Coal Company, Westmoreland | NM Capital | Coal Supply

Debt Instrument [Line Items]

Term loans

50,100,000

Repurchased face amount

$ 50,100,000

San Juan Generating Station | PNM

Debt Instrument [Line Items]

Request issuance of energy transition bonds

$ 361,000,000

$ 361,000,000

San Juan Generating Station | NM Capital | Coal Supply

Debt Instrument [Line Items]

Payments to fund long-term loans to unaffiliated third party

$ 125,000,000

Financing - Short-term Debt and

Financing - Short-term Debt and Liquidity (Details)	12 Months Ended
	Dec. 31, 2020USD ($)numberOfAMIMeters	Feb. 19, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)	Jul. 22, 2019USD ($)
Short-term Debt [Line Items]
Financing capacity	$ 40,000,000				$ 50,000,000
Short-term debt	32,000,000			$ 185,100,000
Letters of credit outstanding	4,700,000
JPMorgan Chase Bank, N.A.
Short-term Debt [Line Items]
Letters of credit outstanding	30,300,000
PNM Resources
Short-term Debt [Line Items]
Short-term debt	12,000,000			112,100,000
Pollution Control Revenue Bonds | Bonds
Short-term Debt [Line Items]
Aggregate principal amount			$ 100,300,000
PNMR Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity	300,000,000
Short-term debt	$ 12,000,000			112,100,000
PNMR Revolving Credit Facility | PNM Resources
Short-term Debt [Line Items]
Interest rates on outstanding borrowings	1.66%
PNMR Development Revolving Credit Facility
Short-term Debt [Line Items]
Short-term debt	$ 10,000,000			0
PNM
Short-term Debt [Line Items]
Short-term debt	10,000,000			58,000,000
Letters of credit outstanding	2,200,000
PNM | Lines of credit
Short-term Debt [Line Items]
NMPRC approved credit facility	40,000,000
PNM | PNM Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity	400,000,000
Short-term debt	0			48,000,000
PNM | PNM 2017 New Mexico Credit Facility
Short-term Debt [Line Items]
Short-term debt	$ 10,000,000			10,000,000
Interest rates on outstanding borrowings	1.41%
TNMP
Short-term Debt [Line Items]
Short-term debt	$ 0			15,000,000
Letters of credit outstanding	0
TNMP | TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity	75,000,000
Short-term debt	$ 0			$ 15,000,000
Interest rates on outstanding borrowings	1.15%
TNMP | TNMP Revolving Credit Facility | First Mortgage Bonds at 9.50% due 2019
Short-term Debt [Line Items]
Aggregate principal amount of bonds	$ 75,000,000
PNM and TNMP | PNMR Development Revolving Credit Facility
Short-term Debt [Line Items]
Letters of credit outstanding	$ 0
Revolving Credit Facility | TNMP | First Mortgage Bonds at 9.50% due 2019
Short-term Debt [Line Items]
Number of extension options | numberOfAMIMeters	2
Extension option period	1 year
Subsequent Event | PNM Resources
Short-term Debt [Line Items]
Consolidated invested cash		$ 900,000
Subsequent Event | PNMR Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		257,700,000
Subsequent Event | Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		773,100,000
Subsequent Event | PNM
Short-term Debt [Line Items]
Consolidated invested cash		32,600,000
Subsequent Event | PNM | PNM Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		397,800,000
Subsequent Event | PNM | PNM 2017 New Mexico Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		40,000,000
Subsequent Event | TNMP
Short-term Debt [Line Items]
Consolidated invested cash		0
Subsequent Event | TNMP | TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		47,600,000
Subsequent Event | PNMR Development | TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity		$ 30,000,000

Financing - Long-term Debt (Det

Financing - Long-term Debt (Details) - USD ($)	Jun. 22, 2020	Mar. 09, 2018	Dec. 31, 2020	Dec. 22, 2020	Dec. 21, 2020	Jun. 30, 2020	Dec. 31, 2019	Dec. 18, 2019	Jan. 18, 2019	Dec. 21, 2018
Debt Instrument [Line Items]
Total			$ 3,294,043,000				$ 3,004,043,000
Principal, less current maturities			576,000,000				490,345,000
Long-term debt, excluding current maturities, gross			2,718,043,000				2,513,698,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			(1,107,000)				(3,674,000)
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities			482,000				77,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities			(1,589,000)				(3,751,000)
PNMR 2018 Two-Year Term Loan due December 2020
Debt Instrument [Line Items]
Aggregate principal amount										$ 50,000,000
Term loans					$ 50,000,000
PNMR 2020 Term Loan due January 2022
Debt Instrument [Line Items]
Term loans					$ 150,000,000
PNMR 2020 Delayed-Draw Term Loan due January 2022
Debt Instrument [Line Items]
Term loans			$ 80,000,000	$ 300,000,000
Bonds
Debt Instrument [Line Items]
Repayments of debt	$ 302,500,000
Bonds | Pollution Control Revenue Bonds
Debt Instrument [Line Items]
Aggregate principal amount						$ 100,300,000
Term loans							100,300,000
Stated percentage			0.19%
Senior Unsecured Notes: | PNMR 3.25% 2018 SUNs due March 2021
Debt Instrument [Line Items]
Aggregate principal amount		$ 300,000,000
Term loans		$ 220,000,000
Stated percentage		3.25%
Public Service Company of New Mexico
Debt Instrument [Line Items]
Total			$ 1,705,845,000				1,755,845,000
Principal, less current maturities			346,000,000				350,345,000
Long-term debt, excluding current maturities, gross			1,359,845,000				1,405,500,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			9,225,000				7,825,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities			430,000				77,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities			$ 8,795,000				7,748,000
Public Service Company of New Mexico | PNM 2019 $250.0 Million Term Loan due July 2020
Debt Instrument [Line Items]
Aggregate principal amount									$ 250,000,000
Public Service Company of New Mexico | PNM 2019 $40.0 Million Term Loan due June 2021
Debt Instrument [Line Items]
Aggregate principal amount								$ 40,000,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.875% due April 2033, mandatory tender - October 1, 2021
Debt Instrument [Line Items]
Stated percentage			1.875%
Unsecured long-term debt, noncurrent			$ 146,000,000				146,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 301,000				662,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 6.25% due January 2038
Debt Instrument [Line Items]
Stated percentage			6.25%
Unsecured long-term debt, noncurrent			$ 0				36,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				205,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.125% due June 2040, mandatory tender - June 1, 2022
Debt Instrument [Line Items]
Stated percentage			2.125%
Unsecured long-term debt, noncurrent			$ 37,000,000				37,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 135,000				224,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.20% due June 2040, mandatory tender - June 1, 2020
Debt Instrument [Line Items]
Stated percentage			5.20%
Unsecured long-term debt, noncurrent			$ 0				40,045,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				17,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.90% due June 2040
Debt Instrument [Line Items]
Stated percentage			5.90%
Unsecured long-term debt, noncurrent			$ 0				255,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				1,857,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 6.25% due June 2040
Debt Instrument [Line Items]
Stated percentage			6.25%
Unsecured long-term debt, noncurrent			$ 0				11,500,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				84,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.45% due September 2042, mandatory tender - June 1, 2022
Debt Instrument [Line Items]
Stated percentage			2.45%
Unsecured long-term debt, noncurrent			$ 20,000,000				20,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 50,000				85,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.40% due June 2043, mandatory tender - June 1, 2020
Debt Instrument [Line Items]
Stated percentage			2.40%
Unsecured long-term debt, noncurrent			$ 0				39,300,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				50,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.20% due June 2043, mandatory tender - June 1, 2020
Debt Instrument [Line Items]
Stated percentage			5.20%
Unsecured long-term debt, noncurrent			$ 0				21,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				10,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | Floating rate, weekly-mode
Debt Instrument [Line Items]
Unsecured long-term debt, noncurrent			100,345,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 798,000				0
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.05% due January 2038, mandatory tender - June 1, 2022
Debt Instrument [Line Items]
Stated percentage			1.05%
Unsecured long-term debt, noncurrent			$ 36,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 226,000				0
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.20% due June 2040, mandatory tender - June 1, 2022
Debt Instrument [Line Items]
Stated percentage			1.20%
Unsecured long-term debt, noncurrent			$ 11,500,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 72,000				0
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.10% due June 2040, mandatory tender June 1, 2023
Debt Instrument [Line Items]
Stated percentage			1.10%
Unsecured long-term debt, noncurrent			$ 130,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 892,000				0
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.15% due June 2040, mandatory tender - June 1, 2024
Debt Instrument [Line Items]
Stated percentage			1.15%
Unsecured long-term debt, noncurrent			$ 125,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 894,000				0
Public Service Company of New Mexico | Senior Unsecured Notes: | 5.35% due October 2021
Debt Instrument [Line Items]
Stated percentage			5.35%
Unsecured long-term debt, noncurrent			$ 160,000,000				160,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 129,000				292,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.15% due May 2023
Debt Instrument [Line Items]
Stated percentage			3.15%
Unsecured long-term debt, noncurrent			$ 55,000,000				55,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 184,000				261,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.45% due May 2025
Debt Instrument [Line Items]
Stated percentage			3.45%
Unsecured long-term debt, noncurrent			$ 104,000,000				104,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 457,000				562,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.85% due August 2025
Debt Instrument [Line Items]
Stated percentage			3.85%
Unsecured long-term debt, noncurrent			$ 250,000,000				250,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 1,375,000				1,675,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.68% due May 2028
Debt Instrument [Line Items]
Stated percentage			3.68%
Unsecured long-term debt, noncurrent			$ 88,000,000				88,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 457,000				518,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.78% due August 2028
Debt Instrument [Line Items]
Stated percentage			3.78%
Unsecured long-term debt, noncurrent			$ 15,000,000				15,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 80,000				91,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.93% due May 2033
Debt Instrument [Line Items]
Stated percentage			3.93%
Unsecured long-term debt, noncurrent			$ 38,000,000				38,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 221,000				238,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.22% due May 2038
Debt Instrument [Line Items]
Stated percentage			4.22%
Unsecured long-term debt, noncurrent			$ 45,000,000				45,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 275,000				291,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.50% due May 2048
Debt Instrument [Line Items]
Stated percentage			4.50%
Unsecured long-term debt, noncurrent			$ 20,000,000				20,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 128,000				133,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.60% due August 2048
Debt Instrument [Line Items]
Stated percentage			4.60%
Unsecured long-term debt, noncurrent			$ 85,000,000				85,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 550,000				570,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.21% due April 2030
Debt Instrument [Line Items]
Stated percentage			3.21%
Unsecured long-term debt, noncurrent			$ 150,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 1,490,000				0
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.57% due April 2039
Debt Instrument [Line Items]
Stated percentage			3.57%
Unsecured long-term debt, noncurrent			$ 50,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			511,000				0
Public Service Company of New Mexico | Senior Unsecured Notes: | PNM 2019 $250.0 Million Term Loan due July 2020
Debt Instrument [Line Items]
Term loans			0				250,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				0
Public Service Company of New Mexico | Senior Unsecured Notes: | PNM 2019 $40.0 Million Term Loan due June 2021
Debt Instrument [Line Items]
Term loans			40,000,000				40,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				0
Texas-New Mexico Power Company
Debt Instrument [Line Items]
Total			843,198,000				658,198,000
Principal, less current maturities			0				0
Long-term debt, excluding current maturities, gross			843,198,000				658,198,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			(10,475,000)				(12,493,000)
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities			0				0
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities			$ (10,475,000)				(12,493,000)
Texas-New Mexico Power Company | First Mortgage Bonds: | 6.95% due April 2043
Debt Instrument [Line Items]
Stated percentage			6.95%
Unsecured long-term debt, noncurrent			$ 93,198,000				93,198,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ (15,917,000)				(16,632,000)
Texas-New Mexico Power Company | First Mortgage Bonds: | 4.03% due July 2024
Debt Instrument [Line Items]
Stated percentage			4.03%
Unsecured long-term debt, noncurrent			$ 80,000,000				80,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 369,000				475,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.53% due February 2026
Debt Instrument [Line Items]
Stated percentage			3.53%
Unsecured long-term debt, noncurrent			$ 60,000,000				60,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 420,000				502,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.22% due August 2027
Debt Instrument [Line Items]
Stated percentage			3.22%
Unsecured long-term debt, noncurrent			$ 60,000,000				60,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 380,000				437,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.85% due June 2028
Debt Instrument [Line Items]
Stated percentage			3.85%
Unsecured long-term debt, noncurrent			$ 60,000,000				60,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 469,000				531,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.79% due March 2034
Debt Instrument [Line Items]
Stated percentage			3.79%
Unsecured long-term debt, noncurrent			$ 75,000,000				75,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 497,000				535,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.92% due March 2039
Debt Instrument [Line Items]
Stated percentage			3.92%
Unsecured long-term debt, noncurrent			$ 75,000,000				75,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 514,000				542,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 4.06% due March 2044
Debt Instrument [Line Items]
Stated percentage			4.06%
Unsecured long-term debt, noncurrent			$ 75,000,000				75,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 524,000				546,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.60% due July 2029
Debt Instrument [Line Items]
Stated percentage			3.60%
Unsecured long-term debt, noncurrent			$ 80,000,000				80,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 511,000				571,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 2.73% due April 24, 2030
Debt Instrument [Line Items]
Stated percentage			2.73%
Unsecured long-term debt, noncurrent			$ 85,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 784,000				0
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.36% due April 24, 2050
Debt Instrument [Line Items]
Stated percentage			3.36%
Unsecured long-term debt, noncurrent			$ 25,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 243,000				0
Texas-New Mexico Power Company | First Mortgage Bonds: | 2.93% due July 15, 2035
Debt Instrument [Line Items]
Stated percentage			2.93%
Unsecured long-term debt, noncurrent			$ 25,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 241,000				0
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.36% due July 15, 2050
Debt Instrument [Line Items]
Stated percentage			3.36%
Unsecured long-term debt, noncurrent			$ 50,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			490,000				0
PNMR
Debt Instrument [Line Items]
Total			745,000,000				590,000,000
Principal, less current maturities			230,000,000				140,000,000
Long-term debt, excluding current maturities, gross			515,000,000				450,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			143,000				994,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities			52,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities			91,000				994,000
PNMR | PNMR 3.25% 2018 SUNs due March 2021
Debt Instrument [Line Items]
Term loans			$ 300,000,000				300,000,000
Stated percentage			3.25%
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 137,000				917,000
PNMR | PNMR Development Term Loan due January 2022
Debt Instrument [Line Items]
Term loans			65,000,000				90,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				42,000
PNMR | PNMR 2018 Two-Year Term Loan due December 2020
Debt Instrument [Line Items]
Term loans			0				50,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				0
PNMR | PNMR 2019 Term Loan due June 2021
Debt Instrument [Line Items]
Term loans			150,000,000				150,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net			6,000				35,000
PNMR | PNMR 2020 Term Loan due January 2022
Debt Instrument [Line Items]
Term loans			150,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			0				0
PNMR | PNMR 2020 Delayed-Draw Term Loan due January 2022
Debt Instrument [Line Items]
Repayments of debt		$ 220,000,000
Term loans			80,000,000				0
Unamortized Discounts, (Premiums), and Issuance Costs, net			$ 0				$ 0

