Texas New Mexico Power 10-K 1 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 20, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	PNM RESOURCES INC
Entity Central Index Key	1,108,426
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		79,653,624
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 3,046,751,118
Public Service Company of New Mexico
Document Information [Line Items]
Entity Registrant Name	PUBLIC SERVICE CO OF NEW MEXICO
Entity Central Index Key	81,023
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		39,117,799
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Texas-New Mexico Power Company
Document Information [Line Items]
Entity Registrant Name	TEXAS NEW MEXICO POWER CO
Entity Central Index Key	22,767
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		6,358
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	No

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Electric Operating Revenues	$ 1,445,003	$ 1,362,951	$ 1,439,082
Operating Expenses:
Cost of energy	407,479	380,596	464,649
Administrative and general	186,345	191,514	179,100
Energy production costs	137,450	146,187	176,752
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Depreciation and amortization	231,942	209,110	185,919
Transmission and distribution costs	71,576	66,227	69,157
Taxes other than income taxes	76,690	76,321	71,684
Total operating expenses	1,138,518	1,084,966	1,314,732
Operating income	306,485	277,985	124,350
Other Income and Deductions:
Interest income	15,916	22,293	6,498
Gains on available-for-sale securities	27,161	19,517	16,060
Other income	19,515	17,796	26,833
Other (deductions)	(15,693)	(13,784)	(12,728)
Net other income and deductions	46,899	45,822	36,663
Interest Charges	127,625	128,633	114,860
Earnings before Income Taxes	225,759	195,174	46,153
Income Taxes	130,340	63,278	15,075
Net Earnings	95,419	131,896	31,078
(Earnings) Attributable to Valencia Non-controlling Interest	(15,017)	(14,519)	(14,910)
Preferred Stock Dividend Requirements of Subsidiary	(528)	(528)	(528)
Net Earnings Attributable to Company	79,874	116,849	15,640
Net Earnings (Loss) Available for PNM Common Stock	$ 79,874	$ 116,849	$ 15,640
Net Earnings Attributable to PNMR per Common Share:
Basic (in dollars per share)	$ 1	$ 1.47	$ 0.20
Diluted (in dollars per share)	$ 1	$ 1.46	$ 0.20
Public Service Company of New Mexico
Electric Operating Revenues	$ 1,104,230	$ 1,035,913	$ 1,131,195
Operating Expenses:
Cost of energy	321,677	299,714	391,131
Administrative and general	172,446	169,209	161,953
Energy production costs	137,450	146,187	176,752
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Depreciation and amortization	147,017	133,447	115,717
Transmission and distribution costs	42,370	39,657	43,642
Taxes other than income taxes	43,709	44,598	41,149
Total operating expenses	891,705	847,823	1,097,815
Operating income	212,525	188,090	33,380
Other Income and Deductions:
Interest income	8,454	10,173	6,574
Gains on available-for-sale securities	27,161	19,517	16,060
Other income	13,527	12,088	19,347
Other (deductions)	(10,002)	(9,539)	(8,493)
Net other income and deductions	39,140	32,239	33,488
Interest Charges	82,697	87,469	79,950
Earnings before Income Taxes	168,968	132,860	(13,082)
Income Taxes	81,555	40,922	(12,758)
Net Earnings	87,413	91,938	(324)
(Earnings) Attributable to Valencia Non-controlling Interest	(15,017)	(14,519)	(14,910)
Preferred Stock Dividend Requirements of Subsidiary	(528)	(528)	(528)
Net Earnings Attributable to Company	72,396	77,419	(15,234)
Net Earnings (Loss) Available for PNM Common Stock	71,868	76,891	(15,762)
Texas-New Mexico Power Company
Electric Operating Revenues	340,773	327,038	307,887
Operating Expenses:
Cost of energy	85,802	80,882	73,518
Administrative and general	39,828	39,423	36,755
Depreciation and amortization	63,146	61,126	56,285
Transmission and distribution costs	29,206	26,570	25,515
Taxes other than income taxes	29,187	27,396	25,781
Total operating expenses	247,169	235,397	217,854
Operating income	93,604	91,641	90,033
Other Income and Deductions:
Other income	4,994	4,629	4,240
Other (deductions)	(1,443)	(1,427)	(504)
Net other income and deductions	3,551	3,202	3,736
Interest Charges	30,084	29,335	27,681
Earnings before Income Taxes	67,071	65,508	66,088
Income Taxes	31,512	23,836	24,125
Net Earnings Attributable to Company	$ 35,559	$ 41,672	$ 41,963

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Earnings	$ 95,419	$ 131,896	$ 31,078
Unrealized Gains on Available-for-Sale Securities:
Unrealized holding gains (losses) arising during the period, net of income tax (expense) benefit	17,233	474	6,688
Reclassification adjustment for (gains) included in net earnings (loss), net of income tax expense	(10,751)	(13,500)	(17,350)
Pension Liability Adjustment:
Experience gain (loss), net of income tax (expense) benefit	2,699	(11,282)	(2,679)
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, net of income tax (expense) benefit	3,948	3,356	3,620
Fair Value Adjustment for Cash Flow Hedges:
Change in fair market value, net of income tax (expense) benefit	612	(533)	44
Reclassification adjustment for (gains) losses included in net earnings (loss), net of income tax expense (benefit)	356	466	0
Total Other Comprehensive Income (Loss)	14,097	(21,019)	(9,677)
Comprehensive Income (Loss)	109,516	110,877	21,401
Comprehensive (Income) Attributable to Valencia Non-controlling Interest	(15,017)	(14,519)	(14,910)
Preferred Stock Dividend Requirements of Subsidiary	(528)	(528)	(528)
Comprehensive Income (Loss) Attributable to PNM	93,971	95,830	5,963
Public Service Company of New Mexico
Net Earnings	87,413	91,938	(324)
Unrealized Gains on Available-for-Sale Securities:
Unrealized holding gains (losses) arising during the period, net of income tax (expense) benefit	17,233	474	6,688
Reclassification adjustment for (gains) included in net earnings (loss), net of income tax expense	(10,751)	(13,500)	(17,350)
Pension Liability Adjustment:
Experience gain (loss), net of income tax (expense) benefit	2,699	(11,282)	(2,679)
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, net of income tax (expense) benefit	3,948	3,356	3,620
Fair Value Adjustment for Cash Flow Hedges:
Total Other Comprehensive Income (Loss)	13,129	(20,952)	(9,721)
Comprehensive Income (Loss)	100,542	70,986	(10,045)
Comprehensive (Income) Attributable to Valencia Non-controlling Interest	(15,017)	(14,519)	(14,910)
Preferred Stock Dividend Requirements of Subsidiary	(528)	(528)	(528)
Comprehensive Income (Loss) Attributable to PNM	$ 85,525	$ 56,467	$ (24,955)

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unrealized holding gains (losses) arising during the period, income tax (expense)	$ (10,927)	$ (304)	$ (4,310)
Reclassification adjustment for (gains) included in net earnings (loss), income tax expense	6,816	8,639	11,181
Experience gain (loss), income tax (expense) benefit	(919)	7,219	1,726
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, income tax (expense) benefit	(2,504)	(2,148)	(2,332)
Change in fair market value, income tax (expense)	(388)	341	(28)
Reclassification adjustment for (gains) losses included in net earnings (loss), income tax expense (benefit)	(225)	(298)	0
Public Service Company of New Mexico
Unrealized holding gains (losses) arising during the period, income tax (expense)	(10,927)	(304)	(4,310)
Reclassification adjustment for (gains) included in net earnings (loss), income tax expense	6,816	8,639	11,181
Experience gain (loss), income tax (expense) benefit	(919)	7,219	1,726
Reclassification adjustment for amortization of experience (gain) loss recognized as net periodic benefit cost, income tax (expense) benefit	$ (2,504)	$ (2,148)	$ (2,332)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities:
Net Earnings	$ 95,419	$ 131,896	$ 31,078
Net Earnings	79,874	116,849	15,640
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	268,194	242,033	222,861
Deferred income tax expense	130,528	63,805	16,451
Net unrealized (gains) losses on commodity derivatives	2,875	1,577	5,188
Realized (gains) on available-for-sale securities	(27,161)	(19,517)	(16,060)
Stock based compensation expense	6,194	5,634	4,863
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Allowance for equity funds used during construction	(9,516)	(4,949)	(10,430)
Other, net	2,329	3,060	3,934
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(1,846)	2,543	(3,298)
Materials, supplies, and fuel stock	1,473	(4,169)	(180)
Other current assets	32,298	(2,469)	29,370
Other assets	(5,486)	(42,864)	2,369
Accounts payable	14,468	3,159	(32,269)
Accrued interest and taxes	(327)	3,345	4,957
Other current liabilities	(6,513)	(12,509)	2,633
Other liabilities	(5,503)	29,868	(42,064)
Net cash flows from operating activities	524,462	415,454	386,874
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(500,461)	(600,076)	(558,589)
Proceeds from sales of available-for-sale securities	637,492	522,601	252,174
Purchases of available-for-sale securities	(650,284)	(538,383)	(262,548)
Return of principal on PVNGS lessor notes	0	8,547	21,694
Investments in NMRD	(4,077)	0	0
Disbursements from NMRD	12,415	0	0
Investment in Westmoreland Loan	0	(122,250)	0
Principal repayments on Westmoreland Loan	38,360	30,000	0
Other, net	392	186	2,741
Net cash flows from investing activities	(466,163)	(699,375)	(544,528)
Cash Flows From Financing Activities:
Short-term loan		100,000	50,000
Repayment of short-term loan	0	(150,000)	0
Revolving credit facilities borrowings (repayments), net	18,300	86,500	95,000
Long-term borrowings	317,000	603,500	463,605
Repayment of long-term debt	(274,070)	(303,793)	(333,066)
Proceeds from stock option exercise	1,739	7,028	5,619
Awards of common stock	(13,929)	(15,451)	(17,720)
Dividends paid	(77,792)	(70,623)	(64,251)
Valencia’s transactions with its owner	(17,742)	(17,006)	(17,049)
Amounts received under transmission interconnection arrangements	11,879	7,171	27
Refunds paid under transmission interconnection arrangements	(21,290)	(2,830)	(2,338)
Other, net	(2,942)	(2,104)	(4,396)
Net cash flows from financing activities	(58,847)	242,392	175,431
Change in Cash and Cash Equivalents	(548)	(41,529)	17,777
Cash and Cash Equivalents at Beginning of Period	4,522	46,051	28,274
Cash and Cash Equivalents at End of Period	3,974	4,522	46,051
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	120,955	115,043	103,382
Income taxes paid (refunded), net	625	(307)	(1,890)
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(25,261)	18,345	(19,080)
Contribution of utility plant to NMRD	24,829
Public Service Company of New Mexico
Cash Flows From Operating Activities:
Net Earnings	87,413	91,938	(324)
Net Earnings	72,396	77,419	(15,234)
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	180,500	166,047	150,538
Deferred income tax expense	82,549	53,119	(2,836)
Net unrealized (gains) losses on commodity derivatives	2,875	1,577	5,188
Realized (gains) on available-for-sale securities	(27,161)	(19,517)	(16,060)
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Allowance for equity funds used during construction	(8,664)	(4,163)	(10,430)
Other, net	2,615	3,046	2,794
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(419)	4,769	(2,515)
Materials, supplies, and fuel stock	3,542	(3,924)	381
Other current assets	32,775	1,127	23,693
Other assets	15,121	(23,880)	4,194
Accounts payable	9,736	5,614	(31,139)
Accrued interest and taxes	21,523	(9,601)	(5,343)
Other current liabilities	(11,099)	(12,136)	(275)
Other liabilities	(9,389)	20,119	(33,503)
Net cash flows from operating activities	408,953	289,146	251,834
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(309,142)	(445,464)	(404,840)
Proceeds from sales of available-for-sale securities	637,492	522,601	252,174
Purchases of available-for-sale securities	(650,284)	(538,383)	(262,548)
Return of principal on PVNGS lessor notes	0	8,547	21,694
Other, net	33	171	2,935
Net cash flows from investing activities	(321,901)	(452,528)	(390,585)
Cash Flows From Financing Activities:
Revolving credit facilities borrowings (repayments), net	(21,200)	61,000	0
Long-term borrowings	257,000	321,000	313,605
Repayment of long-term debt	(232,000)	(271,000)	(214,300)
Equity contribution from parent	0	28,142	175,000
Dividends paid	(61,223)	(4,670)	(94,968)
Valencia’s transactions with its owner	(17,742)	(17,006)	(17,049)
Amounts received under transmission interconnection arrangements	11,879	7,171	27
Refunds paid under transmission interconnection arrangements	(21,290)	(2,830)	(2,338)
Other, net	(1,692)	(1,239)	(3,568)
Net cash flows from financing activities	(86,268)	120,568	156,409
Change in Cash and Cash Equivalents	784	(42,814)	17,658
Cash and Cash Equivalents at Beginning of Period	324	43,138	25,480
Cash and Cash Equivalents at End of Period	1,108	324	43,138
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	77,960	82,514	69,936
Income taxes paid (refunded), net	(23,391)	(967)	(1,450)
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(11,792)	22,433	(17,469)
Texas-New Mexico Power Company
Cash Flows From Operating Activities:
Net Earnings	35,559	41,672	41,963
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	64,939	62,866	57,909
Deferred income tax expense	27,275	12,662	20,883
Allowance for equity funds used during construction	(900)	(800)	0
Allowance for equity funds used during construction and other, net	(1,120)	(772)	18
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(1,427)	(2,226)	(783)
Materials, supplies, and fuel stock	(2,069)	(245)	(561)
Other current assets	(1,253)	(621)	3,928
Other assets	(20,967)	(19,126)	(2,310)
Accounts payable	2,419	(2,040)	(1,782)
Accrued interest and taxes	(15,962)	12,690	4,317
Other current liabilities	(2,236)	298	1,019
Other liabilities	1,334	6,822	(9,823)
Net cash flows from operating activities	86,492	111,980	114,778
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(145,495)	(122,518)	(124,584)
Net cash flows from investing activities	(145,495)	(122,518)	(124,584)
Cash Flows From Financing Activities:
Revolving credit facilities borrowings (repayments), net	0	(59,000)	54,000
Short-term borrowings (repayments) - affiliate, net	(4,600)	(7,200)	(10,900)
Long-term borrowings	60,000	60,000	0
Equity contribution from parent	50,000	50,000	0
Dividends paid	(44,389)	(31,817)	(33,248)
Other, net	(979)	(775)	(46)
Net cash flows from financing activities	60,032	11,208	9,806
Change in Cash and Cash Equivalents	1,029	670	0
Cash and Cash Equivalents at Beginning of Period	671	1	1
Cash and Cash Equivalents at End of Period	1,700	671	1
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	29,251	26,766	26,216
Income taxes paid (refunded), net	21,436	660	290
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	$ (15,737)	$ (1,271)	$ (5)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 3,974,000	$ 4,522,000
Accounts receivable, net of allowance for uncollectible accounts	90,473,000	87,012,000
Unbilled revenues	54,055,000	58,284,000
Other receivables	17,582,000	28,245,000
Current portion of Westmoreland Loan	3,576,000	38,360,000
Materials, supplies, and fuel stock	66,502,000	73,027,000
Regulatory assets	2,933,000	3,855,000
Commodity derivative instruments	1,088,000	5,224,000
Income taxes receivable	6,879,000	6,066,000
Other current assets	47,358,000	73,444,000
Total current assets	294,420,000	378,039,000
Other Property and Investments:
Long-term portion of Westmoreland Loan	53,064,000	56,640,000
Available-for-sale securities	323,524,000	272,977,000
Equity investment in NMRD	16,510,000	0
Other investments	503,000	547,000
Non-utility property	3,404,000	3,404,000
Total other property and investments	397,005,000	333,568,000
Utility Plant:
Plant in service, held for future use, and to be abandoned	7,238,285,000	6,944,534,000
Less accumulated depreciation and amortization	2,592,692,000	2,334,938,000
Net plant in service and plant held for future use	4,645,593,000	4,609,596,000
Construction work in progress	245,933,000	208,206,000
Nuclear fuel, net of accumulated amortization	88,701,000	86,913,000
Net utility plant	4,980,227,000	4,904,715,000
Deferred Charges and Other Assets:
Regulatory assets	600,672,000	501,223,000
Goodwill	278,297,000	278,297,000
Commodity derivative instruments	3,556,000	0
Other deferred charges	91,926,000	75,238,000
Total deferred charges and other assets	974,451,000	854,758,000
Total assets	6,646,103,000	6,471,080,000
Current Liabilities:
Short-term debt	305,400,000	287,100,000
Current installments of long-term debt	256,895,000	273,348,000
Accounts payable	121,383,000	86,705,000
Customer deposits	11,028,000	11,374,000
Accrued interest and taxes	62,357,000	61,871,000
Regulatory liabilities	2,309,000	3,609,000
Commodity derivative instruments	1,182,000	2,339,000
Dividends declared	21,240,000	19,448,000
Other current liabilities	53,850,000	59,314,000
Total current liabilities	835,644,000	805,108,000
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	2,180,750,000	2,119,364,000
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	547,210,000	940,650,000
Regulatory liabilities	933,578,000	455,649,000
Asset retirement obligations	146,679,000	127,519,000
Accrued pension liability and postretirement benefit cost	94,003,000	125,844,000
Commodity derivative instruments	3,556,000	0
Other deferred credits	131,706,000	140,545,000
Total deferred credits and other liabilities	1,856,732,000	1,790,207,000
Total liabilities	4,873,126,000	4,714,679,000
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)	11,529,000	11,529,000
Company common stockholders’ equity:
Common stock outstanding	1,157,665,000	1,163,661,000
Accumulated other comprehensive income (loss), net of income taxes	(95,940,000)	(92,451,000)
Retained earnings	633,528,000	604,742,000
Total PNMR common stockholders’ equity	1,695,253,000	1,675,952,000
Non-controlling interest in Valencia	66,195,000	68,920,000
Total equity	1,761,448,000	1,744,872,000
Total liabilities and stockholders' equity	6,646,103,000	6,471,080,000
Public Service Company of New Mexico
Current Assets:
Cash and cash equivalents	1,108,000	324,000
Accounts receivable, net of allowance for uncollectible accounts	67,227,000	65,003,000
Unbilled revenues	43,869,000	48,289,000
Other receivables	14,541,000	25,514,000
Affiliate receivables	9,486,000	8,886,000
Materials, supplies, and fuel stock	60,859,000	64,401,000
Regulatory assets	2,139,000	3,442,000
Commodity derivative instruments	1,088,000	5,224,000
Income taxes receivable	3,410,000	25,807,000
Other current assets	39,904,000	67,355,000
Total current assets	243,631,000	314,245,000
Other Property and Investments:
Available-for-sale securities	323,524,000	272,977,000
Other investments	283,000	316,000
Non-utility property	96,000	96,000
Total other property and investments	323,903,000	273,389,000
Utility Plant:
Plant in service, held for future use, and to be abandoned	5,501,070,000	5,359,211,000
Less accumulated depreciation and amortization	2,029,534,000	1,809,528,000
Net plant in service and plant held for future use	3,471,536,000	3,549,683,000
Construction work in progress	204,079,000	158,122,000
Nuclear fuel, net of accumulated amortization	88,701,000	86,913,000
Net utility plant	3,764,316,000	3,794,718,000
Deferred Charges and Other Assets:
Regulatory assets	459,239,000	365,413,000
Goodwill	51,632,000	51,632,000
Commodity derivative instruments	3,556,000	0
Other deferred charges	75,286,000	68,149,000
Total deferred charges and other assets	589,713,000	485,194,000
Total assets	4,921,563,000	4,867,546,000
Current Liabilities:
Short-term debt	39,800,000	61,000,000
Short-term debt - affiliate	0	0
Current installments of long-term debt	23,000	231,880,000
Accounts payable	77,094,000	55,566,000
Affiliate payables	22,875,000	23,183,000
Customer deposits	11,028,000	11,374,000
Accrued interest and taxes	33,945,000	34,819,000
Regulatory liabilities	784,000	3,517,000
Commodity derivative instruments	1,182,000	2,339,000
Dividends declared	132,000	132,000
Other current liabilities	31,633,000	33,551,000
Total current liabilities	218,496,000	457,361,000
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	1,657,887,000	1,399,489,000
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	449,012,000	748,666,000
Regulatory liabilities	754,441,000	423,701,000
Asset retirement obligations	145,707,000	126,601,000
Accrued pension liability and postretirement benefit cost	86,124,000	114,427,000
Commodity derivative instruments	3,556,000	0
Other deferred credits	106,442,000	118,980,000
Total deferred credits and other liabilities	1,545,282,000	1,532,375,000
Total liabilities	3,421,665,000	3,389,225,000
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)	11,529,000	11,529,000
Company common stockholders’ equity:
Common stock outstanding	1,264,918,000	1,264,918,000
Accumulated other comprehensive income (loss), net of income taxes	(97,093,000)	(92,428,000)
Retained earnings	254,349,000	225,382,000
Total PNMR common stockholders’ equity	1,422,174,000	1,397,872,000
Non-controlling interest in Valencia	66,195,000	68,920,000
Total equity	1,488,369,000	1,466,792,000
Total liabilities and stockholders' equity	4,921,563,000	4,867,546,000
Texas-New Mexico Power Company
Current Assets:
Cash and cash equivalents	1,700,000	671,000
Accounts receivable, net of allowance for uncollectible accounts	23,246,000	22,009,000
Unbilled revenues	10,186,000	9,995,000
Other receivables	2,860,000	2,090,000
Affiliate receivables	336,000	0
Materials, supplies, and fuel stock	5,643,000	8,626,000
Regulatory assets	794,000	413,000
Other current assets	1,131,000	1,031,000
Total current assets	45,896,000	44,835,000
Other Property and Investments:
Other investments	220,000	231,000
Non-utility property	2,240,000	2,240,000
Total other property and investments	2,460,000	2,471,000
Utility Plant:
Plant in service, held for future use, and to be abandoned	1,504,778,000	1,380,584,000
Less accumulated depreciation and amortization	460,858,000	429,397,000
Net plant in service and plant held for future use	1,043,920,000	951,187,000
Construction work in progress	34,350,000	16,978,000
Net utility plant	1,078,270,000	968,165,000
Deferred Charges and Other Assets:
Regulatory assets	141,433,000	135,810,000
Goodwill	226,665,000	226,665,000
Other deferred charges	6,046,000	5,277,000
Total deferred charges and other assets	374,144,000	367,752,000
Total assets	1,500,770,000	1,383,223,000
Current Liabilities:
Short-term debt - affiliate	0	4,600,000
Accounts payable	29,812,000	16,709,000
Affiliate payables	667,000	3,793,000
Accrued interest and taxes	29,619,000	45,581,000
Regulatory liabilities	1,525,000	92,000
Other current liabilities	2,450,000	2,134,000
Total current liabilities	64,073,000	72,909,000
Long-term Debt, net of Unamortized Premiums, Discounts, and Debt Issuance Costs	480,620,000	420,875,000
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	126,415,000	245,785,000
Regulatory liabilities	179,137,000	31,948,000
Asset retirement obligations	793,000	754,000
Accrued pension liability and postretirement benefit cost	7,879,000	11,417,000
Other deferred credits	7,448,000	6,300,000
Total deferred credits and other liabilities	321,672,000	296,204,000
Total liabilities	866,365,000	789,988,000
Commitments and Contingencies (See Note 16)
Company common stockholders’ equity:
Common stock outstanding	64,000	64,000
Paid-in-capital	504,166,000	454,166,000
Retained earnings	130,175,000	139,005,000
Total PNMR common stockholders’ equity	634,405,000	593,235,000
Total liabilities and stockholders' equity	$ 1,500,770,000	$ 1,383,223,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for uncollectible accounts	$ 1,081	$ 1,209
Accumulated depreciation, nuclear fuel	$ 43,524	$ 43,905
Cumulative preferred stock of subsidiary, stated value (in dollars per share)	$ 100	$ 100
Cumulative preferred stock of subsidiary, shares authorized	10,000,000	10,000,000
Cumulative preferred stock of subsidiary, shares issued	115,293	115,293
Cumulative preferred stock of subsidiary, shares outstanding	115,293	115,293
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	79,653,624	79,653,624
Common stock, shares outstanding	79,653,624	79,653,624
Public Service Company of New Mexico
Allowance for uncollectible accounts	$ 1,081	$ 1,209
Accumulated depreciation, nuclear fuel	$ 43,524	$ 43,905
Cumulative preferred stock of subsidiary, stated value (in dollars per share)	$ 100	$ 100
Cumulative preferred stock of subsidiary, shares authorized	10,000,000	10,000,000
Cumulative preferred stock of subsidiary, shares issued	115,293	115,293
Cumulative preferred stock of subsidiary, shares outstanding	115,293	115,293
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	39,117,799	39,117,799
Common stock, shares outstanding	39,117,799	39,117,799
Texas-New Mexico Power Company
Cumulative preferred stock of subsidiary, shares authorized	1,000,000
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized	12,000,000	12,000,000
Common stock, shares issued	6,358	6,358
Common stock, shares outstanding	6,358	6,358

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Total Stockholders' Equity	Common Stock	AOCI	Retained Earnings	Non- controlling Interest in Valencia	Public Service Company of New Mexico	Public Service Company of New MexicoTotal Stockholders' Equity	Public Service Company of New MexicoCommon Stock	Public Service Company of New MexicoAOCI	Public Service Company of New MexicoRetained Earnings	Public Service Company of New MexicoNon- controlling Interest in Valencia	Texas-New Mexico Power Company	Texas-New Mexico Power CompanyCommon Stock	Texas-New Mexico Power CompanyPaid-in Capital	Texas-New Mexico Power CompanyRetained Earnings
Balance at Dec. 31, 2014	$ 1,795,092	$ 1,721,546	$ 1,173,845	$ (61,755)	$ 609,456	$ 73,546	$ 1,336,402	$ 1,262,856	$ 1,061,776	$ (61,755)	$ 262,835	$ 73,546
Beginning Balance at Dec. 31, 2014				(61,755)						(61,755)			$ 524,665	$ 64	$ 404,166	$ 120,435
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	31,078	16,168			16,168	14,910	(324)	(15,234)			(15,234)	14,910
Net Earnings	15,640						(15,234)						41,963			41,963
Total other comprehensive income (loss)	(9,677)	(9,677)		(9,677)			(9,721)	(9,721)		(9,721)
Equity contribution from parent							175,000						0
Subsidiary preferred stock dividends/dividends declared on preferred stock	(528)	(528)			(528)		(528)	(528)			(528)
Dividends declared on common stock	(65,316)	(65,316)			(65,316)		(94,440)	(94,440)			(94,440)		(33,248)			(33,248)
Proceeds from stock option exercise	5,619	5,619	5,619
Awards of common stock	(17,720)	(17,720)	(17,720)	0	0	0
Excess tax (shortfall) from stock-based payment arrangements	(142)	(142)	(142)
Stock based compensation expense	4,863	4,863	4,863
Valencia’s transactions with its owner	(17,049)					(17,049)	(17,049)
Equity contributions from parent							175,000	175,000	175,000	0	0
Balance at Dec. 31, 2015	1,726,220	1,654,813	1,166,465	(71,432)	559,780	71,407	1,389,340	1,317,933	1,236,776	(71,476)	152,633	71,407
Ending Balance at Dec. 31, 2015				(71,432)						(71,476)			533,380	64	404,166	129,150
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	131,896	117,377			117,377	14,519	91,938	77,419			77,419	14,519
Net Earnings	116,849						77,419						41,672			41,672
Total other comprehensive income (loss)	(21,019)	(21,019)		(21,019)			(20,952)	(20,952)		(20,952)
Equity contribution from parent							28,142						50,000		50,000
Subsidiary preferred stock dividends/dividends declared on preferred stock	(528)	(528)			(528)		(528)	(528)			(528)
Dividends declared on common stock	(71,887)	(71,887)			(71,887)		(4,142)	(4,142)			(4,142)		(31,817)			(31,817)
Proceeds from stock option exercise	7,028	7,028	7,028
Awards of common stock	(15,451)	(15,451)	(15,451)	0	0	0
Excess tax (shortfall) from stock-based payment arrangements	(15)	(15)	(15)
Stock based compensation expense	5,634	5,634	5,634
Valencia’s transactions with its owner	(17,006)					(17,006)	(17,006)
Equity contributions from parent							28,142	28,142	28,142
Balance at Dec. 31, 2016	1,744,872	1,675,952	1,163,661	(92,451)	604,742	68,920	1,466,792	1,397,872	1,264,918	(92,428)	225,382	68,920
Ending Balance at Dec. 31, 2016	1,675,952			(92,451)			1,397,872			(92,428)			593,235	64	454,166	139,005
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment (Note 13) | Accounting Standards Update 2016-09	10,382	10,382			10,382
Balance at January 1, 2017, as adjusted	1,755,254	1,686,334	1,163,661	(92,451)	615,124	68,920
Reclassification of stranded income taxes resulting from tax reform (Note 11)	(17,586)			(17,586)	17,586		(17,794)			(17,794)	17,794
Net earnings	95,419	80,402			80,402	15,017	87,413	72,396			72,396	15,017
Net Earnings	79,874						72,396						35,559			35,559
Total other comprehensive income (loss)	14,097	14,097		14,097	0		13,129	13,129		13,129
Equity contribution from parent							0						50,000		50,000
Subsidiary preferred stock dividends/dividends declared on preferred stock	(528)	(528)			(528)		(528)	(528)			(528)
Dividends declared on common stock	(79,056)	(79,056)			(79,056)		(60,695)	(60,695)			(60,695)		(44,389)			(44,389)
Proceeds from stock option exercise	1,739	1,739	1,739
Awards of common stock	(13,929)	(13,929)	(13,929)	0	0	0
Stock based compensation expense	6,194	6,194	6,194
Valencia’s transactions with its owner	(17,742)					(17,742)	(17,742)
Balance at Dec. 31, 2017	1,761,448	$ 1,695,253	$ 1,157,665	(95,940)	$ 633,528	$ 66,195	1,488,369	$ 1,422,174	$ 1,264,918	(97,093)	$ 254,349	$ 66,195
Ending Balance at Dec. 31, 2017	$ 1,695,253			$ (95,940)			$ 1,422,174			$ (97,093)			$ 634,405	$ 64	$ 504,166	$ 130,175

Summary of the Business and Sig

Summary of the Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
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 of energy and energy-related businesses. 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. 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. For discussion purposes, 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 2016 and 2015 Consolidated Financial Statements and Notes thereto have been reclassified to conform to the 2017 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 9) and, through January 15, 2016, the PVNGS Capital Trust. 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 shared services’ administrative and general expenses, which represent costs that are primarily driven by corporate level activities, are charged to the business segments. These services are billed at cost. Other significant intercompany transactions between PNMR, PNM, and TNMP include interest and income tax sharing payments, as well as equity transactions. All intercompany transactions and balances have been eliminated. See Note 3. 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, even for programs that do not otherwise qualify for recognition of regulatory assets and liabilities. 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 4. 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. In connection with the adoption of Senate Bill 7 by the Texas Legislature in 1999 that deregulated electric utilities operating within ERCOT, TNMP was allowed to recover its stranded costs through the CTC and to recover a carrying charge on the CTC. The amounts yet to be collected are recorded as regulatory assets by TNMP. TNMP’s calculation of allowable carrying charges on stranded costs recoverable from its transmission and distribution customers is based on a Texas Supreme Court ruling and the PUCT’s application of that ruling. TNMP estimates the CTC will be fully recovered in November 2020. Cash and Cash Equivalents Investments in highly liquid investments with original maturities of three months or less at the date of purchase are considered cash equivalents. See New Accounting Pronouncements below. Utility Plant Utility plant is stated at original cost, which 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 contributions in aid of construction (“CIAC”), from customers to pay for all or part of certain construction projects to extent that 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 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 of non-utility property 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 2017 2016 2015 PNM Electric plant 2.52 % 2.33 % 2.27 % Common, intangible, and general plant 8.36 % 5.40 % 4.66 % TNMP 3.57 % 3.66 % 3.65 % 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, 2017 , 2016 , and 2015 , PNM recorded $6.3 million , $5.3 million , and $7.8 million of debt AFUDC and $8.7 million , $4.2 million , and $10.4 million of equity AFUDC. TNMP recorded $1.2 million , $0.9 million , and $0.5 million of debt AFUDC and $0.9 million , $0.8 million , and zero of equity AFUDC. Capitalized Interest The Company capitalizes interest on its construction projects and major computer software projects not subject to the computation of AFUDC. Capitalized interest is recorded in interest charges. Interest was capitalized at the overall weighted average borrowing rate of 5.9% , 6.1% , and 6.6% for 2017 , 2016 , and 2015 . In 2017 , 2016 , and 2015 , capitalized interest was $1.3 million , $1.8 million , and $1.5 million for PNMR consolidated; $0.6 million , $0.8 million , and $0.8 million for PNM; and less than $0.1 million , $0.1 million , and $0.1 million for TNMP. 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 2017 2016 2017 2016 2017 2016 (In thousands) Coal $ 16,714 $ 19,940 $ 16,714 $ 19,940 $ — $ — Materials and supplies 49,788 53,087 44,145 44,461 5,643 8,626 $ 66,502 $ 73,027 $ 60,859 $ 64,401 $ 5,643 $ 8,626 Investments In 1985 and 1986, PNM entered into eleven operating leases for interests in certain PVNGS generation facilities (Note 7). The 10.3% and 10.15% lessor notes that were issued by the owners of the assets subject to these leases were subsequently purchased and held by the PVNGS Capital Trust, which was consolidated by PNM. The PVNGS Capital Trust held certain of the lessor notes to their maturities in January 2015 and January 2016. Upon final maturity of the lessor notes, the PVNGS Capital Trust ceased to exist. The PVNGS lessor notes were carried at amortized cost. 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). All of these investments are classified as available-for-sale. PNM evaluates the securities for impairment on an on-going basis. Since third party investment managers have sole discretion over the purchase and sales of the securities, PNM records a realized loss as an impairment for any security that has a market value that is less than cost at the end of each quarter. For the years ended December 31, 2017 , 2016 , and 2015 , PNM recorded impairment losses on the available-for-sale securities held in the NDT and coal mine reclamation trusts of $7.1 million , $13.9 million , and $10.4 million . No gains or losses are deferred as regulatory assets or liabilities. Through December 31, 2017 , unrealized gains on these investments, net of related tax effects, are included in OCI and AOCI. The available-for-sale securities are primarily comprised of international, United States, state, and municipal government obligations and corporate debt and equity securities. 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. See New Accounting Pronouncements below. Investment in NM Renewable Development, LLC On September 22, 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 2017, PNMR Development and AEP OnSite Partners each made cash contributions of $4.1 million to NMRD for its construction activities. At December 31, 2017, NMRD’s renewable energy capacity under contract is 31.8 MW, which includes 11.8 MW of solar PV facilities in operation, consisting of 10 MW required to supply energy to a new data center in PNM’s service territory (Note 17) and 1.8 MW to supply energy to Columbus Electric Cooperative located in southwest New Mexico, and 20 MW of solar PV under construction. 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. For the year ended December 31, 2017, NMRD revenues, expenses, and net income were each less than $0.1 million . At December 31, 2017, NMRD had $6.0 million in cash, $30.9 million of property, plant, and equipment, $3.9 million in accounts payable, and $33.0 million of owners’ equity. NMRD anticipates it will complete the remaining 20 MW of solar PV facilities under construction by mid-2018, which is anticipated to be funded by additional equity contributions. Goodwill Under GAAP, 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 18. Asset Impairment Tangible long-lived assets 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. 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 the daily generation volumes, estimated customer usage by class, line losses, and applicable customer rates reflecting historical trends and experience. PNM’s wholesale electricity sales are recorded as electric operating revenues and the wholesale electricity purchases are recorded as costs of energy sold. In accordance with GAAP, 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 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 New Accounting Pronouncements below. Accounts Receivable and Allowance for Uncollectible Accounts 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. The Company calculates the allowance for uncollectible accounts based on historical experience and estimated default rates. The accounts receivable balances are reviewed monthly and adjustments to the allowance for uncollectible accounts and bad debt expense are made as necessary. Amounts that are deemed uncollectible are written off. 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 debt premium, discount, and expense related to long-term are reflected as part of the debt liabilities 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. GAAP requires that changes in the derivatives’ fair value be recognized currently in earnings unless specific hedge accounting criteria are met. For qualifying hedges, an entity must formally document, designate, and assess the effectiveness of transactions that receive hedge accounting. GAAP provides that the effective portion of the gain or loss on a derivative instrument designated and qualifying as a cash flow hedging instrument be reported as a component of AOCI and be reclassified into earnings in the period during which the hedged forecasted transaction affects earnings. The results of hedge ineffectiveness and the portion of the change in fair value of a derivative that an entity has chosen to exclude from hedge effectiveness are required to be presented in current earnings. See Note 6 and Note 8. 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. Decommissioning and Reclamation Costs PNM owns and leases nuclear and fossil-fuel generating facilities. In accordance with GAAP, 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 extended PVNGS license periods. PVNGS Units 1 and 2 are included in PNM’s retail rates and PVNGS Unit 3 was excluded through December 31, 2017, but is included beginning in 2018. See Note 15 and Note 16. See Note 17 for information concerning the treatment of nuclear decommissioning for the leased portions of PVNGS in the NMPRC’s order in PNM’s NM 2015 Rate Case and 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 in some instances 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, 2017 , 2016 , and 2015 , as well as the amounts of environmental liabilities at December 31, 2017 and 2016 were insignificant. Pension and Other Postretirement Benefits See Note 12 for a discussion of pension and postretirement benefits expense, including a discussion of the actuarial assumptions. Stock-Based Compensation See Note 13 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. In accordance with GAAP, 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. GAAP requires that rate-regulated enterprises 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 liabilities and assets 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 related to rate regulated assets and amortizes them over the estimated useful lives of those assets. See Note 11 for additional information, including a discussion of the impacts of tax reform under the Tax Cuts and Jobs Act enacted on December 22, 2017. 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. GAAP also provides that certain unusual or infrequently occurring items, as well as adjustments due to enactment of new tax laws, be excluded from the estimated annual effective tax rate calculation. Excise Taxes The Company pays certain fees or taxes which are either considered to be an excise tax or similar to an excise tax. Substantially all of these taxes are recorded on a net basis in the Consolidated Statements of Earnings. 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 2014-09 – Revenue from Contracts with Customers (Topic 606) In May 2014, the FASB issued ASU 2014-09. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also revises the disclosure requirements regarding revenue. Since the issuance of ASU 2014-09, the FASB issued a one -year deferral of the effective date and has issued additional ASUs that clarify implementation guidance regarding principal versus agent considerations, licensing, and identifying performance obligations, as well as adding certain additional practical expedients. The new standard will replace most existing revenue recognition guidance in GAAP. ASU 2014-09 can be applied retrospectively to each prior period presented or on a modified retrospective basis with a cumulative effect adjustment to retained earnings on the date of adoption. The Company will adopt ASU 2014-09 effective as of January 1, 2018, its required effective date, using the modified retrospective method of adoption. The Company has monitored the activities of the FASB and other non-authoritative groups regarding certain issues specific to the power and utility industry. These specific issues include the impacts of the new guidance on accounting for CIAC and the presentation of revenues associated with “alternative revenue programs,” which primarily result from certain of the Company’s approved rate rider programs. The appropriate authoritative accounting organization has given tentative approval of the utility industry’s positions on all power and utility specific issues. The Company has substantially completed its assessment of ASU 2014-09 and does not anticipate a cumulative effect adjustment on the date of adoption or changes to the amount and timing of its current revenue recognition practices. The Company believes its existing policies, processes, information technology infrastructure, and internal controls properly capture and report revenue in accordance with ASU 2014-09. Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU 2016-01, which makes targeted improvements to GAAP regarding financial instruments. ASU 2016-01 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 net earnings rather than in OCI. Unrealized gains, net of income taxes, recorded in AOCI related to equity securities will be reclassified to retained earnings as a cumulative effect adjustment. ASU 2016-01 also revises certain presentation and disclosure requirements. Under ASU 2016-01, accounting for investments in debt securities remains essentially unchanged. PNM currently classifies all investments held in the NDT and coal mine reclamation trusts as available-for-sale securities. Unrealized losses on these securities are recorded immediately through earnings and unrealized gains are recorded in AOCI until the securities are sold. The Company will adopt ASU 2016-01 effective as of January 1, 2018, its required effective date. On January 1, 2018, PNMR and PNM will record a cumulative effect adjustment, net of income taxes, to increase retained earnings by $11.1 million with an offset to AOCI. Future changes in the fair value of equity securities will be recorded in earnings. Accounting Standards Update 2016-02 – Leases (Topic 842) In February 2016, the FASB issued ASU 2016-02 to provide guidance on the recognition, measurement, presentation, and disclosure of leases. ASU 2016-02 will require that a liability be recorded on the balance sheet for all leases, based on the present value of future lease obligations. A corresponding right-of-use asset will also be recorded. Amortization of the lease obligation and the right-of-use asset for certain leases, primarily those classified as operating leases, will be on a straight-line basis, which is not expected to have a significant impact on the statements of earnings, whereas other leases will be required to be accounted for as financing arrangements similar to the accounting treatment for capital leases under current GAAP. ASU 2016-02 also revises certain disclosure requirements. At adoption, ASU 2016-02 requires that leases be recognized and measured as of the earliest period presented using a modified retrospective approach with all periods presented being restated and presented under the new guidance. The ASU allows entities to apply certain practical expedients to arrangements that exist upon adoption or expired during the periods presented. As further discussed in Note 7, the Company has operating leases of office buildings, vehicles, and equipment. The Company also routinely enters into land easements and right-of-way agreements. PNM also has operating lease interests in PVNGS Units 1 and 2 that will expire in January 2023 and 2024. The Company, along with others in the utility industry, is continuing to monitor the activities of the FASB and other non-authoritative groups regarding industry specific issues for further clarification. The Company has formed a project team, conducted outreach activities across its lines of business, and made significant progress in identifying arrangements, in addition to its existing operating lease arrangements, that may be classified as leases under ASU 2016-02. It is likely the arrangements currently classified as leases will continue to be recognized as leases under ASU 2016-02. It is possible that other contractual arrangements not previously meeting the lease definition may contain elements that qualify as leases and that previously identified operating leases may be classified as financing leases under ASU 2016-02. The Company is in the process of analyzing each of the identified contractual arrangement to determine if it contains lease elements under the new standard and quantifying the potential impacts of identified lease arrangements. The Company is also evaluating the practical expedients, if any, it will elect upon adoption. The Company anticipates this process will continue into 2018. The Company will adopt this standard effective as of January 1, 2019, its required effective da

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
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 assets as well as the capacity excluded from retail rates. FERC has jurisdiction over wholesale 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. 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 and NM Capital are also included in Corporate and Other. 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. 2017 PNM TNMP Corporate and Other PNMR Consolidated (In thousands) Electric operating revenues $ 1,104,230 $ 340,773 $ — $ 1,445,003 Cost of energy 321,677 85,802 — 407,479 Utility margin 782,553 254,971 — 1,037,524 Other operating expenses 423,011 98,221 (22,135 ) 499,097 Depreciation and amortization 147,017 63,146 21,779 231,942 Operating income 212,525 93,604 356 306,485 Interest income 8,454 — 7,462 15,916 Other income (deductions) 30,686 3,551 (3,254 ) 30,983 Interest charges (82,697 ) (30,084 ) (14,844 ) (127,625 ) Segment earnings (loss) before income taxes 168,968 67,071 (10,280 ) 225,759 Income taxes 81,555 31,512 17,273 130,340 Segment earnings (loss) 87,413 35,559 (27,553 ) 95,419 Valencia non-controlling interest (15,017 ) — — (15,017 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ 71,868 $ 35,559 $ (27,553 ) $ 79,874 At December 31, 2017: Total Assets $ 4,921,563 $ 1,500,770 $ 223,770 $ 6,646,103 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2016 PNM TNMP Corporate and Other PNMR Consolidated Electric operating revenues $ 1,035,913 $ 327,038 $ — $ 1,362,951 Cost of energy 299,714 80,882 — 380,596 Utility margin 736,199 246,156 — 982,355 Other operating expenses 414,662 93,389 (12,791 ) 495,260 Depreciation and amortization 133,447 61,126 14,537 209,110 Operating income (loss) 188,090 91,641 (1,746 ) 277,985 Interest income 10,173 — 12,120 22,293 Other income (deductions) 22,066 3,202 (1,739 ) 23,529 Interest charges (87,469 ) (29,335 ) (11,829 ) (128,633 ) Segment earnings (loss) before income taxes 132,860 65,508 (3,194 ) 195,174 Income taxes (benefit) 40,922 23,836 (1,480 ) 63,278 Segment earnings (loss) 91,938 41,672 (1,714 ) 131,896 Valencia non-controlling interest (14,519 ) — — (14,519 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ 76,891 $ 41,672 $ (1,714 ) $ 116,849 At December 31, 2016: Total Assets $ 4,867,546 $ 1,383,223 $ 220,311 $ 6,471,080 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2015 PNM TNMP Corporate and Other PNMR Consolidated Electric operating revenues $ 1,131,195 $ 307,887 $ — $ 1,439,082 Cost of energy 391,131 73,518 — 464,649 Utility margin 740,064 234,369 — 974,433 Other operating expenses 590,967 88,051 (14,854 ) 664,164 Depreciation and amortization 115,717 56,285 13,917 185,919 Operating income 33,380 90,033 937 124,350 Interest income 6,574 — (76 ) 6,498 Other income (deductions) 26,914 3,736 (485 ) 30,165 Interest charges (79,950 ) (27,681 ) (7,229 ) (114,860 ) Segment earnings (loss) before income taxes (13,082 ) 66,088 (6,853 ) 46,153 Income taxes (benefit) (12,758 ) 24,125 3,708 15,075 Segment earnings (loss) (324 ) 41,963 (10,561 ) 31,078 Valencia non-controlling interest (14,910 ) — — (14,910 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ (15,762 ) $ 41,963 $ (10,561 ) $ 15,640 At December 31, 2015: Total Assets $ 4,599,344 $ 1,297,139 $ 112,845 $ 6,009,328 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, 2017 2016 2015 REP A 16 % 16 % 16 % REP B 11 % 11 % 13 % REP C 10 % 11 % 11 %

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions PNMR, PNM, and TNMP are considered related parties as defined under GAAP, 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. 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 6 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, 2017 2016 2015 (In thousands) Services billings: PNMR to PNM $ 97,914 $ 94,606 $ 90,827 PNMR to TNMP 31,095 28,907 28,109 PNM to TNMP 382 427 554 TNMP to PNMR 141 66 41 TNMP to PNM 154 172 — Interest billings: PNMR to PNM 21 11 54 PNM to PNMR 220 150 110 PNMR to TNMP 133 132 276 Income tax sharing payments: PNMR to TNMP — — — PNMR to PNM 23,391 — 1,450 TNMP to PNMR 20,686 — —

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2017
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, 2017 2016 2017 2016 Assets: (In thousands) Current: FPPAC $ 363 $ 1,451 $ — $ — Energy efficiency costs 1,776 1,991 794 413 2,139 3,442 794 413 Non-Current: CTC, including carrying charges — — 26,998 36,328 Coal mine reclamation costs 16,462 22,383 — — Deferred income taxes 59,220 62,918 9,621 9,932 Loss on reacquired debt 22,744 24,404 32,808 34,107 Pension and OPEB 222,774 249,286 26,153 27,661 Shutdown of SJGS Units 2 and 3 125,539 — — — Hurricane recovery costs — — 6,640 — AMS surcharge — — 27,903 14,669 AMS retirement costs — — 8,948 11,086 Other 12,500 6,422 2,362 2,027 459,239 365,413 141,433 135,810 Total regulatory assets $ 461,378 $ 368,855 $ 142,227 $ 136,223 PNM TNMP December 31, December 31, 2017 2016 2017 2016 Liabilities: (In thousands) Current: Renewable energy rider $ (779 ) $ (3,411 ) $ — $ — Other (5 ) (106 ) (1,525 ) (92 ) (784 ) (3,517 ) (1,525 ) (92 ) Non-Current: Cost of removal (256,493 ) (297,087 ) (26,541 ) (26,900 ) Deferred income taxes (445,390 ) (62,920 ) (148,455 ) (2,644 ) PVNGS ARO (24,889 ) (30,621 ) — — Renewable energy tax benefits (21,383 ) (22,540 ) — — Nuclear spent fuel reimbursements (5,518 ) (8,875 ) — — Pension and OPEB — — (3,442 ) (1,955 ) Other (768 ) (1,658 ) (699 ) (449 ) (754,441 ) (423,701 ) (179,137 ) (31,948 ) Total regulatory liabilities $ (755,225 ) $ (427,218 ) $ (180,662 ) $ (32,040 ) 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); and PVNGS ARO (to be determined in a future regulatory proceeding). In addition, TNMP does not currently receive a return on its loss on reacquired debt (through 2043). 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. Under GAAP, 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.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock and Equity Contributions PNMR, PNM, and TNMP did not issue any common stock during the three year period ended December 31, 2017 . PNMR funded cash equity contributions of $28.1 million in 2016 and $175.0 million in 2015 to PNM and $50.0 million in 2017 and $50.0 million in 2016 to TNMP. PNMR offers shares of PNMR common stock through the PNMR Direct Plan. PNMR utilizes shares of its common stock purchased on the open market, by an independent agent, rather than issuing additional shares to satisfy subscriptions under the PNMR Direct Plan. The shares of PNMR common stock utilized in the PNMR Direct Plan are offered under a SEC shelf registration statement that expires in August 2018. 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 $60.7 million , $4.1 million , and $94.4 million in 2017 , 2016 , and 2015 . TNMP paid cash dividends to PNMR of $44.4 million , $31.8 million , and $33.2 million in 2017 , 2016 , and 2015 . 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. The Company’s revolving credit facilities and term loans contain a covenant requiring the maintenance of debt-to-capital ratios of not more than 65% , which could limit 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 approval of certain financial counterparties to transfer more than five percent of PNM’s assets. As of December 31, 2017 : none of the numerical tests would restrict the payment of dividends from the retained earnings of TNMP; the transfer of assets limitation would allow the payment of dividends by PNM of up to $246.1 million ; and the 65% debt-to-capital covenant would allow the payment of dividends by PNMR of up to $133.9 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.