Financing - Long-term Debt Matu

Financing - Long-term Debt Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Long-term Debt, by Maturity [Abstract]
2021	$ 576,000
2022	619,500
2023	285,345
2024	205,000
2025	354,000
Thereafter	1,254,198
Total	3,294,043	$ 3,004,043
PNMR
Long-term Debt, by Maturity [Abstract]
2021	230,000
2022	515,000
2023	0
2024	0
2025	0
Thereafter	0
Total	745,000	590,000
Public Service Company of New Mexico
Long-term Debt, by Maturity [Abstract]
2021	346,000
2022	104,500
2023	285,345
2024	125,000
2025	354,000
Thereafter	491,000
Total	1,705,845	1,755,845
Texas-New Mexico Power Company
Long-term Debt, by Maturity [Abstract]
2021	0
2022	0
2023	0
2024	80,000
2025	0
Thereafter	763,198
Total	$ 843,198	$ 658,198

Lease Commitments - Narrative (

Lease Commitments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 15, 2016lease	Jan. 15, 2015lease
Lessee, Lease, Description [Line Items]
Unamortized cost of prepaid right-of-way agreements	$ 55.8	$ 60.2
Amortization of prepaid right-of-way agreements	4.4	3.7	$ 3.8
Operating leases, capitalized financing costs, investing activities	3.4	3.9
Finance leases, capitalized financing costs, investing activities	2.8	0.7
Lessee, operating lease, unguaranteed residual value	26.7
Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Operating leases, capitalized financing costs, investing activities	1	1.3
Finance leases, capitalized financing costs, investing activities	1.1	0.3
Lessee, operating lease, unguaranteed residual value	11
Texas-New Mexico Power Company
Lessee, Lease, Description [Line Items]
Operating leases, capitalized financing costs, investing activities	2.4	2.6
Finance leases, capitalized financing costs, investing activities	1.8	$ 0.4
Lessee, operating lease, unguaranteed residual value	15.6
Palo Verde Nuclear Generating Station, Units 1 And 4 | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Number of leases expiring | lease					4
Number of leases under which lease term was extended | lease					4
Annual lease payments during renewal period	16.5
Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Number of leases expiring | lease				4
Number of leases under which lease term was extended | lease				1
Annual lease payments during renewal period	1.6
Palo Verde Nuclear Generating Station | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Loss contingency, range of possible loss, portion not accrued	154.5
Navajo Nation | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Right-of-way lease, annual payments	6
Right-of-way lease, payments	7.1
Equipment
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset	2.3
Equipment | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset	0.9
Equipment | Texas-New Mexico Power Company
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset	$ 1.4

Lease Commitments - Operating L

Lease Commitments - Operating Lease Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating leases:
Operating lease assets, net of amortization	$ 105,133	$ 131,212
Current portion of operating lease liabilities	27,460	29,068
Long-term portion of operating lease liabilities	81,065	105,512
Public Service Company of New Mexico
Operating leases:
Operating lease assets, net of amortization	97,461	120,585
Current portion of operating lease liabilities	25,130	25,927
Long-term portion of operating lease liabilities	75,941	97,992
Texas-New Mexico Power Company
Operating leases:
Operating lease assets, net of amortization	7,206	9,954
Current portion of operating lease liabilities	2,193	2,753
Long-term portion of operating lease liabilities	$ 4,779	$ 7,039

Lease Commitments - Finance Lea

Lease Commitments - Finance Lease Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing leases:
Non-utility property	$ 25,055	$ 10,028
Accumulated depreciation	(4,383)	(973)
Non-utility property, net	20,672	9,055
Other current liabilities	4,470	1,637
Other deferred credits	15,972	7,102
Public Service Company of New Mexico
Financing leases:
Non-utility property	11,453	4,857
Accumulated depreciation	(2,044)	(482)
Non-utility property, net	9,409	4,375
Other current liabilities	1,993	722
Other deferred credits	7,176	3,333
Texas-New Mexico Power Company
Financing leases:
Non-utility property	13,299	4,910
Accumulated depreciation	(2,241)	(466)
Non-utility property, net	11,058	4,444
Other current liabilities	2,397	850
Other deferred credits	$ 8,669	$ 3,597

Lease Commitments - Schedule of

Lease Commitments - Schedule of Weighted Average Remaining Lease Terms and Discount Rates (Details)	Dec. 31, 2020	Dec. 31, 2019
Weighted average remaining lease term (years):
Operating leases	6 years 14 days	6 years 5 months 26 days
Financing leases	4 years 9 months 14 days	5 years 6 months 14 days
Weighted average discount rate:
Operating leases	3.94%	3.90%
Financing leases	2.80%	3.64%
Public Service Company of New Mexico
Weighted average remaining lease term (years):
Operating leases	6 years 2 months 23 days	6 years 8 months 12 days
Financing leases	4 years 9 months 10 days	5 years 7 months 20 days
Weighted average discount rate:
Operating leases	3.93%	3.89%
Financing leases	2.76%	3.68%
Texas-New Mexico Power Company
Weighted average remaining lease term (years):
Operating leases	3 years 5 months 15 days	4 years 1 month 6 days
Financing leases	4 years 10 months 2 days	5 years 6 months 14 days
Weighted average discount rate:
Operating leases	4.06%	3.95%
Financing leases	2.84%	3.65%

Lease Commitments - Components

Lease Commitments - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 30,418	$ 31,963
Amounts capitalized	(3,395)	(3,913)
Total operating lease expense	27,023	28,050
Financing lease cost:
Amortization of right-of-use assets	3,412	973
Interest on lease liabilities	511	194
Amounts capitalized	(2,810)	(704)
Total financing lease expense	1,113	463
Variable lease expense	221	96
Short-term lease expense	295	414
Total lease expense for the period	28,652	29,023
Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Operating lease cost	27,302	28,254
Amounts capitalized	(1,020)	(1,319)
Total operating lease expense	26,282	26,935
Financing lease cost:
Amortization of right-of-use assets	1,563	481
Interest on lease liabilities	221	92
Amounts capitalized	(1,056)	(280)
Total financing lease expense	728	293
Variable lease expense	221	96
Short-term lease expense	288	346
Total lease expense for the period	27,519	27,670
Texas-New Mexico Power Company
Lessee, Lease, Description [Line Items]
Operating lease cost	2,870	3,341
Amounts capitalized	(2,375)	(2,594)
Total operating lease expense	495	747
Financing lease cost:
Amortization of right-of-use assets	1,775	466
Interest on lease liabilities	285	100
Amounts capitalized	(1,754)	(423)
Total financing lease expense	306	143
Variable lease expense	0	0
Short-term lease expense	5	26
Total lease expense for the period	$ 806	$ 916

Lease Commitments - Schedule _2

Lease Commitments - Schedule of Supplemental Cash Flows Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 27,121	$ 27,849
Operating cash flows from financing leases	136	71
Finance cash flows from financing leases	936	313
Non-cash information related to right-of-use assets obtained in exchange for lease obligations:
Operating leases	0	157,816
Financing leases	15,614	9,645
Public Service Company of New Mexico
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	26,007	26,392
Operating cash flows from financing leases	82	44
Finance cash flows from financing leases	557	183
Non-cash information related to right-of-use assets obtained in exchange for lease obligations:
Operating leases	0	143,816
Financing leases	6,588	4,473
Texas-New Mexico Power Company
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	596	935
Operating cash flows from financing leases	48	25
Finance cash flows from financing leases	307	109
Non-cash information related to right-of-use assets obtained in exchange for lease obligations:
Operating leases	0	12,942
Financing leases	$ 8,985	$ 4,910

Lease Commitments - Schedule _3

Lease Commitments - Schedule of Future Expected Lease Payments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Financing
2021	$ 4,970
2022	4,797
2023	4,511
2024	3,335
2025	2,044
Later years	2,150
Total minimum lease payments	21,807
Less: Imputed interest	1,365
Lease liabilities as of December 31, 2020	20,442
Operating
2021	29,290
2022	28,464
2023	19,395
2024	8,841
2025	7,673
Later years	27,827
Total minimum lease payments	121,490
Less: Imputed interest	12,965
Lease liabilities as of December 31, 2020	108,525
Public Service Company of New Mexico
Financing
2021	2,214
2022	2,159
2023	2,095
2024	1,434
2025	854
Later years	1,030
Total minimum lease payments	9,786
Less: Imputed interest	617
Lease liabilities as of December 31, 2020	9,169
Operating
2021	26,572
2022	26,266
2023	17,735
2024	7,899
2025	6,946
Later years	27,530
Total minimum lease payments	112,948
Less: Imputed interest	11,877
Lease liabilities as of December 31, 2020	101,071
Texas-New Mexico Power Company
Financing
2021	2,672
2022	2,557
2023	2,372
2024	1,897
2025	1,190
Later years	1,120
Total minimum lease payments	11,808
Less: Imputed interest	742
Lease liabilities as of December 31, 2020	11,066
Operating
2021	2,426
2022	1,987
2023	1,481
2024	895
2025	690
Later years	75
Total minimum lease payments	7,554
Less: Imputed interest	582
Lease liabilities as of December 31, 2020	$ 6,972

Fair Value of Derivative and _3

Fair Value of Derivative and Other Financial Instruments - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)MW	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017MW
Debt Securities, Available-for-sale [Line Items]
Contract in a net liability position	$ 0	$ 0
Available for sale securities realized impairment losses	$ (3,200,000)	3,000,000	$ (9,400,000)
Minimum
Debt Securities, Available-for-sale [Line Items]
Investment allocation targets distribution period	10 years
Maximum
Debt Securities, Available-for-sale [Line Items]
Investment allocation targets distribution period	15 years
Equity Securities | Pension Plan
Debt Securities, Available-for-sale [Line Items]
Investment allocation targets	35.00%
Alternative Investments | Pension Plan
Debt Securities, Available-for-sale [Line Items]
Investment allocation targets	15.00%
Fixed income | Pension Plan
Debt Securities, Available-for-sale [Line Items]
Investment allocation targets	50.00%
PNM
Debt Securities, Available-for-sale [Line Items]
Expected exposure to market risk (in megawatts) | MW	65			65
Power to be sold to third party (in megawatts) | MW	36			36
Amounts recognized for the legal right to reclaim cash collateral	$ 0	0
Amounts posted as cash collateral under margin arrangements	500,000	500,000
Obligations to return cash collateral	900,000	900,000
PNM | Commodity Contract | Designated as hedging instrument
Debt Securities, Available-for-sale [Line Items]
Other current assets	1,096,000	1,089,000
PNM | Commodity Contract | Designated as hedging instrument | Cost of Sales
Debt Securities, Available-for-sale [Line Items]
Gain (loss) on derivative	100,000	100,000
PNM | Fuel and purchased power costs | Commodity Contract | Designated as hedging instrument
Debt Securities, Available-for-sale [Line Items]
Other current assets	$ 0	0
PNM | Tri-State
Debt Securities, Available-for-sale [Line Items]
Power to be sold to third party (in megawatts) | MW	100
Measured on a recurring basis | PNM
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	$ 440,115,000	388,832,000
Nuclear Decommissioning Trust | Measured on a recurring basis | PNM
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	379,200,000	336,000,000
Mine Reclamation Trust | Measured on a recurring basis | PNM
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	$ 60,900,000	$ 52,800,000

Fair Value of Derivative and _4

Fair Value of Derivative and Other Financial Instruments - Overview and Commodity Derivatives (Details) - PNM - Designated as hedging instrument - Commodity Contract - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Other current assets	$ 1,096	$ 1,089
Other deferred charges	455	1,507
Derivative asset	1,551	2,596
Other current liabilities	(1,096)	(1,089)
Other deferred credits	(455)	(1,507)
Derivative liability	(1,551)	(2,596)
Net	$ 0	$ 0

Fair Value of Derivative and _5

Fair Value of Derivative and Other Financial Instruments - Investment in NDT and Gross Realized Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity securities:
Net gains from equity securities sold	$ 5,861	$ 5,698	$ 4,864
Net gains (losses) from equity securities still held	17,707	18,319	(10,523)
Total net gains (losses) on equity securities	23,568	24,017	(5,659)
Available-for-sale debt securities:
Net gains (losses) on debt securities	(1,969)	5,572	(11,517)
Net gains (losses) on investment securities	21,599	29,589	(17,176)
Public Service Company of New Mexico
Available-for-sale debt securities:
Proceeds from sales	590,998	494,528	984,533
Gross realized gains	35,904	25,760	19,358
Gross realized (losses)	$ (28,817)	$ (17,453)	$ (16,624)

Fair Value of Derivative and _6

Fair Value of Derivative and Other Financial Instruments - Maturities of Securities (Details) - PNMR and PNM $ in Thousands	Dec. 31, 2020USD ($)
Available-for-Sale
Within 1 year	$ 33,301
After 1 year through 5 years	89,646
After 5 years through 10 years	89,130
After 10 years through 15 years	14,947
After 15 years through 20 years	9,256
After 20 years	43,730
Debt securities, available-for-sale	$ 280,010

Fair Value of Derivative and _7

Fair Value of Derivative and Other Financial Instruments - Items Recorded at Fair Value (Details) - Public Service Company of New Mexico - Measured on a recurring basis - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	$ 440,115	$ 388,832
Unrealized Gains	27,387	14,297
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	6,107	15,606
Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	85,271	64,527
Unrealized Gains
Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	9,910	9,033
Unrealized Gains
Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	58,817	49,848
Unrealized Gains
U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	55,839	48,439
Unrealized Gains	950	535
International government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	16,032	15,292
Unrealized Gains	2,537	1,193
Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	50,139	46,642
Unrealized Gains	2,779	1,768
Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	158,000	139,445
Unrealized Gains	21,121	10,801
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	183,330	163,707
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	6,107	15,606
Quoted Prices in Active Markets for Identical Assets (Level 1) | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	85,271	64,527
Quoted Prices in Active Markets for Identical Assets (Level 1) | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	3,608	2,212
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	58,762	49,786
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	29,579	31,389
Quoted Prices in Active Markets for Identical Assets (Level 1) | International government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	3	187
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	256,785	225,125
Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Significant Other Observable Inputs (Level 2) | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Significant Other Observable Inputs (Level 2) | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	6,302	6,821
Significant Other Observable Inputs (Level 2) | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	55	62
Significant Other Observable Inputs (Level 2) | U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	26,260	17,050
Significant Other Observable Inputs (Level 2) | International government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	16,032	15,292
Significant Other Observable Inputs (Level 2) | Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	50,139	46,642
Significant Other Observable Inputs (Level 2) | Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	$ 157,997	$ 139,258

Fair Value of Derivative and _8

Fair Value of Derivative and Other Financial Instruments - Items not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
PNMR
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 3,355,761	$ 3,142,704
PNMR | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	3,295,150	3,007,717
Public Service Company of New Mexico
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,602,547	1,795,149
Public Service Company of New Mexico | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,696,620	1,748,020
Texas-New Mexico Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,006,722	753,317
Texas-New Mexico Power Company | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 853,673	$ 670,691

Fair Value of Derivative and _9

Fair Value of Derivative and Other Financial Instruments - Defined Benefit Plans Disclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 587,530	$ 531,467	$ 489,978
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	93,402	86,400	69,703
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments: | Fair Value Measurement [Domain]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	498,907	445,984
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	587,891	532,659
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments: | Estimate of Fair Value Measurement
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	88,984	86,675
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	93,710	86,749
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,310	1,022
Public Service Company of New Mexico | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	92,400	85,727
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	241,445	152,158
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	53,594	40,383
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,310	1,022
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	52,284	39,361
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	257,462	293,826
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	40,116	46,366
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	40,116	46,366
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	66,149	59,367	55,074
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	12,885	10,844	$ 8,744
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments: | Fair Value Measurement [Domain]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	56,966	49,353
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	66,196	59,327
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Pension Plan | Participation in PNMR Master Trust Investments: | Estimate of Fair Value Measurement
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	9,230	9,974
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	12,861	10,910
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	18	275
Texas-New Mexico Power Company | Fair Value, Inputs, Level 1, 2 and 3 | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	12,843	10,635
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	28,732	17,335
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	10,824	4,350
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	18	275
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	10,806	4,075
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	28,234	32,018
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,037	6,560
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,037	6,560
PNMR
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 654,087	$ 591,986
PNMR | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember
PNMR | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember
PNMR | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember	us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember
PNMR | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 555,873	$ 495,337
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	20,812	19,982
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | International funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	114,983	68,497
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | Domestic value
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,187	825
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | Domestic growth
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	173,931	172,326
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | U.S. government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	97,460	90,970
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | International government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	6,202	5,411
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	6,277	6,980
PNMR | Fair Value, Inputs, Level 1, 2 and 3 | Corporate and other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	135,021	130,346
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	270,177	169,493
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	20,812	19,982
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | International funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	114,983	68,497
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic value
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	135	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic growth
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	47,418	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	86,829	81,014
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | International government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipals
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate and other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
PNMR | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	285,696	325,844
PNMR | Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
PNMR | Significant Other Observable Inputs (Level 2) | International funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
PNMR | Significant Other Observable Inputs (Level 2) | Domestic value
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,052	825
PNMR | Significant Other Observable Inputs (Level 2) | Domestic growth
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	126,513	172,326
PNMR | Significant Other Observable Inputs (Level 2) | U.S. government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	10,631	9,956
PNMR | Significant Other Observable Inputs (Level 2) | International government
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	6,202	5,411
PNMR | Significant Other Observable Inputs (Level 2) | Municipals
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	6,277	6,980
PNMR | Significant Other Observable Inputs (Level 2) | Corporate and other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	135,021	130,346
PNMR | Fair Value Measured at Net Asset Value Per Share | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	12,552	15,827
PNMR | Fair Value Measured at Net Asset Value Per Share | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	52,285	47,618
PNMR | Fair Value Measured at Net Asset Value Per Share | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 33,377	$ 33,204

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)MW	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 31, 2016USD ($)
Results of Operations
Earnings attributable to non-controlling interest	$ 14,013	$ 14,241	$ 15,112
Financial Position
Current assets	377,479	294,010
Total assets	7,939,854	7,298,774	6,865,551
Current liabilities	977,662	967,481
Owners’ equity – non-controlling interest	59,009	63,052
Public Service Company of New Mexico
Results of Operations
Earnings attributable to non-controlling interest	14,013	14,241	15,112
Financial Position
Current assets	322,128	259,195
Total assets	5,581,033	5,242,991
Current liabilities	594,332	593,236
Owners’ equity – non-controlling interest	$ 59,009	63,052
Public Service Company of New Mexico | Valencia
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) | MW	155
Payment for fixed charges	$ 20,000	19,900	19,600
Payment for variable charges	$ 1,400	1,200	1,400
Purchase price, percentage of the book value reduced by related indebtedness	50.00%
Purchase price, percentage of fair market value	50.00%
Results of Operations
Operating revenues	$ 21,297	21,073	21,025
Operating expenses	7,284	6,832	5,913
Earnings attributable to non-controlling interest	14,013	14,241	$ 15,112
Financial Position
Current assets	3,911	5,094
Net property, plant and equipment	55,744	58,581
Total assets	59,655	63,675
Current liabilities	646	623
Owners’ equity – non-controlling interest	$ 59,009	$ 63,052
Public Service Company of New Mexico | Maximum | Valencia
Variable Interest Entity [Line Items]
Option to purchase a percentage of the plant or VIE (up to )	50.00%
NM Capital | Coal Supply | San Juan Generating Station
Financial Position
Issuance in letters of credit	$ 30,300			$ 30,300

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
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
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
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
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 | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average discount rate related to anticipated contributions	2.90%
Pension Plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	35.00%
Pension Plan | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	50.00%
Pension Plan | Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	15.00%
Pension Plan | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets	5.90%	6.86%	6.54%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 5,200,000
Rate of return for retirement plan	19.30%
Expected employer contributions in year two	$ 10,800,000
Expected employer contributions in year 3	11,500,000
Expected employer contributions in year 4	10,600,000
Actuarial gains (losses) recorded as regulatory assets	21,393,000
Employer contributions	$ 0	$ 0
Pension Plan | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets	5.90%	6.90%	6.57%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 600,000
Rate of return for retirement plan	20.40%
Expected employer contributions in year two	$ 0
Expected employer contributions in year 3	0
Expected employer contributions in year 4	0
Actuarial gains (losses) recorded as regulatory assets	(3,860,000)
Employer contributions	$ 0	$ 0
Other Postretirement Benefits
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 | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	30.00%
Other Postretirement Benefits | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	70.00%
Other Postretirement Benefits | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets	7.00%	7.20%	7.42%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 900,000
Rate of return for retirement plan	11.10%
Actuarial gains (losses) recorded as regulatory assets	$ 600,000
Employer contributions	3,256,000	$ 3,580,000
Expected employer disbursements for next fiscal year	3,700,000
Expected employer disbursements by employer in year 2 through year 5	$ 13,100,000
Other Postretirement Benefits | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets	5.60%	5.80%	5.86%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 100,000
Rate of return for retirement plan	23.60%
Actuarial gains (losses) recorded as regulatory assets	$ 1,200,000
Effect of 1%-point change in assumed health care cost trend rates on net periodic expense and APBO	0
Employer contributions	0	$ 0
Other Postretirement Benefits | PNM and TNMP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	0	0
Expected employer contributions in fiscal year through year 5	0	0
Executive Retirement Program | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gains (losses) recorded as regulatory assets	(78,000)
Expected disbursements by employer	1,400,000	1,400,000
Executive Retirement Program | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gains (losses) recorded as regulatory assets	(58,000)
Expected disbursements by employer	$ 100,000	$ 100,000
Non-US | Pension Plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	13.00%

Pension and Other Postretirem_4

Pension and Other Postretirement Benefits - APBO, PBO, Fair Value of Plan Assets, and Funded Status of the Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	$ 58,101	$ 95,037
Public Service Company of New Mexico
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	56,273	87,838
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	605,745	564,258
Service cost	0	0	$ 0
Interest cost	19,941	25,175	24,270
Actuarial (gain) loss	47,567	61,151
Benefits paid	(42,349)	(44,839)
Balance at end of year	630,904	605,745	564,258
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	531,467	489,978
Actual return on plan assets	98,412	86,328
Employer contributions	0	0
Fair value of plan assets at end of year	587,530	531,467	489,978
Funded status – asset (liability) for pension benefits	(43,374)	(74,278)
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	75,121	75,305
Service cost	38	53	83
Interest cost	2,453	3,316	3,439
Participant contributions	1,714	2,131
Actuarial (gain) loss	3,261	2,587
Benefits paid	(7,391)	(8,271)
Balance at end of year	75,196	75,121	75,305
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	86,400	69,703
Actual return on plan assets	9,423	19,257
Employer contributions	3,256	3,580
Participant contributions	1,714	2,131
Benefits paid	7,391	8,271
Fair value of plan assets at end of year	93,402	86,400	69,703
Funded status – asset (liability) for pension benefits	18,206	11,279
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	14,994	14,726
Service cost	0	0	0
Interest cost	491	651	622
Actuarial (gain) loss	78	1,053
Benefits paid	(1,341)	(1,436)
Balance at end of year	14,222	14,994	14,726
Less current liability	1,323	1,434
Non-current liability	12,899	13,560
Texas-New Mexico Power Company
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	1,828	7,199
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	65,574	60,587
Service cost	0	0	0
Interest cost	2,177	2,686	2,625
Actuarial (gain) loss	4,459	7,889
Benefits paid	(4,820)	(5,588)
Balance at end of year	67,390	65,574	60,587
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	59,367	55,074
Actual return on plan assets	11,602	9,881
Employer contributions	0	0
Fair value of plan assets at end of year	66,149	59,367	55,074
Funded status – asset (liability) for pension benefits	(1,241)	(6,207)
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	11,235	10,064
Service cost	46	50	134
Interest cost	373	451	477
Participant contributions	243	316
Actuarial (gain) loss	747	1,004
Benefits paid	(706)	(650)
Balance at end of year	11,938	11,235	10,064
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	10,844	8,744
Actual return on plan assets	2,505	2,434
Employer contributions	0	0
Participant contributions	243	316
Benefits paid	707	650
Fair value of plan assets at end of year	12,885	10,844	8,744
Funded status – asset (liability) for pension benefits	947	(391)
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	692	702
Service cost	0	0	0
Interest cost	22	30	29
Actuarial (gain) loss	58	54
Benefits paid	(94)	(94)
Balance at end of year	678	692	$ 702
Less current liability	91	91
Non-current liability	$ 587	$ 601

Pension and Other Postretirem_5

Pension and Other Postretirement Benefits - Actuarial (Gain) Loss Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates	$ 44,960	$ 66,108
Claims, contributions, and demographic experience	2,607	(732)
Mortality rate	0	(4,225)
Other assumptions and experience	0	0
Actuarial (gain) loss	47,567	61,151
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rates	4,959	7,236
Claims, contributions, and demographic experience	(1,698)	(4,022)
Mortality rate	0	(627)
Assumed participation rate	0	0
Actuarial (gain) loss	3,261	2,587
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates	4,756	8,006
Claims, contributions, and demographic experience	(54)	394
Mortality rate	0	(296)
Other assumptions and experience	(243)	(215)
Actuarial (gain) loss	4,459	7,889
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rates	1,008	1,375
Claims, contributions, and demographic experience	(261)	(311)
Mortality rate	0	(60)
Assumed participation rate	0	0
Actuarial (gain) loss	$ 747	$ 1,004

Pension and Other Postretirem_6

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, 2020USD ($)
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

Pension and Other Postretirem_7

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Income) Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 0	$ 0	$ 0
Interest cost	19,941	25,175	24,270
Expected return on plan assets	(29,453)	(34,103)	(34,686)
Amortization of net (gain) loss	17,860	15,518	16,348
Amortization of prior service cost	(554)	(965)	(965)
Net periodic benefit cost	7,794	5,625	4,967
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	38	53	83
Interest cost	2,453	3,316	3,439
Expected return on plan assets	(5,548)	(5,278)	(5,414)
Amortization of net (gain) loss	348	675	2,354
Amortization of prior service cost	0	(397)	(1,664)
Net periodic benefit cost	(2,709)	(1,631)	(1,202)
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	491	651	622
Amortization of net (gain) loss	403	318	359
Amortization of prior service cost	0	0	0
Net periodic benefit cost	894	969	981
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	2,177	2,686	2,625
Expected return on plan assets	(3,284)	(3,868)	(3,963)
Amortization of net (gain) loss	1,258	941	1,088
Amortization of prior service cost	0	0	0
Net periodic benefit cost	151	(241)	(250)
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	46	50	134
Interest cost	373	451	477
Expected return on plan assets	(538)	(517)	(542)
Amortization of net (gain) loss	(323)	(444)	(227)
Amortization of prior service cost	0	0	0
Net periodic benefit cost	(442)	(460)	(158)
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	22	30	29
Amortization of net (gain) loss	24	15	15
Amortization of prior service cost	0	0	0
Net periodic benefit cost	$ 46	$ 45	$ 44

Pension and Other Postretirem_8

Pension and Other Postretirement Benefits - Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.00%
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.66%	3.42%	4.65%
Discount rate for determining net periodic benefit cost (income)	3.42%	4.65%	4.05%
Expected return on plan assets	5.90%	6.86%	6.54%
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.65%	3.42%	4.63%
Discount rate for determining net periodic benefit cost (income)	3.42%	4.63%	4.00%
Expected return on plan assets	7.00%	7.20%	7.42%
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.68%	3.44%	4.66%
Discount rate for determining net periodic benefit cost (income)	3.44%	4.66%	4.05%
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.69%	3.46%	4.63%
Discount rate for determining net periodic benefit cost (income)	3.46%	4.63%	4.01%
Expected return on plan assets	5.90%	6.90%	6.57%
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.65%	3.42%	4.63%
Discount rate for determining net periodic benefit cost (income)	3.42%	4.63%	4.00%
Expected return on plan assets	5.60%	5.80%	5.86%
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	2.69%	3.46%	4.63%
Discount rate for determining net periodic benefit cost (income)	3.46%	4.63%	4.01%

Pension and Other Postretirem_9

Pension and Other Postretirement Benefits - Pension Benefit Payments are Expected to be Paid (Details) $ in Thousands	Dec. 31, 2020USD ($)
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	$ 46,312
2022	45,583
2023	44,299
2024	43,066
2025	41,869
2026 - 2030	188,950
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	6,455
2022	6,132
2023	5,960
2024	5,711
2025	5,357
2026 - 2030	22,474
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	1,341
2022	1,303
2023	1,259
2024	1,210
2025	1,156
2026 - 2030	4,856
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	5,301
2022	5,193
2023	4,936
2024	4,702
2025	4,589
2026 - 2030	19,829
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	649
2022	678
2023	698
2024	709
2025	713
2026 - 2030	3,400
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	93
2022	90
2023	85
2024	80
2025	73
2026 - 2030	$ 252

Pension and Other Postretire_10

Pension and Other Postretirement Benefits - Assumed Health Care Cost Trend Rates and Impact of a One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Details) - Public Service Company of New Mexico - Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	6.25%	6.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2026	2026

Pension and Other Postretire_11

Pension and Other Postretirement Benefits - Other Postretirement Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
401(k) plan
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
401(k) plan	$ 16,247	$ 16,097	$ 16,677
401(k) plan | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
401(k) plan	11,676	11,587	12,052
401(k) plan | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
401(k) plan	4,572	4,511	4,625
Non-qualified plan
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Non-qualified plan	2,090	4,551	865
Non-qualified plan | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Non-qualified plan	1,544	3,384	621
Non-qualified plan | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Non-qualified plan	$ 547	$ 1,167	$ 244

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Equity Plan and Accounting for Stock Awards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for stock-based arrangements	$ 8.1	$ 6.4	$ 7.1
Restricted Shares and Performance-Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 4
Period to recognize compensation expense	1 year 6 months 7 days
Public Service Company of New Mexico
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for stock-based arrangements	$ 5.5	4.2	4.9
Texas-New Mexico Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for stock-based arrangements	$ 2.6	$ 2.2	$ 2.2
Performance Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for awards	3 years
Vesting rate	100.00%
Number of shares authorized (in shares)				13,500,000
Charge to share pool for each share awarded	5
Performance Equity Plan | Nonemployee Members of the Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for awards	1 year