Financing

Financing	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Financing	Financing The 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. Each of the Company’s revolving credit facilities and term loans contains a single financial covenant, which requires the maintenance of a debt-to-capital ratio of less than or equal to 65% , and generally also include 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 short-term financing plan with the NMPRC. Financing Activities PNMR At January 1, 2015, PNMR had outstanding the one-year $100.0 million PNMR Term Loan Agreement, which was due in December 2015. In December 2015, PNMR entered into an agreement that extended the maturity date for an additional year and increased the amount outstanding to $150.0 million . The PNMR Term Loan Agreement was repaid on December 21, 2016. On March 9, 2015, PNMR entered into a $150.0 million Term Loan Agreement (the “PNMR 2015 Term Loan Agreement”) between PNMR, the lenders identified therein, and Wells Fargo Bank, National Association, as lender and administrative agent. The PNMR 2015 Term Loan Agreement bears interest at a variable rate, which was 2.34% at December 31, 2017, and must be repaid on or before March 9, 2018. At January 1, 2015, PNMR had an aggregate outstanding principal amount of $118.8 million of its 9.25% Senior Unsecured Notes, Series A, which were due on May 15, 2015. PNMR repaid all of the 9.25% Senior Unsecured Notes at the scheduled maturity, utilizing proceeds from the PNMR 2015 Term Loan Agreement and borrowings under the PNMR Revolving Credit Facility. As discussed in Note 16, NM Capital, a wholly-owned subsidiary of PNMR, entered into a $125.0 million term loan agreement (the “BTMU Term Loan Agreement”) with BTMU, as lender and administrative agent, as of February 1, 2016. The BTMU Term Loan Agreement has a maturity of February 1, 2021 and bears interest at a rate based on LIBOR plus a customary spread, which aggregated 4.13% at December 31, 2017. PNMR, as parent company of NM Capital, has guaranteed NM Capital’s obligations to BTMU. NM Capital utilized the proceeds of the BTMU Term Loan Agreement to provide funding of $125.0 million (the “Westmoreland Loan”) to a ring-fenced, bankruptcy-remote, special-purpose entity that is a subsidiary of Westmoreland Coal Company to finance Westmoreland’s purchase of SJCC. The BTMU Term Loan Agreement requires that NM Capital utilize all amounts, less taxes and fees, it receives under the Westmoreland Loan to repay the BTMU Term Loan Agreement. The principal balance outstanding under the BTMU Term Loan Agreement was $50.1 million at December 31, 2017 and $45.1 million at February 20, 2018. Based on scheduled payments on the Westmoreland Loan and WSJ’s payment of $5.6 million on February 1, 2018, (which included $4.8 million in excess of the scheduled payment), NM Capital estimates it will make principal payments of $10.6 million on the BTMU Term Loan Agreement in the year ended December 31, 2018, including the payment made on February 1, 2018 of $5.0 million (which included $3.3 million in excess of the payment previously scheduled). On October 21, 2016, PNMR entered into letter 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 is required to post in connection with permits relating to the operation of the San Juan mine (Note 16). On December 21, 2016, PNMR entered into two term loan agreements: (1) a $100.0 million term loan agreement (the “PNMR 2016 One-Year Term Loan”) among PNMR, the lenders identified therein, and Wells Fargo Bank, National Association, as administrative agent, that was to mature on December 21, 2017; and (2) a $100.0 million term loan agreement (the “PNMR 2016 Two-Year Term Loan”) among PNMR and JPMorgan Chase Bank, N.A., as lender and administrative agent, that matures on December 21, 2018. The proceeds of the term loans were used to repay the $150.0 million PNMR Term Loan Agreement and to reduce borrowings under the PNMR Revolving Credit Facility. On December 15, 2017, the PNMR 2016 One-Year Term Loan was extended to December 14, 2018. The PNMR 2016 One-Year Term Loan (as extended) and the PNMR 2016 Two-Year Term Loan bear interest at variable rates, which were 2.32% and 2.32% at December 31, 2017. PNM On January 1, 2015, PNM had a $125.0 million multi-draw term loan facility (the “PNM Multi-draw Term Loan”) that had outstanding borrowings of $100.0 million and a maturity date of June 21, 2016. PNM drew the remaining capacity of $25.0 million on May 8, 2015. The PNM Multi-draw Term Loan was repaid on May 20, 2016. At January 1, 2015, PNM had a $39.3 million series of outstanding Senior Unsecured Notes, Pollution Control Revenue Bonds, which have a final maturity of June 1, 2043. These PCRBs were subject to mandatory tender for remarketing on June 1, 2015 and were successfully remarketed on that date. The notes now bear interest at 2.45% , continue to have an outstanding amount of $39.3 million , and are subject to mandatory tender for remarketing on June 1, 2020. On August 11, 2015, PNM issued $250.0 million aggregate principal amount of its 3.850% Senior Unsecured Notes due 2025. The notes will mature on August 1, 2025. Portions of the proceeds from the offering were used to repay an existing $175.0 million term loan and to repay outstanding borrowings under the PNM Revolving Credit Facility, the PNM 2014 New Mexico Credit Facility, and PNM’s intercompany loan from PNMR. On May 20, 2016, PNM entered into a $175.0 million term loan agreement (the “PNM 2016 Term Loan Agreement”) between PNM and JPMorgan Chase Bank, N.A., as lender and administrative agent. The PNM 2016 Term Loan Agreement bore interest at a variable rate and had a maturity date of November 17, 2017. PNM used a portion of the proceeds of the PNM 2016 Term Loan Agreement to prepay without penalty the $125.0 million outstanding under the PNM Multi-draw Term Loan. The PNM 2016 Term Loan Agreement was repaid on July 20, 2017. On September 27, 2016, PNM participated in the issuance and sale of an aggregate of $146.0 million of PCRBs by the City of Farmington, New Mexico. The proceeds from the sale were utilized to refund an aggregate of $146.0 million of outstanding PCRBs previously issued by the City of Farmington. The arrangements governing the PCRBs result in PNM reflecting the bonds as debt on its financial statements. The PCRBs bear interest at a rate of 1.875% for the period from September 27, 2016 through September 30, 2021, have a mandatory tender for remarketing on October 1, 2021, and a final maturity on April 1, 2033. At January 1, 2015, PNM had $37.0 million of outstanding PCRBs, which have a final maturity of June 1, 2040, and $20.0 million of outstanding PCRBs which have a final maturity of June 1, 2042. These PCRBs were subject to mandatory tender for remarketing on June 1, 2017 and were successfully remarketed on that date. The $37.0 million of PCRBs now bear interest at 2.125% and the $20.0 million of PCRBs now bear interest at 2.45% . Both series are now subject to mandatory tender for remarketing on June 1, 2022. On July 20, 2017, PNM entered into a $200.0 million term loan agreement (the “PNM 2017 Term Loan Agreement”) 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 Agreement bears interest at a variable rate, which was 2.29% at December 31, 2017, and must be repaid on or before January 18, 2019. PNM used the proceeds of the PNM 2017 Term Loan Agreement to prepay without penalty the $175.0 million PNM 2016 Term Loan Agreement and to reduce short-term borrowings. 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 Senior Unsecured Notes (the “PNM 2018 SUNs”) offered in private placement transactions. Under the PNM 2017 Senior Unsecured Note Agreement, PNM has agreed to issue $350.0 million of the PNM 2018 SUNs on or about May 15, 2018 and $100.0 million of the PNM 2018 SUNs on or about August 1, 2018. The issuances of the PNM 2018 SUNs are subject to the satisfaction of customary conditions. PNM will use the gross proceeds from the PNM 2018 SUNs to repay $350.0 million of PNM’s 7.95% Senior Unsecured Notes that mature on May 15, 2018 and $100.0 million of PNM’s 7.50% Senior Unsecured Notes that mature on August 1, 2018. The terms of the PNM 2017 Senior Unsecured Note Agreement include customary covenants, including a covenant that requires the maintenance of a debt-to-capital 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. PNM will have 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. In accordance with GAAP, aggregate borrowings of $450.0 million under PNM’s Senior Unsecured Notes due on May 15, 2018 and August 1, 2018, are reflected as being long-term in the Consolidated Balance Sheet at December 31, 2017 since the PNM 2017 Senior Unsecured Note Agreement demonstrates PNM’s ability and intent to re-finance the aggregate $450.0 million Senior Unsecured Notes on a long-term basis. Information concerning the maturities and interest rates on the PNM 2018 SUNs to be issued in May 2018 and August 2018 is as follows: Scheduled Funding Maturity Principal Interest Date Date Amount Rate (In millions) May 15, 2018 May 15, 2023 $ 55.0 3.15 % May 15, 2018 May 15, 2025 104.0 3.45 % May 15, 2018 May 15, 2028 88.0 3.68 % May 15, 2018 May 15, 2033 38.0 3.93 % May 15, 2018 May 15, 2038 45.0 4.22 % May 15, 2018 May 15, 2048 20.0 4.50 % 350.0 August 1, 2018 August 1, 2028 15.0 3.78 % August 1, 2018 August 1, 2048 85.0 4.60 % 100.0 $ 450.0 PNM has a shelf registration statement, which will expire in May 2020, with capacity for the issuance of up to $475.0 million of senior unsecured notes. TNMP On December 17, 2015, TNMP entered into an agreement (the “TNMP 2015 Bond Purchase Agreement”), which provided that TNMP would issue $60.0 million aggregate principal amount of 3.53% first mortgage bonds, due 2026 on or about February 10, 2016, subject to satisfaction of certain conditions. TNMP issued the bonds on February 10, 2016 and used the proceeds to reduce short-term debt and intercompany debt. On June 14, 2017, TNMP entered into an agreement (the “TNMP 2017 Bond Purchase Agreement”), which provided TNMP would issue $60.0 million aggregate principal amount of 3.22% first mortgage bonds, due 2027 on or about August 25, 2017, subject to satisfaction of certain conditions. TNMP issued the bonds on August 24, 2017 and used the proceeds to reduce short-term and intercompany debt and for general corporate purposes. Interest Rate Hedging Activities In September 2015, PNMR entered into a hedging agreement whereby it effectively established a fixed interest rate of 1.927% , subject to change if there is a change in PNMR’s credit rating, for borrowings under the PNMR 2015 Term Loan Agreement for the period from January 11, 2016 through its maturity on March 9, 2018. In 2017, PNMR entered into three separate four -year hedging agreements whereby it 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. The fair value of the hedge related to the PNMR 2015 Term Loan Agreement was a gain of $0.2 million at December 31, 2017 and is included in Other current assets on the Consolidated Balance Sheets and a loss of less than $0.1 million at December 31, 2016. At December 31, 2017, the remaining hedge agreements had fair value gains totaling $1.4 million , which are included in Other current assets on the Consolidated Balance Sheets. The fair values were determined using Level 2 inputs under GAAP, 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 one-year intercompany loan agreements with its subsidiaries. Individual subsidiary loan agreements vary in amount up to $100.0 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. TNMP had no outstanding borrowings from PNMR at December 31, 2017 or February 20, 2018 , and $4.6 million at December 31, 2016. PNM had no outstanding borrowings from PNMR at December 31, 2017, December 31, 2016, or February 20, 2018. Short-term Debt 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 . PNMR and PNM have entered into agreements to extend the maturity of both facilities from October 31, 2020 to October 31, 2022. However, one lender, whose current commitment is $10.0 million under the PNMR Revolving Credit Facility and $40.0 million under the PNM Revolving Credit Facility, did not agree to extend its commitments beyond October 31, 2020. Unless one or more of the other current lenders or a new lender assumes the commitments of the non-extending lender, the financing capacities will be reduced to $290.0 million for the PNMR Revolving Credit Facility and $360.0 million for the PNM Revolving Credit Facility from November 1, 2020 through October 31, 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. In September 2017, the TNMP Revolving Credit Facility was extended to mature on September 23, 2022. At January 1, 2015, PNM had a $50.0 million unsecured revolving credit facility (the “PNM 2014 New Mexico Credit Facility”) that was scheduled to expire on January 8, 2018. On December 12, 2017, PNM entered into a new $40.0 million unsecured revolving credit facility (the “PNM 2017 New Mexico Credit Facility”) by and among PNM, the lenders identified therein, U.S. Bank National Association, as Administrative Agent, and BOKF, NA dba Bank of Albuquerque, as Syndication Agent to replace the PNM 2014 New Mexico Credit Facility. The eight participating lenders are all banks that have a significant presence or are headquartered in New Mexico. The PNM 2017 New Mexico Credit Facility expires on December 12, 2022 and contains covenants and conditions similar to those in the PNM Revolving Credit Facility. Short-term debt outstanding consists of: December 31, Short-term Debt 2017 2016 (In thousands) PNM: PNM Revolving Credit Facility $ 39,800 $ 35,000 PNM 2014 New Mexico Credit Facility — 26,000 PNM 2017 New Mexico Credit Facility — — 39,800 61,000 TNMP Revolving Credit Facility — — PNMR: PNMR Revolving Credit Facility 165,600 126,100 PNMR 2016 One-Year Term Loan 100,000 100,000 $ 305,400 $ 287,100 In addition to the above borrowings, PNMR, PNM, and TNMP had letters of credit outstanding of $6.4 million , $2.5 million , and $0.1 million at December 31, 2017 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 JPM LOC Facility. At December 31, 2017 , interest rates on outstanding borrowings were 2.76% for the PNMR Revolving Credit Facility and 2.59% for the PNM Revolving Credit Facility. At February 20, 2018 , PNMR, PNM, and TNMP had $111.2 million , $340.1 million , and $51.0 million of availability under their respective revolving credit facilities, including reductions of availability due to outstanding letters of credit, and PNM had $20.0 million availability under the PNM 2017 New Mexico Credit Facility. Total availability at February 20, 2018 , on a consolidated basis, was $522.3 million for PNMR. At February 20, 2018 , PNMR had invested cash of $0.9 million . PNM and TNMP had no invested cash at February 20, 2018 . On February 26, 2018, PNMR Development entered into a $24.5 million credit facility with Wells Fargo Bank, National Association, as lender. The facility allows PNMR Development to borrow on a revolving credit basis and also provides for the issuance of letters of credit. The facility matures on February 25, 2019. The 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 anticipates using the facility to finance its participation in NMRD (Note 1). Long-Term Debt Information concerning long-term debt outstanding and unamortized (premiums), discounts, and debt issuance costs is as follows: December 31, 2017 December 31, 2016 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 $ 1,383 $ 146,000 $ 1,807 6.25% due January 2038 36,000 228 36,000 239 4.75% due June 2040, mandatory tender - June 1, 2017 — — 37,000 25 2.125% due June 2040, mandatory tender - June 1, 2022 37,000 404 — — 5.20% due June 2040, mandatory tender - June 1, 2020 40,045 105 40,045 147 5.90% due June 2040 255,000 2,040 255,000 2,131 6.25% due June 2040 11,500 92 11,500 96 2.54% due September 2042, mandatory tender - June 1, 2017 — — 20,000 67 2.45% due September 2042, mandatory tender - June 1, 2022 20,000 153 — — 2.40% due June 2043, mandatory tender - June 1, 2020 39,300 243 39,300 340 5.20% due June 2043, mandatory tender - June 1, 2020 21,000 53 21,000 75 Senior Unsecured Notes: 7.95% due May 2018 350,000 272 350,000 995 7.50% due August 2018 100,025 73 100,025 197 5.35% due October 2021 160,000 617 160,000 780 3.85% due August 2025 250,000 2,274 250,000 2,574 PNM 2016 Term Loan Agreement due November 2017 — — 175,000 28 PNM 2017 Term Loan Agreement due January 2019 200,000 23 — — 1,665,870 7,960 1,640,870 9,501 Less current maturities 25 2 232,000 120 1,665,845 7,958 1,408,870 9,381 TNMP Debt First Mortgage Bonds: 9.50% due April 2019 172,302 1,032 172,302 1,857 6.95% due April 2043 93,198 (18,057 ) 93,198 (18,773 ) 4.03% due July 2024 80,000 686 80,000 792 3.53% due February 2026 60,000 667 60,000 749 3.22% due August 2027 60,000 552 — — 465,500 (15,120 ) 405,500 (15,375 ) Less current maturities — — — — 465,500 (15,120 ) 405,500 (15,375 ) PNMR Debt PNMR 2015 Term Loan Agreement due March 2018 150,000 12 150,000 84 BTMU Term Loan Agreement, payments through February 2021 50,137 1,001 92,207 1,634 PNMR 2016 Two-Year Term Loan due December 2018 100,000 9 100,000 21 300,137 1,022 342,207 1,739 Less current maturities 257,268 396 42,025 557 42,869 626 300,182 1,182 Total Consolidated PNMR Debt 2,431,507 (6,138 ) 2,388,577 (4,135 ) Less current maturities 257,293 398 274,025 677 $ 2,174,214 $ (6,536 ) $ 2,114,552 $ (4,812 ) Reflecting mandatory tender dates and the impacts of the refinancing under the PNM 2017 Senior Unsecured Note Agreement discussed above, long-term debt matures as follows: PNMR PNM TNMP PNMR Consolidated (In thousands) 2018 $ 257,268 $ 25 $ — $ 257,293 2019 12,357 200,000 172,302 384,659 2020 25,862 100,345 — 126,207 2021 4,650 306,000 — 310,650 2022 — 57,000 — 57,000 Thereafter — 1,002,500 293,198 1,295,698 Total $ 300,137 $ 1,665,870 $ 465,500 $ 2,431,507

Lease Commitments

Lease Commitments	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Leases Commitments	Lease Commitments The Company leases office buildings, vehicles, and other equipment under operating leases. In addition, PNM leases interests in Units 1 and 2 of PVNGS and, through April 1, 2015, leased an interest in the EIP transmission line. 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, and has no significant rights-of-way that will expire within the next five years. 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. All of the Company’s leases, as well as the Navajo Nation rights-of-way agreement, are accounted for as operating leases. See New Accounting Pronouncements in Note 1. 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. Each of the leases provided PNM with an option to purchase the leased assets at fair market value at the end of the leases, but PNM did not have a fixed price purchase option. In addition, the leases provided PNM with options to renew the leases at fixed rates set forth in each of the leases for two years beyond the termination of the original lease terms. The option periods on certain leases could be further extended for up to an additional six years (the “Maximum Option Period”) if the appraised remaining useful lives and fair value of the leased assets were greater than parameters set forth in the leases. The rental payments during the fixed renewal option periods are 50% of the amounts during the original terms of the leases. Gross annual lease payments aggregated $33.0 million for the Unit 1 leases and $23.7 million for the Unit 2 leases prior to the expiration of their original terms. Following procedures set forth in the PVNGS leases, PNM notified each of the four lessors under the Unit 1 leases and the lessor under the one Unit 2 lease containing the Maximum Option Period provision that it would elect to renew those leases for the Maximum Option Period on the expiration date of the original leases. PNM and each of those lessors entered into amendments to each of the leases setting forth the terms and conditions that would implement the extension of the term of the leases through the agreed upon Maximum Option Period. 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 payments during the renewal periods aggregate $16.5 million for the PVNGS Unit 1 leases and $1.6 million for the Unit 2 lease, which are included in the table of future lease payments shown below. For leases that were extended, the leases provide PNM with the option to purchase the leased assets at fair market value at the end of the extended lease terms. Each extended lease provides that no later than three years prior to the expiration of the lease, PNM is required to give notice to the lessor if it will “retain” the leased assets, through the purchase of the assets at the end of the lease, or “return” the leased assets to the lessor. The election made under each of the leases is irrevocable and independent of the elections made under the other leases. PNM has begun to analyze what action it will take with respect to each lease. If PNM elects to exercise its purchase option under any of the leases, PNM would attempt to negotiate the purchase price with the lessor of the lease. The leases provide an appraisal process to determine fair market value in the event the lessor and lessee cannot agree on a purchase price. For the three PVNGS Unit 2 leases that did not contain the Maximum Option Period provisions, PNM, following procedures set forth in the leases, notified each of the lessors that PNM would elect to purchase the assets underlying those leases on the expiration date of the original leases. PNM and the lessors under these leases entered into agreements that established the purchase price, representing the fair market value, to be paid by PNM for the assets underlying the leases on January 15, 2016. On January 15, 2016, PNM paid $78.1 million to the lessor under one lease for 31.25 MW of the entitlement from PVNGS Unit 2 and $85.2 million to the lessors under the other two leases for 32.76 MW of the entitlement from PVNGS Unit 2. See Note 17 for information concerning the NMPRC’s treatment of the purchased assets and extended leases in PNM’s NM 2015 Rate Case. Covenants in PNM’s PVNGS Units 1 and 2 lease agreements limit PNM’s ability, without consent of the owner participants in the lease transactions, (i) to enter into any merger or consolidation, or (ii) except in connection with normal dividend policy, to convey, transfer, lease or dividend more than 5% of its assets in any single transaction or series of related transactions. PNM is exposed to losses under the PVNGS lease arrangements upon the occurrence of certain events that PNM does not consider to be 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 owner participants, and take title to the leased interests. Exercise of renewal options under the leases required that amounts payable to the owner participants under the circumstances described above would increase to the fair market value as of the renewal date. If such an event had occurred as of December 31, 2017 , amounts due to the lessors under the circumstances described above would be up to $169.9 million , payable on January 15, 2018 in addition to the scheduled lease payments due on January 15, 2018. In such event, PNM would record the acquired assets at the lower of their fair value or the amount paid. PNM owned 60% of the EIP and leased the other 40% , under a lease that expired on April 1, 2015. The lease provided PNM the option of purchasing the leased assets at the end of the lease for fair market value, as well as options to renew the lease. On November 1, 2012, PNM and the lessor entered into a definitive agreement for PNM to exercise the option to purchase on April 1, 2015 the leased capacity at fair market value, which the parties agreed would be $7.7 million . PNM closed on the purchase on April 1, 2015 and recorded the purchase of the assets underlying the lease at that date. Operating lease expense, including the PVNGS and EIP leases, was: PNMR PNM TNMP (In thousands) 2017 $ 35,972 $ 31,817 $ 3,570 2016 $ 37,432 $ 32,843 $ 3,748 2015 $ 61,088 $ 55,994 $ 3,688 Future minimum operating lease payments at December 31, 2017 are shown below: PNMR PNM TNMP (In thousands) 2018 $ 26,802 $ 25,726 $ 791 2019 25,638 25,241 296 2020 25,208 25,122 — 2021 25,122 25,122 — 2022 25,122 25,122 — Later years 60,708 60,708 — Total minimum lease payments $ 188,600 $ 187,041 $ 1,087

Fair Value of Derivative and Ot

Fair Value of Derivative and Other Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value of Derivative and Other Financial Instruments [Abstract]
Fair Value of Derivative and Other Financial Instruments	Fair Value of Derivative and Other Financial Instruments Fair value is defined under GAAP 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 market liquidity, term of the agreement, and, for commodities, location. 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 a FPPAC. PNM was exposed to market risk for its share of PVNGS Unit 3 through December 31, 2017, at which time PVNGS Unit 3 became a jurisdictional resource to serve New Mexico retail customers. Beginning January 1, 2018, PNM is exposed to market risk for its 65 MW of SJGS Unit 4 that is held as merchant plant as ordered by the NMPRC (Note 16). PNM has entered into agreements to sell the power from 36 MW of that capacity to a third party at a fixed price for the period January 1, 2018 through June 30, 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’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 in wholesale portfolios. PNM monitors the market risk of its commodity contracts to maintain total exposure within management-prescribed limits 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, 2017 , 2016 , and 2015 , PNM was not hedging its exposure to the variability in future cash flows from commodity derivatives through designated cash flows 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, are summarized as follows: Economic Hedges December 31, 2017 2016 (In thousands) Current assets $ 1,088 $ 5,224 Deferred charges 3,556 — 4,644 5,224 Current liabilities (1,182 ) (2,339 ) Long-term liabilities (3,556 ) — (4,738 ) (2,339 ) Net $ (94 ) $ 2,885 Included in the above table are $2.7 million of current assets at December 31, 2016 related to contracts for the sale of energy from PVNGS Unit 3 through 2017 at market price plus a premium. As noted above, PVNGS Unit 3 has become a jurisdictional resource to serve New Mexico retail customers beginning January 1, 2018. Certain of 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. Included in the above table are equal amounts of assets and liabilities aggregating $4.6 million at December 31, 2017 and $0.5 million at December 31, 2016, resulting from PNM’s hazard sharing arrangements with Tri-State (Note 17). The hazard sharing arrangements are net-settled upon delivery. Other amounts that could be offset under master netting agreements were immaterial. At December 31, 2017 and 2016 , PNM had no amounts recognized for the legal right to reclaim cash collateral. However, at December 31, 2017 and 2016 , amounts posted as cash collateral under margin arrangements were $0.8 million and $2.6 million . At December 31, 2017 and 2016 , obligations to return cash collateral were $0.9 million and $0.1 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, 2017. The table above includes $0.2 million of current assets and $0.1 million of current liabilities at December 31, 2016 related to this plan. The offsets to these amounts are recorded as regulatory assets and liabilities on the Consolidated Balance Sheets. The following table presents the effect of mark-to-market commodity derivative instruments on PNM’s earnings, excluding income tax effects. Commodity derivatives had no impact on OCI for the periods presented. Economic Hedges Year Ended 2017 2016 2015 (In thousands) Electric operating revenues $ 5,151 $ (53 ) $ 7,156 Cost of energy (5,386 ) (1,208 ) (293 ) Total gain (loss) $ (235 ) $ (1,261 ) $ 6,863 Commodity contract volume positions are presented in MMBTU for gas related contracts and in MWh for power related contracts. The table below presents PNM’s net buy (sell) volume positions: Economic Hedges MMBTU MWh December 31, 2017 100,000 — December 31, 2016 254,100 (2,471,600 ) 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, 2017 and 2016, 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. Available-for-sale securities are carried at fair value. Available-for-sale 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 (Note 16). At December 31, 2017 and 2016 , the fair value of available-for-sale securities included $293.7 million and $253.9 million for the NDT and $29.8 million and $19.1 million for the mine reclamation trusts. The fair value and gross unrealized gains of investments in available-for-sale securities are presented in the following table. December 31, 2017 December 31, 2016 Unrealized Gains Fair Value Unrealized Gains Fair Value (In thousands) Cash and cash equivalents $ — $ 52,636 $ — $ 23,683 Equity securities: Domestic value 4,011 40,032 1,135 34,796 Domestic growth 3,995 35,456 3,032 47,595 International and other 6,810 45,867 2,029 27,481 Fixed income securities: U.S. Government 273 34,317 115 40,962 Municipals 1,225 48,076 585 43,789 Corporate and other 1,714 67,140 553 54,671 $ 18,028 $ 323,524 $ 7,449 $ 272,977 Due to the funded status of the nuclear decommissioning trust and overall market performance, PNM began to re-balance the decommissioning investment portfolio in late 2017 to increase the percentage of the investments in fixed income (debt) securities to approximately 85% . The portfolio re-balancing was completed in early 2018. The proceeds and gross realized gains and losses on the disposition of available-for-sale securities 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 $3.3 million , $(1.2) million , and $(4.3) million for the years ended December 31, 2017 , 2016 and 2015 . See New Accounting Pronouncements in Note 1. Year Ended December 31, 2017 2016 2015 (In thousands) Proceeds from sales $ 637,492 $ 522,601 $ 252,174 Gross realized gains $ 36,896 $ 46,116 $ 29,663 Gross realized (losses) $ (12,993 ) $ (25,430 ) $ (9,259 ) Held-to-maturity securities are those investments in debt securities that the Company has the ability and intent to hold until maturity. At December 31, 2017 and 2016, PNMR’s held-to-maturity securities consist of the Westmoreland Loan. The Company has no available-for-sale or held-to-maturity securities for which carrying value exceeds fair value. There are no impairments considered to be “other than temporary” that are included in AOCI and not recognized in earnings. At December 31, 2017 , the available-for-sale and held-to-maturity debt securities had the following final maturities: Fair Value Available-for-Sale Held-to-Maturity PNMR and PNM PNMR (In thousands) Within 1 year $ 4,460 $ — After 1 year through 5 years 32,693 66,588 After 5 years through 10 years 48,681 — After 10 years through 15 years 5,934 — After 15 years through 20 years 11,983 — After 20 years 45,782 — $ 149,533 $ 66,588 Fair Value Disclosures The Company determines the fair values of its derivative and other financial instruments based on the hierarchy established in GAAP, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. GAAP describes 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. Level 3 inputs used in determining fair values for the Company consist of internal valuation models. The Company records any transfers between fair value hierarchy levels as of the end of each calendar quarter. There were no transfers between levels during the years ended December 31, 2017 and 2016 . For available-for-sale securities, Level 2 fair values are provided by the trustee utilizing a pricing service. The pricing provider predominantly uses the market approach using bid side market value based upon a hierarchy of information for specific securities or securities with similar characteristics. 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. For investments categorized as Level 3, primarily the Westmoreland Loan, fair values were determined by discounted cash flow models that take into consideration discount rates that are observable for similar types of assets and liabilities. Management of the Company independently verifies the information provided by pricing services. Items recorded at fair value by PNM on the Consolidated Balance Sheets are presented below by level of the fair value hierarchy. There were no Level 3 fair value measurements at December 31, 2017 and 2016 for items recorded at fair value. GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (In thousands) December 31, 2017 Available-for-sale securities Cash and cash equivalents $ 52,636 $ 52,636 $ — Equity securities: Domestic value 40,032 40,032 — Domestic growth 35,456 35,456 — International and other 45,867 42,332 3,535 Fixed income securities: U.S. Government 34,317 33,645 672 Municipals 48,076 — 48,076 Corporate and other 67,140 — 67,140 $ 323,524 $ 204,101 $ 119,423 Commodity derivative assets $ 4,644 $ — $ 4,644 Commodity derivative liabilities (4,738 ) — (4,738 ) Net $ (94 ) $ — $ (94 ) December 31, 2016 Available-for-sale securities Cash and cash equivalents $ 23,683 $ 23,683 $ — Equity securities: Domestic value 34,796 34,796 — Domestic growth 47,595 47,595 — International and other 27,481 27,481 — Fixed income securities: U.S. Government 40,962 39,723 1,239 Municipals 43,789 — 43,789 Corporate and other 54,671 23,158 31,513 $ 272,977 $ 196,436 $ 76,541 Commodity derivative assets $ 5,224 $ — $ 5,224 Commodity derivative liabilities (2,339 ) — (2,339 ) Net $ 2,885 $ — $ 2,885 The carrying amounts and fair values of investments in the Westmoreland Loan, other investments, and long-term debt, which are not recorded at fair value on the Consolidated Balance Sheets are presented below: GAAP Fair Value Hierarchy Carrying Amount Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNMR Long-term debt $ 2,437,645 $ 2,554,836 $ — $ 2,554,836 $ — Westmoreland Loan $ 56,640 $ 66,588 $ — $ — $ 66,588 Other investments $ 503 $ 503 $ 503 $ — $ — PNM Long-term debt $ 1,657,910 $ 1,727,135 $ — $ 1,727,135 $ — Other investments $ 283 $ 283 $ 283 $ — $ — TNMP Long-term debt $ 480,620 $ 527,563 $ — $ 527,563 $ — Other investments $ 220 $ 220 $ 220 $ — $ — December 31, 2016 PNMR Long-term debt $ 2,392,712 $ 2,540,693 $ — $ 2,540,693 $ — Westmoreland Loan $ 95,000 $ 100,893 $ — $ — $ 100,893 Other investments $ 547 $ 1,164 $ 547 $ — $ 617 PNM Long-term debt $ 1,631,369 $ 1,730,157 $ — $ 1,730,157 $ — Other investments $ 316 $ 316 $ 316 $ — $ — TNMP Long-term debt $ 420,875 $ 468,329 $ — $ 468,329 $ — Other investments $ 231 $ 231 $ 231 $ — $ — Investments Held by Employee Benefit Plans As discussed in Note 12, 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 (Note 12), 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 is contemplating changing its investment allocation targets by decreasing the fixed income investments used to match pension liabilities from 65% to 50% beginning in 2018. 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. Under GAAP, 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. Level 3 investments are comprised of corporate term loans. 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 year 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 able to be redeemed in the near term. Audited financial statements are received for each fund and are reviewed by the Company annually. The valuation of Level 3 investments and 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 the trading multiples of public companies that are considered comparable to the company being valued, company specific issues, estimates of liquidation value, current operating performance and future expectations of performance, changes in market outlook and the financing environment, capitalization rates, discount rates, and cash flows. 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 (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 487,498 $ 140,218 $ 347,089 $ 191 Uncategorized investments 74,768 Total Master Trust Investments $ 562,266 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 53,273 $ 15,244 $ 38,008 $ 21 Uncategorized investments 10,260 Total Master Trust Investments $ 63,533 PNM OPEB Plan Cash and cash equivalents $ 437 $ 437 $ — $ — Equity securities: International funds 10,636 — 10,636 — Domestic value 10,816 10,816 — — Domestic growth 6,710 6,710 — — Other funds 31,660 — 31,660 — Fixed income securities: Mutual funds 20,918 20,918 — — $ 81,177 $ 38,881 $ 42,296 $ — TNMP OPEB Plan Cash and cash equivalents $ 149 $ 149 $ — $ — Equity securities: International funds 1,597 — 1,597 — Domestic value 293 293 — — Domestic growth 1,410 1,410 — — Other funds 4,011 — 4,011 — Fixed income securities: Mutual funds 2,685 2,685 — — $ 10,145 $ 4,537 $ 5,608 $ — GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2016 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 467,965 $ 129,624 $ 337,989 $ 352 Uncategorized investments 75,685 Total Master Trust Investments $ 543,650 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 50,901 $ 14,447 $ 36,416 $ 38 Uncategorized investments 9,729 Total Master Trust Investments $ 60,630 PNM OPEB Plan Cash and cash equivalents $ 2,567 $ 2,567 $ — $ — Equity securities: International funds 9,300 — 9,300 — Domestic value 10,260 10,260 — — Domestic growth 6,338 6,338 — — Other funds 26,405 — 26,405 — Fixed income securities: Mutual funds 18,959 18,959 — — $ 73,829 $ 38,124 $ 35,705 $ — TNMP OPEB Plan Cash and cash equivalents $ 308 $ 308 $ — $ — Equity securities: International funds 1,279 — 1,279 — Domestic value 449 449 — — Domestic growth 1,089 1,089 — — Other funds 3,060 — 3,060 — Fixed income securities: Mutual funds 2,593 2,593 — — $ 8,778 $ 4,439 $ 4,339 $ — The fair values of investments in the PNMR Master Trust are as follows: GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNMR Master Trust Cash and cash equivalents $ 7,697 $ 7,697 $ — $ — Equity securities: International 42,048 — 42,048 — Domestic value 37,026 37,026 — — Domestic growth 19,136 19,136 — — Other funds 25,099 — 25,099 — Fixed income securities: Corporate 215,535 — 215,323 212 U.S. Government 117,572 91,603 25,969 — Municipals 11,438 — 11,438 — Other funds 65,220 — 65,220 — Total investments categorized within fair value hierarchy 540,771 $ 155,462 $ 385,097 $ 212 Uncategorized investments: Private equity funds 22,281 Hedge funds 45,615 Real estate funds 17,132 $ 625,799 December 31, 2016 PNMR Master Trust Cash and cash equivalents $ 20,503 $ 20,503 $ — $ — Equity securities: International 38,401 — 38,401 — Domestic value 36,036 36,036 — — Domestic growth 18,484 18,484 — — Other funds 27,532 — 27,532 — Fixed income securities: Corporate 205,419 — 205,029 390 U.S. Government 94,359 69,048 25,311 — Municipals 13,970 — 13,970 — Other funds 64,162 — 64,162 — Total investments categorized within fair value hierarchy 518,866 $ 144,071 $ 374,405 $ 390 Uncategorized investments: Private equity funds 27,060 Hedge funds 42,070 Real estate funds 16,284 $ 604,280 A reconciliation of the changes in Level 3 fair value measurements is as follows: Fixed Income - Corporate PNMR Master Trust PNM Pension TNMP Pension Total Master Trust (In thousands) Balance at December 31, 2015 $ 719 $ 78 $ 797 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end 19 2 21 Purchases — — — Sales (387 ) (42 ) (429 ) Balance at December 31, 2016 352 38 390 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end (7 ) (1 ) (8 ) Purchases 92 10 102 Sales (247 ) (26 ) (273 ) Balance at December 31, 2017 $ 191 $ 21 $ 212

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2017
Variable Interest Entities [Abstract]
Variable Interest Entities	Variable Interest Entities GAAP determines how an enterprise evaluates and accounts for its involvement with variable interest entities, focusing 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”). GAAP also 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 158 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, 2017 , 2016 , and 2015 , PNM paid $19.6 million , $19.3 million , and $19.2 million for fixed charges and $1.3 million , $1.1 million , and $1.6 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 under GAAP 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, 2017 2016 2015 (In thousands) Operating revenues $ 20,887 $ 20,371 $ 20,687 Operating expenses (5,870 ) (5,852 ) (5,777 ) Earnings attributable to non-controlling interest $ 15,017 $ 14,519 $ 14,910 Financial Position December 31, 2017 2016 (In thousands) Current assets $ 2,688 $ 2,551 Net property, plant and equipment 64,109 66,947 Total assets 66,797 69,498 Current liabilities 602 578 Owners’ equity – non-controlling interest $ 66,195 $ 68,920 Westmoreland San Juan LLC (“WSJ”) and SJCC As discussed in the subheading Coal Supply in Note 16, PNM purchases coal for SJGS from SJCC under a coal supply agreement (“SJGS CSA”). That section includes information on the acquisition of SJCC by WSJ, a subsidiary of Westmoreland, on January 31, 2016, as well as a $125.0 million loan (the “Westmoreland Loan”) from NM Capital, a subsidiary of PNMR, to WSJ, which loan provided substantially all of the funds required for the SJCC purchase, and the issuance of $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. The Westmoreland Loan and the letters of credit support result in PNMR being considered to have a variable interest in WSJ, including its subsidiary, SJCC, since PNMR and NM Capital could be subject to possible loss in the event of a default by WSJ under the Westmoreland Loan and/or performance was required under the letter of credit support. Principal payments under the Westmoreland Loan began on August 1, 2016 and are required quarterly thereafter. Interest is also paid quarterly beginning on May 3, 2016. At December 31, 2017, the amount outstanding under the Westmoreland Loan was $56.6 million . In addition, interest receivable of $1.0 million is included in Other receivables. The Westmoreland Loan requires that all cash flows of WSJ, in excess of normal operating expenses, capital additions, and operating reserves, be utilized for principal and interest payments under the loan until it is fully repaid. As of February 20, 2018, the amount outstanding under the Westmoreland Loan was $51.0 million , reflecting the February 1, 2018 principal payment of $5.6 million . The Westmoreland Loan is secured by the assets of and the equity interests in SJCC. In the event of a default by WSJ, NM Capital would have the ability to take over the mining operations. In such event, NM Capital would likely engage a third-party mining company to operate SJCC so that operations of the mine are not disrupted. The acquisition of SJCC for approximately $125.0 million on January 31, 2016 was an arm’s-length negotiated transaction between Westmoreland and BHP, which amount should approximate the fair value of SJCC at the date of acquisition. If WSJ were to default, NM Capital should be able to acquire assets of approximately the value of the Westmoreland Loan without a significant loss. Furthermore, 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 SJCC 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 and the final maturity of the Westmoreland Loan. In addition, each of the SJGS participants has established and funds a trust to meet its future reclamation obligations. Both WSJ and SJCC are considered to be VIEs. PNMR’s analysis of these arrangements concluded that Westmoreland, as the parent of WSJ, has the ability to direct the SJCC mining operations, which is the factor that most significantly impacts the economic performance of WSJ and SJCC. NM Capital’s rights under the Westmoreland Loan are the typical protective rights of a lender, but do not give NM Capital any oversight over mining operations unless there is a default under the loan agreement. 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 Westmoreland and its subsidiaries, 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. Therefore, PNM’s involvement through the SJGS CSA is a protective right rather than a participating right and Westmoreland has the power to direct the activities that most significantly impact the economic performance of SJCC. The SJGS CSA requires SJCC 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 SJCC is able to mine more efficiently than anticipated, its economic performance will be improved. Conversely, if SJCC cannot mine as efficiently as anticipated, its economic performance will be negatively impacted. Accordingly, PNMR believes Westmoreland is the primary beneficiary of WSJ and, therefore, WSJ and SJCC are not consolidated by either PNMR or PNM. The amounts outstanding under the Westmoreland Loan and the letter of credit support constitute PNMR’s maximum exposure to loss from the VIEs. PVNGS Leases PNM leased portions of its interests in Units 1 and 2 of PVNGS under leases, which 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. See Note 7 for additional information regarding the leases and actions PNM has taken with respect to its renewal and purchase options. Each of the lease agreements was with a different trust whose beneficial owners were five different institutional investors. PNM is not the legal or tax owner of the leased assets. The beneficial owners of the trusts possess all of the voting control and pecuniary interests in the trusts. At January 15, 2015, the four Unit 1 leases were extended. At January 15, 2016, one of the Unit 2 leases was extended and PNM purchased the assets underlying the other three Unit 2 leases. See Note 17 for information concerning the NMPRC’s treatment of the purchased assets and extended leases in PNM’s NM 2015 Rate Case. PNM is only obligated to make payments to the trusts for the scheduled semi-annual lease payments and has no other financial obligations or commitments to the trusts or the beneficial owners although PNM is responsible for all decommissioning obligations related to its entire interest in PVNGS both during and after termination of the leases. Creditors of the trusts have no recourse to PNM’s assets other than with respect to the contractual lease payments. PNM has no additional rights to the assets of the trusts other than the use of the leased assets. PNM has no assets or liabilities recorded on its Consolidated Balance Sheets related to the trusts other than accrued lease payments of $8.3 million at December 31, 2017 and 2016 , which are included in other current liabilities on the Consolidated Balance Sheets. Prior to their exercise or expiration, the fixed rate renewal options were considered to be variable interests in the trusts and resulted in the trusts being considered variable interest entities under GAAP. Upon execution of documents establishing terms of the asset purchases or lease extensions, the fixed rate renewal options ceased to exist as did PNM’s variable interest in the trusts. PNM evaluated the PVNGS lease arrangements, including actions taken with respect to the renewal and purchase options, and concluded that it did not have the power to direct the activities that most significantly impacted the economic performance of the trusts and, therefore, was not the primary beneficiary of the trusts under GAAP. The significant factors considered in reaching this conclusion were: the periods covered by fixed price renewal options were significantly shorter than the anticipated remaining useful lives of the assets since the operating licenses for the plants were extended for 20 years through 2045 for Unit 1 and 2046 for Unit 2 ; PNM’s only financial obligation to the trusts is to make the fixed lease payments and the payments do not vary based on the output of the plants or their performance; during the lease terms, the economic performance of the trusts is substantially fixed due to the fixed lease payments; PNM is only one of several participants in PVNGS and is not the operating agent for the plants, so does not significantly influence the day-to-day operations of the plants; the operations of the plants, including plans for their decommissioning, are highly regulated by the NRC, leaving little room for the participants to operate the plants in a manner that impacts the economic performance of the trusts; the economic performance of the trusts at the end of the lease terms is dependent upon the fair value and remaining lives of the plants at that time, which are determined by factors such as power prices, outlook for nuclear power, and the impacts of potential carbon legislation or regulation, all which are outside of PNM’s control; and while PNM had some benefit from its renewal options, the vast majority of the value at the end of the leases would accrue to the beneficial owners of the trusts, particularly given increases in the value of existing nuclear generating facilities, which have no GHG, resulting from potential carbon legislation or regulation.