Stock-Based Compensation - Exce

Stock-Based Compensation - Excess Tax Benefits (Details) - Accounting Standards Update 2016-09 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Service Company of New Mexico
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit from share-based compensation, operating activities	$ 279	$ 559	$ 1,007
Texas-New Mexico Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit from share-based compensation, operating activities	112	236	377
PNMR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit from share-based compensation, operating activities	$ 391	$ 795	$ 1,384

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Shares and Performance-Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected quarterly dividends per share (in dollars per share)	$ 0.3075	$ 0.2900	$ 0.2650
Risk-free interest rate	0.72%	2.47%	2.38%
Market-Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.72%	2.51%	2.36%
Dividend yield	2.51%	2.59%	2.96%
Expected volatility	19.41%	19.55%	19.12%

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards (Details) - USD ($)	Mar. 02, 2018	Mar. 03, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 28, 2018	Feb. 28, 2017	Dec. 31, 2015	Jan. 01, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense			$ 8,100,000	$ 6,400,000	$ 7,100,000
Executive Vice President and Chief Financial Officer | Common Stock | Achieved performance target for 2015 and 2016
Restricted Stock, Shares
Granted (in shares)	7,670	2,754
Restricted Stock, Weighted-Average Grant Date Fair Value
Granted (in dollars per share)	$ 35.85	$ 36.30
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares approved upon meeting target (in shares)							100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted-average grant date fair value (in dollars per share)	$ 35.85	$ 36.30
Executive Vice President and Chief Financial Officer | Common Stock | Achieved performance target for 2015, 2016 and 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Value of stock to be granted if performance targets are achieved									$ 275,000
Chairman, President, and Chief Executive Officer | Common Stock | Achieves a specific performance target by the end of 2019 and she remains an employee
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares authorized (in shares)						35,906		53,859
Chairman, President, and Chief Executive Officer | Common Stock | Achieves a specific performance target by the end of 2017 and she remains an employee
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares authorized (in shares)						17,953
Restricted Stock
Restricted Stock, Shares
Beginning balance (in shares)			161,542
Granted (in shares)			246,029
Exercised (in shares)			(238,054)
Forfeited (in shares)			(1,456)
Ending balance (in shares)			168,061	161,542
Restricted Stock, Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)			$ 38.21
Granted (in dollars per share)			36.73	$ 37.92	$ 29.65
Exercised (in dollars per share)			34.86
Forfeited (in dollars per share)			41.32
Ending balance (in dollars per share)			40.77	38.21
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted-average grant date fair value (in dollars per share)			$ 36.73	$ 37.92	$ 29.65
Total fair value of restricted shares that vested			$ 8,299,000	$ 6,246,000	$ 8,558,000
Stock Options
Stock Options, Shares
Beginning balance (in shares)			2,000
Granted (in shares)			0
Exercised (in shares)			(2,000)
Forfeited (in shares)			0
Ending balance (in shares)			0	2,000
Options, Weighted Average Exercise Price
Beginning balance (in dollars per share)			$ 12.22
Granted (in dollars per share)			0
Exercised (in dollars per share)			12.22
Forfeited (in dollars per share)			0
Ending balance (in dollars per share)			$ 0	$ 12.22
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Aggregate intrinsic value of stock options outstanding				$ 100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Total intrinsic value of options exercised			$ 84,000	2,617,000	3,117,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense					1,000,000
Performance Shares | Executive
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Shares excluded in year two (in shares)			150,543
Shares excluded in year three (in shares)			142,080
Performance period			3 years
Performance Shares | Executive | Achieved performance target for 2016 through 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Shares excluded (in shares)			47,279
Weighted percentage assigned to achieving market targets			40.00%
Weighted percentage assigned to achieving performance targets			60.00%
Performance Shares | Executive | Achieved performance target for 2017 through 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Shares excluded (in shares)			122,277
Public Service Company of New Mexico
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense			$ 5,500,000	4,200,000	4,900,000
Public Service Company of New Mexico | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense					700,000
Texas-New Mexico Power Company
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense			$ 2,600,000	$ 2,200,000	2,200,000
Texas-New Mexico Power Company | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Additional pre tax expense					$ 300,000

Regulatory Assets and Liabili_3

Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Regulatory Assets
Current	$ 202	$ 202	$ 7,373
Non-Current	557,790	557,790	556,930
Regulatory Liabilities
Current	(7,471)	(7,471)	(505)
Non-Current	(850,228)	(850,228)	(866,243)
Public Service Company of New Mexico
Regulatory Assets
Current	0	0	7,373
Non-Current	457,953	457,953	435,467
Total regulatory assets	457,953	457,953	442,840
Regulatory Liabilities
Current	(5,419)	(5,419)	(371)
Non-Current	(664,873)	(664,873)	(683,398)
Total regulatory liabilities	(670,292)	(670,292)	(683,769)
Public Service Company of New Mexico | FPPAC
Regulatory Liabilities
Current	(2,274)	(2,274)	0
Public Service Company of New Mexico | Renewable Energy Rider
Regulatory Liabilities
Current	(2,044)	(2,044)	0
Public Service Company of New Mexico | Other
Regulatory Liabilities
Current	(1,101)	(1,101)	(371)
Public Service Company of New Mexico | Cost of removal
Regulatory Liabilities
Non-Current	(284,695)	(284,695)	(271,025)
Public Service Company of New Mexico | Deferred income taxes
Regulatory Liabilities
Non-Current	(343,844)	(343,844)	(374,122)
Public Service Company of New Mexico | PVNGS ARO
Regulatory Liabilities
Non-Current	(5,394)	(5,394)	(11,341)
Public Service Company of New Mexico | Renewable energy tax benefits
Regulatory Liabilities
Non-Current	(17,912)	(17,912)	(19,069)
Public Service Company of New Mexico | Accelerated depreciation SNCRs(4)
Regulatory Liabilities
Non-Current	(12,045)	(12,045)	(7,758)
Public Service Company of New Mexico | Pension and OPEB
Regulatory Liabilities
Non-Current	0	0	0
Public Service Company of New Mexico | COVID-19 cost savings
Regulatory Liabilities
Non-Current	(900)	(900)	0
Public Service Company of New Mexico | Other
Regulatory Liabilities
Non-Current	(83)	(83)	(83)
Public Service Company of New Mexico | FPPAC
Regulatory Assets
Current	0	0	7,373
Public Service Company of New Mexico | Energy efficiency costs
Regulatory Assets
Current	0	0	0
Public Service Company of New Mexico | CTC, including carrying charges
Regulatory Assets
Non-Current	0	0	0
Public Service Company of New Mexico | Coal mine reclamation costs
Regulatory Assets
Non-Current	9,980	9,980	13,995
Public Service Company of New Mexico | Deferred income taxes
Regulatory Assets
Non-Current	65,564	65,564	66,296
Public Service Company of New Mexico | Loss on reacquired debt
Regulatory Assets
Non-Current	19,748	19,748	19,426
Public Service Company of New Mexico | Pension and OPEB
Regulatory Assets
Non-Current	190,147	190,147	214,771
Public Service Company of New Mexico | Shutdown of SJGS Units 2 and 3
Regulatory Assets
Non-Current	107,231	107,231	113,508
Public Service Company of New Mexico | Hurricane recovery costs
Regulatory Assets
Non-Current	0	0	0
Public Service Company of New Mexico | AMS surcharge
Regulatory Assets
Non-Current	0	0	0
Public Service Company of New Mexico | AMS retirement and other costs
Regulatory Assets
Non-Current	0	0	0
Public Service Company of New Mexico | Renewable energy tax benefits
Regulatory Assets
Non-Current	0	0	643
Public Service Company of New Mexico | Deferred cost under the ETA
Regulatory Assets
Non-Current	42,703	42,703	0
Public Service Company of New Mexico | Deferred COVID-19 costs
Regulatory Assets
Non-Current	8,761	8,761	0
Public Service Company of New Mexico | SJGS replacement resources
Regulatory Assets
Non-Current	8,282	8,282	0
Public Service Company of New Mexico | Other
Regulatory Assets
Non-Current	5,537	5,537	6,828
Texas-New Mexico Power Company
Regulatory Assets
Current	202	202	0
Non-Current	99,837	99,837	121,463
Total regulatory assets	100,039	100,039	121,463
Regulatory Liabilities
Current	(2,052)	(2,052)	(134)
Non-Current	(185,355)	(185,355)	(182,845)
Total regulatory liabilities	(187,407)	(187,407)	(182,979)
Texas-New Mexico Power Company | FPPAC
Regulatory Liabilities
Current	0	0	0
Texas-New Mexico Power Company | Renewable Energy Rider
Regulatory Liabilities
Current	0	0	0
Texas-New Mexico Power Company | Other
Regulatory Liabilities
Current	(2,052)	(2,052)	(134)
Texas-New Mexico Power Company | Cost of removal
Regulatory Liabilities
Non-Current	(59,613)	(59,613)	(46,091)
Texas-New Mexico Power Company | Deferred income taxes
Regulatory Liabilities
Non-Current	(119,695)	(119,695)	(131,871)
Texas-New Mexico Power Company | PVNGS ARO
Regulatory Liabilities
Non-Current	0	0	0
Texas-New Mexico Power Company | Renewable energy tax benefits
Regulatory Liabilities
Non-Current	0	0	0
Texas-New Mexico Power Company | Accelerated depreciation SNCRs(4)
Regulatory Liabilities
Non-Current	0	0	0
Texas-New Mexico Power Company | Pension and OPEB
Regulatory Liabilities
Non-Current	(5,535)	(5,535)	(4,775)
Texas-New Mexico Power Company | COVID-19 cost savings
Regulatory Liabilities
Non-Current	0	0	0
Texas-New Mexico Power Company | Other
Regulatory Liabilities
Non-Current	(512)	(512)	(108)
Texas-New Mexico Power Company | FPPAC
Regulatory Assets
Current	0	0	0
Texas-New Mexico Power Company | Energy efficiency costs
Regulatory Assets
Current	202	202	0
Texas-New Mexico Power Company | CTC, including carrying charges
Regulatory Assets
Non-Current	324	324	7,412
Texas-New Mexico Power Company | Coal mine reclamation costs
Regulatory Assets
Non-Current	0	0	0
Texas-New Mexico Power Company | Deferred income taxes
Regulatory Assets
Non-Current	9,817	9,817	8,997
Texas-New Mexico Power Company | Loss on reacquired debt
Regulatory Assets
Non-Current	28,914	28,914	30,212
Texas-New Mexico Power Company | Pension and OPEB
Regulatory Assets
Non-Current	22,863	22,863	27,947
Texas-New Mexico Power Company | Shutdown of SJGS Units 2 and 3
Regulatory Assets
Non-Current	0	0	0
Texas-New Mexico Power Company | Hurricane recovery costs
Regulatory Assets
Non-Current	480	480	1,041
Texas-New Mexico Power Company | AMS surcharge
Regulatory Assets
Non-Current	18,761	18,761	25,015
Texas-New Mexico Power Company | AMS retirement and other costs
Regulatory Assets
Non-Current	13,915	13,915	15,542
Texas-New Mexico Power Company | Renewable energy tax benefits
Regulatory Assets
Non-Current	0	0	0
Texas-New Mexico Power Company | Deferred cost under the ETA
Regulatory Assets
Non-Current	0	0	0
Texas-New Mexico Power Company | Deferred COVID-19 costs
Regulatory Assets
Non-Current	676	676	0
Texas-New Mexico Power Company | SJGS replacement resources
Regulatory Assets
Non-Current	0	0	0
Texas-New Mexico Power Company | Other
Regulatory Assets
Non-Current	4,087	4,087	5,297
Accounting Standards Update 2017-07 | Public Service Company of New Mexico
Regulatory Liabilities
Non-service cost deferred as regulatory assets		$ 1,600
Increase in coal mine decommissioning liability | Public Service Company of New Mexico
Regulatory Liabilities
Net expense			800
Increase in coal mine decommissioning liability | Underground | Public Service Company of New Mexico
Regulatory Liabilities
Net expense	$ 100		$ 9,300	$ 9,400

Construction Program and Join_3

Construction Program and Jointly-Owned Electric Generating Plants (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)generating_unit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	$ 679,028	$ 616,273	$ 501,213
Plant in Service	8,480,799	7,918,601
Accumulated depreciation	(2,835,170)	(2,713,503)
Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	335,055	341,847	255,627
Plant in Service	6,022,753	5,753,267
Accumulated depreciation	(2,158,915)	(2,076,291)
Texas-New Mexico Power Company
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	321,505	254,006	$ 223,448
Plant in Service	2,193,270	1,919,256
Accumulated depreciation	(537,707)	$ (516,795)
Joint Projects | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	335,100
Joint Projects | Texas-New Mexico Power Company
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	321,500
Joint Projects | PNMR
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	$ 679,000
SJGS (Coal) | Unit 4 | Other Unrelated Entities 2
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership percentage	12.80%
SJGS (Coal) | Unit 4 | Other Unrelated Entities 3
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership percentage	8.475%
SJGS (Coal) | Unit 4 | Other Unrelated Entities 4
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership percentage	7.20%
SJGS (Coal) | Unit 4 | Other Unrelated Entities 5
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership percentage	7.028%
SJGS (Coal) | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 780,544
Accumulated depreciation	(448,213)
Construction Work in Progress	$ 659
Composite Interest	66.35%
SJGS (Coal) | Public Service Company of New Mexico | Unit 4
Jointly Owned Utility Plant Interests [Line Items]
Composite Interest	77.297%
Palo Verde Nuclear Generating Station | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 828,191
Accumulated depreciation	(387,436)
Construction Work in Progress	$ 37,235
Composite Interest	10.20%
Number of units (in generating units) | generating_unit	3
Period of time for the original full power operating licenses	40 years
Operating lease, option term extensions	20 years
Four Corners Units 4 and 5 (Coal) | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 301,867
Accumulated depreciation	(100,187)
Construction Work in Progress	$ 7,820
Composite Interest	13.00%
Luna (Gas) | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 76,917
Accumulated depreciation	(29,758)
Construction Work in Progress	$ 57
Composite Interest	33.33%
SJGS Units 1 and 2 | Other Unrelated Entities 1
Jointly Owned Utility Plant Interests [Line Items]
Composite Interest	50.00%
SJGS Units 1 and 2 | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Composite Interest	50.00%
Four Corners | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Number of units (in generating units) | generating_unit	2

Construction Program and Join_4

Construction Program and Jointly-Owned Electric Generating Plants - Summary of Budgeted Construction Expenditures (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Summary of Budgeted Construction Expenditures [Line Items]
2021	$ 1,016.5
2022	765.1
2023	761.2
2024	713
2025	705.4
Total	3,961.2
Public Service Company of New Mexico
Summary of Budgeted Construction Expenditures [Line Items]
2021	661.9
2022	396.6
2023	382
2024	388.5
2025	379.9
Total	2,208.9
Anticipated expansion of transmission system	277
Texas-New Mexico Power Company
Summary of Budgeted Construction Expenditures [Line Items]
2021	320.1
2022	342
2023	348
2024	298
2025	299
Total	1,607.1
Corporate and Other
Summary of Budgeted Construction Expenditures [Line Items]
2021	34.5
2022	26.5
2023	31.2
2024	26.5
2025	26.5
Total	$ 145.2

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
ARO liabilities related to nuclear decommissioning	76.00%
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 181,962	$ 158,674	$ 146,679
Liabilities incurred	0	0	0
Liabilities settled	(1,444)	(987)	(192)
Accretion expense	11,310	12,635	11,482
Revisions to estimated cash flows	(8,407)	11,640	705
Ending balance	183,421	181,962	158,674
Four Corners
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Revisions to estimated cash flows	800
Palo Verde Nuclear Generating Station
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Revisions to estimated cash flows	9,200
Public Service Company of New Mexico
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	181,081	157,814	145,707
Liabilities incurred	0	0	0
Liabilities settled	(1,192)	(935)	0
Accretion expense	11,235	12,562	11,402
Revisions to estimated cash flows	(8,407)	11,640	705
Ending balance	182,717	181,081	157,814
Texas-New Mexico Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	881	860	793
Liabilities incurred	0	0	0
Liabilities settled	(252)	(52)	0
Accretion expense	75	73	67
Revisions to estimated cash flows	0	0	0
Ending balance	$ 704	$ 881	$ 860

Commitments and Contingencies -

Commitments and Contingencies - PVNGS Decommissioning Funding (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Utilities, General Disclosures [Line Items]
Funding for decommissioning costs in qualified and non-qualified trust funds	$ 1.3	$ 1.3	$ 1.3
Estimated market value of trusts for decommissioning costs	$ 379.2	$ 336

Commitments and Contingencies_2

Commitments and Contingencies - Nuclear Spent Fuel and Waste Disposal (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station - Nuclear spent fuel and waste disposal - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Estimate of possible loss		$ 59.6
Other deferred credits
Loss Contingencies [Line Items]
Liability for interim storage costs	$ 12.8	$ 12.7

Commitments and Contingencies_3

Commitments and Contingencies - The Energy Transition Act (Details) - Electric-Generation Portfolio Standard - Energy Transition Act	Jun. 14, 2019
Required Percentage by 2020
Public Utilities, General Disclosures [Line Items]
Renewable energy, percentage	0.20
Required Percentage by 2025
Public Utilities, General Disclosures [Line Items]
Renewable energy, percentage	0.40
Required Percentage by 2030
Public Utilities, General Disclosures [Line Items]
Renewable energy, percentage	0.50
Required Percentage by 2040
Public Utilities, General Disclosures [Line Items]
Renewable energy, percentage	0.80
Required Percentage by 2045
Public Utilities, General Disclosures [Line Items]
Renewable energy, percentage	1

Commitments and Contingencies_4

Commitments and Contingencies - The Clean Air Act (Details) $ in Millions	Dec. 31, 2020USD ($)lb_PER_MMBTUT	Feb. 21, 2020USD ($)	Dec. 31, 2018USD ($)MW	Dec. 31, 2015MW	Aug. 06, 2012compliance_alternative	Dec. 31, 1999state
Public Service Company of New Mexico | San Juan Generating Station
Public Utilities, General Disclosures [Line Items]
Forecasted undepreciated investment	$ 283	$ 361
Clean Air Act related to Regional Haze
Public Utilities, General Disclosures [Line Items]
Number of states to address regional haze | state						50
Potential to emit tons per year of visibility impairing pollution, maximum (in tons) | T	250
Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station Unit 4
Public Utilities, General Disclosures [Line Items]
Additional ownership to be obtained (in megawatts) | MW				132
Pre-tax impairment of investments			$ 35
Undepreciated investment in ownership to be obtained			11.9
Forecasted undepreciated investment			$ 23.1
Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station
Public Utilities, General Disclosures [Line Items]
Additional ownership to be obtained (in megawatts) | MW			132	132
Clean Air Act, SNCR | PNMR Development | San Juan Generating Station Unit 4
Public Utilities, General Disclosures [Line Items]
Potential acquisition of ownership (in megawatts) | MW			65	65
Clean Air Act Related to Post Combustion Controls | Public Service Company of New Mexico | Four Corners
Public Utilities, General Disclosures [Line Items]
Number of compliance alternatives | compliance_alternative					2
Government standard emissions limit (in pounds per MMBTU) | lb_PER_MMBTU	0.015
Plant requirement to meet opacity limit	20.00%
Rule imposes opacity limitation on certain fugitive dust emissions from coal and material handling operations	20.00%
Estimate of possible loss			$ 88.7
Clean Air Act Related to Post Combustion Controls | Public Service Company of New Mexico | Four Corners Units 4 and 5 (Coal)
Public Utilities, General Disclosures [Line Items]
Ownership percentage	13.00%

Commitments and Contingencies_5

Commitments and Contingencies - National Ambient Air Quality Standards (Details) - parts_per_billion	Feb. 25, 2019	Sep. 30, 2016	Oct. 01, 2015
Public Service Company of New Mexico | Maximum | San Juan Generating Station And Four Corners
Public Utilities, General Disclosures [Line Items]
Government standard emissions limit (in parts per billion)	75	75	70

Commitments and Contingencies_6

Commitments and Contingencies - Cooling Water Intake Structures (Details)	12 Months Ended
	Dec. 31, 2020option
Commitments and Contingencies Disclosure [Abstract]
Number of options for meeting BTA standards	7

Commitments and Contingencies_7

Commitments and Contingencies - Coal Supply (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jan. 31, 2016
Other Commitments [Line Items]
Other current assets	$ 64,549,000	$ 64,549,000	$ 44,472,000
Four Corners | Coal Supply
Other Commitments [Line Items]
Payments for relief from obligations		75,000,000
Public Service Company of New Mexico
Other Commitments [Line Items]
Other current assets	51,908,000	51,908,000	36,561,000
Public Service Company of New Mexico | Loss on long-term purchase commitment | San Juan Generating Station
Other Commitments [Line Items]
Annual funding post-term reclamation trust		3,200,000	5,500,000	$ 10,000,000
Public Service Company of New Mexico | Increase in coal mine decommissioning liability
Other Commitments [Line Items]
Net expense			800,000
Public Service Company of New Mexico | Increase in coal mine decommissioning liability | Loss on long-term purchase commitment
Other Commitments [Line Items]
Estimated underpaid surface mining royalties under proposed rate change					$ 2,500,000
Public Service Company of New Mexico | Mine Reclamation Trust | San Juan Generating Station
Other Commitments [Line Items]
Reclamation trust funding, next fiscal year	5,800,000	5,800,000
Reclamation trust funding, year 2	6,200,000	6,200,000
Reclamation trust funding, year 3	0	0
Public Service Company of New Mexico | Mine Reclamation Trust | Four Corners
Other Commitments [Line Items]
Funds contributed to mine reclamation trust		2,000,000	2,300,000	2,300,000
Funds contributed next fiscal year through year five	2,100,000	2,100,000
Public Service Company of New Mexico | Underground and Surface | Increase in coal mine decommissioning liability
Other Commitments [Line Items]
Net expense				39,200,000
Public Service Company of New Mexico | Surface | Loss on long-term purchase commitment
Other Commitments [Line Items]
Liability for interim storage costs	71,700,000	71,700,000	70,300,000
Public Service Company of New Mexico | Surface | Increase in coal mine decommissioning liability
Other Commitments [Line Items]
Net expense	3,600,000			29,800,000
Public Service Company of New Mexico | Underground | Loss on long-term purchase commitment
Other Commitments [Line Items]
Liability for interim storage costs	26,100,000	26,100,000	25,300,000
Public Service Company of New Mexico | Underground | Increase in coal mine decommissioning liability
Other Commitments [Line Items]
Net expense	100,000		9,300,000	$ 9,400,000
Public Service Company of New Mexico | San Juan Generating Station | Surface | Loss on long-term purchase commitment
Other Commitments [Line Items]
Estimate of possible loss	80,100,000	80,100,000
Public Service Company of New Mexico | San Juan Generating Station | Underground | Loss on long-term purchase commitment
Other Commitments [Line Items]
Estimate of possible loss	35,100,000	35,100,000
Public Service Company of New Mexico | San Juan Generating Station | Coal Supply
Other Commitments [Line Items]
Other current assets	26,300,000	26,300,000	$ 26,300,000
Public Service Company of New Mexico | Four Corners | Increase in coal mine decommissioning liability
Other Commitments [Line Items]
Net expense		2,500,000
Public Service Company of New Mexico | San Juan Generating Station And Four Corners | Surface
Other Commitments [Line Items]
Capacity to be collected for final reclamation		100,000,000
NM Capital | San Juan Generating Station | Coal Supply
Other Commitments [Line Items]
Coal mine reclamation bonds to be posted with NMMMD	118,700,000	118,700,000
Issuance in letters of credit	$ 30,300,000	$ 30,300,000				$ 30,300,000

Commitments and Contingencies_8

Commitments and Contingencies - Mining Royalty Rate (Details) - Continuous Highwall Mining - San Juan Generating Station - USD ($) $ in Millions	Dec. 31, 2020	Aug. 31, 2013
Public Utilities, General Disclosures [Line Items]
Proposed retroactive surface mining royalty rate		12.50%
Surface mining royalty rate applied between 2000 and 2003	8.00%
Estimated underpaid surface mining royalties under proposed rate change	$ 5
PNM's share of estimated underpaid surface mining royalties under proposed rate change	46.30%

Commitments and Contingencies_9

Commitments and Contingencies - Liability and Insurance Matters (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station	12 Months Ended
	Dec. 31, 2020USD ($)generating_unit
Public Utilities, General Disclosures [Line Items]
Number of units (in generating units) | generating_unit	3
Nuclear Plant
Public Utilities, General Disclosures [Line Items]
Ownership percentage in nuclear reactor	10.20%
Number of units (in generating units) | generating_unit	3
Maximum potential assessment per incident	$ 42,100,000
Annual payment limitation related to incident	6,200,000
Aggregate amount of all risk insurance	2,800,000,000
Sublimit amount for non-nuclear property damage losses	2,250,000,000
Retrospective premium assessment	5,400,000
Nuclear Plant | Commercial Providers
Public Utilities, General Disclosures [Line Items]
Liability insurance coverage	450,000,000
Nuclear Plant | Industry Wide Retrospective Assessment Program
Public Utilities, General Disclosures [Line Items]
Liability insurance coverage	13,300,000,000
Nuclear Plant | Maximum
Public Utilities, General Disclosures [Line Items]
Liability insurance coverage	$ 13,800,000,000

Commitments and Contingencie_10

Commitments and Contingencies - Navajo National Allottee Matters (Details) - Navajo Nation Allottee Matters - Public Service Company of New Mexico	1 Months Ended
	Sep. 30, 2012landowner	Dec. 31, 2020Allotment_Parcel	Dec. 01, 2015Allotment_Parcel	Jul. 13, 2015a	Jan. 22, 2015Allotment_Parcel
Loss Contingencies [Line Items]
Number of landowners involved in the appeal | landowner	43
Number of allotments where landowners are revoking rights of way renewal consents (in allotment parcels)		6
Allotments with right-of-way renewals not previously contested (in allotment parcels)					10
Acres of land at issue (in acres) | a				15.49
Number of allotment parcels that cannot be condemned			2
Number of allotment parcels at issue			5

Regulatory and Rate Matters - N

Regulatory and Rate Matters - New Mexico General Rate Cases (Details) $ in Thousands

Feb. 01, 2018

Jan. 10, 2018USD ($)

Dec. 07, 2016USD ($)

Sep. 28, 2016USD ($)leaseMW

Aug. 31, 2016USD ($)leaseMW

Dec. 31, 2020USD ($)

Dec. 31, 2019USD ($)MW

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2018USD ($)

May 16, 2019MW

Sep. 30, 2016MW

Jan. 31, 2016MW

Public Utilities, General Disclosures [Line Items]

Income taxes (benefit)

$ 20,636

$ (25,282)

$ 7,775

Regulatory disallowances and restructuring costs

1,098

151,095

65,598

Percent of non-fuel revenue requirement change implemented

50.00%

NMPRC

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 99,200

Requested return on equity

10.125%

Proposed term for providing benefits to customers related to reduction in state corporate tax

23 years

Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Income taxes (benefit)

21,857

(25,962)

(5,971)

Regulatory disallowances and restructuring costs

1,098

150,599

66,339

Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2 Leases

Public Utilities, General Disclosures [Line Items]

Number of megawatts purchased (in megawatts) | MW

64.1

64.1

64.1

64.1

Number of megawatts (in megawatts) | MW

114.6

114.6

114.6

Number of leases under which assets were purchased | lease

3

3

Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 1 Leases, extended

Public Utilities, General Disclosures [Line Items]

Estimated annual rent expense

$ 18,100

Public Service Company of New Mexico | NMPRC

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 10,300

Requested return on equity

9.575%

Proposed term for providing benefits to customers related to reduction in state corporate tax

3 years

Public Service Company of New Mexico | 2015 Electric Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 123,500

Approved rate increase (decrease)

$ 61,200

Public Service Company of New Mexico | 2015 Electric Rate Case | Palo Verde Nuclear Generating Station, Unit 2 Leases

Public Utilities, General Disclosures [Line Items]

Proposed disallowance of recovery of purchase price of assets

$ 163,300

Approved lease acquisition costs

83,700

Disallowed leasehold improvements

$ 43,800

Public Service Company of New Mexico | 2015 Electric Rate Case | Non-Fuel Energy

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 121,700

Four Corners

Public Utilities, General Disclosures [Line Items]

Regulatory disallowances and restructuring costs

$ 47,600

Pre-tax regulatory disallowance

$ 148,100

Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Number of megawatts purchased (in megawatts) | MW

64.1

Number of megawatts (in megawatts) | MW

114.6

114.6

Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico | 2015 Electric Rate Case

Public Utilities, General Disclosures [Line Items]

Number of megawatts purchased (in megawatts) | MW

64.1

Pre-tax regulatory disallowance for capital costs

$ 4,000

$ 3,100

$ 18,400

New Mexico 2015 Rate Case | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Recorded pre-tax impairments

150,600

Amount of impairment to carrying amount of regulatory assets

39,700

Income taxes (benefit)

$ 45,700

$ (45,700)

New Mexico 2015 Rate Case | Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Number of megawatts purchased (in megawatts) | MW

64.1

Recorded pre-tax impairments portion of purchase price

$ 73,200

Income taxes (benefit)

(45,700)

Leaseholds and Leasehold Improvements | New Mexico 2015 Rate Case | Palo Verde Nuclear Generating Station, Units 1 And 4 | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Amount of impairment to carrying amount of regulatory assets