Earnings and Dividends Per Shar

Earnings and Dividends Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings and Dividends Per Share	Earnings and Dividends Per Share In accordance with GAAP, 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, 2017 2016 2015 (In thousands, except per share amounts) Net Earnings Attributable to PNMR $ 79,874 $ 116,849 $ 15,640 Average Number of Common Shares: Outstanding during year 79,654 79,654 79,654 Vested awards of restricted stock 237 104 105 Average Shares – Basic 79,891 79,758 79,759 Dilutive Effect of Common Stock Equivalents: Stock options and restricted stock 250 374 380 Average Shares – Diluted 80,141 80,132 80,139 Net Earnings Attributable to PNMR Per Share of Common Stock: Basic $ 1.00 $ 1.47 $ 0.20 Diluted $ 1.00 $ 1.46 $ 0.20 Dividends Declared per Common Share $ 0.9925 $ 0.9025 $ 0.8200

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Federal Income Tax Reform On December 22, 2017, comprehensive changes in United States federal income taxes were enacted through legislation commonly known as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act makes 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 eliminates federal bonus depreciation for utilities effective September 28, 2017 and, effective January 1, 2018, limits interest deductibility for non-utility businesses and limits the deductibility of certain officer compensation. Although most of the provisions of the Tax Act are not effective until 2018, GAAP requires that some effects must be recognized in 2017. Under the asset and liability method of accounting for income taxes used by the Company, deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. The deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which the temporary differences are expected to reverse. At the date of enactment of the Tax Act, the Company had net deferred tax liabilities for its regulated activities and net deferred tax assets for non-regulated activities. 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, based on the assumption that PNM and TNMP will be required to return the benefit to ratepayers over time. PNM’s NM 2016 Rate Case (Note 17) reflects that assumption by including an amortization of the estimated benefit of the reduction in existing deferred federal income taxes as a reduction to customer rates over a twenty-one year period beginning in 2018. In addition, in January 2018, the PUCT issued an order requiring Texas utilities, including TNMP, to begin recording regulatory liabilities for the effects of the Tax Act with the stated purpose of reflecting those effects in the utility bills of Texas ratepayers. In December 2017, the SEC issued Staff Accounting Bulletin No. 118, which provides guidance to address the application of GAAP to reflect the Tax Act in circumstances where all information and analysis of the Tax Act is not yet available or complete. This bulletin provides for up to a one-year period in which to complete the required analyses and accounting for the impacts of the Tax Act. The Company believes it has made reasonable estimates of the effects of the Tax Act and reflected the impacts in the Consolidated Financial Statements. However, the reported effects on the Company’s deferred tax assets and liabilities, regulatory assets and liabilities, and income tax expense are provisional and it is possible that changes to U.S. Treasury regulations, IRS interpretations of the provisions of the Tax Act, actions by the NMPRC, PUCT, and FERC, or the Company’s further analysis of historical records could cause these estimates to change. The adjustments to deferred income taxes recorded as increases in regulatory liabilities and income tax expense as a result of the enactment of the Tax Act are presented below: PNM TNMP Corporate and Other Consolidated (In thousands) Net increase in regulatory liabilities $ 402,501 $ 146,451 $ — $ 548,952 Net decrease in deferred income tax liabilities (deferred income tax assets) 372,895 138,586 (19,990 ) 491,491 Net deferred income tax expense $ 29,606 $ 7,865 $ 19,990 $ 57,461 GAAP requires that the impacts of adjusting existing deferred tax assets and liabilities for a change in an income tax rate be recognized in income tax expense during the period of enactment, including impacts that are reflected in AOCI. This results in the tax effects of items within AOCI not reflecting the appropriate tax rate and being stranded in AOCI. In February 2018, the FASB issued Accounting Standards Update 2018-02 - Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income to address this issue by allowing entities to reclassify the income tax effects of the Tax Act on items within AOCI to retained earnings. The Company records in AOCI, net of income taxes, unamortized gains and losses related to PNM’s defined benefit pension plans to the extent not attributed to regulated operations, unrealized gains on PNM’s available-for-sale securities, and unrealized gains and losses on cash flow hedges related to PNMR’s interest rate swaps. When amounts are reclassified from AOCI to the Consolidated Statement of Earnings, the Company recognizes the related income tax expense (benefit) at the tax rate in effect at that time. As permitted by ASU 2018-02, as of December 31, 2017, the Company reclassified the stranded federal income tax effects of the Tax Act on items recorded in AOCI, resulting in a net increase in retained earnings of $17.6 million . See Note 19. PNMR PNMR’s income taxes consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ — $ — $ — Current state income tax (188 ) (527 ) (1,376 ) Deferred federal income tax 119,182 60,892 5,488 Deferred state income tax 11,632 3,886 12,305 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Total income taxes $ 130,340 $ 63,278 $ 15,075 PNMR’s provision for income taxes 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, 2017 2016 2015 (In thousands) Federal income tax at statutory rates $ 79,016 $ 68,311 $ 16,154 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Flow-through of depreciation items 1,147 1,227 1,485 Earnings attributable to non-controlling interest in Valencia (5,256 ) (5,082 ) (5,218 ) State income tax, net of federal benefit 5,398 4,537 (1,781 ) Impairment of state net operating loss carryforwards 819 (311 ) 5,278 Impairment of state production tax credits — — 3,092 Allowance for equity funds used during construction (3,331 ) (1,732 ) (3,650 ) Reversal of deferred items related to BART at SJGS — — 1,826 Impairment of charitable contribution carryforward 909 — 2,042 Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization (2,225 ) (1,877 ) — Federal income tax rate change 57,461 — — Excess tax benefits related to stock compensation awards (2,324 ) — — Other (988 ) (822 ) (2,811 ) Total income taxes $ 130,340 $ 63,278 $ 15,075 Effective tax rate 57.73 % 32.42 % 32.66 % The components of PNMR’s net accumulated deferred income tax liability were: December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss $ 98,301 $ 160,901 Regulatory liabilities related to income taxes 189,501 64,657 Federal tax credit carryforwards 71,849 78,675 Shutdown of SJGS Units 2 and 3 2,204 53,434 Other 45,656 75,805 Total deferred tax assets 407,511 433,472 Deferred tax liabilities: Depreciation and plant related (690,909 ) (1,102,458 ) Investment tax credit (55,731 ) (56,017 ) Regulatory assets related to income taxes (61,956 ) (66,378 ) CTC (5,670 ) (12,715 ) Pension (56,070 ) (57,287 ) Regulatory asset for shutdown of SJGS Units 2 and 3 (31,887 ) — Other (52,498 ) (79,267 ) Total deferred tax liabilities (954,721 ) (1,374,122 ) Net accumulated deferred income tax liabilities $ (547,210 ) $ (940,650 ) 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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (393,440 ) Change in tax effects of income tax related regulatory assets and liabilities (16,444 ) Tax effect of mark-to-market adjustments (4,724 ) Tax effect of excess pension liability (3,421 ) Adjustment for uncertain income tax positions 2,677 Reclassification of unrecognized tax benefits (2,677 ) Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization (2,225 ) Federal income tax rate change 548,952 Cumulative effect adjustment for excess tax benefit related to stock compensation awards 10,382 Alternative minimum tax carryforward reclassified to receivable (8,336 ) Other (216 ) Deferred income taxes $ 130,528 PNM PNM’s income taxes (benefit) consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ 118 $ (10,290 ) $ (7,934 ) Current state income tax (1,112 ) (1,907 ) (1,988 ) Deferred federal income tax 73,308 49,123 (6,827 ) Deferred state income tax 9,527 4,969 5,333 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Total income taxes (benefit) $ 81,555 $ 40,922 $ (12,758 ) 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, 2017 2016 2015 (In thousands) Federal income tax (benefit) at statutory rates $ 59,139 $ 46,501 $ (4,579 ) Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Flow-through of depreciation items 1,103 1,185 1,465 Earnings attributable to non-controlling interest in Valencia (5,256 ) (5,082 ) (5,218 ) State income tax, net of federal benefit 4,926 3,921 (2,162 ) Impairment of state net operating loss carryforwards 627 (213 ) 3,619 Allowance for equity funds used during construction (3,032 ) (1,457 ) (3,650 ) Reversal of deferred items related to BART at SJGS — — 1,826 Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization (2,225 ) (1,877 ) — Federal income tax rate change 29,606 — — Allocation of excess tax benefit related to stock compensation awards (1,708 ) — — Other (1,339 ) (1,083 ) (2,717 ) Total income taxes (benefit) $ 81,555 $ 40,922 $ (12,758 ) Effective tax rate 48.27 % 30.80 % 97.52 % The components of PNM’s net accumulated deferred income tax liability were: December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss $ 67,719 $ 117,922 Regulatory liabilities related to income taxes 152,059 60,940 Federal tax credit carryforwards 60,085 59,156 Shutdown of SJGS Units 2 and 3 2,204 53,434 Other 23,801 41,700 Total deferred tax assets 305,868 333,152 Deferred tax liabilities: Depreciation and plant related (544,270 ) (891,578 ) Investment tax credit (55,731 ) (56,017 ) Regulatory assets related to income taxes (52,392 ) (56,577 ) Pension (51,774 ) (50,134 ) Regulatory asset for shutdown of SJGS Units 2 and 3 (31,887 ) — Other (18,826 ) (27,512 ) Total deferred tax liabilities (754,880 ) (1,081,818 ) Net accumulated deferred income tax liabilities $ (449,012 ) $ (748,666 ) 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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (299,654 ) Change in tax effects of income tax related regulatory assets and liabilities (16,332 ) Tax effect of mark-to-market adjustments (4,110 ) Tax effect of excess pension liability (3,421 ) Adjustment for uncertain income tax positions 2,614 Reclassification of unrecognized tax benefits (2,614 ) Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization (2,225 ) Federal income tax rate change 402,501 Allocation of cumulative effect adjustment for excess tax benefit related to stock compensation awards 7,770 Other (1,980 ) Deferred income taxes $ 82,549 TNMP TNMP’s income taxes consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ 2,472 $ 9,445 $ 1,603 Current state income tax 1,765 1,729 1,639 Deferred federal income tax 27,304 12,690 20,904 Deferred state income tax (29 ) (28 ) (21 ) Total income taxes $ 31,512 $ 23,836 $ 24,125 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, 2017 2016 2015 (In thousands) Federal income tax at statutory rates $ 23,475 $ 22,928 $ 23,131 State income tax, net of federal benefit 1,198 1,132 1,065 Federal income tax rate change 7,865 — — Allocation of excess tax benefit related to stock compensation awards (616 ) — — Other (410 ) (224 ) (71 ) Total income taxes $ 31,512 $ 23,836 $ 24,125 Effective tax rate 46.98 % 36.39 % 36.5 % The components of TNMP’s net accumulated deferred income tax liability at December 31, were: December 31, 2017 2016 (In thousands) Deferred tax assets: Regulatory liabilities related to income taxes $ 43,103 $ 3,718 Other 3,762 6,016 Total deferred tax assets 46,865 9,734 Deferred tax liabilities: Depreciation and plant related (135,647 ) (201,017 ) CTC (5,670 ) (12,715 ) Regulatory assets related to income taxes (9,564 ) (9,800 ) Loss on reacquired debt (6,890 ) (11,937 ) Pension (4,296 ) (7,153 ) AMS (7,707 ) (8,928 ) Other (3,506 ) (3,969 ) Total deferred tax liabilities (173,280 ) (255,519 ) Net accumulated deferred income tax liabilities $ (126,415 ) $ (245,785 ) 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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (119,370 ) Change in tax effects of income tax related regulatory assets and liabilities (112 ) Federal income tax rate change 146,451 Other 306 Deferred income taxes $ 27,275 Other Disclosures GAAP requires that the Company 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 (expenses) is as follows: PNMR PNM TNMP (In thousands) Balance at December 31, 2014 $ 15,031 $ 12,228 $ — Additions based on tax positions related to 2015 1,214 1,214 — Additions (reductions) for tax positions of prior years (9,790 ) (9,790 ) — Settlement payments — — — Balance at December 31, 2015 6,455 3,652 — Additions based on tax positions related to 2016 242 242 — Additions (reductions) for tax positions of prior years 55 55 — Settlement payments — — — Balance at December 31, 2016 6,752 3,949 — Additions based on tax positions related to 2017 262 262 — Additions (reductions) for tax positions of prior years 2,415 2,352 63 Settlement payments — — — Balance at December 31, 2017 $ 9,429 $ 6,563 $ 63 Included in the balance of unrecognized tax benefits at December 31, 2017 are $8.9 million , $6.1 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 2018 . In 2016, the Company undertook an analysis of interest income and interest expense applicable to federal income tax matters. The analysis encompassed the impacts of IRS examinations, amended income tax returns, and filings for carrybacks of tax matters to previous taxable years applicable to all years not closed under the IRS rules. As a result of this effort, PNMR received net refunds from the IRS of $6.5 million . Of the refunds, $2.1 million was recorded as a reduction of the net interest receivable and $5.1 million was recorded as interest income, which was partially offset by $0.7 million of interest expense. In addition, PNMR incurred $0.9 million in professional fees related to the analysis. Of the net pre-tax impacts aggregating $3.5 million , $2.6 million is reflected in the PNM segment, $0.3 million in the TNMP segment, and $0.6 million in the Corporate and Other segment. Estimated interest income related to refunds the Company expects to receive is included in Other income and estimated interest expense and penalties related to potential cash settlements are included in Interest Charges in the Consolidated Statements of Earnings. Interest income (expense) related to income taxes was as follows: PNMR PNM TNMP (In thousands) 2017 $ — $ — $ — 2016 $ 4,398 $ 3,625 $ 345 2015 $ — $ — $ — There was no accumulated accrued interest receivable or payable related to income taxes as of December 31, 2017 and 2016. The Company files a federal consolidated and several consolidated and separate state income tax returns. The tax years prior to 2013 are closed to examination by either federal or state taxing authorities other than Arizona. The tax years prior to 2012 are closed to examination by Arizona taxing authorities. Other tax years are open to examination by federal and state taxing authorities. At December 31, 2017 , the Company has $410.4 million of federal net operating loss carryforwards that expire beginning in 2030 and $71.8 million of federal tax credit carryforwards that expire beginning in 2023. State net operating losses expire beginning in 2017 and vary from federal due to differences between state and federal tax law. In 2013, New Mexico House Bill 641 reduced the New Mexico corporate income tax rate from 7.6% to 5.9% . The rate reduction is being phased-in from 2014 to 2018. In accordance with GAAP, PNMR and PNM adjusted accumulated deferred income taxes to reflect the tax rate at which the balances are expected to reverse during the period that includes the date of enactment, which was in the year ended December 31, 2013. At that time, the portion of the adjustment related to PNM’s regulated activities was recorded as a reduction in deferred tax liabilities and an increase in a regulatory liability, based on the assumption that PNM will be required to return the benefit to customers over time. PNM’s NM 2016 Rate Case (Note 17) reflects that assumption. In addition, the portion of the adjustment that was not related to PNM’s regulated activities was recorded as a reduction in deferred tax assets and an increase in income tax expense. Changes in the estimated timing of reversals of deferred tax assets and liabilities resulted in refinements of the impacts of this change in tax rates being recorded periodically until the rate reduction was fully phased-in. Adjustments to deferred income taxes recorded as increases (decreases) in the regulatory liability and income tax expense are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: Regulatory liability $ (10,109 ) $ (10,109 ) $ — Income tax expense $ (1,259 ) $ (1,179 ) $ — December 31, 2016: Regulatory liability $ (7,132 ) $ (7,132 ) $ — Income tax expense $ 712 $ 804 $ — December 31, 2015: Regulatory liability $ (1,903 ) $ (1,903 ) $ — Income tax expense $ (674 ) $ (470 ) $ — 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 was continuously 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. As a result of the net operating loss carryforwards for income tax purposes created by bonus depreciation and reduced future income taxes payable resulting from New Mexico House Bill 641, certain tax carryforwards are not expected to be utilized before their expiration. In accordance with GAAP, PNMR and PNM have impaired the tax carryforwards which were not expected to be utilized prior to their expiration. The impairments, net of federal tax benefit, for 2015 through 2017 are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ 819 $ 627 $ — Charitable contribution carryforwards $ 909 $ — $ — December 31, 2016: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ (311 ) $ (213 ) $ — Charitable contribution carryforwards $ — $ — $ — December 31, 2015: State tax credit carryforwards $ 3,092 $ — $ — State net operating loss carryforwards $ 5,278 $ 3,619 $ — Charitable contribution carryforwards $ 2,042 $ — $ — 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, 2017 and 2016 are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: State tax credit carryforwards $ 2,487 $ — $ — State net operating loss carryforwards $ 1,131 $ 839 $ — Charitable contribution carryforwards $ 952 $ — $ — December 31, 2016: State tax credit carryforwards $ 3,986 $ — $ — State net operating loss carryforwards $ 361 $ 248 $ — Charitable contribution carryforwards $ 659 $ — $ — The NMPRC’s order in the NM 2015 Rate Case (Note 17) approved PNM’s request to record a regulatory asset, which net of federal income taxes, amounted to $2.1 million , to recover a 2014 impairment of PNM’s New Mexico net operating loss carryforward resulting from an extension of the income tax provision for fifty percent bonus depreciation. The regulatory asset is being recovered through rates over two years. The settlement of the NM 2016 Rate Case (Note 17) included $3.3 million , net of federal tax, resulting from impairment of a 2015 New Mexico net operating loss as an addition to the remaining unamortized balance of the regulatory asset from the NM 2015 Rate Case. The total balance will be recovered over three years beginning in 2018. These impacts, net of amortization, are reflected in income tax expense on the Consolidated Statement of Earnings.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2017
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. GAAP requires a plan sponsor 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. GAAP requires unrecognized prior service costs and unrecognized gains or losses to be recorded in AOCI and subsequently amortized. The amortization of these incurred costs is included as pension and postretirement benefit periodic cost or income in subsequent years. 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 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 Internal Revenue Code. Information concerning the investments is contained in Note 8. 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. GAAP requires that actual gains and losses on pension and OPEB plan assets be 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. 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 Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) PBO at beginning of year $ 621,751 $ 597,900 $ 67,061 $ 64,198 Service cost — — — — Interest cost 26,908 30,307 2,887 3,304 Actuarial (gain) loss 26,298 39,463 3,050 4,318 Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) PBO at end of year 623,983 621,751 68,423 67,061 Fair value of plan assets at beginning of year 543,601 557,923 60,624 62,082 Actual return on plan assets 69,389 31,597 7,450 3,301 Employer contributions — — — — Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) Fair value of plan assets at end of year 562,016 543,601 63,499 60,624 Funded status – asset (liability) for pension benefits $ (61,967 ) $ (78,150 ) $ (4,924 ) $ (6,437 ) Actuarial (gain) loss results from changes in: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (in thousands) Discount rates $ 27,547 $ 41,849 $ 3,528 $ 5,055 Demographic experience (1,249 ) (334 ) (517 ) (556 ) Other assumption and experience — (2,052 ) 39 (181 ) $ 26,298 $ 39,463 $ 3,050 $ 4,318 The following table presents pre-tax information about prior service cost and net actuarial (gain) loss in AOCI as of December 31, 2017 . PNM Plan TNMP Plan December 31, 2017 December 31, 2017 Prior service cost Net actuarial (gain) loss Net actuarial (gain) loss (In thousands) Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year $ (1,450 ) $ 159,149 $ — Experience (gain) loss — (9,288 ) (621 ) Regulatory asset (liability) adjustment — 5,387 621 Amortization recognized in net periodic benefit cost (income) 405 (6,722 ) — Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year $ (1,045 ) $ 148,526 $ — Amortization expected to be recognized in 2018 $ (405 ) $ 6,653 $ — The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ — $ — $ — Interest cost 26,908 30,307 28,255 Expected return on plan assets (33,803 ) (35,416 ) (39,323 ) Amortization of net (gain) loss 16,006 13,820 14,820 Amortization of prior service cost (965 ) (965 ) (965 ) Net periodic benefit cost $ 8,146 $ 7,746 $ 2,787 TNMP Plan Service cost $ — $ — $ — Interest cost 2,887 3,304 3,043 Expected return on plan assets (3,779 ) (3,943 ) (4,420 ) Amortization of net (gain) loss 923 700 782 Amortization of prior service cost — — — Net periodic benefit cost (income) $ 31 $ 61 $ (595 ) 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 Plan 2017 2016 2015 Discount rate for determining December 31 PBO 4.05 % 4.51 % 5.29 % Discount rate for determining net periodic benefit cost (income) 4.51 % 5.29 % 4.48 % Expected return on plan assets 6.40 % 6.50 % 6.80 % Rate of compensation increase N/A N/A N/A TNMP Plan Discount rate for determining December 31 PBO 4.01 % 4.49 % 5.39 % Discount rate for determining net periodic benefit cost (income) 4.49 % 5.39 % 4.39 % Expected return on plan assets 6.40 % 6.50 % 6.80 % 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 2018 net periodic cost to increase $5.3 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 13.4% and 12.8% for the year ended December 31, 2017 . 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 has chosen to implement this strategy known as Liability Driven Investing (“LDI”) by increasing the liability matching investments as the funded status of the pension plans improves. These liability matching investments are currently fixed income securities. Prior to 2018, the pension plans targeted asset allocation was 21% equities, 65% fixed income, and 14% alternative investments. The Company is contemplating modifying the LDI strategy by decreasing the liability matching fixed income investments portfolio from 65% to 50% beginning in 2018. The new asset allocation will be implemented in 2018. Equity investments are primarily in domestic securities that include large, mid, and small capitalization companies. The pension plans have a 6% targeted allocation to equities of companies domiciled primarily in developed countries outside of the United States. This category includes actively managed international and 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 investment is structured as an open-ended, commingled private real estate portfolio that invests in a diversified portfolio of assets including commercial property and multi-family housing. See Note 8 for fair value information concerning assets held by the pension plans. The following pension benefit payments are expected to be paid: PNM Plan TNMP Plan (In thousands) 2018 $ 49,221 $ 5,929 2019 48,639 5,215 2020 47,069 5,108 2021 45,246 5,373 2022 44,232 4,856 2023 - 2027 201,389 22,085 The Company does not expect to make any cash contributions to the pension plans in 2018-2021, but expects to contribute $5.1 million and zero to the PNM and TNMP pension plans in 2022, based on current law, including recent amendments to funding requirements, and estimates of portfolio performance. These anticipations were developed using current funding assumptions with discount rates of 4.0% to 5.1% . Actual amounts to be funded in the future will be dependent on the actuarial assumptions at that time, including the appropriate discount rate. 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 Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) APBO at beginning of year $ 94,269 $ 84,674 $ 12,830 $ 13,106 Service cost 96 140 143 186 Interest cost 4,025 4,346 556 677 Participant contributions 3,069 2,690 379 520 Actuarial (gain) loss (1,601 ) 17,877 (381 ) (96 ) Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Plan design changes — (3,724 ) — — APBO at end of year 89,897 94,269 12,279 12,830 Fair value of plan assets at beginning of year 72,694 72,952 8,544 9,111 Actual return on plan assets 14,222 5,923 1,642 476 Employer contributions 332 2,863 685 — Participant contributions 3,069 2,690 379 520 Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Fair value of plan assets at end of year 80,356 72,694 10,002 8,544 Funded status – asset (liability) $ (9,541 ) $ (21,575 ) $ (2,277 ) $ (4,286 ) Actuarial (gain) loss results from changes in: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (in thousands) Discount rates $ 3,536 $ 6,569 $ 613 $ 1,112 Claims, contributions, and demographic experience (5,845 ) 19,562 (994 ) (102 ) Assumed participation rate — (6,335 ) — (1,013 ) Mortality rate — (691 ) — (93 ) Medical benefits 1,425 (1,228 ) — — Dental trend assumption (717 ) — — — $ (1,601 ) $ 17,877 $ (381 ) $ (96 ) In the year ended December 31, 2017 , actuarial gains of $10.6 million were recorded as adjustments to regulatory assets for the PNM Plan. For the TNMP Plan, actuarial gains of $1.6 million were recorded as adjustments to regulatory liabilities. The following table presents the components of net periodic benefit cost: Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ 96 $ 140 $ 204 Interest cost 4,025 4,346 4,089 Expected return on plan assets (5,230 ) (5,483 ) (5,610 ) Amortization of net (gain) loss 3,682 1,145 1,966 Amortization of prior service credit (1,663 ) (30 ) (642 ) Net periodic benefit cost $ 910 $ 118 $ 7 TNMP Plan Service cost $ 143 $ 186 $ 247 Interest cost 556 677 608 Expected return on plan assets (456 ) (490 ) (520 ) Amortization of net (gain) loss (79 ) (40 ) — Amortization of prior service cost — — — Net periodic benefit cost $ 164 $ 333 $ 335 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 Plan 2017 2016 2015 Discount rate for determining December 31 APBO 4.00 % 4.47 % 5.34 % Discount rate for determining net periodic benefit cost 4.47 % 5.34 % 4.45 % Expected return on plan assets 7.50 % 7.70 % 7.70 % Rate of compensation increase N/A N/A N/A TNMP Plan Discount rate for determining December 31 APBO 4.00 % 4.47 % 5.34 % Discount rate for determining net periodic benefit cost 4.47 % 5.34 % 4.45 % Expected return on plan assets 5.40 % 5.70 % 5.70 % 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 2018 postretirement benefit cost to increase $0.7 million and $0.1 million (analogous changes would result from a 1% increase). The actual rate of return for the PNM and TNMP postretirement benefit plans was 20.5% and 19.4% for the year ended December 31, 2017 . The following table shows the assumed health care cost trend rates for the PNM postretirement benefit plan: PNM Plan December 31, 2017 2016 Health care cost trend rate assumed for next year 6.5 % 6.8 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 5.0 % 5.0 % Year that the rate reaches the ultimate trend rate 2024 2024 The following table shows the impact of a one-percentage-point change in assumed health care cost trend rates: PNM Plan 1-Percentage- Point Increase 1-Percentage- Point Decrease (In thousands) Effect on total of service and interest cost $ 72 $ (111 ) Effect on APBO $ 1,452 $ (2,235 ) 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 are wholly borne by the participants. TNMP reached the cost limit at the end of 2001. 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. 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 other postretirement benefit plans have a target asset allocation of 70% equities and 30% fixed income. See Note 8 for fair value information concerning assets held by the other postretirement benefit plans. The following other postretirement benefit payments, which reflect expected future service and are net of participant contributions, are expected to be paid: PNM Plan TNMP Plan (In thousands) 2018 $ 7,829 $ 708 2019 7,730 725 2020 7,605 748 2021 7,442 774 2022 7,132 795 2023 - 2027 31,250 4,126 PNM expects to make no contributions to the PNM OPEB plan for 2018-2022. TNMP expects to make contributions to the TNMP OPEB totaling $0.3 million in 2018 and $1.4 million for 2019-2022. Executive Retirement Programs For the executive retirement programs, the following table presents information about the PBO and funded status of the plans: PNM Plan TNMP Plan Year Ended Year Ended 2017 2016 2017 2016 (In thousands) PBO at beginning of year $ 16,212 $ 16,105 $ 787 $ 794 Service cost — — — — Interest cost 697 812 33 40 Actuarial (gain) loss 674 768 44 47 Benefits paid (1,466 ) (1,473 ) (93 ) (94 ) PBO at end of year – funded status 16,117 16,212 771 787 Less current liability 1,501 1,510 93 93 Non-current liability $ 14,616 $ 14,702 $ 678 $ 694 The following table presents pre-tax information about net actuarial loss in AOCI as of December 31, 2017 . December 31, 2017 PNM Plan TNMP Plan (In thousands) Amount in AOCI not yet recognized in net periodic benefit cost at beginning of year $ 2,299 $ — Experience (gain) loss 674 44 Regulatory asset (liability) adjustment (391 ) (44 ) Amortization recognized in net periodic benefit cost (income) (132 ) — Amount in AOCI not yet recognized in net periodic benefit cost at end of year $ 2,450 $ — Amortization expected to be recognized in 2018 $ 151 $ — The following table presents the components of net periodic benefit cost: Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ — $ — $ — Interest cost 697 812 760 Amortization of net (gain) loss 313 256 325 Amortization of prior service cost — — — Net periodic benefit cost $ 1,010 $ 1,068 $ 1,085 TNMP Plan Service cost $ — $ — $ — Interest cost 33 40 36 Amortization of net (gain) loss 9 2 5 Amortization of prior service cost — — — Net periodic benefit cost $ 42 $ 42 $ 41 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 Plan 2017 2016 2015 Discount rate for determining December 31 PBO 4.05 % 4.51 % 5.29 % Discount rate for determining net periodic benefit cost 4.51 % 5.29 % 4.48 % 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 Plan Discount rate for determining December 31 PBO 4.01 % 4.49 % 5.39 % Discount rate for determining net periodic benefit cost 4.49 % 5.39 % 4.39 % 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. The following executive retirement plan payments, which reflect expected future service, are expected: PNM Plan TNMP Plan (In thousands) 2018 $ 1,501 $ 93 2019 1,473 91 2020 1,441 89 2021 1,405 85 2022 1,363 81 2023 - 2027 6,014 324 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, 2017 2016 2015 (In thousands) PNMR 401(k) plan $ 16,452 $ 17,762 $ 16,725 Non-qualified plan $ 3,702 $ 2,017 $ 1,436 PNM 401(k) plan $ 12,120 $ 13,397 $ 12,679 Non-qualified plan $ 2,834 $ 1,535 $ 1,090 TNMP 401(k) plan $ 4,332 $ 4,365 $ 4,046 Non-qualified plan $ 868 $ 482 $ 346

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [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. In 2011, the Company changed its approach to awarding stock-based compensation. As a result, no stock options have been granted since 2010 and awards of restricted stock have increased. 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. Beginning with 2017 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. Re-pricing of stock options is prohibited unless specific shareholder approval is obtained. 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 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, 2017 , 2016 , and 2015 was $6.2 million , $5.6 million , and $4.9 million . Stock compensation expense of $4.4 million , $4.2 million , and $3.6 million was charged to PNM and $1.8 million , $1.5 million , and $1.3 million was charged to TNMP. At December 31, 2017 , PNMR had unrecognized compensation expense related to stock awards of $3.8 million , which is expected to be recognized over an average of 1.53 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. The FASB issued Accounting Standards Update 2016-09 – Compensation –- Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting to simplify several aspects of the accounting for share-based payment transactions and eliminate diversity in practice. PNMR’s historical accounting for stock compensation complies with ASU 2016-09, except for the treatment of the income tax consequences of awards and the presentation of reductions to taxes payable on the Consolidated Statements of Cash Flows. Prior to ASU 2016-09, benefits resulting from income tax deductions in excess of compensation cost recognized under GAAP for vested restricted stock and on exercised stock options (collectively, “excess tax benefits”) were recorded to equity provided the excess tax benefits reduced income taxes payable. Deficiencies resulting from tax deductions related to stock awards that were below recognized compensation cost upon vesting and on canceled stock options were recorded to equity. PNMR had not recorded excess tax benefits to equity since 2009 because it is in a net operating loss position for income tax purposes. ASU 2016-09 requires that all excess tax benefits and deficiencies be recorded to tax expense and classified as cash flows from operating activities. PNMR adopted ASU 2016-09 as of January 1, 2017 and recorded excess tax benefits of $2.3 million in the year ended December 31, 2017 of which $1.7 million was allocated to PNM and $0.6 million was allocated to TNMP. As required by ASU 2016-09, PNMR recorded the excess tax benefits that were not recognized in prior years, due to its net operating loss position, as a cumulative effect adjustment of $10.4 million on January 1, 2017, increasing retained earnings and decreasing accumulated deferred income taxes on the Consolidated Balance Sheets. When excess tax benefits are used to reduce income taxes payable, the benefit will be reflected in cash flows from operating activities. 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, which will not be received prior to vesting, 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 2017 2016 2015 Expected quarterly dividends per share $ 0.2425 $ 0.2200 $ 0.2000 Risk-free interest rate 1.50 % 0.94 % 0.92 % Market-Based Shares Dividend yield 2.67 % 2.74 % 2.87 % Expected volatility 20.80 % 20.44 % 18.73 % Risk-free interest rate 1.54 % 0.97 % 1.00 % 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 Average Exercise Price Outstanding at December 31, 2016 218,316 $ 27.59 305,874 $ 12.29 Granted 248,271 $ 23.06 — $ — Exercised (273,530 ) $ 21.01 (109,433 ) $ 15.89 Forfeited (4,012 ) $ 29.96 — $ — Expired — $ — (3,000 ) $ 30.50 Outstanding at December 31, 2017 189,045 $ 31.11 193,441 $ 9.98 PNMR’s stock-based compensation program provides for performance and market targets through 2018. Included as granted and as exercised in the above table are 49,682 previously awarded shares that were earned for the 2014 through 2016 performance measurement period and ratified by the Board in February 2017 (based upon achieving market targets at “target” levels, weighted at 60% , and not meeting performance targets, weighted at 40% ). Excluded from the above table are 97,697 previously awarded shares that were earned for the 2015 through 2017 performance measurement period and ratified by the Board in February 2018 (based upon achieving market targets at above “target” levels, weighted at 40% , and performance targets at below “target” levels, weighted at 60% ), as well as maximums of 137,036 and 133,632 shares for the three -year performance periods ending in 2018 and 2019 that would be awarded if all performance and market criteria are achieved at maximum levels and all executives remain eligible. In March 2012, the Company entered into a retention award agreement with its Chairman, President, and Chief Executive Officer under which she was to receive 135,000 shares of PNMR’s common stock if PNMR met specific market targets at the end of 2016 and she remained an employee of the Company. Under the agreement, she received 35,000 of the total shares in 2015 since PNMR achieved the specified market targets at the end of 2014. The specified market target was achieved at the end of 2016 and the Board ratified her receiving the remaining 100,000 shares, which are included in the above table, in February 2017. The retention award was made under the PEP and was approved by the Board on February 28, 2012. Effective as of January 1, 2015, the Company entered into a retention award agreement with its Executive Vice President and Chief Financial Officer under which he would receive awards of restricted stock if PNMR meets specified performance targets at the end of 2016 and 2017 and he remains an employee of the Company. If PNMR achieved the specific performance target for the period from January 1, 2015 through December 31, 2016, he was to receive $100,000 of PNMR common stock based on the market value per share on the grant date in early 2017. 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, which are included in the above table. 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 the market value per share on the grant date in early March 2018. The above table does not include the restricted stock shares granted in 2018. The retention award was made under the PEP and was approved by the Board on December 9, 2014. In March 2015, the Company entered into an additional retention award agreement with its Chairman, President, and Chief Executive Officer under which she would receive 53,859 shares of PNMR’s common stock if PNMR meets certain performance targets at the end of 2019 and she remains an employee of the Company. Under the agreement, she would receive 17,953 of the total shares if PNMR achieves specified performance targets at the end of 2017. The specified performance target was achieved at the end of 2017 and the Board ratified her receiving the 17,953 shares in February 2018. The above table does not include any restricted stock shares under this retention award agreement. The retention award was made under the PEP and was approved by the Board on February 26, 2015. At December 31, 2017 , the aggregate intrinsic value of stock options outstanding, all of which are exercisable, was $5.9 million with a weighted-average remaining contract life of 1.55 years. At December 31, 2017 , no outstanding stock options had an exercise price greater than the closing price of PNMR common stock on that date. 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 2017 2016 2015 Weighted-average grant date fair value $ 23.06 $ 26.49 $ 20.34 Total fair value of restricted shares that vested (in thousands) $ 5,747 $ 5,079 $ 6,507 Stock Options Weighted-average grant date fair value of options granted $ — $ — $ — Total fair value of options that vested (in thousands) $ — $ — $ — Total intrinsic value of options exercised (in thousands) $ 2,234 $ 1,242 $ 2,350