$ 37,700

Regulatory and Rate Matters - R

Regulatory and Rate Matters - Renewable Portfolio Standard (Details)	Jan. 01, 2021USD ($)	Nov. 18, 2020	Jun. 01, 2020USD ($)	Jun. 03, 2019MW	Dec. 31, 2020USD ($)MW	Mar. 27, 2020MW	Aug. 10, 2018kv	Jun. 01, 2017GWhMW
KV Transmission Line
Public Utilities, General Disclosures [Line Items]
Transmission line and associated facilities | kv							345
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)						300
Public Service Company of New Mexico | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Solar photovoltaic capacity (in mw)					158
Solar distributed generation (in mw)					161
Public Service Company of New Mexico | Renewable Portfolio Standard | Maximum
Public Utilities, General Disclosures [Line Items]
Reasonable cost threshold in megawatts per hour | $					$ 60
NMPRC | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Additional megawatt hours in first year (in mw) | GWh								80
Requested solar production (in mw)								50
NMPRC | Public Service Company of New Mexico | Renewable Energy Rider
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery | $			$ 67,800,000
NMPRC | Public Service Company of New Mexico | Renewable Energy Rider | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery | $	$ 67,800,000
NMPRC | Public Service Company of New Mexico | Renewable Energy Rider, Sky Blue Energy Program
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery | $			$ 2,300,000
Renewable energy procurement plan, carrying charges, percent		4.00%	8.64%
Renewable energy procurement plan, carrying charges | $			$ 700,000
NMPRC | Public Service Company of New Mexico | Renewable Energy Rider, Sky Blue Energy Program | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery | $	$ 2,300,000
New Mexico Wind | Public Service Company of New Mexico | Renewable Portfolio Standard 2014
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)					200
New Mexico Wind | NMPRC | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Additional megawatt hours in second year (in mw) | GWh								105
Red Mesa Wind | Public Service Company of New Mexico | Renewable Portfolio Standard 2014
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)					102
La Joya Wind | Public Service Company of New Mexico | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)					140
Solar distributed generation (in mw)				140
PPA term				20 years
Lightning Dock Geothermal | Public Service Company of New Mexico | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Geothermal energy capacity (in mw)					11
Lightning Dock Geothermal | NMPRC | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Additional megawatt hours in first year (in mw) | GWh								55
Additional megawatt hours in second year (in mw) | GWh								77

Regulatory and Rate Matters -_2

Regulatory and Rate Matters - Renewable Energy Rider (Details) - Public Service Company of New Mexico - USD ($) $ in Millions	Jan. 01, 2021	Jun. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Renewable Energy Rider
Public Utilities, General Disclosures [Line Items]
Revenue from renewable energy rider			$ 56.4	$ 52	$ 41.4
Renewable Energy Rider | NMPRC
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery		$ 67.8
Renewable Energy Rider | NMPRC | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery	$ 67.8
Renewable energy procurement plan, approved recovery amount	65.5
Renewable Energy Rider | Maximum
Public Utilities, General Disclosures [Line Items]
NMPRC-approved return on equity			0.50%
Renewable Energy Rider, Sky Blue Energy Program | NMPRC
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery		$ 2.3
Renewable Energy Rider, Sky Blue Energy Program | NMPRC | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery	$ 2.3

Regulatory and Rate Matters - E

Regulatory and Rate Matters - Energy Efficiency and Load Management (Details) $ in Millions	Apr. 15, 2020USD ($)MMBTUmeter	Jul. 26, 2017USD ($)GWh	Dec. 31, 2019USD ($)GWh	Dec. 31, 2018USD ($)	Nov. 08, 2017	Nov. 07, 2017
Public Service Company of New Mexico | Energy Efficiency and Load Management Program, Proposed 2018 Portfolio | Disincentives/Incentives Added
Public Utilities, General Disclosures [Line Items]
Program costs related to energy efficiency				$ 23.6
Targeted energy savings (in Gigawatts) | GWh		69
Projected earned incentive		$ 1.9	$ 2.7
Energy and load management programs, additional incentive, targeted energy savings (in Gigawatts) | GWh			68
Public Service Company of New Mexico | Energy Efficiency and Load Management Program, Proposed 2019 Portfolio | Disincentives/Incentives Added
Public Utilities, General Disclosures [Line Items]
Program costs related to energy efficiency			$ 24.9
Application of incentive based on target savings		$ 1.7	$ 1.8
Public Service Company of New Mexico | 2017 Energy Efficiency and Load Management Program | Disincentives/Incentives Added
Public Utilities, General Disclosures [Line Items]
Targeted energy savings (in Gigawatts) | GWh			59
Minimum profit incentive			$ 1.8
Public Service Company of New Mexico | Energy Efficiency and Load Management Program
Public Utilities, General Disclosures [Line Items]
Program costs related to energy efficiency, next fiscal year	$ 31.4
Program costs related to energy efficiency, in year two	31
Program costs related to energy efficiency, in year three	$ 29.6
Energy efficiency and load management programs targeted energy savings (in Gigawatts) | MMBTU	80
Number of AMI meters to be installed | meter	5,000
Program costs related to meter installation	$ 2.9
Public Service Company of New Mexico | Minimum | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Sliding scale profit incentive			7.10%
Profit incentive sliding scale multiplier	0.071
Energy efficiency and load management programs targeted energy savings (in Gigawatts) | MMBTU	80
Measurement Input, Discount Rate
Public Utilities, General Disclosures [Line Items]
Tax-adjusted WACC					0.0959	0.0771

Regulatory and Rate Matters - I

Regulatory and Rate Matters - Integrated Resource Plans and Abandonment Applications (Details)	Jan. 29, 2021	Jul. 03, 2017	Dec. 31, 2020
NMPRC
Public Utilities, General Disclosures [Line Items]
Period of action plan			4 years
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Required filing of Integrated Resource Plan			3 years
Integrated Resource Plan, 2011 | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Planning period covered, IRP			20 years
Integrated Resource Plan, 2017 | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Planning period covered, IRP		20 years
Integrated Resource Plan, 2020 | Public Service Company of New Mexico | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Planning period covered, IRP	20 years

Regulatory and Rate Matters - S

Regulatory and Rate Matters - SJGS Abandonment Application (Details) $ in Millions	Apr. 01, 2020USD ($)	Jul. 01, 2019USD ($)scenarioMW	Dec. 31, 2020USD ($)	Nov. 13, 2020MW	Sep. 28, 2020USD ($)MW	Jun. 30, 2020USD ($)	Jun. 24, 2020MW	Mar. 27, 2020MMBTUMW	Feb. 21, 2020USD ($)	May 31, 2019MW
PNM Solar Direct
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)										50
Replacement Resource Portfolio Two | Hearing Examiners Approach Two
Public Utilities, General Disclosures [Line Items]
Number of megawatts for natural gas facility (in Megawatts)							200
Replacement Resource Portfolio Four | Hearing Examiners Approach One
Public Utilities, General Disclosures [Line Items]
Number of megawatts for demand response (in Megawatts)							24
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)								40
Solar distributed generation (in mw)								300
Solar generation capacity, power purchase agreements (in Megawatts) | MMBTU								20
Public Service Company of New Mexico | PNM Solar Direct
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)								50
Public Service Company of New Mexico | Replacement Resource Portfolio One | Hearing Examiners Approach One
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)							150
Solar distributed generation (in mw)							300
Public Service Company of New Mexico | Replacement Resource Portfolio Two | Hearing Examiners Approach One
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)							20
Solar distributed generation (in mw)							50
Public Service Company of New Mexico | Replacement Resource Portfolio Three
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)				100	100
Solar distributed generation (in mw)				200	200
Public Service Company of New Mexico | Replacement Resource Portfolio Three | Hearing Examiners Approach One
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)							100
Solar distributed generation (in mw)							200
Public Service Company of New Mexico | Replacement Resource Portfolio Four
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)				30	30
Solar distributed generation (in mw)				100	100
Public Service Company of New Mexico | Replacement Resource Portfolio Four | Hearing Examiners Approach One
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)							30
Solar distributed generation (in mw)							100
Public Service Company of New Mexico | Replacement Resource Portfolio Five
Public Utilities, General Disclosures [Line Items]
Number of megawatts in battery storage facilities (in megawatts)				130	130
Solar distributed generation (in mw)				299	299
San Juan Generating Station
Public Utilities, General Disclosures [Line Items]
Estimated costs of replacement resources | $					$ 8.1
San Juan Generating Station | Other deferred credits
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $			$ 38.1
San Juan Generating Station | Employee Severance
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $						$ 9.4
San Juan Generating Station | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Number of megawatts in natural gas-fired peaking plant (in megawatts)		280
Number of megawatts in battery storage facilities (in megawatts)		70
Solar distributed generation (in mw)		350
Number of megawatts in battery storage facilities, replacement resource scenario (in megawatts)		60
Number of replacement resource scenarios | scenario		3
Request issuance of energy transition bonds | $	$ 361	$ 361
Forecasted undepreciated investment | $			283						$ 361
Plant decommissioning and coal mine reclamation costs | $			28.6
Upfront financing costs | $			9.6
Severance costs | $			20
Proceeds from securitization bonds | $		$ 19.8
San Juan Generating Station | Public Service Company of New Mexico | Other deferred credits
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $			$ 36.8
San Juan Generating Station | Public Service Company of New Mexico | Employee Severance
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $						8.1
San Juan Generating Station | Public Service Company of New Mexico | Other Restructuring
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $						8.9
San Juan Generating Station | Public Service Company of New Mexico | Economic Development and Workforce Training Costs
Public Utilities, General Disclosures [Line Items]
Restructuring reserve | $						$ 19.8

Regulatory and Rate Matters - F

Regulatory and Rate Matters - Four Corners Abandonment Application (Details) - Public Service Company of New Mexico $ in Millions	Jan. 08, 2021USD ($)	Nov. 01, 2020USD ($)	Nov. 30, 2020USD ($)	Jan. 28, 2021MW	Mar. 27, 2020MW
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw) | MW					300
Four Corners
Public Utilities, General Disclosures [Line Items]
Payments for relief from obligations		$ 75	$ 15
Initial payment for relief from obligations			15
Final payment for relief from obligations			$ 60
Four Corners | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners		13.00%
Four Corners | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Request issuance of energy transition bonds	$ 300
Forecasted undepreciated investment	272
Plant decommissioning and coal mine reclamation costs	4.6
Upfront financing costs	7.3
Proceeds from securitization bonds	$ 16.5
Solar distributed generation (in mw) | MW				200

Regulatory and Rate Matters - C

Regulatory and Rate Matters - Cost Recovery Related to Joining the EIM (Details) - Energy Imbalance Market - Public Service Company of New Mexico $ in Millions	Aug. 22, 2018USD ($)
Public Utilities, General Disclosures [Line Items]
Initial capital investments to be recovered	$ 20.9
Other expenses to be recovered	$ 7.4

Regulatory and Rate Matters - A

Regulatory and Rate Matters - Advanced Metering Infrastructure Application and Facebook Data Center Project (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2017MW	Dec. 31, 2017power_purchase_agreementFacilityMW	Feb. 08, 2021MW	Dec. 31, 2020	Mar. 27, 2020MW	Dec. 31, 2019MW
Public Utilities, General Disclosures [Line Items]
Ownership percentage				50.00%
Facebook Data Center
Public Utilities, General Disclosures [Line Items]
PPA term	25 years
Facebook Data Center | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)			190
Number of megawatts in battery storage facilities (in megawatts)			100
Solar generation capacity expected to be operational (in megawatts)			50
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)					300
Number of megawatts in battery storage facilities (in megawatts)					40
PNMR Development
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)						130
Ownership percentage						50.00%
PNMR Development | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	50	50
Casa Mesa Wind, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	50	50
Avangrid Renewables, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	166	166
Route 66 Solar Energy Center, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	50	50
NMRD | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	100	100
Number of additional PPAs | power_purchase_agreement		2
Number of solar facilities | Facility		2

Regulatory and Rate Matters - P

Regulatory and Rate Matters - PNM Solar Direct, Application for a New 345-kV Transmission Line and Wester Spirit Line (Details) $ in Millions	Oct. 02, 2020USD ($)	May 31, 2019MW	May 01, 2019USD ($)kv	Aug. 10, 2018USD ($)kv
PNM Solar Direct
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw) | MW		50
PPA term		15 years
KV Transmission Line
Public Utilities, General Disclosures [Line Items]
Transmission line and associated facilities | kv				345
Estimated cost of project	$ 109			$ 85
Increase (decrease) in estimated cost of project	$ 24
Western Spirit Line
Public Utilities, General Disclosures [Line Items]
Transmission line and associated facilities | kv			345
Estimated cost of project			$ 285
Estimated self-fund amount under agreement			$ 75

Regulatory and Rate Matters -_3

Regulatory and Rate Matters - Formula Transmission Rate Case (Details)	Dec. 31, 2020
Public Service Company of New Mexico | Formula Transmission Rate Case
Public Utilities, General Disclosures [Line Items]
Return on equity	10.00%

Regulatory and Rate Matters -_4

Regulatory and Rate Matters - COVID-19 Regulatory Matters (Details) - USD ($) $ in Thousands	Feb. 03, 2021	Dec. 31, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Regulatory assets		$ 557,790	$ 556,930
Regulatory liabilities		850,228	866,243
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Regulatory assets		457,953	435,467
Regulatory liabilities		664,873	683,398
Public Service Company of New Mexico | COVID-19 cost savings
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities		900	0
COVID-19 | Public Service Company of New Mexico | COVID-19 cost savings
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities		900
Deferred COVID-19 costs | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Regulatory assets		8,761	$ 0
Deferred COVID-19 costs | COVID-19 | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Regulatory assets		$ 8,800
COVID-19 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Temporary mandatory moratorium on disconnection period	100 days
Disconnection transition period	90 days

Regulatory and Rate Matters - T

Regulatory and Rate Matters - Transportation Electrification Program (Details) - Transportation Electrification Program - Public Service Company of New Mexico $ in Millions	Dec. 18, 2020USD ($)
Public Utilities, General Disclosures [Line Items]
Expected budgeted expenditures	$ 8.4
Budget flexibility, percent	25.00%
Budget portion dedicated to low and moderate income customers, percent	25.00%

Regulatory and Rate Matters -_5

Regulatory and Rate Matters - TNMP Narrative (Details) advanced_meter in Thousands, $ in Thousands

Feb. 05, 2021USD ($)

Jun. 26, 2020USD ($)

Apr. 06, 2020USD ($)

Dec. 20, 2018USD ($)

May 30, 2018USD ($)

Jan. 10, 2018USD ($)

Dec. 07, 2016USD ($)

Oct. 31, 2019USD ($)

Aug. 31, 2019USD ($)

Jul. 31, 2011USD ($)

Dec. 31, 2020USD ($)advanced_meter

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Oct. 02, 2020USD ($)

Jul. 27, 2020USD ($)

May 29, 2020USD ($)

Dec. 31, 2019USD ($)

Public Utilities, General Disclosures [Line Items]

Net increase (decrease) in regulatory liabilities

$ 7,175

Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Regulatory liabilities

$ 670,292

$ 683,769

Net increase (decrease) in regulatory liabilities

11,244

Texas-New Mexico Power Company

Public Utilities, General Disclosures [Line Items]

Regulatory liabilities

$ 187,407

182,979

Net increase (decrease) in regulatory liabilities

(4,069)

Refund of regulatory liability to customers

$ 37,800

Estimate of possible upgrades

$ 46,000

Energy efficiency cost recovery factor, requested change amount

$ 5,900

Energy efficiency cost recovery factor, requested performance bonus

$ 1,000

$ 1,000

Requested increase annual distribution revenue requirement

$ 14,700

Incremental distribution investments

$ 149,200

Annual distribution revenue requirement

$ 14,300

CTC Funding amount interest minimum

15.00%

Reduction to revenue

$ 5,400

Texas-New Mexico Power Company | 2018 TNMP Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 10,000