Construction Program and Jointl

Construction Program and Jointly-Owned Electric Generating Plants	12 Months Ended
	Dec. 31, 2017
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 $309.1 million in 2017 , 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 $145.5 million during 2017 . On a consolidated basis, PNMR’s expenditures for additions to utility plant were $500.5 million in 2017 . 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, 2017 , PNM’s interests and investments in jointly-owned generating facilities are: Station (Fuel Type) Plant in Service Accumulated Depreciation (1) Construction Work in Progress Composite Interest (In thousands) SJGS (Coal) (2) $ 920,950 $ (522,750 ) $ 8,512 46.30 % PVNGS (Nuclear) (3) $ 918,830 $ (353,054 ) $ 35,038 10.20 % Four Corners Units 4 and 5 (Coal) $ 204,432 $ (100,914 ) $ 61,755 13.00 % Luna (Gas) $ 70,995 $ (27,023 ) $ (13 ) 33.33 % (1) Includes cost of removal. (2) See Note 16 for a discussion of the December 2017 shutdown of SJGS Units 2 and 3 and the restructuring of the ownership of SJGS Unit 4. (3) 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 Note 16 for additional information about SJGS, including the shutdown of SJGS Units 2 and 3 in December 2017 and the restructuring of SJGS ownership. Palo Verde Nuclear Generating Station PNM is a participant in the three units of PVNGS, also known as the Arizona Nuclear Power Project, 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 7 for additional information concerning the PVNGS leases, including PNM’s purchase of the assets underlying certain of the leases at the expiration of the leases on January 15, 2016, and Note 17 for the NMPRC’s treatment of those purchases in the ratemaking process. 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. In April 2010, APS entered into a Municipal Effluent Purchase and Sale Agreement that provides effluent water rights necessary for cooling purposes at PVNGS through 2050. 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 leased from the Navajo Nation and is also subject to an easement from the federal government. APS, on behalf of the Four Corners participants, negotiated amendments to an existing facility lease with the Navajo Nation, which extends the Four Corners leasehold interest from 2016 to 2041. See Note 16 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: 2018 2019 2020 2021 2022 Total (In millions) PNM $ 295.0 $ 339.0 $ 313.4 $ 315.8 $ 493.7 $ 1,756.9 TNMP 185.8 170.5 170.0 170.5 170.1 866.9 Corporate and Other 19.4 17.3 17.0 17.5 17.1 88.3 Total PNMR $ 500.2 $ 526.8 $ 500.4 $ 503.8 $ 680.9 $ 2,712.1 The construction expenditure estimates are under continuing review and subject to ongoing adjustment, as well as to Board review and approval. The above construction expenditures include $7.9 million for environmental upgrades at Four Corners, $72.8 million for 50 MW of new solar facilities included in PNM’s 2018 renewable energy procurement plan, approximately $170.0 million for an anticipated expansion of PNM’s transmission system, and approximately $100.0 million in 2021 and $300.0 million in 2022 for the costs of replacement resources related to the potential shutdown of SJGS Units 1 and 4 in 2022. See Note 17. Expenditures for the expansion of PNM’s transmission system and SJGS replacement sources are subject to obtaining necessary approvals of the NMPRC. PNM will be required to file CCN applications with the NMPRC to obtain those approvals.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2017
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 80% of PNM’s total ARO liabilities is 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, as well as SJGS and Four Corners 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, 2014 $ 104,170 $ 103,182 $ 848 Liabilities incurred — — — Liabilities settled (730 ) (506 ) (224 ) Accretion expense 8,625 8,543 71 Revisions to estimated cash flows (170 ) (170 ) — Liability at December 31, 2015 111,895 111,049 695 Liabilities incurred — — — Liabilities settled (14 ) (14 ) — Accretion expense 9,170 9,098 59 Revisions to estimated cash flows 6,468 6,468 — Liability at December 31, 2016 127,519 126,601 754 Liabilities incurred (1) 1,854 1,853 — Liabilities settled (968 ) (944 ) (24 ) Accretion expense 10,680 10,603 63 Revisions to estimated cash flows 7,594 7,594 — Liability at December 31, 2017 $ 146,679 $ 145,707 $ 793 (1) Represents the obligation related to the additional ownership interest in SJGS Unit 4 that PNM acquired on December 31, 2017 due to the restructuring of the ownership of SJGS.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Overview There are various claims and lawsuits pending against the Company. The Company also 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 (Note 17) proceedings in the normal course of its business. 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. Nevertheless, 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. In accordance with GAAP, 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 $2.0 million , $4.2 million , and $4.9 million for the years ended December 31, 2017, 2016, and 2015 into the qualified and non-qualified trust funds. The market value of the trusts at December 31, 2017 and 2016 was $293.7 million and $253.9 million . 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 DOE entered into a settlement agreement, which established a process for the payment of claims for costs incurred. Under the settlement agreement, APS must submit claims annually for payment of allowable costs. In 2015, PNM recorded $5.6 million , including $3.6 million credited back to PNM’s customers, for its share of the settlement under this process for costs incurred from July 2011 through June 2015. Thereafter, PNM began recording estimated claims quarterly. The settlement agreement has been extended to December 31, 2019. PNM estimates that it will incur approximately $57.7 million (in 2016 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 fuel is consumed. At December 31, 2017 and 2016 , PNM had a liability for interim storage costs of $12.3 million and $12.1 million included in other deferred credits. PVNGS has sufficient capacity at its on-site 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 United States 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. On June 8, 2012, the DC Circuit issued its decision on a challenge by several states and environmental groups of the NRC’s rulemaking regarding temporary storage and permanent disposal of high level nuclear waste and spent nuclear fuel. The petitioners had challenged the NRC’s 2010 update to the agency’s Waste Confidence Decision and temporary storage rule (the “Waste Confidence Decision”). The DC Circuit found that the Waste Confidence Decision update constituted a major federal action, which, consistent with NEPA, requires either an environmental impact statement or a finding of no significant impact from the NRC’s actions. The DC Circuit found that the NRC’s evaluation of the environmental risks from spent nuclear fuel was deficient and, therefore, remanded the Waste Confidence Decision update for further action consistent with NEPA. On September 6, 2012, the NRC commissioners issued a directive to the NRC staff to proceed with development of a generic EIS to support an updated Waste Confidence Decision, which was issued in September 2013. On August 26, 2014, the NRC approved a final rule on the environmental effects of continued storage of spent nuclear fuel. The continued storage rule adopted the findings of the generic EIS regarding the environmental impacts of storing spent fuel at any reactor site after the reactor’s licensed period of operations. As a result, those generic impacts do not need to be re-analyzed in the environmental reviews for individual licenses. The August 2014 final rule has been subject to continuing legal challenges before the NRC and the United States Court of Appeals. On May 19, 2016, the NRC denied petitions filed by multiple petitioners to revise the August 2014 rule. The DC Circuit issued an order upholding the August 2014 rule on June 3, 2016 and denied a subsequent petition for rehearing on August 8, 2016. In 2011, the National Association of Regulatory Utility Commissioners and the Nuclear Energy Institute challenged, in the DC Circuit, DOE’s 2010 determination of the adequacy of the one tenth of a cent per KWh fee (the “one-mill fee”) paid by the nation’s commercial nuclear power plant owners pursuant to their individual contracts with the DOE. On January 3, 2014, the DOE notified Congress of its intention to suspend collection of the one-mill fee, subject to Congress’ disapproval, as ordered by the DC Circuit. On May 16, 2014, the DOE adjusted the fee to zero . PNM cannot predict if there will be challenges to this action or the potential outcome of such challenges. 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 have the primary role to regulate visibility requirements by promulgating SIPs. 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 is demonstrated that the emissions from these sources cause or contribute to visibility impairment in any Class I area, then BART must be installed by 2018. For all future SIP planning period, states must evaluate whether additional emissions reduction measures may be needed to continue making reasonable progress toward natural visibility conditions. On January 10, 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. Although EPA’s decision to revisit the rule is not a determination on the merits of the issues raised in those petitions, EPA is likely to propose and take comment on additional revisions to the regional haze rules in the near future. PNM is evaluating the potential impacts of this rule. SJGS BART Compliance – SJGS is a source that is subject to the statutory obligations of the CAA to reduce visibility impacts. The State of New Mexico submitted its SIP on the regional haze and interstate transport elements of the visibility rules for review by EPA in June 2011. The SIP required SJGS to reduce NOx emissions by installing selective non-catalytic reduction technology (“SNCR”) as BART. Nevertheless, in August 2011, EPA published a FIP, which included a regional haze BART determination for SJGS that required installation of selective catalytic reduction technology (“SCR”) as BART on all four units by September 21, 2016. PNM, as the operating agent for SJGS, engaged in discussions with NMED and EPA regarding an alternative to the FIP and SIP, which resulted in a non-binding agreement that included the retirement of SJGS Units 2 and 3 by the end of 2017 and the installation of SNCRs on Units 1 and 4 by the later of January 31, 2016 or 15 months after EPA approval of a revised SIP (the “RSIP”). EPA issued final rules, which became effective on November 10, 2014, approving the RSIP and withdrawing the FIP. In addition to the SNCR equipment required by the RSIP, the NSR permit, which was required to be obtained in order to install the SNCRs, specified that SJGS Units 1 and 4 be converted to balanced draft technology (“BDT”). The requirement to install BDT was made binding and enforceable in the NSR permit issued by NMED that accompanied the RSIP submitted to the EPA. EPA’s rule approving the RSIP specifically references the NSR permit by including a condition that requires “modification of the fan systems on Units 1 and 4 to achieve ‘balanced’ draft configuration ….” Following issuance of the FIP, PNM estimated the total cost to install SCRs on all four units of SJGS to be between approximately $824 million and $910 million , including BDT equipment to assist with compliance with the NAAQS requirements and to eliminate fugitive boiler emissions. PNM had previously indicated it estimated the cost of SNCRs on all four units of SJGS to be between approximately $85 million and $90 million based on a conceptual design study. Along with the SNCR installation, additional BDT equipment would be required to be installed, the cost of which had been estimated to total between approximately $105 million and $110 million for all four units of SJGS. Based upon its SJGS ownership interest at that time, PNM’s share of the costs described above would have been about 46.3% . Following the February 2013 development of the alternative BART compliance plan, PNM began taking steps to prepare for the potential installation of SNCR and BDT equipment on Units 1 and 4 and entered into contracts for the work. Installation of SNCRs on Unit 1 and BDT equipment on both Units 1 and 4 was completed in 2015 and installation of SNCRs on Unit 4 was completed in January 2016, which dates were within the timeframe contained in the RSIP. PNM’s share of the total costs for SNCRs and BDT equipment was $77.7 million . See Note 17 for information concerning the NMPRC’s treatment of BDT in PNM’s NM 2015 Rate Case. Although operating costs will be reduced due to the retirement of SJGS Units 2 and 3, the operating costs for SJGS Units 1 and 4 have increased with the installation of SNCR and BDT equipment. On December 20, 2013, PNM made a filing with the NMPRC requesting certain approvals necessary to effectuate the RSIP. In this filing, PNM requested: • Permission to retire SJGS Units 2 and 3 at December 31, 2017 and to recover over 20 years their net book value at that date along with a regulated return on those costs • A CCN to include PNM’s ownership of PVNGS Unit 3, amounting to 134 MW, as a resource to serve New Mexico retail customers at a proposed value of $2,500 per KW, effective January 1, 2018 • An order allowing cost recovery for PNM’s share of the installation of SNCR and BDT equipment to comply with NAAQS requirements on SJGS Units 1 and 4, not to exceed a total cost of $82 million PNM’s filing also addressed replacement of the capacity from the shutdown of SJGS Units 2 and 3 (which would reduce PNM’s ownership in SJGS by 418 MW), a possible increase in PNM’s ownership in SJGS Unit 4, the identification of a new natural gas-fired generation source, and 40 MW of new utility-scale solar PV. PNM received approval to construct the 40 MW of solar PV facilities in its 2015 Renewable Energy Plan. See Note 17. PNM’s requests in the December 20, 2013 NMPRC filing were based on the status of the negotiations among the SJGS owners at that time regarding ownership restructuring and other matters (see SJGS Ownership Restructuring Matters below). On October 1, 2014, PNM and certain intervenors filed a stipulation with the NMPRC that would have settled all matters in PNM’s filing. On April 8, 2015, the Hearing Examiner in the case issued a Certification of Stipulation, which recommended the NMPRC reject the stipulation as proposed. In June 2015, a NMPRC Commissioner issued an order designating a facilitator to determine whether an uncontested settlement among some or all of the parties in this case could be accomplished. On August 13, 2015, as a result of the facilitation process, PNM, the staff of the NMPRC, the NMAG, Western Resource Advocates, and the Coalition for Clean Affordable Energy filed a settlement agreement with the NMPRC. NMIEC, Interwest Energy Alliance, and New Mexico Independent Power Producers subsequently joined in this agreement and NEE filed in opposition to the agreement. The stipulating parties agreed that the October 2014 stipulation should be approved, as modified by the settlement agreement (collectively, the “Stipulated Settlement”). The Hearing Examiner scheduled a hearing on PNM’s application concerning BART for SJGS to begin on October 13, 2015. NEE previously filed motions before the NMPRC requesting that four of the five NMPRC commissioners recuse themselves, alleging they had improper ex-parte communications, were biased, and had pre-judged the outcome of the BART case. Each of the four commissioners declined to recuse themselves. On October 5, 2015, NEE filed a Petition for a Writ of Mandamus and Request for Stay in the NM Supreme Court requesting the four commissioners be recused from this case and that PNM’s application be dismissed. On October 9, 2015, the NM Supreme Court issued orders that allowed the hearing conducted by the Hearing Examiner to proceed, but ordered that any action by the NMPRC be stayed, pending a decision by the NM Supreme Court on NEE’s petition. The hearing on the Stipulated Settlement was held from October 13, 2015 through October 20, 2015. Oral argument on NEE’s petition was held before the NM Supreme Court on November 9, 2015. On November 9, 2015, the NM Supreme Court denied NEE’s petition. On December 16, 2015, following oral argument, the NMPRC issued an order adopting the Stipulated Settlement. As provided in that order: • PNM would retire SJGS Units 2 and 3 (PNM’s ownership interest was 418 MW) by December 31, 2017 and recover, over 20 years, 50% of their undepreciated net book value at that date and earn a regulated return on those costs • PNM was granted a CCN to acquire an additional 132 MW in SJGS Unit 4, effective January 1, 2018, with an initial book value of zero , plus the costs of SNCR and other capital additions (an aggregate of $20.7 million ) • PNM was granted a CCN for 134 MW of PVNGS Unit 3 with an initial rate base value equal to the book value as of December 31, 2017, including transmission assets associated with PVNGS Unit 3 (an aggregate of $154.9 million ) • No later than December 31, 2018, and before entering into a binding agreement for post-2022 coal supply for SJGS, PNM will file its position and supporting testimony in a NMPRC case to determine the extent to which SJGS should continue serving PNM’s retail customers’ needs after mid-2022; all parties to the stipulation agree to support this case being decided within six months (see Other SJGS Matters below and Note 17) • PNM was authorized to acquire 65 MW of SJGS Unit 4 as merchant plant; PNM and PNMR commit that no further coal-fired merchant plant will be acquired at any time by PNM, PNMR, or any PNM affiliate; PNM is not precluded from seeking a CCN to include the 65 MW or other coal capacity in rate base • Beginning January 1, 2020, for every MWh produced by 197 MW of coal-fired generation from PNM’s ownership share of SJGS, PNM will acquire and retire one MWh of RECs or allowances that include a zero-CO 2 emission attribute compliant with EPA’s Clean Power Plan; this REC retirement is in addition to what is required to meet the RPS; the cost of these RECs are to be capped at $7.0 million per year and will be recovered in rates; PNM should purchase EPA-compliant RECs from New Mexico renewable generation unless those RECs are more costly • PNM would accelerate recovery of SNCR costs on SJGS Units 1 and 4 so that the costs are fully recovered by July 1, 2022 (cost recovery for PNM’s BDT project is discussed in Note 17) • PNM would not recover approximately $20 million of other costs incurred in connection with CAA compliance • The NMPRC would issue a Notice of Proposed Dismissal in PNM’s 2014 IRP At December 31, 2015, PNM’s carrying value for its current ownership share of SJGS Units 2 and 3 included plant in service of $468.2 million , accumulated depreciation and amortization (including cost of removal) of $193.3 million , and construction work in progress of $2.2 million for a net book value of $277.1 million . PNM estimated the undepreciated net book value of SJGS Units 2 and 3 at December 31, 2017 would be approximately $255.3 million , 50% of which would be recovered over a 20 -year period, including a return on the unrecovered amount at PNM’s WACC. At December 31, 2015, PNM recorded a $127.6 million regulatory disallowance to reflect the write-off of the 50% of the estimated December 31, 2017 net book value that would not be recovered. A regulatory disallowance of $21.6 million was also recorded at December 31, 2015 for other unrecoverable costs based on the approved Stipulated Settlement. The new coal mine reclamation arrangement entered into in conjunction with the new coal supply agreement (“SJGS CSA”), described under Coal Supply below, resulted in a $16.5 million increase in the liability recorded for coal mine reclamation. The expense recorded for this increase and the above disallowances, aggregating $165.7 million , is included in regulatory disallowances and restructuring costs on the Consolidated Statements of Earnings. In addition, the shutdown of SJGS Units 2 and 3 would result in the reversal of certain deferred income tax items. The estimated impact of these tax items resulted in an expense of $1.8 million being recorded at December 31, 2015, which amount is included in income tax expense on the Consolidated Statement of Earnings. During 2016, PNM revised its estimates of the December 31, 2017 projected book value of SJGS Units 2 and 3 and the other unrecoverable costs, which resulted in a net expense of $3.7 million , consisting of a $0.9 million expense due to a revision of the estimated net book value of SJGS Units 2 and 3, a $4.5 million expense related to a refinement of the estimated liability for coal mine reclamation resulting from the new coal mine reclamation arrangement, and a $1.7 million reduction of the other unrecoverable costs that is reflected in regulatory disallowances and restructuring costs on the Consolidated Statement of Earnings. In addition, PNMR Development recorded an expense of $0.6 million in 2016 for costs it was obligated to reimburse the other SJGS participants under the restructuring arrangement, which is included in other deductions on the Consolidated Statement of Earnings. At December 31, 2016, the carrying value for PNM’s current ownership share of SJGS Units 2 and 3 was comprised of plant in service of $471.8 million and accumulated depreciation and amortization (including cost of removal) of $203.9 million for a net undepreciated book value of $267.9 million , offset by 50% (which equaled $128.6 million ) of the anticipated December 31, 2017 net undepreciated book value of SJGS Units 2 and 3 that will not be recovered, resulting in the net carrying value for SJGS Units 2 and 3 being $139.3 million at December 31, 2016. SJGS Unit 3 was shut down on December 19, 2017 and SJGS Unit 2 was shut down on December 20, 2017. At shutdown, the carrying value for PNM’s ownership share of SJGS Units 2 and 3 was comprised of plant in service of $439.4 million and accumulated depreciation and amortization (including cost of removal) of $188.3 million for a net book value of $251.1 million . As of December 31, 2017, these amounts were written off and offset by previously recorded losses of $128.6 million . PNM also recorded a regulatory asset of $125.5 million for the 50% of the undepreciated book value that is to be recovered from ratepayers pursuant to the December 15, 2015 NMPRC order described above. This resulted in the reversal of previously recorded losses of $3.0 million being recorded at December 31, 2017. In addition, PNM recognized a reversal of $1.0 million of previously recorded losses for other unrecoverable costs. These reversals, which total $4.0 million , are included in regulatory disallowances and restructuring costs on the Consolidated Statements of Earnings. On January 14, 2016, NEE filed a notice of appeal with the NM Supreme Court of the NMPRC’s December 16, 2015 order. On July 22, 2016, NEE filed a brief alleging that the NMPRC’s decision violated New Mexico statutes and NMPRC regulations because PNM did not adequately consider replacement resources other than those proposed by PNM, the NMPRC did not require PNM to adequately address and mitigate ratepayer risk, the NMPRC unlawfully shifted the burden of proof, and the NMPRC’s decision was arbitrary and capricious. Answer briefs refuting NEE’s claims were filed on November 2, 2016 by PNM, the NMPRC, and certain intervenors. Reply briefs were filed by NEE on January 9, 2017 and the parties presented oral argument to the court on January 25, 2017. The court has not rendered a decision on the appeal and there is no required time frame for a decision. In addition, on March 31, 2016, NEE filed a complaint with the NMPRC against PNM regarding the financing provided by NM Capital to facilitate the sale of SJCC (see Coal Supply below). The complaint alleges that PNM failed to comply with its discovery obligation in the SJGS abandonment case and requests the NMPRC investigate whether the financing transactions could adversely affect PNM’s ability to provide electric service to its retail customers. PNM responded to the complaint on May 4, 2016. The NMPRC has taken no action on this matter. PNM cannot currently predict the outcome of these matters. SJGS Ownership Restructuring Matters – Prior to December 31, 2017, SJGS was jointly owned by PNM and eight other entities, including three participants that operate in the State of California. Furthermore, each participant did not have the same ownership interest in each unit. The SJPPA that governs the operation of SJGS expires on July 1, 2022. In connection with requirements to install SNCR and BDT equipment at SJGS, the California participants indicated that, under California law, they might be prohibited from making significant capital improvements to SJGS and expressed the intent to exit their ownership in SJGS by December 31, 2017. One other participant also expressed a similar intent to exit ownership in the plant. As a result, the SJGS participants negotiated a restructuring of the ownership in SJGS and addressed the obligations of the exiting participants for plant decommissioning, mine reclamation, environmental matters, and certain future operating costs, among other items. Prior to the restructuring, the exiting participants owned 50.0% of SJGS Unit 3 and 38.8% of SJGS Unit 4, but none of SJGS Units 1 and 2, and PNM owned 50.0% of SJGS Units 1, 2, and 3 and 38.5% of SJGS Unit 4. Following mediated negotiations, the SJGS participants executed the San Juan Project Restructuring Agreement (“SJGS RA”) on July 31, 2015. The SJGS RA provides the essential terms of restructured ownership and addresses other related matters, including that the exiting participants remain obligated for their proportionate shares of environmental, mine reclamation, and certain other legacy liabilities that are attributable to activities that occurred prior to their exit. PNMR Development became a party to the SJGS RA and agreed to acquire an ownership interest in SJGS Unit 4 on the December 31, 2017 exit date, but had obligations related to Unit 4 before then. Under the SJGS RA, PNM would acquire 132 MW and PNMR Development would acquire 65 MW of the capacity in SJGS Unit 4 from the exiting owners on the exit date for no initial cost other than funding capital improvements, including the costs of installing SNCR and BDT equipment. PNMR Development’s share of the costs of installing SNCR and BDT equipment amounted to $7.6 million . Consistent with the NMPRC order, PNM acquired the rights and obligations related to the 65 MW from PNMR Development effective on December 31, 2017 in order to facilitate dispatch of power from that capacity. The SJGS RA became effective contemporaneously with the effectiveness of the new SJGS CSA. The effectiveness of the new SJGS CSA was dependent on the closing of the purchase of the existing coal mine operation by a new mine operator, which as discussed in Coal Supply below, occurred on January 31, 2016. The SJGS RA sets forth the terms under which PNM acquired the coal inventory of the exiting SJGS participants as of January 1, 2016 and supplied coal to the exiting participants for the period from January 1, 2016 through December 31, 2017, which arrangement provided economic benefits that were passed on to PNM’s customers through the FPPAC. The SJGS RA also included provisions whereby the exiting owners made payments to certain of the remaining participants, not including PNM, related to the restructuring. PNMR Development’s share of the restructuring fee was recorded at December 31, 2015 and the $3.1 million impact is included in other income on the Consolidated Statements of Earnings. On September 25, 2015, PNM made an application at FERC seeking certain approvals necessary for implementation of the restructured SJGS participation agreements. FERC approved the application on December 30, 2015. SJGS Units 2 and 3 were shut down in December 2017 and the restructuring of SJGS ownership under the SJGS RA occurred on December 31, 2017, including PNM’s acquisition of the additional 132 MW and 65 MW ownership interests in SJGS Unit 4 as set forth above. In accordance with the FERC chart of accounts, plant in service for utility assets acquired is to be recorded at the original cost of the assets less accumulated depreciation. Since PNM did not pay for any costs incurred prior to the effective date of the SJGS RA, PNM increased both plant in service and accumulated depreciation for the original cost of the acquired interests at that date, estimated to be $261.8 million , on December 31, 2017. As ordered by the NMPRC, PNM will treat the 65 MW interest as merchant utility plant that will be excluded from retail rates. In anticipation of the transfer of ownership, PNM entered into agreements to sell the power from 36 MW of that capacity to a third party at a fixed price for the period January 1, 2018 through June 30, 2022 (Note 8). Beginning in 2018, SJGS is jointly owned by five entities. Including the 65 MW considered to be merchant plant, PNM’s ownership share is 77.3% in SJGS Unit 4 and an aggregate of 66.3% in SJGS Units 1 and 4. Other SJGS Matters – The SJPPA requires PNM, as operating agent, to obtain approval of capital improvement project expenditures from participants who have an ownership interest in the relevant unit or property common to more than one unit. The SJPPA also obligates PNM to take reasonable and prudent actions necessary for the successful and proper operation of SJGS if the participants fail to approve the requested expenditures. PNM presented the SNCR project, including BDT equipment, to the SJGS participants in Unit 1 and Unit 4 for approval in October 2013. The project was approved for Unit 1, but the Unit 4 project, which included some of the California participants, was not approved. PNM subsequently submitted several requests to the owners of Unit 4 for approval of certain expenditures critical to comply with the time frame in the RSIP, as well as requests to approve the total forecasted project expenses. The required majority of Unit 4 owners did not approve these requests. PNM, in its capacity as operating agent, subsequently issued several “Prudent Utility Practice” notices under the SJPPA indicating PNM was undertaking certain critical activities to comply with regulatory requirements and keep the Unit 4 SNCR project on schedule. Although the SJGS RA results in an agreement among the SJGS participants enabling compliance with current CAA requirements, it is possible that the financial impact of climate change regulation or legislation, other environmental regulations, the result of litigation, and other business considerations, could jeopardize the economic viability of SJGS or the ability or willingness of individual participants to continue participation in the plant. PNM’s 2017 IRP (Note 17) filed with the NMPRC on July 3, 2017 presented resource portfolio plans for scenarios that assumed SJGS will operate beyond the end of the current coal supply agreement that runs through J

Regulatory and Rate Matters

Regulatory and Rate Matters	12 Months Ended
	Dec. 31, 2017
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”) On December 11, 2014, PNM filed an application for revision of electric retail rates based upon a calendar year 2016 future test year (“FTY”) period. The application proposed a revenue increase of $107.4 million , effective January 1, 2016. Several parties filed briefs, which alleged that PNM’s application was incomplete and challenged other aspects of PNM’s filing. On April 17, 2015, the Hearing Examiner in the case issued an Initial Recommended Decision to the NMPRC recommending that the NMPRC find PNM’s application incomplete and reject it on the grounds that it did not comply with the FTY rule. The Hearing Examiner cited procedural defects in the filing, including a lack of fully functional electronic files and appropriate justification of certain costs in the future test year period. On May 13, 2015, the NMPRC voted to accept the Initial Recommended Decision regarding the completeness of PNM’s application and dismissed PNM’s application. On August 27, 2015, PNM filed a new 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 . PNM’s new application was based on a FTY period beginning October 1, 2015, which met the NMPRC’s May 2015 interpretation of the FTY statute discussed below, and proposed a ROE of 10.5% . The primary drivers of PNM’s identified revenue deficiency were the cost of infrastructure investments, including depreciation expense based on an updated depreciation study, and a decline in energy sales as a result of PNM’s successful energy efficiency programs and economic factors. The new application included several proposed changes in rate design to establish fair and equitable pricing across rate classes and to better align cost recovery with cost causation. Specific rate design proposals included higher customer and demand charges, a revenue decoupling pilot program applicable to residential and small commercial customers, a re-allocation of revenue among PNM’s customer classes, a new economic development rate, and continuation of PNM’s renewable energy rider. PNM requested that the proposed new rates become effective beginning in July 2016. On March 2, 2016, the NMPRC required PNM to file supplemental testimony regarding the treatment of renewable energy in PNM’s FPPAC. See Renewable Portfolio Standard below. A public hearing on the proposed new rates was held in April 2016. Subsequent to this hearing, 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 (Note 7). A subsequent public hearing was held in June 2016. After the June hearing, PNM and other parties were ordered to file supplemental briefs and to provide final recommended revenue requirements that incorporated fuel savings that PNM implemented effective January 1, 2016 from PNM’s SJGS coal supply agreement (“SJGS CSA”). PNM’s filing indicated that recovery for fuel related costs would be reduced by approximately $42.9 million reflecting the current SJGS CSA (Note 16), which also reduced the request for base non-fuel related revenues by $0.2 million to $121.5 million . On August 4, 2016, the Hearing Examiner in the case issued a recommended decision (the “August 2016 RD”). The August 2016 RD proposed an increase in non-fuel revenues of $41.3 million compared to the $121.5 million increase requested by PNM. Major components of the difference in the increase in non-fuel revenues proposed in the August 2016 RD, included: • A ROE of 9.575% compared to the 10.5% requested by PNM • Disallowing recovery of the entire $163.3 million purchase price for the January 15, 2016 purchases of the assets underlying three leases of portions of PVNGS Unit 2 (Note 7); the August 2016 RD proposed that power from the previously leased assets, aggregating 64.1 MW of capacity, be dedicated to serving New Mexico retail customers with those customers being charged for the costs of fuel and operating and maintenance expenses (other than property taxes, which were $0.8 million per year at that time), but the customers would not bear any capital or depreciation costs other than those related to improvements made after the date of the original leases • Disallowing recovery from retail customers of the rent expense, which aggregates $18.1 million per year, under the four leases of capacity in PVNGS Unit 1 that were extended for eight years beginning January 15, 2015 and the one lease of capacity in PVNGS Unit 2 that was extended for eight years beginning January 15, 2016 (Note 7) and related property taxes, which were $1.5 million per year at that time; the August 2016 RD proposed that power from the leased assets, aggregating 114.6 MW of capacity, be dedicated to serving New Mexico retail customers with those customers being charged for the costs of fuel and operating and maintenance expense, except that customers would not bear rental costs or property taxes • Disallowing recovery of the costs of converting SJGS Units 1 and 4 to BDT, which is required by the NSR permit for SJGS, (Note 16); PNM’s share of the costs of installing the BDT equipment was $52.3 million of which $40.0 million was included in rate base in PNM’s rate request • Disallowing recovery of $4.5 million of amounts recorded as regulatory assets and deferred charges The August 2016 RD 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. The August 2016 RD also proposed that all fuel costs be removed from base rates and be recovered through the FPPAC. The August 2016 RD would credit retail customers with 100% of the New Mexico jurisdictional portion of revenues from “refined coal” (a third-party pre-treatment process) at SJGS. In addition, the August 2016 RD would remove recovery of the costs of power obtained from New Mexico Wind from the FPPAC and include recovery of those costs through PNM’s renewable energy rider discussed below. The August 2016 RD recommended continuation of the renewable energy rider and certain aspects of PNM’s proposals regarding rate design, but would not approve certain other rate design proposals or PNM’s request for a revenue decoupling pilot program. The August 2016 RD proposed approving PNM’s proposals for revised depreciation rates (except the August 2016 RD would require depreciation on Four Corners be calculated based on a 2041 life rather than the 2031 life proposed by PNM), the inclusion of construction work in progress in rate base, and ratemaking treatment of the “prepaid pension asset.” The August 2016 RD did not preclude PNM from supporting the prudence of the PVNGS purchases and lease renewals in its next general rate case and seeking recovery of those costs. PNM disagreed with many of the key conclusions reached by the Hearing Examiner in the August 2016 RD and filed exceptions to defend its prudent utility investments. Other parties also filed exceptions to the August 2016 RD. 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 • Full recovery of the rent expense and property taxes associated with the extended leases for capacity, aggregating 114.6 MW, in Palo Verde Units 1 and 2 • 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 • Recovery of assumed operating and maintenance expense savings of $0.3 million annually related to BDT On September 30, 2016, PNM filed a notice of appeal with the NM Supreme Court regarding the order in the NM 2015 Rate Case. Subsequently, NEE, NMIEC, and ABCWUA filed notices of cross-appeal to PNM’s appeal. On October 26, 2016, PNM filed a statement of issues related to its appeal with the NM Supreme Court, which stated PNM is appealing the NMPRC’s determination that 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 BDT equipment on SJGS Units 1 and 4. Specifically, PNM’s statement indicated it is appealing the following elements of the NMPRC’s order: • Disallowance of recovery of the full purchase price, representing fair market value, of the 64.1 MW of capacity in PVNGS Unit 2 purchased in January 2016 • Disallowance of the recovery of the undepreciated costs of capitalized improvements made during the period the 64.1 MW of capacity was leased by PNM • Disallowance of recovery of 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 • Disallowance of recovery of the costs of converting SJGS Units 1 and 4 to BDT The issues that are being appealed by the various cross-appellants include: • The NMPRC allowing PNM to recover the costs of the lease extensions for the 114.6 MW of PVNGS Units 1 and 2 and any of the purchase price for the 64.1 MW in PVNGS Unit 2 • The NMPRC allowing PNM to recover the costs incurred under the new coal supply contract for Four Corners • The revised method to collect PNM’s fuel and purchased power costs under the FPPAC • The final rate design • The NMPRC allowing PNM to include the “prepaid pension asset” in rate base NEE subsequently filed a motion for a partial stay of the order at the NM Supreme Court. This motion was denied. The NM Supreme Court stated that the court’s intent was to request that PNM reimburse ratepayers for any amount overcharged should the cross-appellants prevail on the merits. On February 17, 2017, PNM filed its Brief in Chief, and pursuant to the court’s rules, the briefing schedule was completed on July 21, 2017. Oral argument at the NM Supreme Court was held on October 30, 2017. Although appeals of regulatory actions of the NMPRC have a priority at the NM Supreme Court under New Mexico law, there is no required time frame for the court to act on the appeals. GAAP requires that a loss is to be recognized when it is probable that a loss has been incurred and the amount of loss can be reasonably estimated. When there is a range of the amount of the probable loss, the minimum amount of the range is to be accrued unless an amount within the range is a better estimate than any other amount. As of September 30, 2016, PNM evaluated the accounting consequences of the order in the NM 2015 Rate Case and the likelihood of being successful on the issues it is appealing in the NM Supreme Court as required under GAAP. The evaluation indicated it is reasonably possible that PNM will be successful on the issues it is appealing. If the NM Supreme Court rules in PNM’s favor on some or all of the issues, those issues would be remanded back to the NMPRC for further action. At that time, PNM estimated that it would take a minimum of 15 months, from the date PNM filed its appeal, for the NM Supreme Court to render a decision and for the NMPRC to take action on any remanded issues. During such time, the rates specified in the order would remain in effect. PNM concluded that a range of probable loss resulted from the NMPRC order in the NM 2015 Rate Case; that the minimum amount of loss was 15 months of capital cost recovery that the order disallowed for PNM’s investments in the PVNGS Unit 2 purchases, PVNGS Unit 2 capitalized improvements, and BDT; and that no amount within the range of possible loss was a better estimate than any other amount. Accordingly, PNM recorded a pre-tax regulatory disallowance of $6.8 million at September 30, 2016 for the capital costs that will not be covered during that 15 month appeal period. In addition, PNM recorded a pre-tax regulatory disallowance for $4.5 million of costs recorded as regulatory assets and deferred charges (which the order disallowed and which PNM did not challenge in its appeal) since PNM could no longer assert that those assets were probable of being recovered through the ratemaking process. The NMPRC’s order approved PNM’s request to record a regulatory asset to recover a 2014 impairment of PNM’s New Mexico net operating loss carryforward resulting from an extension of the income tax provision for fifty percent bonus depreciation. The impact, net of federal income taxes, amounting to $2.1 million was reflected as a reduction of income tax expense on the Consolidated Statement of Earnings. PNM also evaluated the accounting consequences of the issues that are being appealed by the cross-appellants. PNM does not believe the issues raised in the cross-appeals have substantial merit. Accordingly, PNM does not believe that the likelihood of the cross-appeals being successful is probable and, therefore, no loss was recorded in 2016 related to the issues subject to the cross-appeals. Since the NM Supreme Court did not issue a decision on the appeals related to the NM 2015 Rate Case by December 31, 2017, which was 15 months from the date of the NMPRC’s order in that case, PNM has reevaluated the accounting consequences of the order in the NM 2015 Rate Case. PNM continues to believe that it is reasonably possible that PNM will be successful on the issues it is appealing and that it is not probable the cross appeals will be successful. However, based on the proceedings to date in the appeal process and other actions by the NM Supreme Court, PNM now estimates that it will take an additional seven months from December 31, 2017 for the NM Supreme Court to issue a decision and any remanded issues to be addressed by the NMPRC. Accordingly, PNM recorded an additional loss of $3.1 million at December 31, 2017, representing an additional disallowance of seven months of capital cost recovery that the order disallowed. Further losses will be recorded if the currently estimated time frame for the NM Supreme Court to render a decision and for the NMPRC to take action on any remanded issues in extended. PNM continues to believe that the disallowed investments, which are the subject of PNM’s appeal, were prudent and that PNM is entitled to full recovery of those investments through the ratemaking process. Although PNM believes it is reasonably possible that its appeals will be successful, it cannot predict what decision the NM Supreme Court will reach or what further actions the NMPRC will take on any issues remanded to it by the court. If PNM’s appeal is unsuccessful, PNM would record further pre-tax losses related to the capitalized costs for any unsuccessful issues. The impacts of not recovering future contributions for decommissioning would be recognized in future periods reflecting that rates charged to customers would not recover those costs as they are incurred. The amounts of any such losses to be recorded would depend on the ultimate outcome of the appeal and NMPRC process, as well as the actual amounts reflected on PNM books at the time of the resolution. However, based on the book values recorded by PNM as of December 31, 2017, such losses could include: • The remaining costs to acquire the assets previously leased under three leases aggregating 64.1 MW of PVNGS Unit 2 capacity in excess of the recovery permitted under the NMPRC’s order; the net book value of such excess amount was $75.3 million , after considering the loss recorded in 2016 and 2017 • The undepreciated costs of capitalized improvements made during the period the 64.1 MW of capacity in PVNGS Unit 2 purchased by PNM in January 2016 was being leased by PNM; the net book value of these improvements was $39.1 million , after considering the loss recorded in 2016 and 2017 • The remaining costs to convert SJGS Units 1 and 4 to BDT; the net book value of these assets was $49.4 million , after considering the loss recorded in 2016 and 2017 Although PNM does not believe that the likelihood of the cross-appeals being successful is probable, it is unable to predict what decision the NM Supreme Court will reach. If the NM Supreme Court were to overturn all of the issues subject to the cross-appeals and, upon remand, the NMPRC did not provide any cost recovery of those items, PNM would write-off all of the costs to acquire the assets previously leased under three leases, aggregating 64.1 MW of PVNGS Unit 2 capacity, totaling $151.1 million (which amount includes $75.3 million that is the subject of PNM’s appeal discussed above) at December 31, 2017, after considering the loss recorded in 2016 and 2017. The impacts of not recovering costs for the lease extensions, new coal supply contract for Four Corners, and “prepaid pension asset” in rate base would be recognized in future periods reflecting that rates charged to customers would not recover those costs as they are incurred. The outcomes of the cross-appeals regarding the FPPAC and rate design should not have a financial impact to PNM. PNM is unable to predict the outcome of this matter. New Mexico 2016 General Rate Case (“NM 2016 Rate Case”) On December 7, 2016, PNM filed an application with the NMPRC for a general increase in retail electric rates. PNM did not include any of the costs disallowed in the NM 2015 Rate Case that are at issue in its pending appeal to the NM Supreme Court. Key aspects of PNM’s request were: • An increase in base non-fuel revenues of $99.2 million • Based on a FTY beginning January 1, 2018 (the NMPRC’s rules specify that a FTY is a 12 month period beginning up to 13 months after the filing of a rate case application) • ROE of 10.125% • Drivers of revenue deficiency ◦ Implementation of the modifications in PNM’s resource portfolio, which were previously approved by the NMPRC as part of the SJGS regional haze compliance plan (Note 16) ◦ Infrastructure investments, including environmental upgrades at Four Corners ◦ Declines in forecasted energy sales due to successful energy efficiency programs and other economic factors ◦ Updates in the FERC/retail jurisdictional allocations • Proposed changes to rate design to establish fair and equitable pricing across rate classes and to better align cost recovery with cost causation ◦ Increased customer and demand charges ◦ A “lost contribution to fixed cost” mechanism applicable to residential and small commercial customers to address the regulatory disincentive associated with PNM’s energy efficiency programs The NMPRC scheduled a public hearing to begin on June 5, 2017, ordered that a settlement conference should be held, and that any resulting stipulation should be filed by March 27, 2017. Settlement discussions were held, but no agreements were reached by March 27, 2017, after which the date for filing a stipulation was extended. In early May 2017, PNM and thirteen intervenors (the “Signatories”) entered into a comprehensive stipulation. On May 12, 2017, the Hearing Examiners issued an order rejecting the stipulation in its then current form, but allowed the Signatories to revise the stipulation. On May 23, 2017, the Signatories filed a revised stipulation that addressed the issues raised by the Hearing Examiners in their order. NEE was the sole party opposing the revised stipulation. The terms of the revised stipulation, which required NMPRC approval in order to take effect, included: • A revenue increase totaling $62.3 million , with an initial increase of $32.3 million beginning January 1, 2018 and the remaining increase beginning January 1, 2019 • A ROE of 9.575% • Full recovery of PNM’s investment in SCRs at Four Corners with a debt-only return • An agreement not to adjust non-fuel base rate changes to be effective prior to January 1, 2020 • An agreement to adjust the January 2019 increase for certain changes in federal corporate tax laws enacted prior to November 1, 2018 and effective and applicable to PNM by January 1, 2019 and to true-up PNM’s cost of debt for refinancing transactions through 2018 • Returning to customers over a three -year period the benefit of the reduction in the New Mexico corporate income tax rate (Note 11) to the extent attributable to PNM’s retail operations • PNM would withdraw its proposal for a “lost contribution to fixed cost” mechanism with the issue to be addressed in a future docket • PNM would perform a cost benefit analysis in its 2020 IRP of the impact of a possible early exit from Four Corners in 2024 and 2028 A hearing on the revised stipulation was held in August 2017. On October 31, 2017, the Hearing Examiners issued a Certification of Stipulation recommending a Modified Revised Stipulation. The significant changes to the revised stipulation in the Hearing Examiners’ Modified Revised Stipulation included: • Identifying PNM’s decision to continue its participation in Four Corners as imprudent • Disallowing PNM’s ability to collect a debt or equity return on its $90.1 million investment in SCRs at Four Corners and on $58.0 million of projected capital improvements during the period July 1, 2016 through December 31, 2018 • Recommending a temporary disallowance of $36.8 million of PNM’s projected capital improvements at SJGS through December 31, 2018 On December 20, 2017, the NMPRC issued an Order Partially Adopting Certification of Stipulation, which approved the Hearing Examiners’ Certification of Stipulation with certain changes. Substantive changes from the Certification of Stipulation included requiring the impacts of changes related to the reduction in the federal corporate income tax rate be implemented effective January 1, 2018 rather than January 1, 2019 and deferring further consideration regarding the prudency of PNM’s decision to continue its participation in Four Corners to a future proceeding. On December 28, 2017 PNM filed a Motion for Rehearing and Request for Oral Argument asking the NMPRC to vacate their December 20, 2017 order and allow the parties to present oral argument. Additionally, several signatories to the revised stipulation filed a Joint Motion for Partial Rehearing asking that the NMPRC approve the Revised Stipulation without modification. On January 2, 2018, NEE filed a response urging the NMPRC to reject PNM’s Motion. On January 3, 2018, the NMPRC vacated its December 20, 2017 order and granted the motions for rehearing. The rehearing was held on January 10, 2017. The NMPRC issued a Revised Order Partially Adopting Certification of Stipulation dated January 10, 2018 (the “Revised Order”). The Revised Order approved the Hearing Examiners’ Certification of Stipulation with certain changes including: • Requiring the impacts of changes related to the reduction in the federal corporate income tax rate and PNM’s cost of debt be implemented in 2018 rather than January 1, 2019 • Deferring further consideration regarding the prudency of PNM’s decision to continue its participation in Four Corners to PNM’s next rate case • Disallowing PNM’s ability to collect an equity return on its $90.1 million investment in SCRs at Four Corners and on $58.0 million of projected capital improvements during the period July 1, 2016 through December 31, 2018, but allowed recovery of the total $148.1 million of investments with a debt-only return • Requiring PNM to reduce the requested $62.3 million increase in non-fuel revenue by $9.1 million • Implementation of the first phase of the rate increase for services rendered, rather than bills rendered, on or after February 1, 2018 and of the second for services rendered on or after January 1, 2019 On January 16, 2018, PNM requested clarifying changes to the Revised Order to adjust the $9.1 million reduction to $4.4 million , asserting that $4.7 million of the reduction was duplicative. On January 17, 2018, the NMPRC issued an order approving the adjustment requested by PNM. On January 19, 2018, PNM and the Signatories filed a Joint Notice of All Signatories of Acceptance of the Order on Notice of Acceptance. On January 31, 2018, the NMPRC issued an order closing the docket in the NM 2016 Rate Case. After implementation of changes to the federal corporate income tax rate and cost of debt, the final order results in a net increase to PNM’s non-fuel revenue requirement of $10.3 million . PNM implemented 50% of the approved increase for service rendered on or after February 1, 2018 and will implement the rest of the increase for service rendered on or after January 1, 2019. GAAP requires PNM to recognize a loss to reflect that PNM will not earn an equity return on $148.1 million of investments at Four Corners. As of December 31, 2017, PNM recorded a pre-tax regulatory disallowance of $27.9 million . The amount of the loss was calculated by determining the present value of disallowed cash flows, which equals the difference between the cash flows resulting from recovery of those investments at PNM’s embedded cost of debt and the cash flows with a full return on investment (including an equity component), and discounting the differences at PNM’s WACC. On February 7, 2018, NEE filed a notice of appeal with the NM Supreme Court asking the court to review the NMPRC’s decisions in the NM 2016 Rate Case. The notice does not set forth the basis of the appeal, which, as required by the court’s rules, is to be filed by March 9, 2018. PNM cannot predict the outcome of this matter. Proceeding Regarding Definition of Future Test Year On May 27, 2015, the NMPRC approved an order that defines a FTY as a period that begins no later than 45 days following the filing of an application to increase rates. PNM disagreed with the interpretation adopted by the NMPRC and believes that the correct interpretation of the New Mexico FTY statute allows a FTY to begin up to 13 months after the filing of an application. On June 25, 2015, PNM filed a notice of appeal to the NM Supreme Court, challenging the NMPRC’s June 3, 2015 written order. On July 31, 2015, PNM and the NMPRC filed a joint motion for a temporary 30 -day stay and remand of PNM’s appeal so that the NMPRC could reconsider its FTY order in PNM’s 2014 rate case. The NM Supreme Court remanded this matter back to the NMPRC. On November 30, 2015, the NMPRC modified its previous order to provide for a FTY to begin up to 13 months after the filing of a rate case application. PNM and the NMPRC filed for dismissal of the appeal and the NM Supreme Court dismissed the appeal on February 15, 2016. Investigation/Rulemaking Concerning NMPRC Ratemaking Policies On March 22, 2017, the NMPRC issued an order opening an investigation and rulemaking to simplify and increase “the transparency of NMPRC rate cases by reducing the number of issues litigated in rate cases,” and provide a “more level playing field among intervenors and NMPRC staff on the one hand, and the utilities on the other.” The order posed the following questions: whether a standardized method should be established for determining ROE; should the ROE be subject to reward or penalty based on utilities meeting or failing to meet certain metrics, which could include customer complaints, outages, peak demand reductions, and RPS and energy efficiency compliance; whether recovery of utility rate case expenses should be limited to 50% unless the case is settled; whether intervenors should be allowed to recover their expenses if the NMPRC accepts their position; whether parties should have access to software used by utilities to support their positions; and how regulatory assets should be authorized and recovered. Initial comments were filed in July 2017 and several public workshops have been held. PNM cannot predict the outcome of this proceeding. Renewable Portfolio Standard The REA establishes a mandatory RPS requiring a utility to acquire a renewable energy portfolio equal to 10% of retail electric sales by 2011, 15% by 2015, and 20% by 2020. PNM files annual renewable energy procurement plans for approval by the NMPRC. The NMPRC requires renewable energy portfolios to be “fully diversified.” The current diversity requirements, which are subject to the limitation of the RCT, are minimums of 30% wind, 20% solar, 3% distributed generation, and 5% other. 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. Currently, the RCT is set at 3% of customers’ annual electric charges. PNM makes renewable procurements consistent with the NMPRC approved plans. PNM 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: • 107 MW of PNM-owned solar PV facilities, including 40 MW constructed in 2015 that were identified as a cost-effective resource in PNM’s application to retire SJGS Units 2 and 3 (Note 16) and are being recovered in the base rates provided in the NM 2015 Rate Case discussed above rather than through PNM’s renewable energy rider; and an additional procurement of 1.5 MW of PNM-owned solar PV facilities to supply the energy sold under PNM’s voluntary renewable energy tariff • A PPA through 2044 for the output of New Mexico Wind, having a current aggregate capacity of 204 MW and a PPA through 2035 for the output of Red Mesa Wind, an existing wind generator having an aggregate capacity of 102 MW • A PPA through 2042 for the output of the Lightning Dock Geothermal facility; the geothermal facility began providing power to PNM in January 2014; the current capacity of the facility is 4 MW • Solar distributed generation, aggregating 81.6 MW at December 31, 2017, owned by customers or third parties from whom PNM purchases any net excess output and RECs • Solar and wind RECs as needed to meet the RPS requirements PNM filed its 2016 renewable energy procurement plan on June 1, 2015. The plan met RPS and diversity requirements within the RCT in 2016 and 2017 using existing resources and did not propose any significant new procurements. The NMPRC approved the plan in November 2015, and, after granting a rehearing motion to consider issues regarding the rate treatment of certain customers eligible for a cap on, or an exemption from, RPS procurement, the NMPRC again approved the plan in an order issued on February 3, 2016. The NMPRC deferred issues related to capped and exempt customers to PNM’s NM 2015 Rate Case and to a new case, which the NMPRC subsequently initiated through issuance of an order to show cause. The NM 2015 Rate Case and show cause proceeding were to examine whether PNM miscalculated the FPPAC factor and base fuel costs in its treatment of renewable energy costs and application of the renewable procurement cost caps and exemptions. The show cause proceeding was stayed pending the outcome of the NM 2015 Rate Case. The September 28, 2016 order in the NM 2015 Rate Case directed that the cost of New Mexico Wind be recovered through PNM’s renewable rider, rather than the FPPAC, and ordered certain other modifications regarding the accounting for renewable energy in PNM’s FPPAC. These modifications do not affect the amount of fuel and purchased power or renewable costs that PNM will collect. No action has been taken in the show cause proceeding and PNM cannot predict its outcome. PNM filed its 2017 renewable energy procurement plan on June 1, 2016. The plan met RPS and diversity requirements for 2017 and 2018 using existing resources and PNM did not propose any significant new pr