$ 25,900

Requested return on equity

9.65%

10.50%

Requested cost of debt, percentage

7.20%

Requested debt capital structure, percentage

55.00%

50.00%

Requested equity capital structure, percentage

45.00%

50.00%

Regulatory liabilities

146,500

Net increase (decrease) in regulatory liabilities

$ 14,400

Refund of federal income tax rates period

3 years

5 years

Investments excluded from rate, amount

$ 10,600

Recovery of direct costs

$ 3,300

$ 3,800

Remaining recovery period of regulatory assets for which no return investment during recovery period is provided

3 years

Write off regulatory dissallowance

$ 500

Texas-New Mexico Power Company | Advanced Meter System Deployment and Surcharge Request

Public Utilities, General Disclosures [Line Items]

Approved deployment costs

$ 113,400

Period of time to collect deployment costs through surcharge period

12 years

Number of advanced meters installed | advanced_meter

242

Texas-New Mexico Power Company | Transmission Cost of Service Rates | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 112,600

Requested increase in annual transmission service revenue

$ 14,100

NMPRC

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 99,200

Requested return on equity

10.125%

Proposed term for providing benefits to customers related to reduction in state corporate tax

23 years

NMPRC | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 10,300

Requested return on equity

9.575%

Proposed term for providing benefits to customers related to reduction in state corporate tax

3 years

Regulatory and Rate Matters -_6

Regulatory and Rate Matters - TNMP Schedules (Details) - Texas-New Mexico Power Company - USD ($) $ in Millions	Oct. 07, 2020	Mar. 27, 2020	Sep. 19, 2019	Mar. 21, 2019	Mar. 27, 2018	Feb. 28, 2021	Feb. 28, 2020	Feb. 28, 2019
Energy efficiency costs
Public Utilities, General Disclosures [Line Items]
Aggregate Collection Amount							$ 5.6	$ 6
Performance Bonus							$ 0.8	$ 1.1
Transmission Cost of Service Rates
Public Utilities, General Disclosures [Line Items]
Approved Increase in Rate Base	$ 10.8	$ 59.2	$ 21.9	$ 111.8	$ 32
Annual Increase in Revenue	$ 2	$ 7.8	$ 3.3	$ 14.3	$ 0.6
Subsequent Event | Energy efficiency costs
Public Utilities, General Disclosures [Line Items]
Aggregate Collection Amount						$ 5.9
Performance Bonus						$ 0.8

Regulatory and Rate Matters -_7

Regulatory and Rate Matters - COVID-19 Electricity Relief Program (Details) - Texas-New Mexico Power Company $ in Thousands	Apr. 14, 2020USD ($)	Dec. 31, 2020USD ($)	Mar. 30, 2020MWh	Dec. 31, 2019USD ($)
Public Utilities, General Disclosures [Line Items]
Rider charge from electricity relief program | MWh			0.33
Regulatory liabilities		$ 187,407		$ 182,979
Proceeds from short-term debt	$ 500
COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities		100
Other deferred costs, gross, CARES Act		$ 700

Income Taxes - Federal Income T

Income Taxes - Federal Income Tax Reform (Details) - USD ($) $ in Thousands	Jan. 10, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Net increase (decrease) in regulatory liabilities				$ 7,175
Net decrease in deferred income tax liabilities (deferred income tax assets)				1,910
Net increase in affiliate receivables (affiliate payables)				0
Net deferred income tax expense				5,265
Income taxes (benefit)		$ 20,636	$ (25,282)	7,775
Public Service Company of New Mexico
Income Taxes [Line Items]
Net increase (decrease) in regulatory liabilities				11,244
Net decrease in deferred income tax liabilities (deferred income tax assets)				(2,175)
Net increase in affiliate receivables (affiliate payables)				12,300
Net deferred income tax expense				1,119
Income taxes (benefit)		21,857	(25,962)	(5,971)
TNMP
Income Taxes [Line Items]
Net increase (decrease) in regulatory liabilities				(4,069)
Net decrease in deferred income tax liabilities (deferred income tax assets)				(9,784)
Net increase in affiliate receivables (affiliate payables)				4,042
Net deferred income tax expense				1,673
Income taxes (benefit)		6,308	5,046	16,880
Corporate and Other
Income Taxes [Line Items]
Net increase (decrease) in regulatory liabilities				0
Net decrease in deferred income tax liabilities (deferred income tax assets)				13,869
Net increase in affiliate receivables (affiliate payables)				(16,342)
Net deferred income tax expense				2,473
Income taxes (benefit)		(7,529)	(4,366)	$ (3,134)
NMPRC
Income Taxes [Line Items]
Proposed term for providing benefits to customers related to reduction in state corporate tax					23 years
NMPRC | Public Service Company of New Mexico
Income Taxes [Line Items]
Proposed term for providing benefits to customers related to reduction in state corporate tax	3 years
New Mexico 2015 Rate Case | Public Service Company of New Mexico
Income Taxes [Line Items]
Pre-tax impairment of investments		150,600	150,600
Income taxes (benefit)		$ 45,700	$ (45,700)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Current federal income tax	$ 0	$ 60	$ 0
Current state income tax	231	43	(244)
Deferred federal income tax	17,574	(20,372)	7,716
Deferred state income tax	3,721	(4,491)	648
Amortization of accumulated investment tax credits	(890)	(522)	(345)
Total income taxes (benefit)	20,636	(25,282)	7,775
Public Service Company of New Mexico
Income Taxes [Line Items]
Current federal income tax	0	(6,266)	(6,644)
Current state income tax	(585)	449	(2,661)
Deferred federal income tax	20,125	(12,308)	5,661
Deferred state income tax	2,560	(7,590)	(2,080)
Amortization of accumulated investment tax credits	(243)	(247)	(247)
Total income taxes (benefit)	21,857	(25,962)	(5,971)
Texas-New Mexico Power Company
Income Taxes [Line Items]
Current federal income tax	12,048	10,792	13,347
Current state income tax	2,033	1,904	1,753
Deferred federal income tax	(7,744)	(7,621)	(540)
Deferred state income tax	(29)	(29)	2,320
Total income taxes (benefit)	$ 6,308	$ 5,046	$ 16,880

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 43,670	$ 14,038	$ 22,902
Amortization of accumulated investment tax credits	(890)	(522)	(345)
Amortization of excess deferred income tax	(30,723)	(37,799)	(19,779)
Flow-through of depreciation items	1,368	1,136	712
Earnings attributable to non-controlling interest in Valencia	(2,943)	(2,991)	(3,173)
State income tax, net of federal benefit	6,961	298	1,358
Impairment of state net operating loss carryforwards	0	0	0
Allowance for equity funds used during construction	(2,363)	(1,990)	(2,185)
Impairment of charitable contribution carryforward	0	0	0
Regulatory recovery of prior year impairments of state net operating loss carryforward, including amortization	1,367	1,367	1,367
Federal income tax rate change	0	0	2,914
Tax expense (benefit) related to stock compensation awards	(392)	(795)	4,647
Non-deductible compensation	2,630	1,156	891
Other	1,951	820	(1,534)
Total income taxes (benefit)	$ 20,636	$ (25,282)	$ 7,775
Effective tax rate	9.92%	(37.82%)	7.13%
Public Service Company of New Mexico
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 38,193	$ 6,187	$ 13,514
Amortization of accumulated investment tax credits	(243)	(247)	(247)
Amortization of excess deferred income tax	(21,609)	(28,923)	(19,779)
Flow-through of depreciation items	1,279	1,077	674
Earnings attributable to non-controlling interest in Valencia	(2,943)	(2,991)	(3,173)
State income tax, net of federal benefit	7,111	92	1,323
Impairment of state net operating loss carryforwards	0	0	0
Allowance for equity funds used during construction	(1,461)	(1,398)	(1,716)
Regulatory recovery of prior year impairments of state net operating loss carryforward, including amortization	1,367	1,367	1,367
Federal income tax rate change	0	0	(683)
Tax expense (benefit) related to stock compensation awards	(279)	(559)	3,967
Non-deductible compensation	1,554	683	612
Other	(1,112)	(1,250)	(1,830)
Total income taxes (benefit)	$ 21,857	$ (25,962)	$ (5,971)
Effective tax rate	12.02%	(88.13%)	(9.28%)
Texas-New Mexico Power Company
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 13,628	$ 12,778	$ 14,379
Amortization of excess deferred income tax	(9,113)	(8,876)	0
State income tax, net of federal benefit	1,625	1,532	1,454
Tax expense (benefit) related to stock compensation awards	(112)	(236)	735
Non-deductible compensation	1,071	471	277
Other	(791)	(623)	35
Total income taxes (benefit)	$ 6,308	$ 5,046	$ 16,880
Effective tax rate	9.71%	8.29%	24.65%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss	$ 41,419	$ 59,488
Regulatory liabilities related to income taxes	148,961	145,087
Federal tax credit carryforwards	121,354	101,231
Regulatory disallowances	38,531	34,639
Other	42,885	54,199
Total deferred tax assets	393,150	394,644
Deferred tax liabilities:
Depreciation and plant related	(738,342)	(787,928)
Investment tax credit	(98,669)	(81,186)
Regulatory assets related to income taxes	(61,330)	(58,495)
CTC	0	(1,466)
Pension	(37,099)	(35,029)
Regulatory asset for shutdown of SJGS Units 2 and 3	(27,237)	(28,831)
Other	(124,985)	(27,767)
Total deferred tax liabilities	(1,087,662)	(1,020,702)
Net accumulated deferred income tax liabilities	(694,512)	(626,058)
Public Service Company of New Mexico
Deferred tax assets:
Net operating loss	0	25,889
Regulatory liabilities related to income taxes	121,569	114,849
Federal tax credit carryforwards	84,719	82,983
Shutdown of SJGS Units 2 and 3	0	0
Regulatory disallowances	38,531	34,639
Other	46,444	38,735
Total deferred tax assets	291,263	297,095
Deferred tax liabilities:
Depreciation and plant related	(576,079)	(630,293)
Investment tax credit	(74,424)	(74,667)
Regulatory assets related to income taxes	(51,493)	(49,479)
Pension	(32,413)	(30,609)
Regulatory asset for shutdown of SJGS Units 2 and 3	(27,237)	(28,831)
Other	(108,767)	(5,206)
Total deferred tax liabilities	(870,413)	(819,085)
Net accumulated deferred income tax liabilities	(579,150)	(521,990)
Texas-New Mexico Power Company
Deferred tax assets:
Regulatory liabilities related to income taxes	27,392	30,238
Other	4,548	3,788
Total deferred tax assets	31,940	34,026
Deferred tax liabilities:
Depreciation and plant related	(148,279)	(142,791)
Regulatory assets related to income taxes	(9,836)	(9,016)
Loss on reacquired debt	(6,072)	(6,345)
CTC	0	(1,466)
Pension	(4,685)	(4,420)
AMS	(6,915)	(8,473)
Other	(1,522)	(1,666)
Total deferred tax liabilities	(177,309)	(174,177)
Net accumulated deferred income tax liabilities	$ (145,369)	$ (140,151)

Income Taxes - Schedule of De_2

Income Taxes - Schedule of Deferred Income Tax Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	$ 68,454
Change in tax effects of income tax related regulatory assets and liabilities	(11,602)
Amortization of excess deferred income tax	(30,723)
Tax effect of mark-to-market adjustments	(3,206)
Tax effect of excess pension liability	(3,670)
Adjustment for uncertain income tax positions	2,459
Reclassification of unrecognized tax benefits	(2,459)
Amortization of state net operating loss recovered in prior years	1,367
Refundable alternative minimum tax credit carryforward reclassified to receivable	0
Other	(215)
Deferred income taxes (benefits)	20,405	$ (25,385)	$ 8,019
Public Service Company of New Mexico
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	57,160
Change in tax effects of income tax related regulatory assets and liabilities	(7,936)
Amortization of excess deferred income tax	(21,609)
Tax effect of mark-to-market adjustments	(3,325)
Tax effect of excess pension liability	(3,670)
Adjustment for uncertain income tax positions	2,454
Reclassification of unrecognized tax benefits	(1,999)
Amortization of state net operating loss recovered in prior years	1,367
Other	0
Deferred income taxes (benefits)	22,442	(20,145)	3,334
Texas-New Mexico Power Company
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	5,218
Change in tax effects of income tax related regulatory assets and liabilities	(3,666)
Amortization of excess deferred income tax	(9,113)
Other	(212)
Deferred income taxes (benefits)	$ (7,773)	$ (7,650)	$ 1,780

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Expense) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, interest on income taxes expense	$ 0	$ 0	$ 0
PNMR
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	10,693,000	10,194,000	9,429,000
Additions based on tax positions	2,286,000	329,000	543,000
Additions (reductions) for tax positions of prior years	173,000	170,000	222,000
Settlement payments	0	0	0
Ending balance	13,152,000	10,693,000	10,194,000
Unrecognized tax benefits that would impact effective tax rate	10,700,000
Public Service Company of New Mexico
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	7,776,000	7,288,000	6,563,000
Additions based on tax positions	2,286,000	329,000	543,000
Additions (reductions) for tax positions of prior years	168,000	159,000	182,000
Settlement payments	0	0	0
Ending balance	10,230,000	7,776,000	7,288,000
Unrecognized tax benefits that would impact effective tax rate	7,800,000
Unrecognized tax benefits, interest on income taxes expense	0	0	0
Texas-New Mexico Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	114,000	103,000	63,000
Additions based on tax positions	0	0	0
Additions (reductions) for tax positions of prior years	5,000	11,000	40,000
Settlement payments	0	0	0
Ending balance	119,000	114,000	103,000
Unrecognized tax benefits that would impact effective tax rate	100,000
Unrecognized tax benefits, interest on income taxes expense	$ 0	$ 0	$ 0

Income Taxes - Carryforwards (D

Income Taxes - Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes, Impairment of Carryforwards
State tax credit carryforwards	$ (425)	$ 425	$ 0
State net operating loss carryforwards	0	0	0
Charitable contribution carryforwards	0	0	0
Compensation expense	96	(99)	410
Income Taxes, Reserve Balances
State tax credit carryforwards	0	425
State net operating loss carryforwards	0	0
Charitable contribution carryforwards	0	0
Compensation expense	407	311
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforwards	222,100
Federal tax credit carryforwards that expire beginning in 2023	121,400
Public Service Company of New Mexico
Income Taxes, Impairment of Carryforwards
State tax credit carryforwards	0	0	0
State net operating loss carryforwards	0	0	0
Charitable contribution carryforwards	0	0	0
Compensation expense	61	(100)	298
Income Taxes, Reserve Balances
State tax credit carryforwards	0	0
State net operating loss carryforwards	0	0
Charitable contribution carryforwards	0	0
Compensation expense	259	198
Texas-New Mexico Power Company
Income Taxes, Impairment of Carryforwards
State tax credit carryforwards	0	0	0
State net operating loss carryforwards	0	0	0
Charitable contribution carryforwards	0	0	0
Compensation expense	35	2	$ 111
Income Taxes, Reserve Balances
State tax credit carryforwards	0	0
State net operating loss carryforwards	0	0
Charitable contribution carryforwards	0	0
Compensation expense	$ 148	$ 113