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2017
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. GAAP requires the Company to evaluate 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. GAAP provides that 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 the totality of events or 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, GAAP currently requires the entity to perform the second step of the impairment analysis, determining the amount of goodwill impairment to be recorded. The amount is calculated by comparing the implied fair value of the goodwill to its carrying amount. This exercise would require the entity to allocate the fair value determined in step one to the individual assets and liabilities of the reporting unit. Any remaining fair value would be the implied fair value of goodwill on the testing date. To the extent the recorded amount of goodwill of a reporting unit exceeds the implied fair value determined in step two, an impairment loss would be reflected in results of operations. As further discussed under New Accounting Pronouncements in Note 1, a new accounting pronouncement changes how goodwill impairment is determined by eliminating the second step of the quantitative impairment analysis. For both the PNM and TNMP reporting units, PNMR utilized qualitative analyses for the annual evaluations performed as of April 1, 2017 and quantitative analyses for the evaluations performed as of April 1, 2016. For the annual evaluations performed as of April 1, 2015, PNMR utilized a quantitative analysis for the PNM reporting unit and a qualitative analysis for the TNMP reporting unit. For the April 1, 2017 evaluation for both the PNM and TNMP reporting units, the qualitative analyses were performed by considering changes in the Company’s expectations of future financial performance since the April 1, 2016 quantitative analyses. These analyses considered Company specific events such as the potential impacts of legal and regulatory matters discussed in Note 16 and Note 17, including the estimated impacts of the proposed revised stipulation in the PNM NM 2016 Rate Case, the impacts of potential outcomes of the matters appealed to the NM Supreme Court under the NM 2015 Rate Case, and the impacts of changes in PNM’s resource needs based on PNM’s 2017 IRP. These evaluations also considered changes in TNMP’s regulatory environment such as the PUCT’s proposed amendments to the interim transmission cost of service filing rule, as well as potential outcomes associated with TNMP’s general rate case filing, which the Company anticipates filing in May 2018. The qualitative analyses also considered market and macroeconomic factors including changes in anticipated growth rates, anticipated changes in the WACC, and changes in discount rates. The Company also evaluated its stock price relative to historical performance, industry peers, and to major market indices, including an evaluation of the Company’s market capitalization relative to the carrying value of its reporting units. Based on an evaluation of these and other factors, the Company determined it is not more likely than not that the April 1, 2017 carrying values of PNM or TNMP exceed their fair values. For its annual evaluations performed as of April 1, 2016, PNMR performed quantitative analyses for both the PNM and TNMP reporting units. For the quantitative analyses, a discounted cash flow methodology was primarily used to estimate the fair value of the reporting unit. This analysis requires significant judgments, including estimation of future cash flows, which is dependent on internal forecasts, estimation of long-term growth rates for the business, and determination of appropriate WACC for each reporting unit. Changes in these estimates and assumptions could materially affect the determination of fair value and the conclusion of impairment. The April 1, 2016 and 2015 quantitative evaluations for PNM both indicated the fair value of the PNM reporting unit, which has goodwill of $51.6 million , exceeded its carrying value by approximately 25% . An increase of 0.5% in the expected return on equity capital utilized in discounting the forecasted cash flows, would have reduced the excess of PNM’s fair value over carrying value to approximately 18% . The April 1, 2016 quantitative evaluation indicated the fair value of the TNMP reporting unit, which has goodwill of $226.7 million , exceeded its carrying value by 32% . An increase of 0.5% in the expected return on equity capital utilized in calculating the WACC used to discount the forecasted cash flows, would have reduced the excess of TNMP’s fair value over carrying value to approximately 21% at April 1, 2016. The 2015 qualitative analysis for TNMP included the consideration of various reporting unit specific factors as well as industry and macroeconomic factors to determine whether these factors were reasonably likely to have a material impact on the fair value of the reporting unit. Factors considered included the results of the April 1, 2012 quantitative analysis, which indicated that fair value of the reporting unit exceeded its carrying value by approximately 26% , current and long-term forecasted financial results, regulatory environment, credit rating, interest rate environment, absolute and relative price of PNMR’s common stock, and operating strategy. TNMP believes it is operating within a generally favorable regulatory environment, its historical and forecasted financial results are positive, and its credit is generally perceived positively. Based on the analysis of the relevant factors, PNMR concluded that it was more likely than not that the fair value of the TNMP reporting unit exceeds its carrying value at April 1, 2015. Prior annual evaluations have not indicated impairments of any of PNMR’s reporting units, except in 2008. During 2008, the market capitalization of PNMR’s common stock was significantly below book value. In addition, a PNMR reporting unit, which was sold in 2011 was significantly impacted by depressed economic conditions and changes in the market in which it operated. As a result, goodwill impairments of $51.1 million for PNM, $34.5 million for TNMP, and an aggregate of $174.4 million for PNMR were recorded in 2008. Since 2008, the price of PNMR’s common stock has increased, improving the relationship between PNMR’s market capitalization and book value. In addition, improved regulatory treatment has been experienced by PNM in New Mexico and by TNMP in Texas. These factors resulted in more predictable earnings and increased fair values of the reporting units. Since 2008, the annual evaluations have not indicated that the fair values of the reporting units with recorded goodwill have decreased below their carrying values.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
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 Liability Adjustment Total Fair Value Adjustment for Cash Flow Hedges Total (In thousands) Balance at December 31, 2014 $ 28,008 $ (89,763 ) $ (61,755 ) $ — $ (61,755 ) Amounts reclassified from AOCI (pre-tax) (28,531 ) 5,952 (22,579 ) — (22,579 ) Income tax impact of amounts reclassified 11,181 (2,332 ) 8,849 — 8,849 Other OCI changes (pre-tax) 10,998 (4,405 ) 6,593 72 6,665 Income tax impact of other OCI changes (4,310 ) 1,726 (2,584 ) (28 ) (2,612 ) Net after-tax change (10,662 ) 941 (9,721 ) 44 (9,677 ) Balance at December 31, 2015 17,346 (88,822 ) (71,476 ) 44 (71,432 ) Amounts reclassified from AOCI (pre-tax) (22,139 ) 5,504 (16,635 ) 764 (15,871 ) Income tax impact of amounts reclassified 8,639 (2,148 ) 6,491 (298 ) 6,193 Other OCI changes (pre-tax) 778 (18,501 ) (17,723 ) (874 ) (18,597 ) Income tax impact of other OCI changes (304 ) 7,219 6,915 341 7,256 Net after-tax change (13,026 ) (7,926 ) (20,952 ) (67 ) (21,019 ) Balance at December 31, 2016 4,320 (96,748 ) (92,428 ) (23 ) (92,451 ) Amounts reclassified from AOCI (pre-tax) (17,567 ) 6,452 (11,115 ) 581 (10,534 ) Income tax impact of amounts reclassified 6,816 (2,504 ) 4,312 (225 ) 4,087 Other OCI changes (pre-tax) 28,160 3,618 31,778 1,000 32,778 Income tax impact of other OCI changes (10,927 ) (919 ) (11,846 ) (388 ) (12,234 ) Net after-tax change 6,482 6,647 13,129 968 14,097 Reclassification of stranded income taxes to retained earnings Note 11 2,367 (20,161 ) (17,794 ) 208 (17,586 ) Balance at December 31, 2017 $ 13,169 $ (110,262 ) $ (97,093 ) $ 1,153 $ (95,940 ) Pre-tax amounts reclassified from AOCI related to “Unrealized Gains on Available-for-Sale Securities” are included in “Gains on available-for-sale securities” in the Consolidated Statements of Earnings. Pre-tax amounts reclassified from AOCI related to “Pension Liability Adjustment” are reclassified to “Operating Expenses – Administrative and general” in the Consolidated Statements of Earnings. Pre-tax amounts reclassified from AOCI related to “Fair Value Adjustment for Cash Flow Hedges” are reclassified to “Interest Charges” in the Consolidated Statements of Earnings. An insignificant amount is included in capitalized interest. The income tax impacts of all amounts reclassified from AOCI are included in “Income Taxes” in the Consolidated Statements of Earnings.

Quarterly Operating Results (Un

Quarterly Operating Results (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Quarterly Operating Results (Unaudited)	Quarterly Operating Results (Unaudited) Unaudited operating results by quarters for 2017 and 2016 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. Quarter Ended March 31 June 30 September 30 December 31 (1) (In thousands, except per share amounts) PNMR 2017 Operating revenues $ 330,178 $ 362,320 $ 419,900 $ 332,605 Operating income 55,960 85,105 142,484 22,936 Net earnings (loss) 26,446 41,231 78,327 (50,585 ) Net earnings (loss) attributable to PNMR 22,862 37,555 73,739 (54,282 ) Net earnings (loss) attributable to PNMR per common share: Basic 0.29 0.47 0.92 (0.68 ) Diluted 0.29 0.47 0.92 (0.68 ) 2016 Operating revenues $ 310,961 $ 315,391 $ 400,374 $ 336,225 Operating income 41,508 64,822 108,071 63,584 Net earnings 13,965 30,952 58,556 28,423 Net earnings attributable to PNMR 10,546 27,076 54,418 24,809 Net earnings attributable to PNMR per common share: Basic 0.13 0.34 0.68 0.32 Diluted 0.13 0.34 0.68 0.31 PNM 2017 Operating revenues $ 251,558 $ 276,097 $ 327,254 $ 249,321 Operating income 38,331 59,164 113,252 1,778 Net earnings (loss) 20,110 30,476 65,283 (28,456 ) Net earnings (loss) attributable to PNM 16,658 26,932 60,827 (32,021 ) 2016 Operating revenues $ 235,606 $ 233,346 $ 311,276 $ 255,685 Operating income 23,297 41,760 80,057 42,976 Net earnings 7,561 19,793 44,990 19,594 Net earnings attributable to PNM 4,274 16,049 40,984 16,112 TNMP 2017 Operating revenues $ 78,620 $ 86,223 $ 92,646 $ 83,284 Operating income 17,965 26,286 29,474 19,879 Net earnings 7,604 12,204 14,727 1,024 2016 Operating revenues $ 75,355 $ 82,045 $ 89,098 $ 80,540 Operating income 18,554 23,375 28,359 21,353 Net earnings 7,456 10,508 13,853 9,855 (1) Reflects the impacts of changes in federal income tax rate of $57.5 million , $29.6 million , and $7.9 million for PNMR, PNM, and TNMP (Note 11); also reflects a pre-tax regulatory disallowance resulting from PNM’s NM 2016 Rate Case of $27.9 million for PNMR and PNM (Note 17).

Schedule I - Condensed Financia

Schedule I - Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only 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, 2017 2016 2015 (In thousands) Operating Revenues $ — $ — $ — Operating Expenses 2,902 2,871 1,221 Operating income (loss) (2,902 ) (2,871 ) (1,221 ) Other Income and Deductions: Equity in earnings of subsidiaries 111,877 122,252 27,352 Other income 1,181 1,711 747 Net other income and deductions 113,058 123,963 28,099 Interest Charges 12,490 8,102 8,275 Earnings Before Income Taxes 97,666 112,990 18,603 Income Tax Expense (Benefit) 17,792 (3,859 ) 2,963 Net Earnings $ 79,874 $ 116,849 $ 15,640 SCHEDULE I PNM RESOURCES, INC. CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY STATEMENTS OF CASH FLOWS Year Ended December 31, 2017 2016 2015 (In thousands) Net Cash Flows From Operating Activities $ (7,814 ) $ 5,702 $ 1,375 Cash Flows From Investing Activities: Utility plant additions (180 ) 341 368 Investments in subsidiaries (50,000 ) (98,343 ) (175,000 ) Cash dividends from subsidiaries 105,084 35,959 127,688 Net cash flows from investing activities 54,904 (62,043 ) (46,944 ) Cash Flows From Financing Activities: Short-term loan — 100,000 50,000 Repayment of short-term loan — (150,000 ) — Revolving credit facility borrowings (repayments), net 42,600 84,500 41,000 Long-term borrowings — 100,000 150,000 Repayment of long-term debt — — (118,766 ) Proceeds from stock option exercise 1,739 7,028 5,619 Purchases to satisfy awards of common stock (13,929 ) (15,451 ) (17,720 ) Dividends paid (77,264 ) (70,095 ) (63,723 ) Other, net (269 ) (28 ) (782 ) Net cash flows from financing activities (47,123 ) 55,954 45,628 Change in Cash and Cash Equivalents (33 ) (387 ) 59 Cash and Cash Equivalents at Beginning of Period 54 441 382 Cash and Cash Equivalents at End of Period $ 21 $ 54 $ 441 Supplemental Cash Flow Disclosures: Interest paid, net of amounts capitalized $ 10,899 $ 5,906 $ 7,559 Income taxes paid (refunded), net $ — $ — $ (730 ) SCHEDULE I PNM RESOURCES, INC. CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY BALANCE SHEETS December 31, 2017 2016 (In thousands) Assets Cash and cash equivalents $ 21 $ 54 Intercompany receivables 96,227 92,234 Income taxes receivable 1,818 — Other, net 1,937 233 Total current assets 100,003 92,521 Property, plant and equipment, net of accumulated depreciation of $13,229 and $12,291 26,546 26,366 Investment in subsidiaries 2,056,198 1,986,276 Other long-term assets 66,090 79,314 Total long-term assets 2,148,834 2,091,956 $ 2,248,837 $ 2,184,477 Liabilities and Stockholders’ Equity Short-term debt $ 265,600 $ 226,100 Short-term debt-affiliate 11,919 8,819 Current maturities of long-term debt 249,979 — Accrued interest and taxes 1,661 1,333 Other current liabilities 21,274 19,374 Total current liabilities 550,433 255,626 Long-term debt — 249,895 Other long-term liabilities 3,151 3,004 Total liabilities 553,584 508,525 Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 79,653,624 shares) 1,157,665 1,163,661 Accumulated other comprehensive income (loss), net of tax (95,940 ) (92,451 ) Retained earnings 633,528 604,742 Total common stockholders’ equity 1,695,253 1,675,952 $ 2,248,837 $ 2,184,477 See Notes 6, 7, 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, 2017
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 beginning of year Charged to costs and expenses Charged to other accounts Write-offs and other Balance at end of year (In thousands) Allowance for doubtful accounts, year ended December 31: 2015 $ 1,466 $ 3,358 $ — $ 3,427 $ 1,397 2016 $ 1,397 $ 2,885 $ — $ 3,073 $ 1,209 2017 $ 1,209 $ 2,619 $ — $ 2,747 $ 1,081 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 beginning of year Charged to costs and expenses Charged to other accounts Write-offs Balance at end of year (In thousands) Allowance for doubtful accounts, year ended December 31: 2015 $ 1,466 $ 3,344 $ — $ 3,413 $ 1,397 2016 $ 1,397 $ 2,871 $ — $ 3,059 $ 1,209 2017 $ 1,209 $ 2,615 $ — $ 2,743 $ 1,081 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 beginning of year Charged to costs and expenses Charged to other accounts Write-offs Balance at end of year (In thousands) Allowance for doubtful accounts, year ended December 31: 2015 $ — $ 14 $ — $ 14 $ — 2016 $ — $ 14 $ — $ 14 $ — 2017 $ — $ 4 $ — $ 4 $ —

Summary of the Business and S31

Summary of the Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of accounting	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 9) and, through January 15, 2016, the PVNGS Capital Trust. 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 shared services’ administrative and general expenses, which represent costs that are primarily driven by corporate level activities, are charged to the business segments. These services are billed at cost. Other significant intercompany transactions between PNMR, PNM, and TNMP include interest and income tax sharing payments, as well as equity transactions. All intercompany transactions and balances have been eliminated.
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, even for programs that do not otherwise qualify for recognition of regulatory assets and liabilities. 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 4. 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 Cash Equivalents	Cash and Cash Equivalents Investments in highly liquid investments with original maturities of three months or less at the date of purchase are considered cash equivalents.
Utility Plant	Utility Plant Utility plant is stated at original cost, which 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 contributions in aid of construction (“CIAC”), from customers to pay for all or part of certain construction projects to extent that 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 does not receive a financing component.
Depreciation and Amortization	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 of non-utility property 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 2017 2016 2015 PNM Electric plant 2.52 % 2.33 % 2.27 % Common, intangible, and general plant 8.36 % 5.40 % 4.66 % TNMP 3.57 % 3.66 % 3.65 %
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 “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.
Capitalized Interest	Capitalized Interest The Company capitalizes interest on its construction projects and major computer software projects not subject to the computation of AFUDC. Capitalized interest is recorded in interest charges.
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	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). All of these investments are classified as available-for-sale. PNM evaluates the securities for impairment on an on-going basis. Since third party investment managers have sole discretion over the purchase and sales of the securities, PNM records a realized loss as an impairment for any security that has a market value that is less than cost at the end of each quarter. For the years ended December 31, 2017 , 2016 , and 2015 , PNM recorded impairment losses on the available-for-sale securities held in the NDT and coal mine reclamation trusts of $7.1 million , $13.9 million , and $10.4 million . No gains or losses are deferred as regulatory assets or liabilities. Through December 31, 2017 , unrealized gains on these investments, net of related tax effects, are included in OCI and AOCI. The available-for-sale securities are primarily comprised of international, United States, state, and municipal government obligations and corporate debt and equity securities. 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.
Goodwill	Goodwill Under GAAP, 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 Impairment Tangible long-lived assets 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.
Revenue Recognition	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 the daily generation volumes, estimated customer usage by class, line losses, and applicable customer rates reflecting historical trends and experience. PNM’s wholesale electricity sales are recorded as electric operating revenues and the wholesale electricity purchases are recorded as costs of energy sold. In accordance with GAAP, 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 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.
Accounts Receivable and Allowance for Uncollectible Accounts	Accounts Receivable and Allowance for Uncollectible Accounts 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. The Company calculates the allowance for uncollectible accounts based on historical experience and estimated default rates. The accounts receivable balances are reviewed monthly and adjustments to the allowance for uncollectible accounts and bad debt expense are made as necessary. Amounts that are deemed uncollectible are written off.
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 debt premium, discount, and expense related to long-term are reflected as part of the debt liabilities on the Consolidated Balance Sheets.
Derivatives and Accounting for 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. GAAP requires that changes in the derivatives’ fair value be recognized currently in earnings unless specific hedge accounting criteria are met. For qualifying hedges, an entity must formally document, designate, and assess the effectiveness of transactions that receive hedge accounting. GAAP provides that the effective portion of the gain or loss on a derivative instrument designated and qualifying as a cash flow hedging instrument be reported as a component of AOCI and be reclassified into earnings in the period during which the hedged forecasted transaction affects earnings. The results of hedge ineffectiveness and the portion of the change in fair value of a derivative that an entity has chosen to exclude from hedge effectiveness are required to be presented in current earnings. See Note 6 and Note 8. 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. 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, 2017 , 2016 , and 2015 , PNM was not hedging its exposure to the variability in future cash flows from commodity derivatives through designated cash flows 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 owns and leases nuclear and fossil-fuel generating facilities. In accordance with GAAP, 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 extended PVNGS license periods. PVNGS Units 1 and 2 are included in PNM’s retail rates and PVNGS Unit 3 was excluded through December 31, 2017, but is included beginning in 2018. See Note 15 and Note 16. See Note 17 for information concerning the treatment of nuclear decommissioning for the leased portions of PVNGS in the NMPRC’s order in PNM’s NM 2015 Rate Case and 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	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 in some instances 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.
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. In accordance with GAAP, 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. GAAP requires that rate-regulated enterprises 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 liabilities and assets 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 related to rate regulated assets and amortizes them over the estimated useful lives of those assets. See Note 11 for additional information, including a discussion of the impacts of tax reform under the Tax Cuts and Jobs Act enacted on December 22, 2017. 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. GAAP also provides that certain unusual or infrequently occurring items, as well as adjustments due to enactment of new tax laws, be excluded from the estimated annual effective tax rate calculation.
Excise Taxes	Excise Taxes The Company pays certain fees or taxes which are either considered to be an excise tax or similar to an excise tax. Substantially all of these taxes are recorded on a net basis in the Consolidated Statements of Earnings.
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 2014-09 – Revenue from Contracts with Customers (Topic 606) In May 2014, the FASB issued ASU 2014-09. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also revises the disclosure requirements regarding revenue. Since the issuance of ASU 2014-09, the FASB issued a one -year deferral of the effective date and has issued additional ASUs that clarify implementation guidance regarding principal versus agent considerations, licensing, and identifying performance obligations, as well as adding certain additional practical expedients. The new standard will replace most existing revenue recognition guidance in GAAP. ASU 2014-09 can be applied retrospectively to each prior period presented or on a modified retrospective basis with a cumulative effect adjustment to retained earnings on the date of adoption. The Company will adopt ASU 2014-09 effective as of January 1, 2018, its required effective date, using the modified retrospective method of adoption. The Company has monitored the activities of the FASB and other non-authoritative groups regarding certain issues specific to the power and utility industry. These specific issues include the impacts of the new guidance on accounting for CIAC and the presentation of revenues associated with “alternative revenue programs,” which primarily result from certain of the Company’s approved rate rider programs. The appropriate authoritative accounting organization has given tentative approval of the utility industry’s positions on all power and utility specific issues. The Company has substantially completed its assessment of ASU 2014-09 and does not anticipate a cumulative effect adjustment on the date of adoption or changes to the amount and timing of its current revenue recognition practices. The Company believes its existing policies, processes, information technology infrastructure, and internal controls properly capture and report revenue in accordance with ASU 2014-09. Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU 2016-01, which makes targeted improvements to GAAP regarding financial instruments. ASU 2016-01 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 net earnings rather than in OCI. Unrealized gains, net of income taxes, recorded in AOCI related to equity securities will be reclassified to retained earnings as a cumulative effect adjustment. ASU 2016-01 also revises certain presentation and disclosure requirements. Under ASU 2016-01, accounting for investments in debt securities remains essentially unchanged. PNM currently classifies all investments held in the NDT and coal mine reclamation trusts as available-for-sale securities. Unrealized losses on these securities are recorded immediately through earnings and unrealized gains are recorded in AOCI until the securities are sold. The Company will adopt ASU 2016-01 effective as of January 1, 2018, its required effective date. On January 1, 2018, PNMR and PNM will record a cumulative effect adjustment, net of income taxes, to increase retained earnings by $11.1 million with an offset to AOCI. Future changes in the fair value of equity securities will be recorded in earnings. Accounting Standards Update 2016-02 – Leases (Topic 842) In February 2016, the FASB issued ASU 2016-02 to provide guidance on the recognition, measurement, presentation, and disclosure of leases. ASU 2016-02 will require that a liability be recorded on the balance sheet for all leases, based on the present value of future lease obligations. A corresponding right-of-use asset will also be recorded. Amortization of the lease obligation and the right-of-use asset for certain leases, primarily those classified as operating leases, will be on a straight-line basis, which is not expected to have a significant impact on the statements of earnings, whereas other leases will be required to be accounted for as financing arrangements similar to the accounting treatment for capital leases under current GAAP. ASU 2016-02 also revises certain disclosure requirements. At adoption, ASU 2016-02 requires that leases be recognized and measured as of the earliest period presented using a modified retrospective approach with all periods presented being restated and presented under the new guidance. The ASU allows entities to apply certain practical expedients to arrangements that exist upon adoption or expired during the periods presented. As further discussed in Note 7, the Company has operating leases of office buildings, vehicles, and equipment. The Company also routinely enters into land easements and right-of-way agreements. PNM also has operating lease interests in PVNGS Units 1 and 2 that will expire in January 2023 and 2024. The Company, along with others in the utility industry, is continuing to monitor the activities of the FASB and other non-authoritative groups regarding industry specific issues for further clarification. The Company has formed a project team, conducted outreach activities across its lines of business, and made significant progress in identifying arrangements, in addition to its existing operating lease arrangements, that may be classified as leases under ASU 2016-02. It is likely the arrangements currently classified as leases will continue to be recognized as leases under ASU 2016-02. It is possible that other contractual arrangements not previously meeting the lease definition may contain elements that qualify as leases and that previously identified operating leases may be classified as financing leases under ASU 2016-02. The Company is in the process of analyzing each of the identified contractual arrangement to determine if it contains lease elements under the new standard and quantifying the potential impacts of identified lease arrangements. The Company is also evaluating the practical expedients, if any, it will elect upon adoption. The Company anticipates this process will continue into 2018. The Company will adopt this standard effective as of January 1, 2019, its required effective date. In January 2018, the FASB issued ASU 2018-01, which clarifies that land easements are to be evaluated under ASU 2016-02, but provides an additional optional practical expedient to not evaluate existing or expired land easements that were not accounted for as leases under the current guidance. The Company has numerous land easements and right-of-way agreements that would fall under this clarification. The only such agreement that has been accounted for as a lease under current guidance is the right-of-way agreement with the Navajo Nation (Note 7). The Company anticipates it will elect to use the practical expedient for its existing and expired land easements upon adoption of ASU 2016-02. Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU 2016-13, which changes the way entities recognize impairment of many financial assets, including accounts receivable and investments in debt securities, by requiring immediate recognition of estimated credit losses expected to occur over the remaining lives of the assets. The Company anticipates adopting ASU 2016-13 effective as of January 1, 2020 although early adoption is permitted beginning on January 1, 2019. The Company is in the process of analyzing the impacts of this new standard, but does not anticipate it will have a significant impact on its financial statements. Accounting Standards Update 2016-18 – Statement of Cash Flows (Topic 230): Restricted Cash In November 2016, the FASB issued ASU 2016-18, which requires that amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning of period and end of period amounts shown on the statements of cash flows and adds disclosures necessary to reconcile such amounts to cash and cash equivalents on the balance sheets. ASU 2016-18 does not provide a definition of what should be considered restricted cash. Upon adoption, ASU 2016-18 requires the use of a retrospective transition method for each period presented. The Company has substantially completed its analysis of ASU 2016-18 and will adopt the standard effective as of January 1, 2018, its required effective date. During 2015, PNM received a deposit of $8.2 million from a third party that was restricted for PNM’s construction of transmission interconnection facilities for that party. PNM recorded the deposit in Other deferred charges and it was not included in cash on the Consolidated Statements of Cash Flows. Construction of the interconnection was completed in 2018, at which time $7.1 million was refunded to the third party. Other amounts considered to be restricted cash under ASU 2016-18 were insignificant. In 2018, PNM will reclassify amounts related to restricted cash on the Consolidated Statements of Cash Flows in accordance with ASU 2016-18 and provide the required additional disclosures. Accounting Standards Update 2017-04 – Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU 2017-04 to simplify the annual goodwill impairment assessment process. Currently, the first step of a quantitative impairment test requires an entity to compare the fair value of each reporting unit containing goodwill 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 entity is required to perform the second step of the impairment analysis, determining the amount of goodwill impairment to be recorded. The amount is calculated by comparing the implied fair value of the goodwill to its carrying amount. This exercise requires the entity to allocate the fair value determined in step one to the individual assets and liabilities of the reporting unit. Any remaining fair value would be the implied fair value of goodwill on the testing date. To the extent the recorded amount of goodwill of a reporting unit exceeds the implied fair value determined in step two, an impairment loss would be reflected in results of operations. ASU 2017-04 eliminates the second step of the impairment analysis. Accordingly, if the first step of a quantitative goodwill impairment analysis performed after adoption of ASU 2017-04 indicates that the fair value of a reporting unit is less than its carrying value, the goodwill of that reporting unit would be impaired to the extent of that difference. The Company anticipates it will adopt ASU 2017-04 for impairment testing after January 1, 2020, its required effective date, although early adoption is permitted. However, if there is an indication of potential impairment of goodwill as a result of an impairment assessment prior to 2020, the Company will evaluate the impact of ASU 2017-04 and could elect to early adopt this standard. Accounting Standards Update 2017-07 – Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the FASB issued ASU 2017-07 to improve the presentation of net periodic pension and other postretirement benefit costs. Currently, the Company presents all of its net periodic benefit costs, net of amounts capitalized to construction and other accounts, as administrative and general expenses on its statements of earnings. The amendments in ASU 2017-07 require the service cost component of net benefit costs be presented in the same line item or items as employees’ compensation. The other components of net benefit cost (the “non-service cost components”) are required to be presented in the income statement separately from the service cost component and outside of operating income with disclosures identifying where the non-service cost components have been presented. ASU 2017-07 also limits capitalization to only the service cost component of benefit costs. PNMR and its subsidiaries maintain qualified defined benefit pension and OPEB plans. Currently, net periodic benefit cost for the Company’s defined benefit pension plans do not include a service cost component and there is only a minor amount of service cost for the OPEB plans. Additional information about the Company’s benefit plans is discussed in Note 12. ASU 2017-07 requires retrospective presentation of the service and non-service cost components of net benefit costs in the income statement and prospective application regarding the capitalization of only the service cost component of net benefit costs. The Company will adopt the standard effective as of January 1, 2018, its required effective date. In 2017 and 2016, PNM recorded pre-tax Administrative and general expenses of $4.7 million and $3.0 million and TNMP recorded less than $0.1 million and less than $0.1 million related to their non-service cost components of net periodic benefit costs. Beginning in 2018, such costs will be reclassified to Other (deductions) on the Consolidated Statements of Earnings. The Company believes PNM and TNMP can continue to capitalize the non-service cost components of net benefit costs as regulatory assets to the extent attributable to regulated operations and does not anticipate ASU 2017-07 will have a significant impact on its financial statements. Accounting Standards Update 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities In August 2017, the FASB issued ASU 2017-12 to better align hedge accounting with an organization’s risk management activities and to simplify the application of hedge accounting guidance. ASU 2017-12 is effective for the Company on January 1, 2019 although early adoption is permitted beginning on January 1, 2018. As discussed in Note 6, the Company periodically enters into, and designates as cash flow hedges, interest rate swaps to hedge its exposure to changes in interest rates. In addition, as discussed in Note 8, the Company enters into various derivative instruments to economically hedge the risk of changes in commodity prices, which are not currently designated as cash flow hedges. The Company is evaluating the requirements of ASU 2017-12, but does not anticipate the changes will have a significant impact on the Company’s accounting treatment for derivative instruments or on its financial statements.
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.
Fair Value of Derivatives	The Company determines the fair values of its derivative and other financial instruments based on the hierarchy established in GAAP, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. GAAP describes 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. Level 3 inputs used in determining fair values for the Company consist of internal valuation models. The Company records any transfers between fair value hierarchy levels as of the end of each calendar quarter. There were no transfers between levels during the years ended December 31, 2017 and 2016 . For available-for-sale securities, Level 2 fair values are provided by the trustee utilizing a pricing service. The pricing provider predominantly uses the market approach using bid side market value based upon a hierarchy of information for specific securities or securities with similar characteristics. 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. For investments categorized as Level 3, primarily the Westmoreland Loan, fair values were determined by discounted cash flow models that take into consideration discount rates that are observable for similar types of assets and liabilities. Management of the Company independently verifies the information provided by pricing services.
Variable Interest Entities	GAAP determines how an enterprise evaluates and accounts for its involvement with variable interest entities, focusing 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”). GAAP also requires continual reassessment of the primary beneficiary of a VIE.
Pension and Other Postretirement Benefits	GAAP requires a plan sponsor 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. GAAP requires unrecognized prior service costs and unrecognized gains or losses to be recorded in AOCI and subsequently amortized. The amortization of these incurred costs is included as pension and postretirement benefit periodic cost or income in subsequent years. 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 expected long-term rate of return on pension and postretirement plan assets is calculated on the market-related value of assets. GAAP requires that actual gains and losses on pension and OPEB plan assets be recognized in the market-related value of assets equally over a period of not more than five years, which reduces year-to-year volatility.
Commitments and Contingencies	There are various claims and lawsuits pending against the Company. The Company also 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 (Note 17) proceedings in the normal course of its business. 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. Nevertheless, 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. In accordance with GAAP, 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 S32

Summary of the Business and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
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 2017 2016 2015 PNM Electric plant 2.52 % 2.33 % 2.27 % Common, intangible, and general plant 8.36 % 5.40 % 4.66 % TNMP 3.57 % 3.66 % 3.65 %
Schedule of Inventory	Inventories consisted of the following at December 31 : PNMR PNM TNMP 2017 2016 2017 2016 2017 2016 (In thousands) Coal $ 16,714 $ 19,940 $ 16,714 $ 19,940 $ — $ — Materials and supplies 49,788 53,087 44,145 44,461 5,643 8,626 $ 66,502 $ 73,027 $ 60,859 $ 64,401 $ 5,643 $ 8,626

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
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. 2017 PNM TNMP Corporate and Other PNMR Consolidated (In thousands) Electric operating revenues $ 1,104,230 $ 340,773 $ — $ 1,445,003 Cost of energy 321,677 85,802 — 407,479 Utility margin 782,553 254,971 — 1,037,524 Other operating expenses 423,011 98,221 (22,135 ) 499,097 Depreciation and amortization 147,017 63,146 21,779 231,942 Operating income 212,525 93,604 356 306,485 Interest income 8,454 — 7,462 15,916 Other income (deductions) 30,686 3,551 (3,254 ) 30,983 Interest charges (82,697 ) (30,084 ) (14,844 ) (127,625 ) Segment earnings (loss) before income taxes 168,968 67,071 (10,280 ) 225,759 Income taxes 81,555 31,512 17,273 130,340 Segment earnings (loss) 87,413 35,559 (27,553 ) 95,419 Valencia non-controlling interest (15,017 ) — — (15,017 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ 71,868 $ 35,559 $ (27,553 ) $ 79,874 At December 31, 2017: Total Assets $ 4,921,563 $ 1,500,770 $ 223,770 $ 6,646,103 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2016 PNM TNMP Corporate and Other PNMR Consolidated Electric operating revenues $ 1,035,913 $ 327,038 $ — $ 1,362,951 Cost of energy 299,714 80,882 — 380,596 Utility margin 736,199 246,156 — 982,355 Other operating expenses 414,662 93,389 (12,791 ) 495,260 Depreciation and amortization 133,447 61,126 14,537 209,110 Operating income (loss) 188,090 91,641 (1,746 ) 277,985 Interest income 10,173 — 12,120 22,293 Other income (deductions) 22,066 3,202 (1,739 ) 23,529 Interest charges (87,469 ) (29,335 ) (11,829 ) (128,633 ) Segment earnings (loss) before income taxes 132,860 65,508 (3,194 ) 195,174 Income taxes (benefit) 40,922 23,836 (1,480 ) 63,278 Segment earnings (loss) 91,938 41,672 (1,714 ) 131,896 Valencia non-controlling interest (14,519 ) — — (14,519 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ 76,891 $ 41,672 $ (1,714 ) $ 116,849 At December 31, 2016: Total Assets $ 4,867,546 $ 1,383,223 $ 220,311 $ 6,471,080 Goodwill $ 51,632 $ 226,665 $ — $ 278,297 2015 PNM TNMP Corporate and Other PNMR Consolidated Electric operating revenues $ 1,131,195 $ 307,887 $ — $ 1,439,082 Cost of energy 391,131 73,518 — 464,649 Utility margin 740,064 234,369 — 974,433 Other operating expenses 590,967 88,051 (14,854 ) 664,164 Depreciation and amortization 115,717 56,285 13,917 185,919 Operating income 33,380 90,033 937 124,350 Interest income 6,574 — (76 ) 6,498 Other income (deductions) 26,914 3,736 (485 ) 30,165 Interest charges (79,950 ) (27,681 ) (7,229 ) (114,860 ) Segment earnings (loss) before income taxes (13,082 ) 66,088 (6,853 ) 46,153 Income taxes (benefit) (12,758 ) 24,125 3,708 15,075 Segment earnings (loss) (324 ) 41,963 (10,561 ) 31,078 Valencia non-controlling interest (14,910 ) — — (14,910 ) Subsidiary preferred stock dividends (528 ) — — (528 ) Segment earnings (loss) attributable to PNMR $ (15,762 ) $ 41,963 $ (10,561 ) $ 15,640 At December 31, 2015: Total Assets $ 4,599,344 $ 1,297,139 $ 112,845 $ 6,009,328 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, 2017 2016 2015 REP A 16 % 16 % 16 % REP B 11 % 11 % 13 % REP C 10 % 11 % 11 %

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 2016 2015 (In thousands) Services billings: PNMR to PNM $ 97,914 $ 94,606 $ 90,827 PNMR to TNMP 31,095 28,907 28,109 PNM to TNMP 382 427 554 TNMP to PNMR 141 66 41 TNMP to PNM 154 172 — Interest billings: PNMR to PNM 21 11 54 PNM to PNMR 220 150 110 PNMR to TNMP 133 132 276 Income tax sharing payments: PNMR to TNMP — — — PNMR to PNM 23,391 — 1,450 TNMP to PNMR 20,686 — —

Regulatory Assets and Liabili35

Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 2016 2017 2016 Assets: (In thousands) Current: FPPAC $ 363 $ 1,451 $ — $ — Energy efficiency costs 1,776 1,991 794 413 2,139 3,442 794 413 Non-Current: CTC, including carrying charges — — 26,998 36,328 Coal mine reclamation costs 16,462 22,383 — — Deferred income taxes 59,220 62,918 9,621 9,932 Loss on reacquired debt 22,744 24,404 32,808 34,107 Pension and OPEB 222,774 249,286 26,153 27,661 Shutdown of SJGS Units 2 and 3 125,539 — — — Hurricane recovery costs — — 6,640 — AMS surcharge — — 27,903 14,669 AMS retirement costs — — 8,948 11,086 Other 12,500 6,422 2,362 2,027 459,239 365,413 141,433 135,810 Total regulatory assets $ 461,378 $ 368,855 $ 142,227 $ 136,223 PNM TNMP December 31, December 31, 2017 2016 2017 2016 Liabilities: (In thousands) Current: Renewable energy rider $ (779 ) $ (3,411 ) $ — $ — Other (5 ) (106 ) (1,525 ) (92 ) (784 ) (3,517 ) (1,525 ) (92 ) Non-Current: Cost of removal (256,493 ) (297,087 ) (26,541 ) (26,900 ) Deferred income taxes (445,390 ) (62,920 ) (148,455 ) (2,644 ) PVNGS ARO (24,889 ) (30,621 ) — — Renewable energy tax benefits (21,383 ) (22,540 ) — — Nuclear spent fuel reimbursements (5,518 ) (8,875 ) — — Pension and OPEB — — (3,442 ) (1,955 ) Other (768 ) (1,658 ) (699 ) (449 ) (754,441 ) (423,701 ) (179,137 ) (31,948 ) Total regulatory liabilities $ (755,225 ) $ (427,218 ) $ (180,662 ) $ (32,040 )

Financing (Tables)

Financing (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Short-term Debt	Short-term debt outstanding consists of: December 31, Short-term Debt 2017 2016 (In thousands) PNM: PNM Revolving Credit Facility $ 39,800 $ 35,000 PNM 2014 New Mexico Credit Facility — 26,000 PNM 2017 New Mexico Credit Facility — — 39,800 61,000 TNMP Revolving Credit Facility — — PNMR: PNMR Revolving Credit Facility 165,600 126,100 PNMR 2016 One-Year Term Loan 100,000 100,000 $ 305,400 $ 287,100
Schedule of maturities and interest rates	Information concerning the maturities and interest rates on the PNM 2018 SUNs to be issued in May 2018 and August 2018 is as follows: Scheduled Funding Maturity Principal Interest Date Date Amount Rate (In millions) May 15, 2018 May 15, 2023 $ 55.0 3.15 % May 15, 2018 May 15, 2025 104.0 3.45 % May 15, 2018 May 15, 2028 88.0 3.68 % May 15, 2018 May 15, 2033 38.0 3.93 % May 15, 2018 May 15, 2038 45.0 4.22 % May 15, 2018 May 15, 2048 20.0 4.50 % 350.0 August 1, 2018 August 1, 2028 15.0 3.78 % August 1, 2018 August 1, 2048 85.0 4.60 % 100.0 $ 450.0 Information concerning long-term debt outstanding and unamortized (premiums), discounts, and debt issuance costs is as follows: December 31, 2017 December 31, 2016 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 $ 1,383 $ 146,000 $ 1,807 6.25% due January 2038 36,000 228 36,000 239 4.75% due June 2040, mandatory tender - June 1, 2017 — — 37,000 25 2.125% due June 2040, mandatory tender - June 1, 2022 37,000 404 — — 5.20% due June 2040, mandatory tender - June 1, 2020 40,045 105 40,045 147 5.90% due June 2040 255,000 2,040 255,000 2,131 6.25% due June 2040 11,500 92 11,500 96 2.54% due September 2042, mandatory tender - June 1, 2017 — — 20,000 67 2.45% due September 2042, mandatory tender - June 1, 2022 20,000 153 — — 2.40% due June 2043, mandatory tender - June 1, 2020 39,300 243 39,300 340 5.20% due June 2043, mandatory tender - June 1, 2020 21,000 53 21,000 75 Senior Unsecured Notes: 7.95% due May 2018 350,000 272 350,000 995 7.50% due August 2018 100,025 73 100,025 197 5.35% due October 2021 160,000 617 160,000 780 3.85% due August 2025 250,000 2,274 250,000 2,574 PNM 2016 Term Loan Agreement due November 2017 — — 175,000 28 PNM 2017 Term Loan Agreement due January 2019 200,000 23 — — 1,665,870 7,960 1,640,870 9,501 Less current maturities 25 2 232,000 120 1,665,845 7,958 1,408,870 9,381 TNMP Debt First Mortgage Bonds: 9.50% due April 2019 172,302 1,032 172,302 1,857 6.95% due April 2043 93,198 (18,057 ) 93,198 (18,773 ) 4.03% due July 2024 80,000 686 80,000 792 3.53% due February 2026 60,000 667 60,000 749 3.22% due August 2027 60,000 552 — — 465,500 (15,120 ) 405,500 (15,375 ) Less current maturities — — — — 465,500 (15,120 ) 405,500 (15,375 ) PNMR Debt PNMR 2015 Term Loan Agreement due March 2018 150,000 12 150,000 84 BTMU Term Loan Agreement, payments through February 2021 50,137 1,001 92,207 1,634 PNMR 2016 Two-Year Term Loan due December 2018 100,000 9 100,000 21 300,137 1,022 342,207 1,739 Less current maturities 257,268 396 42,025 557 42,869 626 300,182 1,182 Total Consolidated PNMR Debt 2,431,507 (6,138 ) 2,388,577 (4,135 ) Less current maturities 257,293 398 274,025 677 $ 2,174,214 $ (6,536 ) $ 2,114,552 $ (4,812 )
Schedule of Maturities of Long-term Debt	Reflecting mandatory tender dates and the impacts of the refinancing under the PNM 2017 Senior Unsecured Note Agreement discussed above, long-term debt matures as follows: PNMR PNM TNMP PNMR Consolidated (In thousands) 2018 $ 257,268 $ 25 $ — $ 257,293 2019 12,357 200,000 172,302 384,659 2020 25,862 100,345 — 126,207 2021 4,650 306,000 — 310,650 2022 — 57,000 — 57,000 Thereafter — 1,002,500 293,198 1,295,698 Total $ 300,137 $ 1,665,870 $ 465,500 $ 2,431,507

Lease Commitments (Tables)

Lease Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Schedule of Rent Expense	Operating lease expense, including the PVNGS and EIP leases, was: PNMR PNM TNMP (In thousands) 2017 $ 35,972 $ 31,817 $ 3,570 2016 $ 37,432 $ 32,843 $ 3,748 2015 $ 61,088 $ 55,994 $ 3,688
Schedule of Future Minimum Operating Lease Payments	Future minimum operating lease payments at December 31, 2017 are shown below: PNMR PNM TNMP (In thousands) 2018 $ 26,802 $ 25,726 $ 791 2019 25,638 25,241 296 2020 25,208 25,122 — 2021 25,122 25,122 — 2022 25,122 25,122 — Later years 60,708 60,708 — Total minimum lease payments $ 188,600 $ 187,041 $ 1,087

Fair Value of Derivative and 38

Fair Value of Derivative and Other Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value of Derivative and Other Financial Instruments [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, are summarized as follows: Economic Hedges December 31, 2017 2016 (In thousands) Current assets $ 1,088 $ 5,224 Deferred charges 3,556 — 4,644 5,224 Current liabilities (1,182 ) (2,339 ) Long-term liabilities (3,556 ) — (4,738 ) (2,339 ) Net $ (94 ) $ 2,885
Summary of the Effect of Mark-to-Market Commodity Derivative Instruments on Earnings	The following table presents the effect of mark-to-market commodity derivative instruments on PNM’s earnings, excluding income tax effects. Commodity derivatives had no impact on OCI for the periods presented. Economic Hedges Year Ended 2017 2016 2015 (In thousands) Electric operating revenues $ 5,151 $ (53 ) $ 7,156 Cost of energy (5,386 ) (1,208 ) (293 ) Total gain (loss) $ (235 ) $ (1,261 ) $ 6,863
Schedule of Net Buy (Sell) Volume Positions	The table below presents PNM’s net buy (sell) volume positions: Economic Hedges MMBTU MWh December 31, 2017 100,000 — December 31, 2016 254,100 (2,471,600 )
Schedule of Fair Value and Unrealized Gains of Available-for-sale Securities	The fair value and gross unrealized gains of investments in available-for-sale securities are presented in the following table. December 31, 2017 December 31, 2016 Unrealized Gains Fair Value Unrealized Gains Fair Value (In thousands) Cash and cash equivalents $ — $ 52,636 $ — $ 23,683 Equity securities: Domestic value 4,011 40,032 1,135 34,796 Domestic growth 3,995 35,456 3,032 47,595 International and other 6,810 45,867 2,029 27,481 Fixed income securities: U.S. Government 273 34,317 115 40,962 Municipals 1,225 48,076 585 43,789 Corporate and other 1,714 67,140 553 54,671 $ 18,028 $ 323,524 $ 7,449 $ 272,977
Schedule of Realized Gain (Loss)	Gross realized losses shown below exclude the (increase)/decrease in realized impairment losses of $3.3 million , $(1.2) million , and $(4.3) million for the years ended December 31, 2017 , 2016 and 2015 . See New Accounting Pronouncements in Note 1. Year Ended December 31, 2017 2016 2015 (In thousands) Proceeds from sales $ 637,492 $ 522,601 $ 252,174 Gross realized gains $ 36,896 $ 46,116 $ 29,663 Gross realized (losses) $ (12,993 ) $ (25,430 ) $ (9,259 )
Investments Classified by Contractual Maturity Date	At December 31, 2017 , the available-for-sale and held-to-maturity debt securities had the following final maturities: Fair Value Available-for-Sale Held-to-Maturity PNMR and PNM PNMR (In thousands) Within 1 year $ 4,460 $ — After 1 year through 5 years 32,693 66,588 After 5 years through 10 years 48,681 — After 10 years through 15 years 5,934 — After 15 years through 20 years 11,983 — After 20 years 45,782 — $ 149,533 $ 66,588
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. There were no Level 3 fair value measurements at December 31, 2017 and 2016 for items recorded at fair value. GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (In thousands) December 31, 2017 Available-for-sale securities Cash and cash equivalents $ 52,636 $ 52,636 $ — Equity securities: Domestic value 40,032 40,032 — Domestic growth 35,456 35,456 — International and other 45,867 42,332 3,535 Fixed income securities: U.S. Government 34,317 33,645 672 Municipals 48,076 — 48,076 Corporate and other 67,140 — 67,140 $ 323,524 $ 204,101 $ 119,423 Commodity derivative assets $ 4,644 $ — $ 4,644 Commodity derivative liabilities (4,738 ) — (4,738 ) Net $ (94 ) $ — $ (94 ) December 31, 2016 Available-for-sale securities Cash and cash equivalents $ 23,683 $ 23,683 $ — Equity securities: Domestic value 34,796 34,796 — Domestic growth 47,595 47,595 — International and other 27,481 27,481 — Fixed income securities: U.S. Government 40,962 39,723 1,239 Municipals 43,789 — 43,789 Corporate and other 54,671 23,158 31,513 $ 272,977 $ 196,436 $ 76,541 Commodity derivative assets $ 5,224 $ — $ 5,224 Commodity derivative liabilities (2,339 ) — (2,339 ) Net $ 2,885 $ — $ 2,885
Summary of Carrying Amounts and Fair Value of Instruments	The carrying amounts and fair values of investments in the Westmoreland Loan, other investments, and long-term debt, which are not recorded at fair value on the Consolidated Balance Sheets are presented below: GAAP Fair Value Hierarchy Carrying Amount Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNMR Long-term debt $ 2,437,645 $ 2,554,836 $ — $ 2,554,836 $ — Westmoreland Loan $ 56,640 $ 66,588 $ — $ — $ 66,588 Other investments $ 503 $ 503 $ 503 $ — $ — PNM Long-term debt $ 1,657,910 $ 1,727,135 $ — $ 1,727,135 $ — Other investments $ 283 $ 283 $ 283 $ — $ — TNMP Long-term debt $ 480,620 $ 527,563 $ — $ 527,563 $ — Other investments $ 220 $ 220 $ 220 $ — $ — December 31, 2016 PNMR Long-term debt $ 2,392,712 $ 2,540,693 $ — $ 2,540,693 $ — Westmoreland Loan $ 95,000 $ 100,893 $ — $ — $ 100,893 Other investments $ 547 $ 1,164 $ 547 $ — $ 617 PNM Long-term debt $ 1,631,369 $ 1,730,157 $ — $ 1,730,157 $ — Other investments $ 316 $ 316 $ 316 $ — $ — TNMP Long-term debt $ 420,875 $ 468,329 $ — $ 468,329 $ — Other investments $ 231 $ 231 $ 231 $ — $ —
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 (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 487,498 $ 140,218 $ 347,089 $ 191 Uncategorized investments 74,768 Total Master Trust Investments $ 562,266 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 53,273 $ 15,244 $ 38,008 $ 21 Uncategorized investments 10,260 Total Master Trust Investments $ 63,533 PNM OPEB Plan Cash and cash equivalents $ 437 $ 437 $ — $ — Equity securities: International funds 10,636 — 10,636 — Domestic value 10,816 10,816 — — Domestic growth 6,710 6,710 — — Other funds 31,660 — 31,660 — Fixed income securities: Mutual funds 20,918 20,918 — — $ 81,177 $ 38,881 $ 42,296 $ — TNMP OPEB Plan Cash and cash equivalents $ 149 $ 149 $ — $ — Equity securities: International funds 1,597 — 1,597 — Domestic value 293 293 — — Domestic growth 1,410 1,410 — — Other funds 4,011 — 4,011 — Fixed income securities: Mutual funds 2,685 2,685 — — $ 10,145 $ 4,537 $ 5,608 $ — GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2016 (In thousands) PNM Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 467,965 $ 129,624 $ 337,989 $ 352 Uncategorized investments 75,685 Total Master Trust Investments $ 543,650 TNMP Pension Plan Participation in PNMR Master Trust Investments: Investments categorized within fair value hierarchy $ 50,901 $ 14,447 $ 36,416 $ 38 Uncategorized investments 9,729 Total Master Trust Investments $ 60,630 PNM OPEB Plan Cash and cash equivalents $ 2,567 $ 2,567 $ — $ — Equity securities: International funds 9,300 — 9,300 — Domestic value 10,260 10,260 — — Domestic growth 6,338 6,338 — — Other funds 26,405 — 26,405 — Fixed income securities: Mutual funds 18,959 18,959 — — $ 73,829 $ 38,124 $ 35,705 $ — TNMP OPEB Plan Cash and cash equivalents $ 308 $ 308 $ — $ — Equity securities: International funds 1,279 — 1,279 — Domestic value 449 449 — — Domestic growth 1,089 1,089 — — Other funds 3,060 — 3,060 — Fixed income securities: Mutual funds 2,593 2,593 — — $ 8,778 $ 4,439 $ 4,339 $ — The fair values of investments in the PNMR Master Trust are as follows: GAAP Fair Value Hierarchy Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (In thousands) PNMR Master Trust Cash and cash equivalents $ 7,697 $ 7,697 $ — $ — Equity securities: International 42,048 — 42,048 — Domestic value 37,026 37,026 — — Domestic growth 19,136 19,136 — — Other funds 25,099 — 25,099 — Fixed income securities: Corporate 215,535 — 215,323 212 U.S. Government 117,572 91,603 25,969 — Municipals 11,438 — 11,438 — Other funds 65,220 — 65,220 — Total investments categorized within fair value hierarchy 540,771 $ 155,462 $ 385,097 $ 212 Uncategorized investments: Private equity funds 22,281 Hedge funds 45,615 Real estate funds 17,132 $ 625,799 December 31, 2016 PNMR Master Trust Cash and cash equivalents $ 20,503 $ 20,503 $ — $ — Equity securities: International 38,401 — 38,401 — Domestic value 36,036 36,036 — — Domestic growth 18,484 18,484 — — Other funds 27,532 — 27,532 — Fixed income securities: Corporate 205,419 — 205,029 390 U.S. Government 94,359 69,048 25,311 — Municipals 13,970 — 13,970 — Other funds 64,162 — 64,162 — Total investments categorized within fair value hierarchy 518,866 $ 144,071 $ 374,405 $ 390 Uncategorized investments: Private equity funds 27,060 Hedge funds 42,070 Real estate funds 16,284 $ 604,280
Summary of Level 3 Measurements	A reconciliation of the changes in Level 3 fair value measurements is as follows: Fixed Income - Corporate PNMR Master Trust PNM Pension TNMP Pension Total Master Trust (In thousands) Balance at December 31, 2015 $ 719 $ 78 $ 797 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end 19 2 21 Purchases — — — Sales (387 ) (42 ) (429 ) Balance at December 31, 2016 352 38 390 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end (7 ) (1 ) (8 ) Purchases 92 10 102 Sales (247 ) (26 ) (273 ) Balance at December 31, 2017 $ 191 $ 21 $ 212 The following table presents information about the PBO, fair value of plan assets, and funded status of the plans: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) PBO at beginning of year $ 621,751 $ 597,900 $ 67,061 $ 64,198 Service cost — — — — Interest cost 26,908 30,307 2,887 3,304 Actuarial (gain) loss 26,298 39,463 3,050 4,318 Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) PBO at end of year 623,983 621,751 68,423 67,061 Fair value of plan assets at beginning of year 543,601 557,923 60,624 62,082 Actual return on plan assets 69,389 31,597 7,450 3,301 Employer contributions — — — — Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) Fair value of plan assets at end of year 562,016 543,601 63,499 60,624 Funded status – asset (liability) for pension benefits $ (61,967 ) $ (78,150 ) $ (4,924 ) $ (6,437 ) The following table presents information about the APBO, the fair value of plan assets, and the funded status of the plans: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) APBO at beginning of year $ 94,269 $ 84,674 $ 12,830 $ 13,106 Service cost 96 140 143 186 Interest cost 4,025 4,346 556 677 Participant contributions 3,069 2,690 379 520 Actuarial (gain) loss (1,601 ) 17,877 (381 ) (96 ) Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Plan design changes — (3,724 ) — — APBO at end of year 89,897 94,269 12,279 12,830 Fair value of plan assets at beginning of year 72,694 72,952 8,544 9,111 Actual return on plan assets 14,222 5,923 1,642 476 Employer contributions 332 2,863 685 — Participant contributions 3,069 2,690 379 520 Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Fair value of plan assets at end of year 80,356 72,694 10,002 8,544 Funded status – asset (liability) $ (9,541 ) $ (21,575 ) $ (2,277 ) $ (4,286 )

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 2016 2015 (In thousands) Operating revenues $ 20,887 $ 20,371 $ 20,687 Operating expenses (5,870 ) (5,852 ) (5,777 ) Earnings attributable to non-controlling interest $ 15,017 $ 14,519 $ 14,910 Financial Position December 31, 2017 2016 (In thousands) Current assets $ 2,688 $ 2,551 Net property, plant and equipment 64,109 66,947 Total assets 66,797 69,498 Current liabilities 602 578 Owners’ equity – non-controlling interest $ 66,195 $ 68,920

Earnings and Dividends Per Sh40

Earnings and Dividends Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 2016 2015 (In thousands, except per share amounts) Net Earnings Attributable to PNMR $ 79,874 $ 116,849 $ 15,640 Average Number of Common Shares: Outstanding during year 79,654 79,654 79,654 Vested awards of restricted stock 237 104 105 Average Shares – Basic 79,891 79,758 79,759 Dilutive Effect of Common Stock Equivalents: Stock options and restricted stock 250 374 380 Average Shares – Diluted 80,141 80,132 80,139 Net Earnings Attributable to PNMR Per Share of Common Stock: Basic $ 1.00 $ 1.47 $ 0.20 Diluted $ 1.00 $ 1.46 $ 0.20 Dividends Declared per Common Share $ 0.9925 $ 0.9025 $ 0.8200

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Summary of Tax Reform Adjustments	The adjustments to deferred income taxes recorded as increases in regulatory liabilities and income tax expense as a result of the enactment of the Tax Act are presented below: PNM TNMP Corporate and Other Consolidated (In thousands) Net increase in regulatory liabilities $ 402,501 $ 146,451 $ — $ 548,952 Net decrease in deferred income tax liabilities (deferred income tax assets) 372,895 138,586 (19,990 ) 491,491 Net deferred income tax expense $ 29,606 $ 7,865 $ 19,990 $ 57,461
Schedule of Components of Income Tax Expense (Benefit)	PNM’s income taxes (benefit) consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ 118 $ (10,290 ) $ (7,934 ) Current state income tax (1,112 ) (1,907 ) (1,988 ) Deferred federal income tax 73,308 49,123 (6,827 ) Deferred state income tax 9,527 4,969 5,333 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Total income taxes (benefit) $ 81,555 $ 40,922 $ (12,758 ) PNMR’s income taxes consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ — $ — $ — Current state income tax (188 ) (527 ) (1,376 ) Deferred federal income tax 119,182 60,892 5,488 Deferred state income tax 11,632 3,886 12,305 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Total income taxes $ 130,340 $ 63,278 $ 15,075 TNMP’s income taxes consist of the following components: Year Ended December 31, 2017 2016 2015 (In thousands) Current federal income tax $ 2,472 $ 9,445 $ 1,603 Current state income tax 1,765 1,729 1,639 Deferred federal income tax 27,304 12,690 20,904 Deferred state income tax (29 ) (28 ) (21 ) Total income taxes $ 31,512 $ 23,836 $ 24,125
Schedule of Effective Income Tax Rate Reconciliation	The differences are attributable to the following factors: Year Ended December 31, 2017 2016 2015 (In thousands) Federal income tax at statutory rates $ 23,475 $ 22,928 $ 23,131 State income tax, net of federal benefit 1,198 1,132 1,065 Federal income tax rate change 7,865 — — Allocation of excess tax benefit related to stock compensation awards (616 ) — — Other (410 ) (224 ) (71 ) Total income taxes $ 31,512 $ 23,836 $ 24,125 Effective tax rate 46.98 % 36.39 % 36.5 % The differences are attributable to the following factors: Year Ended December 31, 2017 2016 2015 (In thousands) Federal income tax (benefit) at statutory rates $ 59,139 $ 46,501 $ (4,579 ) Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Flow-through of depreciation items 1,103 1,185 1,465 Earnings attributable to non-controlling interest in Valencia (5,256 ) (5,082 ) (5,218 ) State income tax, net of federal benefit 4,926 3,921 (2,162 ) Impairment of state net operating loss carryforwards 627 (213 ) 3,619 Allowance for equity funds used during construction (3,032 ) (1,457 ) (3,650 ) Reversal of deferred items related to BART at SJGS — — 1,826 Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization (2,225 ) (1,877 ) — Federal income tax rate change 29,606 — — Allocation of excess tax benefit related to stock compensation awards (1,708 ) — — Other (1,339 ) (1,083 ) (2,717 ) Total income taxes (benefit) $ 81,555 $ 40,922 $ (12,758 ) Effective tax rate 48.27 % 30.80 % 97.52 % PNMR’s provision for income taxes 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, 2017 2016 2015 (In thousands) Federal income tax at statutory rates $ 79,016 $ 68,311 $ 16,154 Amortization of accumulated investment tax credits (286 ) (973 ) (1,342 ) Flow-through of depreciation items 1,147 1,227 1,485 Earnings attributable to non-controlling interest in Valencia (5,256 ) (5,082 ) (5,218 ) State income tax, net of federal benefit 5,398 4,537 (1,781 ) Impairment of state net operating loss carryforwards 819 (311 ) 5,278 Impairment of state production tax credits — — 3,092 Allowance for equity funds used during construction (3,331 ) (1,732 ) (3,650 ) Reversal of deferred items related to BART at SJGS — — 1,826 Impairment of charitable contribution carryforward 909 — 2,042 Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization (2,225 ) (1,877 ) — Federal income tax rate change 57,461 — — Excess tax benefits related to stock compensation awards (2,324 ) — — Other (988 ) (822 ) (2,811 ) Total income taxes $ 130,340 $ 63,278 $ 15,075 Effective tax rate 57.73 % 32.42 % 32.66 %
Components of Deferred Tax Assets and Liabilities	The components of PNM’s net accumulated deferred income tax liability were: December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss $ 67,719 $ 117,922 Regulatory liabilities related to income taxes 152,059 60,940 Federal tax credit carryforwards 60,085 59,156 Shutdown of SJGS Units 2 and 3 2,204 53,434 Other 23,801 41,700 Total deferred tax assets 305,868 333,152 Deferred tax liabilities: Depreciation and plant related (544,270 ) (891,578 ) Investment tax credit (55,731 ) (56,017 ) Regulatory assets related to income taxes (52,392 ) (56,577 ) Pension (51,774 ) (50,134 ) Regulatory asset for shutdown of SJGS Units 2 and 3 (31,887 ) — Other (18,826 ) (27,512 ) Total deferred tax liabilities (754,880 ) (1,081,818 ) Net accumulated deferred income tax liabilities $ (449,012 ) $ (748,666 ) The components of TNMP’s net accumulated deferred income tax liability at December 31, were: December 31, 2017 2016 (In thousands) Deferred tax assets: Regulatory liabilities related to income taxes $ 43,103 $ 3,718 Other 3,762 6,016 Total deferred tax assets 46,865 9,734 Deferred tax liabilities: Depreciation and plant related (135,647 ) (201,017 ) CTC (5,670 ) (12,715 ) Regulatory assets related to income taxes (9,564 ) (9,800 ) Loss on reacquired debt (6,890 ) (11,937 ) Pension (4,296 ) (7,153 ) AMS (7,707 ) (8,928 ) Other (3,506 ) (3,969 ) Total deferred tax liabilities (173,280 ) (255,519 ) Net accumulated deferred income tax liabilities $ (126,415 ) $ (245,785 ) The components of PNMR’s net accumulated deferred income tax liability were: December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss $ 98,301 $ 160,901 Regulatory liabilities related to income taxes 189,501 64,657 Federal tax credit carryforwards 71,849 78,675 Shutdown of SJGS Units 2 and 3 2,204 53,434 Other 45,656 75,805 Total deferred tax assets 407,511 433,472 Deferred tax liabilities: Depreciation and plant related (690,909 ) (1,102,458 ) Investment tax credit (55,731 ) (56,017 ) Regulatory assets related to income taxes (61,956 ) (66,378 ) CTC (5,670 ) (12,715 ) Pension (56,070 ) (57,287 ) Regulatory asset for shutdown of SJGS Units 2 and 3 (31,887 ) — Other (52,498 ) (79,267 ) Total deferred tax liabilities (954,721 ) (1,374,122 ) Net accumulated deferred income tax liabilities $ (547,210 ) $ (940,650 )
Reconciliation of Accumulated Deferred Income Tax Liability to Deferred Income Tax Benefit	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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (119,370 ) Change in tax effects of income tax related regulatory assets and liabilities (112 ) Federal income tax rate change 146,451 Other 306 Deferred income taxes $ 27,275 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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (299,654 ) Change in tax effects of income tax related regulatory assets and liabilities (16,332 ) Tax effect of mark-to-market adjustments (4,110 ) Tax effect of excess pension liability (3,421 ) Adjustment for uncertain income tax positions 2,614 Reclassification of unrecognized tax benefits (2,614 ) Regulatory recovery of prior year impairment of state net operating loss carryforward, net of amortization (2,225 ) Federal income tax rate change 402,501 Allocation of cumulative effect adjustment for excess tax benefit related to stock compensation awards 7,770 Other (1,980 ) Deferred income taxes $ 82,549 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, 2017 (In thousands) Net change in deferred income tax liability per above table $ (393,440 ) Change in tax effects of income tax related regulatory assets and liabilities (16,444 ) Tax effect of mark-to-market adjustments (4,724 ) Tax effect of excess pension liability (3,421 ) Adjustment for uncertain income tax positions 2,677 Reclassification of unrecognized tax benefits (2,677 ) Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization (2,225 ) Federal income tax rate change 548,952 Cumulative effect adjustment for excess tax benefit related to stock compensation awards 10,382 Alternative minimum tax carryforward reclassified to receivable (8,336 ) Other (216 ) Deferred income taxes $ 130,528
Reconciliation of Unrecognized Tax Benefits (Expenses)	A reconciliation of unrecognized tax benefits (expenses) is as follows: PNMR PNM TNMP (In thousands) Balance at December 31, 2014 $ 15,031 $ 12,228 $ — Additions based on tax positions related to 2015 1,214 1,214 — Additions (reductions) for tax positions of prior years (9,790 ) (9,790 ) — Settlement payments — — — Balance at December 31, 2015 6,455 3,652 — Additions based on tax positions related to 2016 242 242 — Additions (reductions) for tax positions of prior years 55 55 — Settlement payments — — — Balance at December 31, 2016 6,752 3,949 — Additions based on tax positions related to 2017 262 262 — Additions (reductions) for tax positions of prior years 2,415 2,352 63 Settlement payments — — — Balance at December 31, 2017 $ 9,429 $ 6,563 $ 63
Interest Income (Expense) Related to Income Taxes	Interest income (expense) related to income taxes was as follows: PNMR PNM TNMP (In thousands) 2017 $ — $ — $ — 2016 $ 4,398 $ 3,625 $ 345 2015 $ — $ — $ —
Deferred Income Taxes, Increase (Decrease) In Regulatory Liability and Income Tax Expense	Adjustments to deferred income taxes recorded as increases (decreases) in the regulatory liability and income tax expense are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: Regulatory liability $ (10,109 ) $ (10,109 ) $ — Income tax expense $ (1,259 ) $ (1,179 ) $ — December 31, 2016: Regulatory liability $ (7,132 ) $ (7,132 ) $ — Income tax expense $ 712 $ 804 $ — December 31, 2015: Regulatory liability $ (1,903 ) $ (1,903 ) $ — Income tax expense $ (674 ) $ (470 ) $ —
Tax Carryforward, Impairments, net of Federal Tax Benefit	The impairments, net of federal tax benefit, for 2015 through 2017 are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ 819 $ 627 $ — Charitable contribution carryforwards $ 909 $ — $ — December 31, 2016: State tax credit carryforwards $ — $ — $ — State net operating loss carryforwards $ (311 ) $ (213 ) $ — Charitable contribution carryforwards $ — $ — $ — December 31, 2015: State tax credit carryforwards $ 3,092 $ — $ — State net operating loss carryforwards $ 5,278 $ 3,619 $ — Charitable contribution carryforwards $ 2,042 $ — $ —
Summary of Tax Credit Carryforwards	The reserve balances, after reflecting expiration of carryforwards under applicable tax laws, at December 31, 2017 and 2016 are as follows: PNMR PNM TNMP (In thousands) December 31, 2017: State tax credit carryforwards $ 2,487 $ — $ — State net operating loss carryforwards $ 1,131 $ 839 $ — Charitable contribution carryforwards $ 952 $ — $ — December 31, 2016: State tax credit carryforwards $ 3,986 $ — $ — State net operating loss carryforwards $ 361 $ 248 $ — Charitable contribution carryforwards $ 659 $ — $ —

Pension and Other Postretirem42

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures	A reconciliation of the changes in Level 3 fair value measurements is as follows: Fixed Income - Corporate PNMR Master Trust PNM Pension TNMP Pension Total Master Trust (In thousands) Balance at December 31, 2015 $ 719 $ 78 $ 797 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end 19 2 21 Purchases — — — Sales (387 ) (42 ) (429 ) Balance at December 31, 2016 352 38 390 Actual return on assets sold during the period 1 — 1 Actual return on assets still held at period end (7 ) (1 ) (8 ) Purchases 92 10 102 Sales (247 ) (26 ) (273 ) Balance at December 31, 2017 $ 191 $ 21 $ 212 The following table presents information about the PBO, fair value of plan assets, and funded status of the plans: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) PBO at beginning of year $ 621,751 $ 597,900 $ 67,061 $ 64,198 Service cost — — — — Interest cost 26,908 30,307 2,887 3,304 Actuarial (gain) loss 26,298 39,463 3,050 4,318 Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) PBO at end of year 623,983 621,751 68,423 67,061 Fair value of plan assets at beginning of year 543,601 557,923 60,624 62,082 Actual return on plan assets 69,389 31,597 7,450 3,301 Employer contributions — — — — Benefits paid (50,974 ) (45,919 ) (4,575 ) (4,759 ) Fair value of plan assets at end of year 562,016 543,601 63,499 60,624 Funded status – asset (liability) for pension benefits $ (61,967 ) $ (78,150 ) $ (4,924 ) $ (6,437 ) The following table presents information about the APBO, the fair value of plan assets, and the funded status of the plans: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (In thousands) APBO at beginning of year $ 94,269 $ 84,674 $ 12,830 $ 13,106 Service cost 96 140 143 186 Interest cost 4,025 4,346 556 677 Participant contributions 3,069 2,690 379 520 Actuarial (gain) loss (1,601 ) 17,877 (381 ) (96 ) Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Plan design changes — (3,724 ) — — APBO at end of year 89,897 94,269 12,279 12,830 Fair value of plan assets at beginning of year 72,694 72,952 8,544 9,111 Actual return on plan assets 14,222 5,923 1,642 476 Employer contributions 332 2,863 685 — Participant contributions 3,069 2,690 379 520 Benefits paid (9,961 ) (11,734 ) (1,248 ) (1,563 ) Fair value of plan assets at end of year 80,356 72,694 10,002 8,544 Funded status – asset (liability) $ (9,541 ) $ (21,575 ) $ (2,277 ) $ (4,286 )
Schedule of Assumptions Used	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 Plan 2017 2016 2015 Discount rate for determining December 31 PBO 4.05 % 4.51 % 5.29 % Discount rate for determining net periodic benefit cost (income) 4.51 % 5.29 % 4.48 % Expected return on plan assets 6.40 % 6.50 % 6.80 % Rate of compensation increase N/A N/A N/A TNMP Plan Discount rate for determining December 31 PBO 4.01 % 4.49 % 5.39 % Discount rate for determining net periodic benefit cost (income) 4.49 % 5.39 % 4.39 % Expected return on plan assets 6.40 % 6.50 % 6.80 % Rate of compensation increase N/A N/A N/A Actuarial (gain) loss results from changes in: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (in thousands) Discount rates $ 27,547 $ 41,849 $ 3,528 $ 5,055 Demographic experience (1,249 ) (334 ) (517 ) (556 ) Other assumption and experience — (2,052 ) 39 (181 ) $ 26,298 $ 39,463 $ 3,050 $ 4,318 Actuarial (gain) loss results from changes in: PNM Plan TNMP Plan Year Ended December 31, Year Ended December 31, 2017 2016 2017 2016 (in thousands) Discount rates $ 3,536 $ 6,569 $ 613 $ 1,112 Claims, contributions, and demographic experience (5,845 ) 19,562 (994 ) (102 ) Assumed participation rate — (6,335 ) — (1,013 ) Mortality rate — (691 ) — (93 ) Medical benefits 1,425 (1,228 ) — — Dental trend assumption (717 ) — — — $ (1,601 ) $ 17,877 $ (381 ) $ (96 ) 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 Plan 2017 2016 2015 Discount rate for determining December 31 APBO 4.00 % 4.47 % 5.34 % Discount rate for determining net periodic benefit cost 4.47 % 5.34 % 4.45 % Expected return on plan assets 7.50 % 7.70 % 7.70 % Rate of compensation increase N/A N/A N/A TNMP Plan Discount rate for determining December 31 APBO 4.00 % 4.47 % 5.34 % Discount rate for determining net periodic benefit cost 4.47 % 5.34 % 4.45 % Expected return on plan assets 5.40 % 5.70 % 5.70 % 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 Plan 2017 2016 2015 Discount rate for determining December 31 PBO 4.05 % 4.51 % 5.29 % Discount rate for determining net periodic benefit cost 4.51 % 5.29 % 4.48 % 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 Plan Discount rate for determining December 31 PBO 4.01 % 4.49 % 5.39 % Discount rate for determining net periodic benefit cost 4.49 % 5.39 % 4.39 % 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 loss in AOCI as of December 31, 2017 . December 31, 2017 PNM Plan TNMP Plan (In thousands) Amount in AOCI not yet recognized in net periodic benefit cost at beginning of year $ 2,299 $ — Experience (gain) loss 674 44 Regulatory asset (liability) adjustment (391 ) (44 ) Amortization recognized in net periodic benefit cost (income) (132 ) — Amount in AOCI not yet recognized in net periodic benefit cost at end of year $ 2,450 $ — Amortization expected to be recognized in 2018 $ 151 $ — The following table presents pre-tax information about prior service cost and net actuarial (gain) loss in AOCI as of December 31, 2017 . PNM Plan TNMP Plan December 31, 2017 December 31, 2017 Prior service cost Net actuarial (gain) loss Net actuarial (gain) loss (In thousands) Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year $ (1,450 ) $ 159,149 $ — Experience (gain) loss — (9,288 ) (621 ) Regulatory asset (liability) adjustment — 5,387 621 Amortization recognized in net periodic benefit cost (income) 405 (6,722 ) — Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year $ (1,045 ) $ 148,526 $ — Amortization expected to be recognized in 2018 $ (405 ) $ 6,653 $ —
Schedule of Net Benefit Costs	The following table presents the components of net periodic benefit cost: Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ — $ — $ — Interest cost 697 812 760 Amortization of net (gain) loss 313 256 325 Amortization of prior service cost — — — Net periodic benefit cost $ 1,010 $ 1,068 $ 1,085 TNMP Plan Service cost $ — $ — $ — Interest cost 33 40 36 Amortization of net (gain) loss 9 2 5 Amortization of prior service cost — — — Net periodic benefit cost $ 42 $ 42 $ 41 The following table presents the components of net periodic benefit cost (income): Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ — $ — $ — Interest cost 26,908 30,307 28,255 Expected return on plan assets (33,803 ) (35,416 ) (39,323 ) Amortization of net (gain) loss 16,006 13,820 14,820 Amortization of prior service cost (965 ) (965 ) (965 ) Net periodic benefit cost $ 8,146 $ 7,746 $ 2,787 TNMP Plan Service cost $ — $ — $ — Interest cost 2,887 3,304 3,043 Expected return on plan assets (3,779 ) (3,943 ) (4,420 ) Amortization of net (gain) loss 923 700 782 Amortization of prior service cost — — — Net periodic benefit cost (income) $ 31 $ 61 $ (595 ) The following table presents the components of net periodic benefit cost: Year Ended December 31, 2017 2016 2015 (In thousands) PNM Plan Service cost $ 96 $ 140 $ 204 Interest cost 4,025 4,346 4,089 Expected return on plan assets (5,230 ) (5,483 ) (5,610 ) Amortization of net (gain) loss 3,682 1,145 1,966 Amortization of prior service credit (1,663 ) (30 ) (642 ) Net periodic benefit cost $ 910 $ 118 $ 7 TNMP Plan Service cost $ 143 $ 186 $ 247 Interest cost 556 677 608 Expected return on plan assets (456 ) (490 ) (520 ) Amortization of net (gain) loss (79 ) (40 ) — Amortization of prior service cost — — — Net periodic benefit cost $ 164 $ 333 $ 335
Schedule of Expected Benefit Payments	The following pension benefit payments are expected to be paid: PNM Plan TNMP Plan (In thousands) 2018 $ 49,221 $ 5,929 2019 48,639 5,215 2020 47,069 5,108 2021 45,246 5,373 2022 44,232 4,856 2023 - 2027 201,389 22,085 The following other postretirement benefit payments, which reflect expected future service and are net of participant contributions, are expected to be paid: PNM Plan TNMP Plan (In thousands) 2018 $ 7,829 $ 708 2019 7,730 725 2020 7,605 748 2021 7,442 774 2022 7,132 795 2023 - 2027 31,250 4,126 The following executive retirement plan payments, which reflect expected future service, are expected: PNM Plan TNMP Plan (In thousands) 2018 $ 1,501 $ 93 2019 1,473 91 2020 1,441 89 2021 1,405 85 2022 1,363 81 2023 - 2027 6,014 324
Schedule of Health Care Cost Trend Rates	The following table shows the assumed health care cost trend rates for the PNM postretirement benefit plan: PNM Plan December 31, 2017 2016 Health care cost trend rate assumed for next year 6.5 % 6.8 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 5.0 % 5.0 % Year that the rate reaches the ultimate trend rate 2024 2024
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	The following table shows the impact of a one-percentage-point change in assumed health care cost trend rates: PNM Plan 1-Percentage- Point Increase 1-Percentage- Point Decrease (In thousands) Effect on total of service and interest cost $ 72 $ (111 ) Effect on APBO $ 1,452 $ (2,235 )
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 Plan TNMP Plan Year Ended Year Ended 2017 2016 2017 2016 (In thousands) PBO at beginning of year $ 16,212 $ 16,105 $ 787 $ 794 Service cost — — — — Interest cost 697 812 33 40 Actuarial (gain) loss 674 768 44 47 Benefits paid (1,466 ) (1,473 ) (93 ) (94 ) PBO at end of year – funded status 16,117 16,212 771 787 Less current liability 1,501 1,510 93 93 Non-current liability $ 14,616 $ 14,702 $ 678 $ 694
Summary of Expenses for Other Retirement Plans	A summary of expenses for these other retirement plans is as follows: Year Ended December 31, 2017 2016 2015 (In thousands) PNMR 401(k) plan $ 16,452 $ 17,762 $ 16,725 Non-qualified plan $ 3,702 $ 2,017 $ 1,436 PNM 401(k) plan $ 12,120 $ 13,397 $ 12,679 Non-qualified plan $ 2,834 $ 1,535 $ 1,090 TNMP 401(k) plan $ 4,332 $ 4,365 $ 4,046 Non-qualified plan $ 868 $ 482 $ 346

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
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 2017 2016 2015 Expected quarterly dividends per share $ 0.2425 $ 0.2200 $ 0.2000 Risk-free interest rate 1.50 % 0.94 % 0.92 % Market-Based Shares Dividend yield 2.67 % 2.74 % 2.87 % Expected volatility 20.80 % 20.44 % 18.73 % Risk-free interest rate 1.54 % 0.97 % 1.00 % 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 Average Exercise Price Outstanding at December 31, 2016 218,316 $ 27.59 305,874 $ 12.29 Granted 248,271 $ 23.06 — $ — Exercised (273,530 ) $ 21.01 (109,433 ) $ 15.89 Forfeited (4,012 ) $ 29.96 — $ — Expired — $ — (3,000 ) $ 30.50 Outstanding at December 31, 2017 189,045 $ 31.11 193,441 $ 9.98 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 2017 2016 2015 Weighted-average grant date fair value $ 23.06 $ 26.49 $ 20.34 Total fair value of restricted shares that vested (in thousands) $ 5,747 $ 5,079 $ 6,507 Stock Options Weighted-average grant date fair value of options granted $ — $ — $ — Total fair value of options that vested (in thousands) $ — $ — $ — Total intrinsic value of options exercised (in thousands) $ 2,234 $ 1,242 $ 2,350

Construction Program and Join44

Construction Program and Jointly-Owned Electric Generating Plants (Tables)	12 Months Ended
	Dec. 31, 2017
Construction Program and Jointly-Owned Electric Generating Plants [Abstract]
Summary of Interests and Investments in Jointly-Owned Generating Facilities	At December 31, 2017 , PNM’s interests and investments in jointly-owned generating facilities are: Station (Fuel Type) Plant in Service Accumulated Depreciation (1) Construction Work in Progress Composite Interest (In thousands) SJGS (Coal) (2) $ 920,950 $ (522,750 ) $ 8,512 46.30 % PVNGS (Nuclear) (3) $ 918,830 $ (353,054 ) $ 35,038 10.20 % Four Corners Units 4 and 5 (Coal) $ 204,432 $ (100,914 ) $ 61,755 13.00 % Luna (Gas) $ 70,995 $ (27,023 ) $ (13 ) 33.33 % (1) Includes cost of removal. (2) See Note 16 for a discussion of the December 2017 shutdown of SJGS Units 2 and 3 and the restructuring of the ownership of SJGS Unit 4. (3) 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: 2018 2019 2020 2021 2022 Total (In millions) PNM $ 295.0 $ 339.0 $ 313.4 $ 315.8 $ 493.7 $ 1,756.9 TNMP 185.8 170.5 170.0 170.5 170.1 866.9 Corporate and Other 19.4 17.3 17.0 17.5 17.1 88.3 Total PNMR $ 500.2 $ 526.8 $ 500.4 $ 503.8 $ 680.9 $ 2,712.1

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2014 $ 104,170 $ 103,182 $ 848 Liabilities incurred — — — Liabilities settled (730 ) (506 ) (224 ) Accretion expense 8,625 8,543 71 Revisions to estimated cash flows (170 ) (170 ) — Liability at December 31, 2015 111,895 111,049 695 Liabilities incurred — — — Liabilities settled (14 ) (14 ) — Accretion expense 9,170 9,098 59 Revisions to estimated cash flows 6,468 6,468 — Liability at December 31, 2016 127,519 126,601 754 Liabilities incurred (1) 1,854 1,853 — Liabilities settled (968 ) (944 ) (24 ) Accretion expense 10,680 10,603 63 Revisions to estimated cash flows 7,594 7,594 — Liability at December 31, 2017 $ 146,679 $ 145,707 $ 793 (1) Represents the obligation related to the additional ownership interest in SJGS Unit 4 that PNM acquired on December 31, 2017 due to the restructuring of the ownership of SJGS.

Regulatory and Rate Matters Reg

Regulatory and Rate Matters Regulatory and Rate Matters (Tables)	12 Months Ended
	Dec. 31, 2017
Regulated Operations [Abstract]
Schedule of Energy/Capacity Transactions	Information about PNM’s purchases and sales is as follows: Sales Purchases GWh Amount GWh Amount (In millions) (In millions) Year ended December 31, 2017 827.1 $ 23.6 849.0 $ 24.2 Year ended December 31, 2016 482.3 12.8 484.6 12.9
Schedule of Rate Increases for Transmission Costs	TNMP can update its transmission rates twice per year to reflect changes in its invested capital although updates are not allowed while a general rate case is in progress. Updated rates reflect the addition and retirement of transmission facilities, including appropriate depreciation, federal income tax and other associated taxes, and the approved rate of return on such facilities. 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 16, 2015 $ 27.1 $ 4.4 September 10, 2015 7.0 1.4 March 23, 2016 25.8 4.3 September 8, 2016 9.5 1.8 March 14, 2017 30.2 4.8 September 13, 2017 27.5 4.7 TNMP recovers the costs of its energy efficiency programs through an energy efficiency cost recovery factor (“EECRF”), which includes projected program costs, under or over collected costs from prior years, rate case expenses, and performance bonuses (if the programs exceed mandated savings goals). The following sets forth TNMP’s EECRF increases: Effective Date Aggregate Collection Amount Performance Bonus (In millions) March 1, 2015 $ 5.7 $ 1.5 March 1, 2016 6.0 0.7 March 1, 2017 6.0 0.8 March 1, 2018 6.0 1.1

Accumulated Other Comprehensi47

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
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 Liability Adjustment Total Fair Value Adjustment for Cash Flow Hedges Total (In thousands) Balance at December 31, 2014 $ 28,008 $ (89,763 ) $ (61,755 ) $ — $ (61,755 ) Amounts reclassified from AOCI (pre-tax) (28,531 ) 5,952 (22,579 ) — (22,579 ) Income tax impact of amounts reclassified 11,181 (2,332 ) 8,849 — 8,849 Other OCI changes (pre-tax) 10,998 (4,405 ) 6,593 72 6,665 Income tax impact of other OCI changes (4,310 ) 1,726 (2,584 ) (28 ) (2,612 ) Net after-tax change (10,662 ) 941 (9,721 ) 44 (9,677 ) Balance at December 31, 2015 17,346 (88,822 ) (71,476 ) 44 (71,432 ) Amounts reclassified from AOCI (pre-tax) (22,139 ) 5,504 (16,635 ) 764 (15,871 ) Income tax impact of amounts reclassified 8,639 (2,148 ) 6,491 (298 ) 6,193 Other OCI changes (pre-tax) 778 (18,501 ) (17,723 ) (874 ) (18,597 ) Income tax impact of other OCI changes (304 ) 7,219 6,915 341 7,256 Net after-tax change (13,026 ) (7,926 ) (20,952 ) (67 ) (21,019 ) Balance at December 31, 2016 4,320 (96,748 ) (92,428 ) (23 ) (92,451 ) Amounts reclassified from AOCI (pre-tax) (17,567 ) 6,452 (11,115 ) 581 (10,534 ) Income tax impact of amounts reclassified 6,816 (2,504 ) 4,312 (225 ) 4,087 Other OCI changes (pre-tax) 28,160 3,618 31,778 1,000 32,778 Income tax impact of other OCI changes (10,927 ) (919 ) (11,846 ) (388 ) (12,234 ) Net after-tax change 6,482 6,647 13,129 968 14,097 Reclassification of stranded income taxes to retained earnings Note 11 2,367 (20,161 ) (17,794 ) 208 (17,586 ) Balance at December 31, 2017 $ 13,169 $ (110,262 ) $ (97,093 ) $ 1,153 $ (95,940 )

Quarterly Operating Results (48

Quarterly Operating Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Schedule of Quarterly Financial Information	Unaudited operating results by quarters for 2017 and 2016 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. Quarter Ended March 31 June 30 September 30 December 31 (1) (In thousands, except per share amounts) PNMR 2017 Operating revenues $ 330,178 $ 362,320 $ 419,900 $ 332,605 Operating income 55,960 85,105 142,484 22,936 Net earnings (loss) 26,446 41,231 78,327 (50,585 ) Net earnings (loss) attributable to PNMR 22,862 37,555 73,739 (54,282 ) Net earnings (loss) attributable to PNMR per common share: Basic 0.29 0.47 0.92 (0.68 ) Diluted 0.29 0.47 0.92 (0.68 ) 2016 Operating revenues $ 310,961 $ 315,391 $ 400,374 $ 336,225 Operating income 41,508 64,822 108,071 63,584 Net earnings 13,965 30,952 58,556 28,423 Net earnings attributable to PNMR 10,546 27,076 54,418 24,809 Net earnings attributable to PNMR per common share: Basic 0.13 0.34 0.68 0.32 Diluted 0.13 0.34 0.68 0.31 PNM 2017 Operating revenues $ 251,558 $ 276,097 $ 327,254 $ 249,321 Operating income 38,331 59,164 113,252 1,778 Net earnings (loss) 20,110 30,476 65,283 (28,456 ) Net earnings (loss) attributable to PNM 16,658 26,932 60,827 (32,021 ) 2016 Operating revenues $ 235,606 $ 233,346 $ 311,276 $ 255,685 Operating income 23,297 41,760 80,057 42,976 Net earnings 7,561 19,793 44,990 19,594 Net earnings attributable to PNM 4,274 16,049 40,984 16,112 TNMP 2017 Operating revenues $ 78,620 $ 86,223 $ 92,646 $ 83,284 Operating income 17,965 26,286 29,474 19,879 Net earnings 7,604 12,204 14,727 1,024 2016 Operating revenues $ 75,355 $ 82,045 $ 89,098 $ 80,540 Operating income 18,554 23,375 28,359 21,353 Net earnings 7,456 10,508 13,853 9,855 (1) Reflects the impacts of changes in federal income tax rate of $57.5 million , $29.6 million , and $7.9 million for PNMR, PNM, and TNMP (Note 11); also reflects a pre-tax regulatory disallowance resulting from PNM’s NM 2016 Rate Case of $27.9 million for PNMR and PNM (Note 17).