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Apr. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 01, 2018
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill	$ 278,297		$ 278,297	$ 278,297
Public Service Company of New Mexico
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill	51,632		51,632		$ 51,600
Percentage of fair value in excess of carrying amount					19.00%
Texas-New Mexico Power Company
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill	$ 226,665	$ 226,700	$ 226,665		$ 226,700
Percentage of fair value in excess of carrying amount		38.00%			32.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Services billings: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	$ 100,872	$ 96,327	$ 95,637
Services billings: | PNMR to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	39,053	36,554	33,493
Services billings: | PNM to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	383	375	367
Services billings: | TNMP to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	141	141	140
Services billings: | TNMP to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	0	0	0
Services billings: | PNMR to NMRD
Related Party Transaction [Line Items]
Amount of related party transaction	260	238	183
Renewable energy purchases: | PNM from NMRD
Related Party Transaction [Line Items]
Amount of related party transaction	9,638	3,124	2,924
Interconnection and facility study billings: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	0	68,820	0
Interconnection and facility study billings: | PNM to NMRD
Related Party Transaction [Line Items]
Amount of related party transaction	350	650	2,108
Interconnection and facility study billings: | PNM to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	0	0	68,820
Interest billings: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	6	3,365	2,585
Interest billings: | PNMR to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	2	42	136
Interest billings: | PNM to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	255	299	289
Income tax sharing payments: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	0	0	0
Income tax sharing payments: | PNMR to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	0	0	0
Income tax sharing payments: | TNMP to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	15,820	12,996	3,424
Income tax sharing payments: | PNM to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	$ 0	$ 0	$ 134

Equity Method Investment - Narr

Equity Method Investment - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)MW	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)FacilityMW
Business Acquisition [Line Items]
Plant in service, held for future use, and to be abandoned | $	$ 8,480,799	$ 7,918,601
PNMR Development
Business Acquisition [Line Items]
Solar distributed generation (in mw)		130
NMRD
Business Acquisition [Line Items]
Solar distributed generation (in mw)				30
Plant in service, held for future use, and to be abandoned | $				$ 12,400
Renewable energy capacity in operating (in mw)				135.1
Megawatts supplying energy to data center (in mw)				130
Megawatts supplying energy to cooperative (in mw)				1.9
Megawatts supplying energy to power city (in mw)				1.2
NMRD | PNMR Development
Business Acquisition [Line Items]
Ownership percentage	50.00%
Number of solar facilities | Facility				3
Solar distributed generation (in mw)				10
Plant in service, held for future use, and to be abandoned | $				$ 24,800
Cash contribution percentage				50.00%
Contribution to construction activities | $	$ 23,300	$ 38,300	$ 9,000
NMRD | Central New Mexico Electric Cooperative
Business Acquisition [Line Items]
Megawatts supplying energy to cooperative (in mw)				2

Equity Method Investment - Summ

Equity Method Investment - Summarized Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Operating Revenues	$ 359,276	$ 472,465	$ 357,649	$ 333,622	$ 344,144	$ 433,586	$ 330,228	$ 349,645	$ 1,523,012	$ 1,457,603	$ 1,436,613
Net earnings	8,778	$ 121,768	$ 57,489	$ (15,260)	31,805	$ 102,771	$ (75,914)	$ 18,700
Balance Sheet Related Disclosures [Abstract]
Net property, plant, and equipment	218,719				161,106				218,719	161,106
Total assets	7,939,854				7,298,774				7,939,854	7,298,774	6,865,551
Total PNMR common stockholders’ equity	2,049,465				1,678,698				2,049,465	1,678,698
NMRD
Income Statement [Abstract]
Operating Revenues									10,366	3,662	3,147
Operating expenses									7,476	2,971	2,136
Net earnings									2,890	691	$ 1,011
Balance Sheet Related Disclosures [Abstract]
Current assets	8,046				7,187				8,046	7,187
Net property, plant, and equipment	172,585				132,772				172,585	132,772
Non-current assets	1,900				0				1,900	0
Total assets	182,531				139,959				182,531	139,959
Current liabilities	841				9,640				841	9,640
Non-current liabilities	380				0				380	0
Total PNMR common stockholders’ equity	$ 181,310				$ 130,319				$ 181,310	$ 130,319

Merger (Details)

Merger (Details) - Forecast - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Avangrid | Iberdrola, S.A.
Business Acquisition [Line Items]
Noncontrolling interest, ownership percentage by parent		81.50%
Merger Agreement
Business Acquisition [Line Items]
Business combination, cash right per common share (in dollars per share)		$ 50.30
Out-of-pocket fees and expenses reimbursement	$ 10
Merger Agreement | PNMR
Business Acquisition [Line Items]
Termination fees	130
Merger Agreement | Avangrid
Business Acquisition [Line Items]
Termination fees	$ 184

Quarterly Operating Results (_3

Quarterly Operating Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating Revenues	$ 359,276	$ 472,465	$ 357,649	$ 333,622	$ 344,144	$ 433,586	$ 330,228	$ 349,645	$ 1,523,012	$ 1,457,603	$ 1,436,613
Operating income (loss)	18,588	147,805	71,150	47,738	60,552	140,540	(93,615)	36,723	285,281	144,200	236,047
Net earnings (loss)	11,701	125,453	61,561	(11,399)	35,989	106,763	(72,283)	21,662	$ 187,316	$ 92,131	$ 101,282
Net Earnings Attributable to PNMR	$ 8,778	$ 121,768	$ 57,489	$ (15,260)	$ 31,805	$ 102,771	$ (75,914)	$ 18,700
Net Earnings Attributable to PNMR per Common Share:
Basic (in dollars per share)	$ 0.11	$ 1.52	$ 0.72	$ (0.19)	$ 0.40	$ 1.29	$ (0.95)	$ 0.23	$ 2.16	$ 0.97	$ 1.07
Diluted (in dollars per share)	$ 0.10	$ 1.52	$ 0.72	$ (0.19)	$ 0.40	$ 1.28	$ (0.95)	$ 0.23	$ 2.15	$ 0.97	$ 1.07
Income taxes (benefit)									$ 20,636	$ (25,282)	$ 7,775
Public Service Company of New Mexico
Segment Reporting Information [Line Items]
Operating Revenues	$ 266,409	$ 364,504	$ 260,788	$ 248,133	$ 255,172	$ 331,113	$ 238,219	$ 269,318	1,139,834	1,093,822	1,091,965
Operating income (loss)	15,168	116,540	49,584	33,605	44,299	108,453	(115,977)	24,293	214,897	61,068	145,033
Net earnings (loss)	19,594	103,004	49,612	(12,196)	32,040	84,721	(83,313)	21,974	160,014	55,422	70,323
Net Earnings Attributable to PNMR	16,803	99,451	45,672	(15,925)	27,988	80,861	(86,812)	19,144	146,001	41,181	55,211
Net Earnings Attributable to PNMR per Common Share:
Income taxes (benefit)									21,857	(25,962)	(5,971)
Texas-New Mexico Power Company
Segment Reporting Information [Line Items]
Operating Revenues	92,867	107,961	96,861	85,489	88,972	102,473	92,009	80,327	383,178	363,781	344,648
Operating income (loss)	19,154	31,779	23,175	14,345	18,055	32,596	22,578	12,585	88,453	85,814	96,497
Net Earnings Attributable to PNMR	11,398	$ 23,921	$ 16,174	$ 7,092	11,347	$ 25,087	$ 15,267	$ 4,098	58,585	55,799	51,591
Net Earnings Attributable to PNMR per Common Share:
Income taxes (benefit)									6,308	5,046	$ 16,880
New Mexico 2015 Rate Case | Public Service Company of New Mexico
Net Earnings Attributable to PNMR per Common Share:
Pre-tax impairment of investments	$ 150,600				$ 150,600				150,600	150,600
Income taxes (benefit)									$ 45,700	$ (45,700)

Schedule I - Condensed Financ_2

Schedule I - Condensed Financial Information of Parent Company - Statements of Earnings (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Operating Revenues	$ 359,276	$ 472,465	$ 357,649	$ 333,622	$ 344,144	$ 433,586	$ 330,228	$ 349,645	$ 1,523,012	$ 1,457,603	$ 1,436,613
Operating Expenses									1,237,731	1,313,403	1,200,566
Operating income	18,588	147,805	71,150	47,738	60,552	140,540	(93,615)	36,723	285,281	144,200	236,047
Other Income and Deductions:
Other income									19,973	15,382	17,586
Net other income and (deductions)									37,063	43,665	254
Interest Charges									114,392	121,016	127,244
Earnings before Income Taxes									207,952	66,849	109,057
Income taxes (benefit)									20,636	(25,282)	7,775
Net earnings	$ 8,778	$ 121,768	$ 57,489	$ (15,260)	$ 31,805	$ 102,771	$ (75,914)	$ 18,700
PNM Resources
Condensed Financial Statements, Captions [Line Items]
Operating Revenues									0	0	0
Operating Expenses									28,299	3,983	7,475
Operating income									(28,299)	(3,983)	(7,475)
Other Income and Deductions:
Equity in earnings of subsidiaries									211,291	96,324	109,995
Other income									(269)	731	2,048
Net other income and (deductions)									211,022	97,055	112,043
Interest Charges									19,078	19,581	19,453
Earnings before Income Taxes									163,645	73,491	85,115
Income taxes (benefit)									(9,130)	(3,872)	(527)
Net earnings									$ 172,775	$ 77,363	$ 85,642

Schedule I - Condensed Financ_3

Schedule I - Condensed Financial Information of Parent Company - Statement of Cash flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	$ 485,700	$ 503,163	$ 428,226
Cash Flows From Investing Activities:
Net cash flows from investing activities	(733,799)	(673,898)	(475,724)
Cash Flows From Financing Activities:
Revolving credit facility borrowings (repayments), net	(153,100)	99,200	(119,500)
Long-term borrowings	1,267,845	745,000	984,652
Repayment of long-term debt	(977,845)	(407,302)	(750,162)
Issuance of common stock	283,208	0	0
Proceeds from stock option exercise	24	943	963
Dividends paid	(98,502)	(92,926)	(84,961)
Other, net	(4,943)	(2,840)	(6,846)
Net cash flows from financing activities	292,194	172,446	45,646
Change in Cash and Cash Equivalents	44,095	1,711	(1,852)
Cash and Cash Equivalents at Beginning of Year	3,833	2,122	3,974
Cash and Cash Equivalents at End of Year	47,928	3,833	2,122
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	106,575	115,476	119,308
Income taxes paid (refunded), net	969	(2,929)	842
PNM Resources
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	(17,646)	2,001	(2,566)
Cash Flows From Investing Activities:
Utility plant additions	1,122	1,100	826
Investments in subsidiaries	(301,000)	(80,000)	(30,000)
Cash dividends from subsidiaries	99,187	54,465	129,379
Net cash flows from investing activities	(200,691)	(24,435)	100,205
Cash Flows From Financing Activities:
Short-term loan borrowings (repayments)		(150,000)	50,000
Revolving credit facility borrowings (repayments), net	(131,900)	123,900	(148,700)
Long-term borrowings	230,000	150,000	349,652
Repayment of long-term debt	(50,000)	0	(250,000)
Proceeds from stock option exercise	24	943	963
Awards of common stock	(11,984)	(9,918)	(12,635)
Dividends paid	(97,974)	(92,398)	(84,433)
Other, net	(3,064)	(107)	(2,414)
Net cash flows from financing activities	218,310	22,420	(97,567)
Change in Cash and Cash Equivalents	(27)	(14)	72
Cash and Cash Equivalents at Beginning of Year	79	93	21
Cash and Cash Equivalents at End of Year	52	79	93
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	16,869	18,702	15,450
Income taxes paid (refunded), net	$ 0	$ 0	$ 0

Schedule I - Condensed Financ_4

Schedule I - Condensed Financial Information of Parent Company - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 47,928	$ 3,833
Income taxes receivable	5,672	4,933
Other, net	64,549	44,472
Total current assets	377,479	294,010
Property, plant and equipment, net of accumulated depreciation of $15,706 and $14,583	5,965,149	5,466,009
Other long-term assets	284	356
Total assets	7,939,854	7,298,774	$ 6,865,551
Liabilities and Stockholders’ Equity
Short-term debt	32,000	185,100
Current maturities of long-term debt	575,518	490,268
Accrued interest and taxes	68,206	76,815
Other current liabilities	62,841	47,397
Total current liabilities	977,662	967,481
Long-term debt	2,719,632	2,517,449
Total liabilities	5,819,851	5,545,495
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 85,834,874 shares)	1,429,941	1,150,552
Accumulated other comprehensive income (loss), net of tax	(79,183)	(99,377)
Retained earnings	698,707	627,523
Total PNMR common stockholders’ equity	2,049,465	1,678,698
Total liabilities and stockholders' equity	7,939,854	7,298,774
PNM Resources
Assets
Cash and cash equivalents	52	79
Intercompany receivables	71,567	79,059
Income taxes receivable	0	4,635
Other, net	5,545	2,876
Total current assets	77,164	86,649
Property, plant and equipment, net of accumulated depreciation of $15,706 and $14,583	23,191	24,313
Investment in subsidiaries	2,631,567	2,197,918
Other long-term assets	58,695	55,077
Total long-term assets	2,713,453	2,277,308
Total assets	2,790,617	2,363,957
Liabilities and Stockholders’ Equity
Short-term debt	12,000	112,100
Short-term debt-affiliate	8,819	40,619
Current maturities of long-term debt	229,948	50,000
Accrued interest and taxes	8,124	5,239
Other current liabilities	29,549	25,450
Total current liabilities	288,440	233,408
Long-term debt	449,909	449,048
Other long-term liabilities	2,803	2,803
Total liabilities	741,152	685,259
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 85,834,874 shares)	1,429,941	1,150,552
Accumulated other comprehensive income (loss), net of tax	(79,183)	(99,377)
Retained earnings	698,707	627,523
Total PNMR common stockholders’ equity	2,049,465	1,678,698
Total liabilities and stockholders' equity	$ 2,790,617	$ 2,363,957

Schedule I - Condensed Financ_5

Schedule I - Condensed Financial Information of Parent Company - Balance Sheets Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	85,834,874	85,834,874
Common stock, shares outstanding (in shares)	79,653,624	79,653,624
PNM Resources
Condensed Financial Statements, Captions [Line Items]
Accumulated depreciation	$ 15,706	$ 14,583
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	85,834,874	85,834,874
Common stock, shares outstanding (in shares)	85,834,874	85,834,874

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - SEC Schedule, 12-09, Reserve, Allowance For Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 1,163	$ 1,406	$ 1,081
Charged to costs and expenses	3,527	2,835	3,360
Charged to other accounts	6,070	0	0
Write-offs and other	2,427	3,078	3,035
Balance at end of year	8,333	1,163	1,406
Public Service Company of New Mexico
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	1,163	1,406	1,081
Charged to costs and expenses	3,482	2,790	3,338
Charged to other accounts	6,070	0	0
Write-offs and other	2,382	3,033	3,013
Balance at end of year	8,333	1,163	1,406
Texas-New Mexico Power Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	0	0	0
Charged to costs and expenses	45	44	22
Charged to other accounts	0	0	0
Write-offs and other	45	44	22
Balance at end of year	$ 0	$ 0	$ 0