Summary of the Business and S49

Summary of the Business and Significant Accounting Policies - Narrative (Details)	Mar. 01, 2018USD ($)	Dec. 31, 2017USD ($)FacilityMW	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)FacilityMW	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jun. 30, 2018MW	Sep. 29, 2017	Sep. 22, 2017	Jul. 08, 2016MW	Dec. 31, 2014USD ($)	Dec. 31, 1986lease
Accounting Policies Disclosures [Line Items]
Payment defaults		$ 0								$ 0
Allowance for equity funds used during construction										$ 9,516,000	$ 4,949,000	$ 10,430,000
Weighted average borrowing rate		5.90%				6.10%				5.90%	6.10%	6.60%
Interest costs incurred, capitalized										$ 1,300,000	$ 1,800,000	$ 1,500,000
Plant in Service		$ 7,238,285,000				$ 6,944,534,000				7,238,285,000	6,944,534,000
Operating Expenses (less than $0.1 million)										1,138,518,000	1,084,966,000	1,314,732,000
Net income (less than $0.1 million)		(54,282,000)	$ 73,739,000	$ 37,555,000	$ 22,862,000	24,809,000	$ 54,418,000	$ 27,076,000	$ 10,546,000	79,874,000	116,849,000	15,640,000
Construction work in progress		245,933,000				208,206,000				245,933,000	208,206,000
Owner's equity		1,695,253,000				1,675,952,000				1,695,253,000	1,675,952,000
Unrealized gains, net of income taxes, recorded in AOCI		11,100,000								11,100,000
Public Service Company of New Mexico
Accounting Policies Disclosures [Line Items]
Allowance for funds used during construction, capitalized interest										6,300,000	5,300,000	7,800,000
Allowance for equity funds used during construction										8,664,000	4,163,000	10,430,000
Interest costs incurred, capitalized										600,000	800,000	800,000
Impairment losses on securities held in the NDT										7,100,000	13,900,000	10,400,000
Plant in Service		5,501,070,000				5,359,211,000				5,501,070,000	5,359,211,000
Operating Expenses (less than $0.1 million)										891,705,000	847,823,000	1,097,815,000
Net income (less than $0.1 million)		(32,021,000)	60,827,000	26,932,000	16,658,000	16,112,000	40,984,000	16,049,000	4,274,000	72,396,000	77,419,000	(15,234,000)
Construction work in progress		204,079,000				158,122,000				204,079,000	158,122,000
Owner's equity		$ 1,422,174,000				1,397,872,000				1,422,174,000	1,397,872,000
Restricted cash deposits												8,200,000
Administrative and general, pre-tax										$ 4,700,000	3,000,000
Public Service Company of New Mexico | Subsequent Event
Accounting Policies Disclosures [Line Items]
Refund to third party	$ 7,100,000
Public Service Company of New Mexico | 10.3% Lessor Notes
Accounting Policies Disclosures [Line Items]
Notes receivable, stated percentage rate		10.30%								10.30%
Public Service Company of New Mexico | 10.15% Lessor Notes
Accounting Policies Disclosures [Line Items]
Notes receivable, stated percentage rate		10.15%								10.15%
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station
Accounting Policies Disclosures [Line Items]
Number of operating leases | lease																		11
Texas-New Mexico Power Company
Accounting Policies Disclosures [Line Items]
Allowance for funds used during construction, capitalized interest										$ 1,200,000	900,000	500,000
Allowance for equity funds used during construction										900,000	800,000	0
Interest costs incurred, capitalized										100,000	100,000	100,000
Plant in Service		$ 1,504,778,000				1,380,584,000				1,504,778,000	1,380,584,000
Operating Expenses (less than $0.1 million)										247,169,000	235,397,000	217,854,000
Net income (less than $0.1 million)		1,024,000	$ 14,727,000	$ 12,204,000	$ 7,604,000	9,855,000	$ 13,853,000	$ 10,508,000	$ 7,456,000	35,559,000	41,672,000	41,963,000
Construction work in progress		34,350,000				16,978,000				34,350,000	16,978,000
Owner's equity		634,405,000				$ 593,235,000				634,405,000	593,235,000	$ 533,380,000					$ 524,665,000
Net periodic benefit cost (less than $0.1 million)										100,000	$ 100,000
PNMR Development
Accounting Policies Disclosures [Line Items]
Solar distributed generation (in mw) | MW																30
Solar capacity (in mw) | MW																10
NMRD
Accounting Policies Disclosures [Line Items]
Revenues (less than $0.1 million)										100,000
Operating Expenses (less than $0.1 million)										100,000
Net income (less than $0.1 million)										100,000
Cash		6,000,000								6,000,000
Construction work in progress		30,900,000								30,900,000
Accounts payable		3,900,000								3,900,000
Owner's equity		$ 33,000,000								$ 33,000,000
NMRD
Accounting Policies Disclosures [Line Items]
Solar distributed generation (in mw) | MW		30								30
Plant in Service		$ 12,400,000								$ 12,400,000
Renewable energy capacity under contract | MW		31.8								31.8
Megawatts for solar PV facilities in operation (in mw) | MW		11.8								11.8
Megawatts supplying energy to data center (in mw) | MW		10								10
Megawatts supplying energy to Columbus Electric Cooperative (in mw) | MW		1.8								1.8
Solar capacity (in mw) | MW		20								20
NMRD | PNMR Development
Accounting Policies Disclosures [Line Items]
Ownership percentage															50.00%
Number of solar facilities | Facility		3								3
Solar distributed generation (in mw) | MW		10								10
Plant in Service		$ 24,800,000								$ 24,800,000
Cash contribution percentage		50.00%								50.00%
NMRD | AEP OnSite Partners
Accounting Policies Disclosures [Line Items]
Ownership percentage														50.00%
NMRD | PNMR Development and AEP OnSite
Accounting Policies Disclosures [Line Items]
Contribution to construction activities										$ 4,100,000
Scenario, forecast | NMRD
Accounting Policies Disclosures [Line Items]
Solar distributed generation (in mw) | MW													20

Summary of the Business and S50

Summary of the Business and Significant Accounting Policies - Inventories/Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Public Utilities, Inventory [Line Items]
Inventory	$ 66,502	$ 73,027
Coal
Public Utilities, Inventory [Line Items]
Inventory	16,714	19,940
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	49,788	53,087
Public Service Company of New Mexico
Public Utilities, Inventory [Line Items]
Inventory	60,859	64,401
Public Service Company of New Mexico | Coal
Public Utilities, Inventory [Line Items]
Inventory	16,714	19,940
Public Service Company of New Mexico | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 44,145	$ 44,461
Public Service Company of New Mexico | Electric plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	2.52%	2.33%	2.27%
Public Service Company of New Mexico | Common, intangible, and general plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	8.36%	5.40%	4.66%
Texas-New Mexico Power Company
Public Utilities, Inventory [Line Items]
Depreciation average rates used	3.57%	3.66%	3.65%
Inventory	$ 5,643	$ 8,626
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	$ 5,643	$ 8,626

Segment Information - Schedule

Segment Information - Schedule (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Electric Operating Revenues	$ 332,605	$ 419,900	$ 362,320	$ 330,178	$ 336,225	$ 400,374	$ 315,391	$ 310,961	$ 1,445,003	$ 1,362,951	$ 1,439,082
Cost of energy									407,479	380,596	464,649
Utility margin									1,037,524	982,355	974,433
Other operating expenses									499,097	495,260	664,164
Depreciation and amortization									231,942	209,110	185,919
Operating income	22,936	142,484	85,105	55,960	63,584	108,071	64,822	41,508	306,485	277,985	124,350
Interest income									15,916	22,293	6,498
Other income (deductions)									30,983	23,529	30,165
Interest charges									(127,625)	(128,633)	(114,860)
Earnings before Income Taxes									225,759	195,174	46,153
Income taxes									130,340	63,278	15,075
Net Earnings	(50,585)	$ 78,327	$ 41,231	$ 26,446	28,423	$ 58,556	$ 30,952	$ 13,965	95,419	131,896	31,078
Valencia non-controlling interest									(15,017)	(14,519)	(14,910)
Subsidiary preferred stock dividends									(528)	(528)	(528)
Segment earnings (loss) attributable to PNMR									79,874	116,849	15,640
Total Assets	6,646,103				6,471,080				6,646,103	6,471,080	6,009,328
Goodwill	278,297				278,297				278,297	278,297	278,297
PNM
Segment Reporting Information [Line Items]
Electric Operating Revenues									1,104,230	1,035,913	1,131,195
Cost of energy									321,677	299,714	391,131
Utility margin									782,553	736,199	740,064
Other operating expenses									423,011	414,662	590,967
Depreciation and amortization									147,017	133,447	115,717
Operating income									212,525	188,090	33,380
Interest income									8,454	10,173	6,574
Other income (deductions)									30,686	22,066	26,914
Interest charges									(82,697)	(87,469)	(79,950)
Earnings before Income Taxes									168,968	132,860	(13,082)
Income taxes									81,555	40,922	(12,758)
Net Earnings									87,413	91,938	(324)
Valencia non-controlling interest									(15,017)	(14,519)	(14,910)
Subsidiary preferred stock dividends									(528)	(528)	(528)
Segment earnings (loss) attributable to PNMR									71,868	76,891	(15,762)
Total Assets	4,921,563				4,867,546				4,921,563	4,867,546	4,599,344
Goodwill	51,632				51,632				51,632	51,632	51,632
TNMP
Segment Reporting Information [Line Items]
Electric Operating Revenues									340,773	327,038	307,887
Cost of energy									85,802	80,882	73,518
Utility margin									254,971	246,156	234,369
Other operating expenses									98,221	93,389	88,051
Depreciation and amortization									63,146	61,126	56,285
Operating income									93,604	91,641	90,033
Interest income									0	0	0
Other income (deductions)									3,551	3,202	3,736
Interest charges									(30,084)	(29,335)	(27,681)
Earnings before Income Taxes									67,071	65,508	66,088
Income taxes									31,512	23,836	24,125
Net Earnings									35,559	41,672	41,963
Valencia non-controlling interest									0	0	0
Subsidiary preferred stock dividends									0	0	0
Segment earnings (loss) attributable to PNMR									35,559	41,672	41,963
Total Assets	1,500,770				1,383,223				1,500,770	1,383,223	1,297,139
Goodwill	226,665				226,665				226,665	226,665	226,665
Corporate and Other
Segment Reporting Information [Line Items]
Electric Operating Revenues									0	0	0
Cost of energy									0	0	0
Utility margin									0	0	0
Other operating expenses									(22,135)	(12,791)	(14,854)
Depreciation and amortization									21,779	14,537	13,917
Operating income									356	(1,746)	937
Interest income									7,462	12,120	(76)
Other income (deductions)									(3,254)	(1,739)	(485)
Interest charges									(14,844)	(11,829)	(7,229)
Earnings before Income Taxes									(10,280)	(3,194)	(6,853)
Income taxes									17,273	(1,480)	3,708
Net Earnings									(27,553)	(1,714)	(10,561)
Valencia non-controlling interest									0	0	0
Subsidiary preferred stock dividends									0	0	0
Segment earnings (loss) attributable to PNMR									(27,553)	(1,714)	(10,561)
Total Assets	223,770				220,311				223,770	220,311	112,845
Goodwill	$ 0				$ 0				$ 0	$ 0	$ 0

Segment Information - Major Cus

Segment Information - Major Customers (Details) - Electric operating revenues - customer	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
PNMR and PNM
Concentration Risk [Line Items]
Number of customers that make up more than 10% of total revenue	0
PNMR and PNM | Maximum
Concentration Risk [Line Items]
Operating revenues from continuing operations	10.00%
Texas-New Mexico Power Company
Concentration Risk [Line Items]
Number of customers that make up more than 10% of total revenue	3
Texas-New Mexico Power Company | REP A
Concentration Risk [Line Items]
Operating revenues from continuing operations	16.00%	16.00%	16.00%
Texas-New Mexico Power Company | REP B
Concentration Risk [Line Items]
Operating revenues from continuing operations	11.00%	11.00%	13.00%
Texas-New Mexico Power Company | REP C
Concentration Risk [Line Items]
Operating revenues from continuing operations	10.00%	11.00%	11.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Services billings: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	$ 97,914	$ 94,606	$ 90,827
Services billings: | PNMR to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	31,095	28,907	28,109
Services billings: | PNM to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	382	427	554
Services billings: | TNMP to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	141	66	41
Services billings: | TNMP to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	154	172	0
Interest billings: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	21	11	54
Interest billings: | PNMR to TNMP
Related Party Transaction [Line Items]
Amount of related party transaction	133	132	276
Interest billings: | PNM to PNMR
Related Party Transaction [Line Items]
Amount of related party transaction	220	150	110
Income tax sharing payments: | PNMR to PNM
Related Party Transaction [Line Items]
Amount of related party transaction	23,391	0	1,450
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	$ 20,686	$ 0	$ 0

Regulatory Assets and Liabili54

Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Regulatory Assets
Current	$ 2,933	$ 3,855
Non-Current	600,672	501,223
Regulatory Liabilities
Current	(2,309)	(3,609)
Non-Current	(933,578)	(455,649)
Public Service Company of New Mexico
Regulatory Assets
Current	2,139	3,442
Non-Current	459,239	365,413
Total regulatory assets	461,378	368,855
Regulatory Liabilities
Current	(784)	(3,517)
Non-Current	(754,441)	(423,701)
Total regulatory liabilities	(755,225)	(427,218)
Public Service Company of New Mexico | Renewable energy rider
Regulatory Liabilities
Current	(779)	(3,411)
Public Service Company of New Mexico | Other
Regulatory Liabilities
Current	(5)	(106)
Public Service Company of New Mexico | Cost of removal
Regulatory Liabilities
Non-Current	(256,493)	(297,087)
Public Service Company of New Mexico | Deferred income taxes
Regulatory Liabilities
Non-Current	(445,390)	(62,920)
Public Service Company of New Mexico | PVNGS ARO
Regulatory Liabilities
Non-Current	(24,889)	(30,621)
Public Service Company of New Mexico | Renewable energy tax benefits
Regulatory Liabilities
Non-Current	(21,383)	(22,540)
Public Service Company of New Mexico | Nuclear spent fuel reimbursements
Regulatory Liabilities
Non-Current	(5,518)	(8,875)
Public Service Company of New Mexico | Pension and OPEB
Regulatory Liabilities
Non-Current	0	0
Public Service Company of New Mexico | Other
Regulatory Liabilities
Non-Current	(768)	(1,658)
Public Service Company of New Mexico | FPPAC
Regulatory Assets
Current	363	1,451
Public Service Company of New Mexico | Energy efficiency costs
Regulatory Assets
Current	1,776	1,991
Public Service Company of New Mexico | CTC, including carrying charges
Regulatory Assets
Non-Current	0	0
Public Service Company of New Mexico | Coal mine reclamation costs
Regulatory Assets
Non-Current	16,462	22,383
Public Service Company of New Mexico | Deferred income taxes
Regulatory Assets
Non-Current	59,220	62,918
Public Service Company of New Mexico | Loss on reacquired debt
Regulatory Assets
Non-Current	22,744	24,404
Public Service Company of New Mexico | Pension and OPEB
Regulatory Assets
Non-Current	222,774	249,286
Public Service Company of New Mexico | Shutdown of SJGS Units 2 and 3
Regulatory Assets
Non-Current	125,539	0
Public Service Company of New Mexico | Hurricane recovery costs
Regulatory Assets
Non-Current	0	0
Public Service Company of New Mexico | AMS surcharge
Regulatory Assets
Non-Current	0	0
Public Service Company of New Mexico | AMS retirement costs
Regulatory Assets
Non-Current	0	0
Public Service Company of New Mexico | Other
Regulatory Assets
Non-Current	12,500	6,422
Texas-New Mexico Power Company
Regulatory Assets
Current	794	413
Non-Current	141,433	135,810
Total regulatory assets	142,227	136,223
Regulatory Liabilities
Current	(1,525)	(92)
Non-Current	(179,137)	(31,948)
Total regulatory liabilities	(180,662)	(32,040)
Texas-New Mexico Power Company | Renewable energy rider
Regulatory Liabilities
Current	0	0
Texas-New Mexico Power Company | Other
Regulatory Liabilities
Current	(1,525)	(92)
Texas-New Mexico Power Company | Cost of removal
Regulatory Liabilities
Non-Current	(26,541)	(26,900)
Texas-New Mexico Power Company | Deferred income taxes
Regulatory Liabilities
Non-Current	(148,455)	(2,644)
Texas-New Mexico Power Company | PVNGS ARO
Regulatory Liabilities
Non-Current	0	0
Texas-New Mexico Power Company | Renewable energy tax benefits
Regulatory Liabilities
Non-Current	0	0
Texas-New Mexico Power Company | Nuclear spent fuel reimbursements
Regulatory Liabilities
Non-Current	0	0
Texas-New Mexico Power Company | Pension and OPEB
Regulatory Liabilities
Non-Current	(3,442)	(1,955)
Texas-New Mexico Power Company | Other
Regulatory Liabilities
Non-Current	(699)	(449)
Texas-New Mexico Power Company | FPPAC
Regulatory Assets
Current	0	0
Texas-New Mexico Power Company | Energy efficiency costs
Regulatory Assets
Current	794	413
Texas-New Mexico Power Company | CTC, including carrying charges
Regulatory Assets
Non-Current	26,998	36,328
Texas-New Mexico Power Company | Coal mine reclamation costs
Regulatory Assets
Non-Current	0	0
Texas-New Mexico Power Company | Deferred income taxes
Regulatory Assets
Non-Current	9,621	9,932
Texas-New Mexico Power Company | Loss on reacquired debt
Regulatory Assets
Non-Current	32,808	34,107
Texas-New Mexico Power Company | Pension and OPEB
Regulatory Assets
Non-Current	26,153	27,661
Texas-New Mexico Power Company | Shutdown of SJGS Units 2 and 3
Regulatory Assets
Non-Current	0	0
Texas-New Mexico Power Company | Hurricane recovery costs
Regulatory Assets
Non-Current	6,640	0
Texas-New Mexico Power Company | AMS surcharge
Regulatory Assets
Non-Current	27,903	14,669
Texas-New Mexico Power Company | AMS retirement costs
Regulatory Assets
Non-Current	8,948	11,086
Texas-New Mexico Power Company | Other
Regulatory Assets
Non-Current	$ 2,362	$ 2,027

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Payment of dividends	$ 133,900
Line of Credit
Class of Stock [Line Items]
Debt-to-capital ratio (not more than)	65.00%
Public Service Company of New Mexico
Class of Stock [Line Items]
Equity contribution from parent	$ 0	$ 28,142	$ 175,000
Payment of dividends	$ 246,100
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 | Affiliated Entity
Class of Stock [Line Items]
Cash dividends paid to parent company by consolidated subsidiaries	$ 60,700	$ 4,100	94,400
Texas-New Mexico Power Company
Class of Stock [Line Items]
Equity contribution from parent	$ 50,000	50,000	0
Preferred stock, cumulative shares authorized (in shares)	1,000,000
Texas-New Mexico Power Company | Line of Credit
Class of Stock [Line Items]
Debt-to-capital ratio (not more than)	65.00%
Texas-New Mexico Power Company | Affiliated Entity
Class of Stock [Line Items]
Cash dividends paid to parent company by consolidated subsidiaries	$ 44,400	$ 31,800	$ 33,200
PNMR and TNMP
Class of Stock [Line Items]
Preferred stock outstanding (in shares)	0

Financing - Activities, PNM and

Financing - Activities, PNM and TNMP (Details)

Feb. 01, 2018USD ($)

Jul. 28, 2017USD ($)

Feb. 01, 2016USD ($)

Dec. 21, 2015USD ($)

Aug. 11, 2015USD ($)

May 08, 2015USD ($)

Jan. 01, 2015USD ($)

Jun. 21, 2016USD ($)

Dec. 31, 2017USD ($)derivative

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Feb. 20, 2018USD ($)

Sep. 30, 2017USD ($)

Jul. 20, 2017USD ($)

Jun. 14, 2017USD ($)

Dec. 21, 2016USD ($)loan

Oct. 21, 2016USD ($)

Sep. 27, 2016USD ($)

May 20, 2016USD ($)

Dec. 17, 2015USD ($)

Sep. 30, 2015

Jun. 01, 2015USD ($)

Mar. 09, 2015USD ($)

Jan. 01, 2014USD ($)

Debt Instrument [Line Items]

Outstanding amount

$ 305,400,000

$ 287,100,000

Amount outstanding

100,000,000

$ 50,000,000

Payment of debt

274,070,000

303,793,000

333,066,000

Fixed interest rate

1.927%

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]

Outstanding amount

$ 100,000,000

100,000,000

$ 100,000,000

Variable interest rate

2.32%

PNMR 2016 Two-Year Term Loan due December 2018

Debt Instrument [Line Items]

Loan entered into

100,000,000

Variable interest rate

2.32%

Variable Rate Short-Term Debt

Debt Instrument [Line Items]

Aggregate principal amount

$ 50,000,000

Time hedged in interest rate cash flow hedge

4 years

Level 2 | Cash Flow Hedging

Debt Instrument [Line Items]

Fair value gain (loss, less than)

$ 200,000

(100,000)

Notes Payable to Banks | PNMR Term Loan Agreement

Debt Instrument [Line Items]

Outstanding amount

$ 100,000,000

Amount outstanding

$ 150,000,000

NM Capital | San Juan Generating Station | Coal Supply

Debt Instrument [Line Items]

Payments to fund long-term loans to unaffiliated third party

$ 125,000,000

PNMR | PNMR 2016 Two-Year Term Loan due December 2018

Debt Instrument [Line Items]

Loan entered into

100,000,000

100,000,000

Public Service Company of New Mexico

Debt Instrument [Line Items]

Outstanding amount

39,800,000

61,000,000

Payment of debt

$ 232,000,000

271,000,000

$ 214,300,000

Public Service Company of New Mexico | NMPRC

Debt Instrument [Line Items]

Requirement to obtain approval for any financing transaction, period of time (more than)

18 months

Line of Credit

Debt Instrument [Line Items]

Debt-to-capital ratios (less than or equal to)

65.00%

Line of Credit | Texas-New Mexico Power Company

Debt Instrument [Line Items]

Debt-to-capital ratios (less than or equal to)

65.00%

PNMR 2015 Term Loan Agreement

Debt Instrument [Line Items]

Loan entered into

$ 150,000,000

$ 150,000,000

Stated percentage

2.34%

Unsecured Debt | Senior unsecured notes, 9.25% due 2015

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 118,800,000

Stated percentage

9.25%

Unsecured Debt | Public Service Company of New Mexico

Debt Instrument [Line Items]

Shelf registration statement, capacity of issuance (up to)

$ 475,000,000

Unsecured Debt | Public Service Company of New Mexico | 3.85% due August 2025

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 250,000,000

250,000,000

250,000,000

Stated percentage

3.85%

Unsecured Debt | Public Service Company of New Mexico | PNM 2017 Term Loan Agreement

Debt Instrument [Line Items]

Loan entered into

200,000,000

0

Unsecured Debt | Public Service Company of New Mexico | 7.95% due May 2018

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 350,000,000

350,000,000

$ 450,000,000

Stated percentage

7.95%

Extinguishment of debt

$ 350,000,000

Unsecured Debt | Public Service Company of New Mexico | 7.50% due August 2018

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 100,025,000

100,025,000

Stated percentage

7.50%

BTMU Term Loan Agreement | NM Capital

Debt Instrument [Line Items]

Loan entered into

$ 125,000,000

$ 50,100,000

Stated percentage

4.13%

Estimated principal payments

$ 10,600,000

BTMU Term Loan Agreement | NM Capital | Subsequent Event

Debt Instrument [Line Items]

Loan entered into

$ 45,100,000

Payment of debt

$ 5,000,000

Excess amount of scheduled payment

3,300,000

Westmoreland loan | NM Capital | Subsequent Event

Debt Instrument [Line Items]

Payment of debt

5,600,000

Excess amount of scheduled payment

$ 4,800,000

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

Debt Instrument [Line Items]

Aggregate principal amount

$ 30,300,000

PNM 2014 Term Loan Agreement | Public Service Company of New Mexico

Debt Instrument [Line Items]

Repayments of debt

$ 175,000,000

PNM 2014 Multi-Draw Term Loan Agreement | Public Service Company of New Mexico

Debt Instrument [Line Items]

Loan entered into

$ 125,000,000

Outstanding borrowings

$ 25,000,000

$ 100,000,000

Repayments of debt

$ 125,000,000

Unsecured notes, Pollution control revenue bonds | Public Service Company of New Mexico | Senior unsecured note, PCRB Due 2043, at 4 percent

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 39,300,000

Unsecured notes, Pollution control revenue bonds | Public Service Company of New Mexico | Senior Unsecured Note PCRB Dude 2020 at 2.45 Percent

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 39,300,000

Stated percentage

2.45%

PNM 2016 Term Loan Agreement due 2017 | Public Service Company of New Mexico

Debt Instrument [Line Items]

Aggregate principal amount

$ 175,000,000

Senior Unsecured Notes | Public Service Company of New Mexico | Senior Unsecured Note Agreement (SUNs)

Debt Instrument [Line Items]

Aggregate principal amount

$ 450,000,000

Debt to capital ratio

65.00%

Pollution Control Bonds | Public Service Company of New Mexico | Pollution Control Revenue Bonds 1 Point 875 Percent, due 2021

Debt Instrument [Line Items]

Stated percentage

1.875%

Aggregate principal amount

$ 146,000,000

Pollution Control Bonds | Public Service Company of New Mexico | Pollution Control Revenue Bonds 2.125 Percent, due 2040

Debt Instrument [Line Items]

Stated percentage

2.125%

Aggregate principal amount

$ 37,000,000

Pollution Control Bonds | Public Service Company of New Mexico | Pollution Control Revenue Bonds 2.45 Percent, due 2042

Debt Instrument [Line Items]

Stated percentage

2.45%

Aggregate principal amount

$ 20,000,000

First Mortgage Bonds | Texas-New Mexico Power Company | 4.03% due 2024, Series 2014A

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 80,000,000

$ 80,000,000

Stated percentage

4.03%

4.03%

First Mortgage Bonds | Texas-New Mexico Power Company | 3.53% due February 2026

Debt Instrument [Line Items]

Aggregate outstanding principal amount

$ 60,000,000

$ 60,000,000

Stated percentage

3.53%

3.53%

3.53%

Aggregate principal amount

$ 60,000,000

JPMorgan Chase Bank, N.A. | PNM 2016 Term Loan Agreement due 2017 | Public Service Company of New Mexico

Debt Instrument [Line Items]

Aggregate principal amount

$ 175,000,000

JPMorgan Chase Bank, N.A. | Notes Payable to Banks | Public Service Company of New Mexico | PNM 2017 Term Loan Agreement

Debt Instrument [Line Items]

Stated percentage

2.29%

Aggregate principal amount

$ 200,000,000

Scenario, plan | Senior Unsecured Notes | Public Service Company of New Mexico | SUNs, Issuance in May 2018

Debt Instrument [Line Items]

Aggregate principal amount

$ 350,000,000

Scenario, plan | Senior Unsecured Notes | Public Service Company of New Mexico | SUN's, Issuance in August 2018

Debt Instrument [Line Items]

Aggregate principal amount

$ 100,000,000

Scenario, plan | First Mortgage Bonds | Texas-New Mexico Power Company | Interest Rate of 3.22%, Due 2027

Debt Instrument [Line Items]

Stated percentage

3.22%

Aggregate principal amount

$ 60,000,000

Interest rate contract

Debt Instrument [Line Items]

Number of derivative instruments held | derivative

3

Interest rate contract one | Variable Rate Short-Term Debt

Debt Instrument [Line Items]

Fixed interest rate

1.926%

Interest rate contract two | Variable Rate Short-Term Debt

Debt Instrument [Line Items]

Fixed interest rate

1.823%

Interest rate contract three | Variable Rate Short-Term Debt

Debt Instrument [Line Items]

Fixed interest rate

1.629%

Interest rate contract three | Level 2 | Cash Flow Hedging

Debt Instrument [Line Items]

Fair value gain (loss, less than)

$ 1,400,000

Financing - Schedule of maturit

Financing - Schedule of maturities and interest rates (Details) - Public Service Company of New Mexico - Senior Unsecured Notes	Jul. 28, 2017USD ($)
SUNs, Issuance in May 2018, Interest rate of 3.15%
Debt Instrument [Line Items]
Aggregate principal amount	$ 55,000,000
Stated percentage	3.15%
Senior SUNs, Issuance in May 2018, Interest rate of 3.45% Note Agreement (SUNs), Private Placement Transaction with Institutional Investors, Issuance in May 2018, Interest Rate of 3.45%
Debt Instrument [Line Items]
Aggregate principal amount	$ 104,000,000
Stated percentage	3.45%
SUNs, Issuance in May 2018, Interest rate of 3.69%
Debt Instrument [Line Items]
Aggregate principal amount	$ 88,000,000
Stated percentage	3.68%
SUNs, Issuance in May 2018, Interest rate of 3.93%
Debt Instrument [Line Items]
Aggregate principal amount	$ 38,000,000
Stated percentage	3.93%
SUNs, Issuance in May 2018, Interest rate of 4.22%
Debt Instrument [Line Items]
Aggregate principal amount	$ 45,000,000
Stated percentage	4.22%
SUNs, Issuance in May 2018, Interest rate of 4.50%
Debt Instrument [Line Items]
Aggregate principal amount	$ 20,000,000
Stated percentage	4.50%
SUNs, Issuance in August 2018, Interest rate of 3.78%
Debt Instrument [Line Items]
Aggregate principal amount	$ 15,000,000
Stated percentage	3.78%
SUNs, Issuance in August 2018, Interest rate of 4.60%
Debt Instrument [Line Items]
Aggregate principal amount	$ 85,000,000
Stated percentage	4.60%
Senior Unsecured Note Agreement (SUNs)
Debt Instrument [Line Items]
Aggregate principal amount	$ 450,000,000
Scenario, plan | SUNs, Issuance in May 2018
Debt Instrument [Line Items]
Aggregate principal amount	350,000,000
Scenario, plan | SUN's, Issuance in August 2018
Debt Instrument [Line Items]
Aggregate principal amount	$ 100,000,000

Financing - Borrowing Arrangeme

Financing - Borrowing Arrangements Between PNMR and Its Subsidiaries and Short-term Debt (Details)	Nov. 01, 2020USD ($)	Feb. 26, 2018USD ($)	Feb. 20, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 12, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 21, 2016USD ($)	Nov. 30, 2016USD ($)	Jan. 08, 2014USD ($)bank
Short-term Debt [Line Items]
Short-term debt				$ 305,400,000		$ 287,100,000
Letters of credit outstanding				6,400,000
JPMorgan Chase Bank, N.A.
Short-term Debt [Line Items]
Letters of credit outstanding				30,300,000
PNMR 2016 One Year Term Loan
Short-term Debt [Line Items]
Short-term debt				100,000,000		100,000,000	$ 100,000,000
PNMR Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity				300,000,000				$ 10,000,000
Short-term debt				165,600,000		126,100,000
PNMR Revolving Credit Facility | Scenario, forecast
Short-term Debt [Line Items]
Financing capacity	$ 290,000,000
Subsequent Event
Short-term Debt [Line Items]
Invested cash			$ 900,000
Subsequent Event | PNMR Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity			111,200,000
Subsequent Event | Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity			522,300,000
PNM Resources
Short-term Debt [Line Items]
Short-term debt				$ 265,600,000		226,100,000
PNM Resources | PNMR Revolving Credit Facility
Short-term Debt [Line Items]
Interest rates on outstanding borrowings				2.76%
Texas-New Mexico Power Company
Short-term Debt [Line Items]
Subsidiary loan agreements				$ 0		4,600,000
Letters of credit outstanding				100,000
Texas-New Mexico Power Company | TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity				75,000,000
Short-term debt				0		0
Texas-New Mexico Power Company | TNMP Revolving Credit Facility | 9.50% due April 2019
Short-term Debt [Line Items]
Aggregate principal amount of bonds				75,000,000
Texas-New Mexico Power Company | Subsequent Event
Short-term Debt [Line Items]
Subsidiary loan agreements			0
Invested cash			0
Texas-New Mexico Power Company | Subsequent Event | TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity			51,000,000
Public Service Company of New Mexico
Short-term Debt [Line Items]
Subsidiary loan agreements				0		0
Short-term debt				39,800,000		61,000,000
Letters of credit outstanding				2,500,000
Public Service Company of New Mexico | PNM 2017 New Mexico Credit Facility
Short-term Debt [Line Items]
Financing capacity					$ 40,000,000
Public Service Company of New Mexico | PNM 2014 New Mexico Credit Facility
Short-term Debt [Line Items]
Financing capacity									$ 50,000,000
Number of participating lenders (in banks) | bank									8
Public Service Company of New Mexico | PNM Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity				$ 400,000,000				$ 40,000,000
Interest rates on outstanding borrowings				2.59%
Short-term debt				$ 39,800,000		35,000,000
Public Service Company of New Mexico | PNM Revolving Credit Facility | Scenario, forecast
Short-term Debt [Line Items]
Financing capacity	$ 360,000,000
Public Service Company of New Mexico | PNM 2014 New Mexico Credit Facility
Short-term Debt [Line Items]
Short-term debt				0		26,000,000
Public Service Company of New Mexico | PNM 2017 New Mexico Credit Facility
Short-term Debt [Line Items]
Short-term debt				0		$ 0
Public Service Company of New Mexico | Subsequent Event
Short-term Debt [Line Items]
Subsidiary loan agreements			0
Invested cash			0
Public Service Company of New Mexico | Subsequent Event | PNM Revolving Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity			340,100,000
Public Service Company of New Mexico | Subsequent Event | PNM 2014 New Mexico Credit Facility
Short-term Debt [Line Items]
Available borrowing capacity			$ 20,000,000
PNMR Development | Subsequent Event | PNMR 2018 Revolving Credit Facility
Short-term Debt [Line Items]
Financing capacity		$ 24,500,000
Maximum
Short-term Debt [Line Items]
Subsidiary loan agreements				$ 100,000,000

Financing - Long-term Debt (Det

Financing - Long-term Debt (Details) - USD ($)	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 21, 2016	Dec. 17, 2015	Aug. 11, 2015
Debt Instrument [Line Items]
Total	$ 2,431,507,000		$ 2,388,577,000
Principal, less current maturities	257,293,000		274,025,000
Long-term debt, excluding current maturities, gross	2,174,214,000		2,114,552,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	(6,138,000)		(4,135,000)
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities	398,000		677,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities	(6,536,000)		(4,812,000)
PNMR 2016 Two-Year Term Loan due December 2018
Debt Instrument [Line Items]
Long-term debt				$ 100,000,000
Public Service Company of New Mexico
Debt Instrument [Line Items]
Total	1,665,870,000		1,640,870,000
Principal, less current maturities	25,000		232,000,000
Long-term debt, excluding current maturities, gross	1,665,845,000		1,408,870,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	7,960,000		9,501,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities	2,000		120,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities	$ 7,958,000		$ 9,381,000
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%		1.875%
Unsecured long-term debt, noncurrent	$ 146,000,000		$ 146,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 1,383,000		$ 1,807,000
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%		6.25%
Unsecured long-term debt, noncurrent	$ 36,000,000		$ 36,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	228,000		$ 239,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 4.75% due June 2040, mandatory tender - June 1, 2017
Debt Instrument [Line Items]
Stated percentage			4.75%
Unsecured long-term debt, noncurrent	0		$ 37,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 0		25,000
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		0
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 404,000		$ 0
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%		5.20%
Unsecured long-term debt, noncurrent	$ 40,045,000		$ 40,045,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 105,000		$ 147,000
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%		5.90%
Unsecured long-term debt, noncurrent	$ 255,000,000		$ 255,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 2,040,000		$ 2,131,000
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%		6.25%
Unsecured long-term debt, noncurrent	$ 11,500,000		$ 11,500,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	92,000		$ 96,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.54% due September 2042, mandatory tender - June 1, 2017
Debt Instrument [Line Items]
Stated percentage			2.54%
Unsecured long-term debt, noncurrent	0		$ 20,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 0		67,000
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		0
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 153,000		$ 0
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%		2.40%
Unsecured long-term debt, noncurrent	$ 39,300,000		$ 39,300,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 243,000		$ 340,000
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%		5.20%
Unsecured long-term debt, noncurrent	$ 21,000,000		$ 21,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 53,000		$ 75,000
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 7.95% due May 2018
Debt Instrument [Line Items]
Stated percentage	7.95%		7.95%
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 7.50% due August 2018
Debt Instrument [Line Items]
Stated percentage	7.50%		7.50%
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.35% due October 2021
Debt Instrument [Line Items]
Stated percentage	5.35%		5.35%
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.85% due August 2025
Debt Instrument [Line Items]
Stated percentage	3.85%		3.85%
Public Service Company of New Mexico | Senior Unsecured Notes: | 7.95% due May 2018
Debt Instrument [Line Items]
Stated percentage	7.95%
Unsecured long-term debt, noncurrent	$ 350,000,000	$ 450,000,000	$ 350,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 272,000		995,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 7.50% due August 2018
Debt Instrument [Line Items]
Stated percentage	7.50%
Unsecured long-term debt, noncurrent	$ 100,025,000		100,025,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	73,000		197,000
Public Service Company of New Mexico | Senior Unsecured Notes: | 5.35% due October 2021
Debt Instrument [Line Items]
Unsecured long-term debt, noncurrent	160,000,000		160,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	617,000		780,000
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			$ 250,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	2,274,000		2,574,000
Public Service Company of New Mexico | Senior Unsecured Notes: | PNM 2016 Term Loan Agreement due November 2017
Debt Instrument [Line Items]
Long-term debt	0		175,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	0		28,000
Public Service Company of New Mexico | Senior Unsecured Notes: | PNM 2017 Term Loan Agreement due January 2019
Debt Instrument [Line Items]
Long-term debt	200,000,000		0
Unamortized Discounts, (Premiums), and Issuance Costs, net	23,000		0
Texas-New Mexico Power Company
Debt Instrument [Line Items]
Total	465,500,000		405,500,000
Principal, less current maturities	0		0
Long-term debt, excluding current maturities, gross	465,500,000		405,500,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	(15,120,000)		(15,375,000)
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities	0		0
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities	$ (15,120,000)		$ (15,375,000)
Texas-New Mexico Power Company | First Mortgage Bonds: | 9.50% due April 2019
Debt Instrument [Line Items]
Stated percentage	9.50%		9.50%
Unsecured long-term debt, noncurrent	$ 172,302,000		$ 172,302,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 1,032,000		$ 1,857,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 6.95% due April 2043
Debt Instrument [Line Items]
Stated percentage	6.95%		6.95%
Unsecured long-term debt, noncurrent	$ 93,198,000		$ 93,198,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ (18,057,000)		$ (18,773,000)
Texas-New Mexico Power Company | First Mortgage Bonds: | 4.03% due July 2024
Debt Instrument [Line Items]
Stated percentage	4.03%		4.03%
Unsecured long-term debt, noncurrent	$ 80,000,000		$ 80,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 686,000		$ 792,000
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.53% due February 2026
Debt Instrument [Line Items]
Stated percentage	3.53%		3.53%		3.53%
Unsecured long-term debt, noncurrent	$ 60,000,000		$ 60,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 667,000		749,000
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		0
Unamortized Discounts, (Premiums), and Issuance Costs, net	552,000		0
PNMR
Debt Instrument [Line Items]
Total	300,137,000		342,207,000
Principal, less current maturities	257,268,000		42,025,000
Long-term debt, excluding current maturities, gross	42,869,000		300,182,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	1,022,000		1,739,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities	396,000		557,000
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities	626,000		1,182,000
PNMR | PNMR 2015 Term Loan Agreement due March 2018
Debt Instrument [Line Items]
Long-term debt	150,000,000		150,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	12,000		84,000
PNMR | BTMU Term Loan Agreement, payments through February 2021
Debt Instrument [Line Items]
Long-term debt	50,137,000		92,207,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	1,001,000		1,634,000
PNMR | PNMR 2016 Two-Year Term Loan due December 2018
Debt Instrument [Line Items]
Long-term debt	100,000,000		100,000,000
Unamortized Discounts, (Premiums), and Issuance Costs, net	$ 9,000		$ 21,000

Financing - Long-term Debt Matu

Financing - Long-term Debt Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long-term Debt, by Maturity [Abstract]
2,018	$ 257,293
2,019	384,659
2,020	126,207
2,021	310,650
2,022	57,000
Thereafter	1,295,698
Total	2,431,507	$ 2,388,577
PNMR
Long-term Debt, by Maturity [Abstract]
2,018	257,268
2,019	12,357
2,020	25,862
2,021	4,650
2,022	0
Thereafter	0
Total	300,137	342,207
Public Service Company of New Mexico
Long-term Debt, by Maturity [Abstract]
2,018	25
2,019	200,000
2,020	100,345
2,021	306,000
2,022	57,000
Thereafter	1,002,500
Total	1,665,870	1,640,870
Texas-New Mexico Power Company
Long-term Debt, by Maturity [Abstract]
2,018	0
2,019	172,302
2,020	0
2,021	0
2,022	0
Thereafter	293,198
Total	$ 465,500	$ 405,500

Lease Commitments - Narrative (

Lease Commitments - Narrative (Details) $ in Millions	Jan. 15, 2016USD ($)leaseMW	Dec. 31, 2017USD ($)leaselessor	Apr. 01, 2015USD ($)	Jan. 15, 2015lease	Dec. 31, 1986lease	Dec. 31, 1985lease
Lease commitments
Operating lease, option term extensions		2 years
Operating leases, renewal options after original lease term		6 years
Operating leases, period to notify of lease retention		3 years
Public Service Company of New Mexico | TGP Granada, LLC and its affiliate Complaint
Lease commitments
Lease ownership in EIP		60.00%
Additional area leased of the EIP			40.00%
Option to purchase leased capacity at fair value			$ 7.7
Public Service Company of New Mexico | Navajo Nation
Lease commitments
Number of operating leases set to expire | lease		0
Operating leases, period to expiration of the lease		5 years
Annual lease payments		$ 6
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station
Lease commitments
Number of leases | lease					4	4
Rental payments, fixed renewal option period during original terms of leases		50.00%
Lease covenants, restrictions on conveying, transferring, leasing, and dividends (more than)		5.00%
Loss contingency, range of possible loss, portion not accrued (up to)		$ 169.9
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 1 Leases
Lease commitments
Annual lease payments		33
Number of leases | lease				4		4
Annual lease payments during renewal period		16.5
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2 Leases
Lease commitments
Annual lease payments		$ 23.7
Number of leases | lease	1	3			4
Annual lease payments during renewal period		$ 1.6
Estimated purchase price of leased asset	$ 78.1
Leased capacity to be purchased (in megawatts) | MW	31.25
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 1, Lease with Maximum Option Period Provision
Lease commitments
Number of lessors | lessor		4
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2, Lease with Maximum Option Period Provision
Lease commitments
Number of leases | lease		1
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 1, Lease Expires in 2023
Lease commitments
Number of leases | lease		4
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2, Lease Expires in 2024
Lease commitments
Number of leases | lease		1
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station, Unit 2 Leases 32.76 MW
Lease commitments
Number of leases | lease	2
Estimated purchase price of leased asset	$ 85.2
Additional capacity to be leased (in megawatts) | MW	32.76

Lease Commitments - Schedule of

Lease Commitments - Schedule of Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
PNMR
Operating lease expense [Line Items]
Operating lease expense	$ 35,972	$ 37,432	$ 61,088
Public Service Company of New Mexico
Operating lease expense [Line Items]
Operating lease expense	31,817	32,843	55,994
Texas-New Mexico Power Company
Operating lease expense [Line Items]
Operating lease expense	$ 3,570	$ 3,748	$ 3,688

Lease Commitments - Future Mini

Lease Commitments - Future Minimum Rental Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2017USD ($)
PNMR
Lease commitments
2,018	$ 26,802
2,019	25,638
2,020	25,208
2,021	25,122
2,022	25,122
Later years	60,708
Total minimum lease payments	188,600
Public Service Company of New Mexico
Lease commitments
2,018	25,726
2,019	25,241
2,020	25,122
2,021	25,122
2,022	25,122
Later years	60,708
Total minimum lease payments	187,041
Texas-New Mexico Power Company
Lease commitments
2,018	791
2,019	296
2,020	0
2,021	0
2,022	0
Later years	0
Total minimum lease payments	$ 1,087

Fair Value of Derivative and 64

Fair Value of Derivative and Other Financial Instruments - Overview and Commodity Derivatives (Details)	Dec. 31, 2017USD ($)MW	Dec. 31, 2016USD ($)
Derivatives, Fair Value [Line Items]
Current assets	$ 1,088,000	$ 5,224,000
Deferred charges	3,556,000	0
Current liabilities	(1,182,000)	(2,339,000)
Long-term liabilities	(3,556,000)	0
PNMR and PNM
Derivatives, Fair Value [Line Items]
Amounts recognized for the legal right to reclaim cash collateral	0	0
Amounts posted as cash collateral under margin arrangements	800,000	2,600,000
Obligations to return cash collateral	900,000	100,000
PNMR and PNM | Designated as hedging instrument | Commodity Contract
Derivatives, Fair Value [Line Items]
Current assets	1,088,000	5,224,000
Deferred charges	3,556,000	0
Total assets	4,644,000	5,224,000
Current liabilities	(1,182,000)	(2,339,000)
Long-term liabilities	(3,556,000)	0
Total Liabilities	(4,738,000)	(2,339,000)
Net	(94,000)	2,885,000
PNMR and PNM | Designated as hedging instrument | Commodity Contract | Palo Verde Nuclear Generating Station
Derivatives, Fair Value [Line Items]
Current assets	$ 2,700,000
Public Service Company of New Mexico
Derivatives, Fair Value [Line Items]
Expected exposure to market risk (in megawatts) | MW	65
Power to be sold to third party (in megawatts) | MW	36
Current assets	$ 1,088,000	5,224,000
Deferred charges	3,556,000	0
Current liabilities	(1,182,000)	(2,339,000)
Long-term liabilities	(3,556,000)	0
Public Service Company of New Mexico | Designated as hedging instrument | Commodity Contract | Fuel and Purchased Power Adjustment Clause
Derivatives, Fair Value [Line Items]
Current assets		200,000
Current liabilities		(100,000)
Other credit derivatives | Public Service Company of New Mexico | Designated as hedging instrument | Commodity Contract
Derivatives, Fair Value [Line Items]
Total assets	$ 4,600,000	$ 500,000

Fair Value of Derivative and 65

Fair Value of Derivative and Other Financial Instruments - Effect of Mark-to-Market Instruments on Earnings (Details) - PNMR and PNM - Designated as hedging instrument - Commodity Contract - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss)	$ (235)	$ (1,261)	$ 6,863
Electric operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss)	5,151	(53)	7,156
Cost of energy
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss)	$ (5,386)	$ (1,208)	$ (293)

Fair Value of Derivative and 66

Fair Value of Derivative and Other Financial Instruments - Volume Positions and Requirements to Provide Collateral (Details) - Commodity Contract - Economic Hedges - PNMR and PNM	12 Months Ended
	Dec. 31, 2017MMBTUMWh	Dec. 31, 2016MMBTUMWh
Long
Derivative [Line Items]
Power-related contracts | MMBTU	100,000	254,100
Short
Derivative [Line Items]
Power-related contracts | MWh	0	2,471,600

Fair Value of Derivative and 67

Fair Value of Derivative and Other Financial Instruments - Non-Derivative Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Investment percentage in fixed income (debt) securities	85.00%
Realized impairment loss	$ 3,300,000	$ (1,200,000)	$ (4,300,000)
Fixed income investments
Schedule of Available-for-sale Securities [Line Items]
Investment allocation targets	65.00%
Fixed income investments | Scenario, adjustment
Schedule of Available-for-sale Securities [Line Items]
Investment allocation targets	50.00%
PNMR and PNM
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 323,524,000	272,977,000
Unrealized Gains	18,028,000	7,449,000
Proceeds from sales	637,492,000	522,601,000	252,174,000
Gross realized gains	36,896,000	46,116,000	29,663,000
Gross realized (losses)	(12,993,000)	(25,430,000)	$ (9,259,000)
Value of other than temporary impairments	0
PNMR and PNM | Cash and cash equivalents
Schedule of Available-for-sale Securities [Line Items]
Fair Value	52,636,000	23,683,000
Unrealized Gains	0	0
PNMR and PNM | Domestic value
Schedule of Available-for-sale Securities [Line Items]
Fair Value	40,032,000	34,796,000
Unrealized Gains	4,011,000	1,135,000
PNMR and PNM | Domestic growth
Schedule of Available-for-sale Securities [Line Items]
Fair Value	35,456,000	47,595,000
Unrealized Gains	3,995,000	3,032,000
PNMR and PNM | International and other
Schedule of Available-for-sale Securities [Line Items]
Fair Value	45,867,000	27,481,000
Unrealized Gains	6,810,000	2,029,000
PNMR and PNM | U.S. Government
Schedule of Available-for-sale Securities [Line Items]
Fair Value	34,317,000	40,962,000
Unrealized Gains	273,000	115,000
PNMR and PNM | Municipals
Schedule of Available-for-sale Securities [Line Items]
Fair Value	48,076,000	43,789,000
Unrealized Gains	1,225,000	585,000
PNMR and PNM | Corporate and other
Schedule of Available-for-sale Securities [Line Items]
Fair Value	67,140,000	54,671,000
Unrealized Gains	1,714,000	553,000
PNMR and PNM | Measured on a recurring basis
Schedule of Available-for-sale Securities [Line Items]
Fair Value	323,524,000	272,977,000
PNMR and PNM | Measured on a recurring basis | Nuclear Decommissioning Trust
Schedule of Available-for-sale Securities [Line Items]
Fair Value	293,700,000	253,900,000
PNMR and PNM | Measured on a recurring basis | Mine Reclamation Trust
Schedule of Available-for-sale Securities [Line Items]
Fair Value	29,800,000	19,100,000
PNMR and PNM | Measured on a recurring basis | Cash and cash equivalents
Schedule of Available-for-sale Securities [Line Items]
Fair Value	52,636,000	23,683,000
PNMR and PNM | Measured on a recurring basis | Domestic value
Schedule of Available-for-sale Securities [Line Items]
Fair Value	40,032,000	34,796,000
PNMR and PNM | Measured on a recurring basis | Domestic growth
Schedule of Available-for-sale Securities [Line Items]
Fair Value	35,456,000	47,595,000
PNMR and PNM | Measured on a recurring basis | International and other
Schedule of Available-for-sale Securities [Line Items]
Fair Value	45,867,000	27,481,000
PNMR and PNM | Measured on a recurring basis | U.S. Government
Schedule of Available-for-sale Securities [Line Items]
Fair Value	34,317,000	40,962,000
PNMR and PNM | Measured on a recurring basis | Municipals
Schedule of Available-for-sale Securities [Line Items]
Fair Value	48,076,000	43,789,000
PNMR and PNM | Measured on a recurring basis | Corporate and other
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 67,140,000	$ 54,671,000

Fair Value of Derivative and 68

Fair Value of Derivative and Other Financial Instruments - Maturities of Securities (Details) $ in Thousands	Dec. 31, 2017USD ($)
PNM Resources
Held-to-Maturity
Within 1 year	$ 0
After 1 year through 5 years	66,588
After 5 years through 10 years	0
After 10 years through 15 years	0
After 15 years through 20 years	0
After 20 years	0
Held-to-maturity debt securities	66,588
PNMR and PNM
Available-for-Sale
Within 1 year	4,460
After 1 year through 5 years	32,693
After 5 years through 10 years	48,681
After 10 years through 15 years	5,934
After 15 years through 20 years	11,983
After 20 years	45,782
Available-for-sale debt securities	$ 149,533

Fair Value of Derivative and 69

Fair Value of Derivative and Other Financial Instruments - Items Recorded at Fair Value (Details) - PNMR and PNM - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 323,524	$ 272,977
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	52,636	23,683
Domestic value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	40,032	34,796
Domestic growth
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	35,456	47,595
International and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	45,867	27,481
U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	34,317	40,962
Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,076	43,789
Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	67,140	54,671
Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	323,524	272,977
Measured on a recurring basis | Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative assets	4,644	5,224
Commodity derivative liabilities	(4,738)	(2,339)
Net	(94)	2,885
Measured on a recurring basis | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	52,636	23,683
Measured on a recurring basis | Domestic value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	40,032	34,796
Measured on a recurring basis | Domestic growth
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	35,456	47,595
Measured on a recurring basis | International and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	45,867	27,481
Measured on a recurring basis | U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	34,317	40,962
Measured on a recurring basis | Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,076	43,789
Measured on a recurring basis | Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	67,140	54,671
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	204,101	196,436
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative assets	0	0
Commodity derivative liabilities	0	0
Net	0	0
Measured on a recurring basis | 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]
Fair Value	52,636	23,683
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	40,032	34,796
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic growth
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	35,456	47,595
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | International and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	42,332	27,481
Measured on a recurring basis | 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]
Fair Value	33,645	39,723
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Measured on a recurring basis | 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]
Fair Value	0	23,158
Measured on a recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	119,423	76,541
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative assets	4,644	5,224
Commodity derivative liabilities	(4,738)	(2,339)
Net	(94)	2,885
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Domestic value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Domestic growth
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | International and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,535	0
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	672	1,239
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,076	43,789
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Corporate and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 67,140	$ 31,513

Fair Value of Derivative and 70

Fair Value of Derivative and Other Financial Instruments - Items not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
PNMR
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 2,554,836	$ 2,540,693
Westmoreland Loan	66,588	100,893
Other investments	503	1,164
PNMR | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,437,645	2,392,712
Westmoreland Loan	56,640	95,000
Other investments	503	547
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Westmoreland Loan	0	0
Other investments	503	547
PNMR | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,554,836	2,540,693
Westmoreland Loan	0	0
Other investments	0	0
PNMR | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Westmoreland Loan	66,588	100,893
Other investments	0	617
Public Service Company of New Mexico
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,727,135	1,730,157
Other investments	283	316
Public Service Company of New Mexico | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,657,910	1,631,369
Other investments	283	316
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Other investments	283	316
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,727,135	1,730,157
Other investments	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Other investments	0	0
Texas-New Mexico Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	527,563	468,329
Other investments	220	231
Texas-New Mexico Power Company | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	480,620	420,875
Other investments	220	231
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Other investments	220	231
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	527,563	468,329
Other investments	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	0
Other investments	$ 0	$ 0

Fair Value of Derivative and 71

Fair Value of Derivative and Other Financial Instruments - Defined Benefit Plans Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 543,601	$ 557,923
Fair value of plan assets at end of year	562,016	543,601
Public Service Company of New Mexico | Pension Plan | Participation in PNMR Master Trust Investments: | Fair Value Measurement [Domain]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	467,965
Fair value of plan assets at end of year	487,498	467,965
Public Service Company of New Mexico | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	543,650
Fair value of plan assets at end of year	562,266	543,650
Public Service Company of New Mexico | Pension Plan | Participation in PNMR Master Trust Investments: | Estimate of Fair Value Measurement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	75,685
Fair value of plan assets at end of year	74,768	75,685
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	81,177	73,829
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	72,694	72,952
Fair value of plan assets at end of year	80,356	72,694
Public Service Company of New Mexico | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,567
Fair value of plan assets at end of year	437	2,567
Public Service Company of New Mexico | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	9,300
Fair value of plan assets at end of year	10,636	9,300
Public Service Company of New Mexico | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	10,260
Fair value of plan assets at end of year	10,816	10,260
Public Service Company of New Mexico | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	6,338
Fair value of plan assets at end of year	6,710	6,338
Public Service Company of New Mexico | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	26,405
Fair value of plan assets at end of year	31,660	26,405
Public Service Company of New Mexico | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	18,959
Fair value of plan assets at end of year	20,918	18,959
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, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	129,624
Fair value of plan assets at end of year	140,218	129,624
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]
Total fair value of plan assets owned	38,881	38,124
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, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,567
Fair value of plan assets at end of year	437	2,567
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	10,260
Fair value of plan assets at end of year	10,816	10,260
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	6,338
Fair value of plan assets at end of year	6,710	6,338
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	18,959
Fair value of plan assets at end of year	20,918	18,959
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	337,989
Fair value of plan assets at end of year	347,089	337,989
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	42,296	35,705
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	9,300
Fair value of plan assets at end of year	10,636	9,300
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	26,405
Fair value of plan assets at end of year	31,660	26,405
Public Service Company of New Mexico | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		719
Actual return on assets sold during the period	1	1
Actual return on assets still held at period end	(7)	19
Purchases	92	0
Sales	(247)	(387)
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	352
Fair value of plan assets at end of year	191	352
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Public Service Company of New Mexico | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	60,624	62,082
Fair value of plan assets at end of year	63,499	60,624
Texas-New Mexico Power Company | Pension Plan | Participation in PNMR Master Trust Investments: | Fair Value Measurement [Domain]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	50,901
Fair value of plan assets at end of year	53,273	50,901
Texas-New Mexico Power Company | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	60,630
Fair value of plan assets at end of year	63,533	60,630
Texas-New Mexico Power Company | Pension Plan | Participation in PNMR Master Trust Investments: | Estimate of Fair Value Measurement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	9,729
Fair value of plan assets at end of year	10,260	9,729
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	10,145	8,778
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	8,544	9,111
Fair value of plan assets at end of year	10,002	8,544
Texas-New Mexico Power Company | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	308
Fair value of plan assets at end of year	149	308
Texas-New Mexico Power Company | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,279
Fair value of plan assets at end of year	1,597	1,279
Texas-New Mexico Power Company | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	449
Fair value of plan assets at end of year	293	449
Texas-New Mexico Power Company | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,089
Fair value of plan assets at end of year	1,410	1,089
Texas-New Mexico Power Company | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	3,060
Fair value of plan assets at end of year	4,011	3,060
Texas-New Mexico Power Company | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,593
Fair value of plan assets at end of year	2,685	2,593
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, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	14,447
Fair value of plan assets at end of year	15,244	14,447
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	4,537	4,439
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, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	308
Fair value of plan assets at end of year	149	308
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	449
Fair value of plan assets at end of year	293	449
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,089
Fair value of plan assets at end of year	1,410	1,089
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,593
Fair value of plan assets at end of year	2,685	2,593
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	36,416
Fair value of plan assets at end of year	38,008	36,416
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	5,608	4,339
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,279
Fair value of plan assets at end of year	1,597	1,279
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	3,060
Fair value of plan assets at end of year	4,011	3,060
Texas-New Mexico Power Company | Significant Other Observable Inputs (Level 2) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		78
Actual return on assets sold during the period	0	0
Actual return on assets still held at period end	(1)	2
Purchases	10	0
Sales	(26)	(42)
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Pension Plan | Participation in PNMR Master Trust Investments:
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38
Fair value of plan assets at end of year	21	38
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets owned	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Texas-New Mexico Power Company | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Fair Value Measurement [Domain]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	518,866
Fair value of plan assets at end of year	540,771	518,866
PNMR
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	604,280
Fair value of plan assets at end of year	625,799	604,280
PNMR | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	20,503
Fair value of plan assets at end of year	7,697	20,503
PNMR | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38,401
Fair value of plan assets at end of year	42,048	38,401
PNMR | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	36,036
Fair value of plan assets at end of year	37,026	36,036
PNMR | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	18,484
Fair value of plan assets at end of year	19,136	18,484
PNMR | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	27,532
Fair value of plan assets at end of year	25,099	27,532
PNMR | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	205,419
Fair value of plan assets at end of year	215,535	205,419
PNMR | U.S. Government
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	94,359
Fair value of plan assets at end of year	117,572	94,359
PNMR | Municipals
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	13,970
Fair value of plan assets at end of year	11,438	13,970
PNMR | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	64,162
Fair value of plan assets at end of year	65,220	64,162
PNMR | Private equity funds | Estimate of Fair Value Measurement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	27,060
Fair value of plan assets at end of year	22,281	27,060
PNMR | Hedge funds | Estimate of Fair Value Measurement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	42,070
Fair value of plan assets at end of year	45,615	42,070
PNMR | Real estate funds | Estimate of Fair Value Measurement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	16,284
Fair value of plan assets at end of year	17,132	16,284
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	144,071
Fair value of plan assets at end of year	155,462	144,071
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	20,503
Fair value of plan assets at end of year	7,697	20,503
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	36,036
Fair value of plan assets at end of year	37,026	36,036
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	18,484
Fair value of plan assets at end of year	19,136	18,484
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	69,048
Fair value of plan assets at end of year	91,603	69,048
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipals
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	374,405
Fair value of plan assets at end of year	385,097	374,405
PNMR | Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Other Observable Inputs (Level 2) | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38,401
Fair value of plan assets at end of year	42,048	38,401
PNMR | Significant Other Observable Inputs (Level 2) | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Other Observable Inputs (Level 2) | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Other Observable Inputs (Level 2) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	27,532
Fair value of plan assets at end of year	25,099	27,532
PNMR | Significant Other Observable Inputs (Level 2) | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	205,029
Fair value of plan assets at end of year	215,323	205,029
PNMR | Significant Other Observable Inputs (Level 2) | U.S. Government
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	25,311
Fair value of plan assets at end of year	25,969	25,311
PNMR | Significant Other Observable Inputs (Level 2) | Municipals
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	13,970
Fair value of plan assets at end of year	11,438	13,970
PNMR | Significant Other Observable Inputs (Level 2) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	64,162
Fair value of plan assets at end of year	65,220	64,162
PNMR | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	390
Fair value of plan assets at end of year	212	390
PNMR | Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | International funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Domestic value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Domestic growth
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	390	797
Actual return on assets sold during the period	1	1
Actual return on assets still held at period end	(8)	21
Purchases	102	0
Sales	(273)	(429)
Fair value of plan assets at end of year	212	390
PNMR | Significant Unobservable Inputs (Level 3) | U.S. Government
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Municipals
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Other funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
PNMR | Significant Unobservable Inputs (Level 3) | Private equity funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	352
Fair value of plan assets at end of year	191	352
PNMR | Significant Unobservable Inputs (Level 3) | Hedge funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38
Fair value of plan assets at end of year	$ 21	$ 38

Variable Interest Entities (Det

Variable Interest Entities (Details)	Feb. 01, 2018USD ($)	Feb. 01, 2016USD ($)	Jan. 31, 2016USD ($)	Dec. 31, 2017USD ($)leaseinvestorMW	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Feb. 20, 2018USD ($)	Jul. 19, 2016USD ($)	May 31, 2016MW	Jan. 15, 2016leaseMW	Jan. 15, 2015lease	Dec. 31, 1986lease	Dec. 31, 1985lease
Variable Interest Entity, Statement Of Operation [Abstract]
Earnings attributable to non-controlling interest				$ 15,017,000	$ 14,519,000	$ 14,910,000
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Current assets				294,420,000	378,039,000
Total assets				6,646,103,000	6,471,080,000	6,009,328,000
Current liabilities				835,644,000	805,108,000
Owners’ equity – non-controlling interest				66,195,000	68,920,000
Public Service Company of New Mexico
Variable Interest Entity, Statement Of Operation [Abstract]
Earnings attributable to non-controlling interest				15,017,000	14,519,000	14,910,000
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Current assets				243,631,000	314,245,000
Total assets				4,921,563,000	4,867,546,000
Current liabilities				218,496,000	457,361,000
Owners’ equity – non-controlling interest				$ 66,195,000	68,920,000
Number of different institutional investors of trust lessors | investor				5
Accrued lease payments				$ 25,726,000
Public Service Company of New Mexico | Palo Verde Nuclear Generating Station
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entities, Other financial obligations due to beneficial owner				0
Variable interest entities, Exposure beyond contractual lease payments				0
Variable interest entities, Additional rights to assets beyond use of leased assets				0
Variable interest entity, nonconsolidated, carrying amount, assets				$ 0
Public Service Company of New Mexico | Valencia
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) | MW				158
Payment for fixed charges				$ 19,600,000	19,300,000	19,200,000
Payment for variable charges				$ 1,300,000	1,100,000	1,600,000
Purchase price, percentage of the book value reduced by related indebtedness				50.00%
Purchase price, percentage of fair market value				50.00%
Variable Interest Entity, Statement Of Operation [Abstract]
Operating revenues				$ 20,887,000	20,371,000	20,687,000
Operating expenses				(5,870,000)	(5,852,000)	(5,777,000)
Earnings attributable to non-controlling interest				15,017,000	14,519,000	$ 14,910,000
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Current assets				2,688,000	2,551,000
Net property, plant and equipment				64,109,000	66,947,000
Total assets				66,797,000	69,498,000
Current liabilities				602,000	578,000
Owners’ equity – non-controlling interest				$ 66,195,000	68,920,000
Number of years the operating licenses for plants were extended				20 years
Public Service Company of New Mexico | Valencia | Maximum
Variable Interest Entity [Line Items]
Option to purchase a percentage of the plant or VIE (up to )				50.00%
Public Service Company of New Mexico | PVNGS | Palo Verde Nuclear Generating Station
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Accrued lease payments					$ 8,300,000
NM Capital | Coal Supply | San Juan Generating Station
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Loan agreement		$ 125,000,000	$ 125,000,000
Issuance in letters of credit			30,300,000					$ 30,300,000
NM Capital | Coal Supply | San Juan Coal Company, Westmoreland
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Amount outstanding			$ 125,000,000	$ 56,600,000
Interest receivable				$ 1,000,000
NM Capital | Coal Supply | San Juan Coal Company, Westmoreland | Subsequent Event
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Amount outstanding							$ 51,000,000
Scheduled principal payment	$ 5,600,000
Palo Verde Nuclear Generating Station, Unit 1 Leases | Public Service Company of New Mexico
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Number of leases | lease											4		4
Palo Verde Nuclear Generating Station, Unit 2 Leases | Public Service Company of New Mexico
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) | MW									64.1	64.1
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Number of leases | lease				3						1		4
Number of leases under which assets were purchased | lease										3

Earnings and Dividends Per Sh73

Earnings and Dividends Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Earnings Attributable to PNMR	$ (54,282)	$ 73,739	$ 37,555	$ 22,862	$ 24,809	$ 54,418	$ 27,076	$ 10,546	$ 79,874	$ 116,849	$ 15,640
Average Number of Common Shares:
Outstanding during year (in shares)									79,654	79,654	79,654
Vested awards of restricted stock (in shares)									237	104	105
Average Shares – Basic (in shares)									79,891	79,758	79,759
Dilutive Effect of Common Stock Equivalents:
Stock options and restricted stock (in shares)									250	374	380
Average Shares – Diluted (in shares)									80,141	80,132	80,139
Net Earnings Attributable to PNMR Per Share of Common Stock:
Basic (in dollars per share)	$ (0.68)	$ 0.92	$ 0.47	$ 0.29	$ 0.32	$ 0.68	$ 0.34	$ 0.13	$ 1	$ 1.47	$ 0.20
Diluted (in dollars per share)	$ (0.68)	$ 0.92	$ 0.47	$ 0.29	$ 0.31	$ 0.68	$ 0.34	$ 0.13	1	1.46	0.20
Dividends Declared per Common Share (in dollars per share)									$ 0.9925	$ 0.9025	$ 0.82

Income Taxes - Federal Income T

Income Taxes - Federal Income Tax Reform (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Income Taxes [Line Items]
Net increase in regulatory liabilities	$ 548,952
Net decrease in deferred income tax liabilities (deferred income tax assets)	491,491
Net deferred income tax expense	57,461
Reclassification of stranded income taxes to retained earnings	(17,586)
Retained Earnings
Income Taxes [Line Items]
Reclassification of stranded income taxes to retained earnings	17,586
PNM
Income Taxes [Line Items]
Net increase in regulatory liabilities	402,501
Net decrease in deferred income tax liabilities (deferred income tax assets)	372,895
Net deferred income tax expense	29,606
Reclassification of stranded income taxes to retained earnings	(17,794)
PNM | Retained Earnings
Income Taxes [Line Items]
Reclassification of stranded income taxes to retained earnings	17,794
TNMP
Income Taxes [Line Items]
Net increase in regulatory liabilities	146,451
Net decrease in deferred income tax liabilities (deferred income tax assets)	138,586
Net deferred income tax expense	7,865
Corporate and Other
Income Taxes [Line Items]
Net increase in regulatory liabilities	0
Net decrease in deferred income tax liabilities (deferred income tax assets)	(19,990)
Net deferred income tax expense	$ 19,990

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Current federal income tax	$ 0	$ 0	$ 0
Current state income tax	(188)	(527)	(1,376)
Deferred federal income tax	119,182	60,892	5,488
Deferred state income tax	11,632	3,886	12,305
Amortization of accumulated investment tax credits	(286)	(973)	(1,342)
Total income taxes (benefit)	130,340	63,278	15,075
Public Service Company of New Mexico
Income Taxes [Line Items]
Current federal income tax	118	(10,290)	(7,934)
Current state income tax	(1,112)	(1,907)	(1,988)
Deferred federal income tax	73,308	49,123	(6,827)
Deferred state income tax	9,527	4,969	5,333
Amortization of accumulated investment tax credits	(286)	(973)	(1,342)
Total income taxes (benefit)	81,555	40,922	(12,758)
Texas-New Mexico Power Company
Income Taxes [Line Items]
Current federal income tax	2,472	9,445	1,603
Current state income tax	1,765	1,729	1,639
Deferred federal income tax	27,304	12,690	20,904
Deferred state income tax	(29)	(28)	(21)
Total income taxes (benefit)	$ 31,512	$ 23,836	$ 24,125

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 79,016	$ 68,311	$ 16,154
Amortization of accumulated investment tax credits	(286)	(973)	(1,342)
Flow-through of depreciation items	1,147	1,227	1,485
Earnings attributable to non-controlling interest in Valencia	(5,256)	(5,082)	(5,218)
State income tax, net of federal benefit	5,398	4,537	(1,781)
Impairment of state net operating loss carryforwards	819	(311)	5,278
Impairment of state production tax credits	0	0	3,092
Allowance for equity funds used during construction	(3,331)	(1,732)	(3,650)
Reversal of deferred items related to BART at SJGS	0	0	1,826
Impairment of charitable contribution carryforward	909	0	2,042
Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization	(2,225)	(1,877)	0
Federal income tax rate change	57,461	0	0
Excess tax benefits related to stock compensation awards	(2,324)	0	0
Other	(988)	(822)	(2,811)
Total income taxes (benefit)	$ 130,340	$ 63,278	$ 15,075
Effective tax rate	57.73%	32.42%	32.66%
Public Service Company of New Mexico
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 59,139	$ 46,501	$ (4,579)
Amortization of accumulated investment tax credits	(286)	(973)	(1,342)
Flow-through of depreciation items	1,103	1,185	1,465
Earnings attributable to non-controlling interest in Valencia	(5,256)	(5,082)	(5,218)
State income tax, net of federal benefit	4,926	3,921	(2,162)
Impairment of state net operating loss carryforwards	627	(213)	3,619
Allowance for equity funds used during construction	(3,032)	(1,457)	(3,650)
Reversal of deferred items related to BART at SJGS	0	0	1,826
Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization	(2,225)	(1,877)	0
Federal income tax rate change	29,606	0	0
Excess tax benefits related to stock compensation awards	(1,708)	0	0
Other	(1,339)	(1,083)	(2,717)
Total income taxes (benefit)	$ 81,555	$ 40,922	$ (12,758)
Effective tax rate	48.27%	30.80%	97.52%
Texas-New Mexico Power Company
Income Taxes [Line Items]
Federal income tax at statutory rates	$ 23,475	$ 22,928	$ 23,131
State income tax, net of federal benefit	1,198	1,132	1,065
Federal income tax rate change	7,865	0	0
Excess tax benefits related to stock compensation awards	(616)	0	0
Other	(410)	(224)	(71)
Total income taxes (benefit)	$ 31,512	$ 23,836	$ 24,125
Effective tax rate	46.98%	36.39%	36.50%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss	$ 98,301	$ 160,901
Regulatory liabilities related to income taxes	189,501	64,657
Federal tax credit carryforwards	71,849	78,675
Shutdown of SJGS Units 2 and 3	2,204	53,434
Other	45,656	75,805
Total deferred tax assets	407,511	433,472
Deferred tax liabilities:
Depreciation and plant related	(690,909)	(1,102,458)
Investment tax credit	(55,731)	(56,017)
Regulatory assets related to income taxes	(61,956)	(66,378)
CTC	(5,670)	(12,715)
Pension	(56,070)	(57,287)
Regulatory asset for shutdown of SJGS Units 2 and 3	(31,887)	0
Other	(52,498)	(79,267)
Total deferred tax liabilities	(954,721)	(1,374,122)
Net accumulated deferred income tax liabilities	(547,210)	(940,650)
Public Service Company of New Mexico
Deferred tax assets:
Net operating loss	67,719	117,922
Regulatory liabilities related to income taxes	152,059	60,940
Federal tax credit carryforwards	60,085	59,156
Shutdown of SJGS Units 2 and 3	2,204	53,434
Other	23,801	41,700
Total deferred tax assets	305,868	333,152
Deferred tax liabilities:
Depreciation and plant related	(544,270)	(891,578)
Investment tax credit	(55,731)	(56,017)
Regulatory assets related to income taxes	(52,392)	(56,577)
Pension	(51,774)	(50,134)
Regulatory asset for shutdown of SJGS Units 2 and 3	(31,887)	0
Other	(18,826)	(27,512)
Total deferred tax liabilities	(754,880)	(1,081,818)
Net accumulated deferred income tax liabilities	(449,012)	(748,666)
Texas-New Mexico Power Company
Deferred tax assets:
Regulatory liabilities related to income taxes	43,103	3,718
Other	3,762	6,016
Total deferred tax assets	46,865	9,734
Deferred tax liabilities:
Depreciation and plant related	(135,647)	(201,017)
Regulatory assets related to income taxes	(9,564)	(9,800)
Loss on reacquired debt	(6,890)	(11,937)
CTC	(5,670)	(12,715)
Pension	(4,296)	(7,153)
AMS	(7,707)	(8,928)
Other	(3,506)	(3,969)
Total deferred tax liabilities	(173,280)	(255,519)
Net accumulated deferred income tax liabilities	$ (126,415)	$ (245,785)

Income Taxes - Schedule of De78

Income Taxes - Schedule of Deferred Income Tax Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	$ (393,440)
Change in tax effects of income tax related regulatory assets and liabilities	(16,444)
Tax effect of mark-to-market adjustments	(4,724)
Tax effect of excess pension liability	(3,421)
Adjustment for uncertain income tax positions	2,677
Reclassification of unrecognized tax benefits	(2,677)
Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization	(2,225)
Federal income tax rate change	548,952
Cumulative effect adjustment for excess tax benefit related to stock compensation awards	10,382
Alternative minimum tax carryforward reclassified to receivable	(8,336)
Other	(216)
Deferred income taxes	130,528	$ 63,805	$ 16,451
Public Service Company of New Mexico
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	(299,654)
Change in tax effects of income tax related regulatory assets and liabilities	(16,332)
Tax effect of mark-to-market adjustments	(4,110)
Tax effect of excess pension liability	(3,421)
Adjustment for uncertain income tax positions	2,614
Reclassification of unrecognized tax benefits	(2,614)
Regulatory recovery of prior year impairments of state net operating loss carryforward, net of amortization	(2,225)
Federal income tax rate change	402,501
Cumulative effect adjustment for excess tax benefit related to stock compensation awards	7,770
Other	(1,980)
Deferred income taxes	82,549	53,119	(2,836)
Texas-New Mexico Power Company
Income Taxes [Line Items]
Net change in deferred income tax liability per above table	(119,370)
Change in tax effects of income tax related regulatory assets and liabilities	(112)
Federal income tax rate change	146,451
Other	306
Deferred income taxes	$ 27,275	$ 12,662	$ 20,883

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
PNMR
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 6,752	$ 6,455	$ 15,031
Additions based on tax positions	262	242	1,214
Additions (reductions) for tax positions of prior years			(9,790)
Additions (reductions) for tax positions of prior years	2,415	55
Settlement payments	0	0	0
Ending balance	9,429	6,752	6,455
Unrecognized tax benefits that would impact effective tax rate	8,900
Public Service Company of New Mexico
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	3,949	3,652	12,228
Additions based on tax positions	262	242	1,214
Additions (reductions) for tax positions of prior years			(9,790)
Additions (reductions) for tax positions of prior years	2,352	55
Settlement payments	0	0	0
Ending balance	6,563	3,949	3,652
Unrecognized tax benefits that would impact effective tax rate	6,100
Texas-New Mexico Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	0	0	0
Additions based on tax positions	0	0	0
Additions (reductions) for tax positions of prior years			0
Additions (reductions) for tax positions of prior years	63	0
Settlement payments	0	0	0
Ending balance	63	$ 0	$ 0
Unrecognized tax benefits that would impact effective tax rate	$ 100

Income Taxes - Interest Income

Income Taxes - Interest Income (Expense) Related to Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Interest income related to income taxes	$ 0	$ 4,398	$ 0
Public Service Company of New Mexico
Income Taxes [Line Items]
Interest income related to income taxes	0	3,625	0
Texas-New Mexico Power Company
Income Taxes [Line Items]
Interest income related to income taxes	$ 0	345	$ 0
Interest income and interest expense applicable to federal income tax matters
Income Taxes [Line Items]
Net refunds received		6,500
Increase (decrease) of net interest receivable		(2,100)
Interest income		5,100
Interest expense		700
Professional fees		900
Net pre-tax impacts		3,500
Interest income and interest expense applicable to federal income tax matters | Public Service Company of New Mexico
Income Taxes [Line Items]
Net pre-tax impacts		2,600
Interest income and interest expense applicable to federal income tax matters | Texas-New Mexico Power Company
Income Taxes [Line Items]
Net pre-tax impacts		300
Interest income and interest expense applicable to federal income tax matters | Corporate and Other
Income Taxes [Line Items]
Net pre-tax impacts		$ 600

Income Taxes - Carryforwards (D

Income Taxes - Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
New Mexico corporate tax rate being phased in					7.60%
New Mexico Corporate tax rate, effective by 2018				5.90%
Regulatory liability	$ (10,109)	$ (7,132)	$ (1,903)
Income tax expense	1,259	(712)	674
Income Taxes, Impairment of Carryforwards
State tax credit carryforwards	0	0	3,092
State net operating loss carryforwards	819	(311)	5,278
Charitable contribution carryforwards	909	0	2,042
Income Taxes, Reserve Balances
State tax credit carryforwards	2,487	3,986
State net operating loss carryforwards	1,131	361
Charitable contribution carryforwards	952	659
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforwards	410,400
Federal tax credit carryforwards that expire beginning in 2023	71,800
Public Service Company of New Mexico
Operating Loss Carryforwards [Line Items]
Regulatory liability	(10,109)	(7,132)	(1,903)
Income tax expense	1,179	(804)	470
Income Taxes, Impairment of Carryforwards
State tax credit carryforwards	0	0	0
State net operating loss carryforwards	627	(213)	3,619
Charitable contribution carryforwards	0	0	0
Income Taxes, Reserve Balances
State tax credit carryforwards	0	0
State net operating loss carryforwards	839	248
Charitable contribution carryforwards	0	0
Texas-New Mexico Power Company
Operating Loss Carryforwards [Line Items]
Regulatory liability	0	0	0
Income tax expense	0	0	0
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
Income Taxes, Reserve Balances
State tax credit carryforwards	0	0
State net operating loss carryforwards	0	0
Charitable contribution carryforwards	0	$ 0
2015 Electric Rate Case | Public Service Company of New Mexico
Income Taxes, Reserve Balances
Approval to recover impairment of net operating loss carryforward	(2,100)
Recovery period of regulatory asset		2 years
2016 Electric Rate Case | Public Service Company of New Mexico
Income Taxes, Reserve Balances
Approval to recover impairment of net operating loss carryforward	$ (3,300)

Pension and Other Postretirem82

Pension and Other Postretirement Benefits - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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	4.00%
Pension Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average discount rate related to anticipated contributions	5.10%
Pension Plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	21.00%
Pension Plan | Equity Securities | Developed Countries Outside of United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	6.00%
Pension Plan | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	65.00%
Pension Plan | Fixed income | Scenario, plan
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	14.00%
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	6.40%	6.50%	6.80%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 5,300,000
Actual rate of return for pension plans	13.40%
Expected employer contributions in year 5	$ 5,100,000
Actuarial gains (losses) recorded as regulatory assets	$ 9,288,000
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	6.40%	6.50%	6.80%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 600,000
Actual rate of return for pension plans	12.80%
Expected employer contributions in year 5	$ 0
Actuarial gains (losses) recorded as regulatory assets	$ 621,000
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	70.00%
Other Postretirement Benefits | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets	30.00%
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	7.50%	7.70%	7.70%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 700,000
Actual rate of return for pension plans	20.50%
Actuarial gains (losses) recorded as regulatory assets	$ 10,600,000
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	5.40%	5.70%	5.70%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year	$ 100,000
Actual rate of return for pension plans	19.40%
Actuarial gains (losses) recorded as regulatory assets	$ 1,600,000
Effect of 1%-point change in assumed health care cost trend rates on net periodic expense and APBO	0
Estimated future employer contributions in next fiscal year	300,000
Estimated future employer contributions in years two through five	$ 1,400,000

Pension and Other Postretirem83

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	$ 94,003	$ 125,844
Public Service Company of New Mexico
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	86,124	114,427
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	621,751	597,900
Service cost	0	0	$ 0
Interest cost	26,908	30,307	28,255
Actuarial (gain) loss	26,298	39,463
Benefits paid	(50,974)	(45,919)
Balance at end of year	623,983	621,751	597,900
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	543,601	557,923
Actual return on plan assets	69,389	31,597
Employer contributions	0	0
Fair value of plan assets at end of year	562,016	543,601	557,923
Funded status – asset (liability) for pension benefits	(61,967)	(78,150)
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	94,269	84,674
Service cost	96	140	204
Interest cost	4,025	4,346	4,089
Participant contributions	3,069	2,690
Actuarial (gain) loss	(1,601)	17,877
Benefits paid	(9,961)	(11,734)
Plan design changes	0	(3,724)
Balance at end of year	89,897	94,269	84,674
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	72,694	72,952
Actual return on plan assets	14,222	5,923
Employer contributions	332	2,863
Fair value of plan assets at end of year	80,356	72,694	72,952
Funded status – asset (liability) for pension benefits	(9,541)	(21,575)
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	16,212	16,105
Service cost	0	0	0
Interest cost	697	812	760
Actuarial (gain) loss	674	768
Benefits paid	(1,466)	(1,473)
Balance at end of year	16,117	16,212	16,105
Less current liability	1,501	1,510
Non-current liability	14,616	14,702
Texas-New Mexico Power Company
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Non-current liability	7,879	11,417
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	67,061	64,198
Service cost	0	0	0
Interest cost	2,887	3,304	3,043
Actuarial (gain) loss	3,050	4,318
Benefits paid	(4,575)	(4,759)
Balance at end of year	68,423	67,061	64,198
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	60,624	62,082
Actual return on plan assets	7,450	3,301
Employer contributions	0	0
Fair value of plan assets at end of year	63,499	60,624	62,082
Funded status – asset (liability) for pension benefits	(4,924)	(6,437)
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	12,830	13,106
Service cost	143	186	247
Interest cost	556	677	608
Participant contributions	379	520
Actuarial (gain) loss	(381)	(96)
Benefits paid	(1,248)	(1,563)
Plan design changes	0	0
Balance at end of year	12,279	12,830	13,106
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	8,544	9,111
Actual return on plan assets	1,642	476
Employer contributions	685	0
Fair value of plan assets at end of year	10,002	8,544	9,111
Funded status – asset (liability) for pension benefits	(2,277)	(4,286)
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	787	794
Service cost	0	0	0
Interest cost	33	40	36
Actuarial (gain) loss	44	47
Benefits paid	(93)	(94)
Balance at end of year	771	787	$ 794
Less current liability	93	93
Non-current liability	$ 678	$ 694

Pension and Other Postretirem84

Pension and Other Postretirement Benefits - Actuarial (Gain) Loss Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates	$ 27,547	$ 41,849
Claims, contributions, and demographic experience	(1,249)	(334)
Other assumption and experience	0	(2,052)
Actuarial (gain) loss	26,298	39,463
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rates	3,536	6,569
Claims, contributions, and demographic experience	(5,845)	19,562
Assumed participation rate	0	(6,335)
Mortality rate	0	(691)
Medical benefits	1,425	(1,228)
Dental trend assumption	(717)	0
Actuarial (gain) loss	(1,601)	17,877
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates	3,528	5,055
Claims, contributions, and demographic experience	(517)	(556)
Other assumption and experience	39	(181)
Actuarial (gain) loss	3,050	4,318
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rates	613	1,112
Claims, contributions, and demographic experience	(994)	(102)
Assumed participation rate	0	(1,013)
Mortality rate	0	(93)
Medical benefits	0	0
Dental trend assumption	0	0
Actuarial (gain) loss	$ (381)	$ (96)

Pension and Other Postretirem85

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, 2017USD ($)
Public Service Company of New Mexico | Pension Plan
Prior service cost
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	$ (1,450)
Experience (gain) loss	0
Regulatory asset (liability) adjustment	0
Amortization recognized in net periodic benefit cost (income)	405
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	(1,045)
Amortization expected to be recognized in 2018	(405)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax [Abstract]
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	159,149
Experience (gain) loss	(9,288)
Regulatory asset (liability) adjustment	5,387
Amortization recognized in net periodic benefit cost (income)	(6,722)
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	148,526
Amortization expected to be recognized in 2018	6,653
Public Service Company of New Mexico | Executive Retirement Program
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax [Abstract]
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	2,299
Experience (gain) loss	674
Regulatory asset (liability) adjustment	(391)
Amortization recognized in net periodic benefit cost (income)	(132)
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at end of year	2,450
Amortization expected to be recognized in 2018	151
Texas-New Mexico Power Company | Pension Plan
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax [Abstract]
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	0
Experience (gain) loss	(621)
Regulatory asset (liability) adjustment	621
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
Amortization expected to be recognized in 2018	0
Texas-New Mexico Power Company | Executive Retirement Program
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax [Abstract]
Amounts in AOCI not yet recognized in net periodic benefit cost (income) at beginning of year	0
Experience (gain) loss	44
Regulatory asset (liability) adjustment	(44)
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
Amortization expected to be recognized in 2018	$ 0

Pension and Other Postretirem86

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Income) Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 0	$ 0	$ 0
Interest cost	26,908	30,307	28,255
Expected return on plan assets	(33,803)	(35,416)	(39,323)
Amortization of net (gain) loss	16,006	13,820	14,820
Amortization of prior service cost	(965)	(965)	(965)
Net periodic benefit cost	8,146	7,746	2,787
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	96	140	204
Interest cost	4,025	4,346	4,089
Expected return on plan assets	(5,230)	(5,483)	(5,610)
Amortization of net (gain) loss	3,682	1,145	1,966
Amortization of prior service cost	(1,663)	(30)	(642)
Net periodic benefit cost	910	118	7
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	697	812	760
Amortization of net (gain) loss	313	256	325
Amortization of prior service cost	0	0	0
Net periodic benefit cost	1,010	1,068	1,085
Texas-New Mexico Power Company
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	100	100
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	2,887	3,304	3,043
Expected return on plan assets	(3,779)	(3,943)	(4,420)
Amortization of net (gain) loss	923	700	782
Amortization of prior service cost	0	0	0
Net periodic benefit cost	31	61	(595)
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	143	186	247
Interest cost	556	677	608
Expected return on plan assets	(456)	(490)	(520)
Amortization of net (gain) loss	(79)	(40)	0
Amortization of prior service cost	0	0	0
Net periodic benefit cost	164	333	335
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	33	40	36
Amortization of net (gain) loss	9	2	5
Amortization of prior service cost	0	0	0
Net periodic benefit cost	$ 42	$ 42	$ 41

Pension and Other Postretirem87

Pension and Other Postretirement Benefits - Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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	4.05%	4.51%	5.29%
Discount rate for determining net periodic benefit cost (income)	4.51%	5.29%	4.48%
Expected return on plan assets	6.40%	6.50%	6.80%
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	4.00%	4.47%	5.34%
Discount rate for determining net periodic benefit cost (income)	4.47%	5.34%	4.45%
Expected return on plan assets	7.50%	7.70%	7.70%
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	4.05%	4.51%	5.29%
Discount rate for determining net periodic benefit cost (income)	4.51%	5.29%	4.48%
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	4.01%	4.49%	5.39%
Discount rate for determining net periodic benefit cost (income)	4.49%	5.39%	4.39%
Expected return on plan assets	6.40%	6.50%	6.80%
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	4.00%	4.47%	5.34%
Discount rate for determining net periodic benefit cost (income)	4.47%	5.34%	4.45%
Expected return on plan assets	5.40%	5.70%	5.70%
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	4.01%	4.49%	5.39%
Discount rate for determining net periodic benefit cost (income)	4.49%	5.39%	4.39%

Pension and Other Postretirem88

Pension and Other Postretirement Benefits - Pension Benefit Payments are Expected to be Paid (Details) $ in Thousands	Dec. 31, 2017USD ($)
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	$ 49,221
2,019	48,639
2,020	47,069
2,021	45,246
2,022	44,232
2023 - 2027	201,389
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	7,829
2,019	7,730
2,020	7,605
2,021	7,442
2,022	7,132
2023 - 2027	31,250
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	1,501
2,019	1,473
2,020	1,441
2,021	1,405
2,022	1,363
2023 - 2027	6,014
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	5,929
2,019	5,215
2,020	5,108
2,021	5,373
2,022	4,856
2023 - 2027	22,085
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	708
2,019	725
2,020	748
2,021	774
2,022	795
2023 - 2027	4,126
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	93
2,019	91
2,020	89
2,021	85
2,022	81
2023 - 2027	$ 324

Pension and Other Postretirem89

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 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	6.50%	6.80%
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	2,024	2,024
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
1-Percentage-Point Increase, Effect on total of service and interest cost	$ 72
1-Percentage-Point Increase, Effect on APBO	1,452
1-Percentage-Point Decrease, Effect on total of service and interest cost	(111)
1-Percentage-Point Decrease, Effect on APBO	$ (2,235)

Pension and Other Postretirem90

Pension and Other Postretirement Benefits - Other Postretirement Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
401(k) plan
Defined Contribution Plan [Abstract]
401(k) plan	$ 16,452	$ 17,762	$ 16,725
401(k) plan | Public Service Company of New Mexico
Defined Contribution Plan [Abstract]
401(k) plan	12,120	13,397	12,679
401(k) plan | Texas-New Mexico Power Company
Defined Contribution Plan [Abstract]
401(k) plan	4,332	4,365	4,046
Non-qualified plan
Defined Contribution Plan [Abstract]
Non-qualified plan	3,702	2,017	1,436
Non-qualified plan | Public Service Company of New Mexico
Defined Contribution Plan [Abstract]
Non-qualified plan	2,834	1,535	1,090
Non-qualified plan | Texas-New Mexico Power Company
Defined Contribution Plan [Abstract]
Non-qualified plan	$ 868	$ 482	$ 346

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Equity Plan and Accounting for Stock Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted (in shares)	0
Compensation expense for stock-based arrangements	$ 6,200	$ 5,600	$ 4,900
Excess tax benefits	2,324	0	0
Retained Earnings | Accounting Standards Update 2016-09
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative effect adjustment (Note 13)		10,400
Restricted Shares and Performance-Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 3,800
Period to recognize compensation expense	1 year 6 months 11 days
Public Service Company of New Mexico
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for stock-based arrangements	$ 4,400	4,200	3,600
Excess tax benefits	1,708	0	0
Texas-New Mexico Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for stock-based arrangements	1,800	1,500	1,300
Excess tax benefits	$ 616	$ 0	$ 0
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 - Weig

Stock-Based Compensation - Weighted Average Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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)	$ 0.2425	$ 0.2200	$ 0.2000
Risk-free interest rate	1.50%	0.94%	0.92%
Market-Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	2.67%	2.74%	2.87%
Expected volatility	20.80%	20.44%	18.73%
Risk-free interest rate	1.54%	0.97%	1.00%

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards (Details) - USD ($)	Mar. 03, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 28, 2017	Mar. 31, 2015	Jan. 01, 2015	Mar. 31, 2012
Chairman, President, and Chief Executive Officer | Common Stock | Achieves a specified improvement in total shareholder return at the end of 2016 compared to 2011 and she remains an employee
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares authorized (in shares)								135,000
Chairman, President, and Chief Executive Officer | Common Stock | Achieves Specified Improvement In Total Shareholder Return At End Of 2014 Compared To 2011 And She Remains Employee
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares authorized (in shares)								35,000
Number of shares approved upon meeting target (in shares)					100,000
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)						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
Executive Vice President and Chief Financial Officer | Common Stock | Achieved performance target for 2015 and 2016
Restricted Stock
Granted (in shares)	2,754
Weighted-Average Grant Date Fair Value
Granted (in dollars per share)	$ 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
Value of stock to be granted if performance targets are achieved							$ 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)	$ 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
Restricted Stock
Restricted Stock
Beginning balance (in shares)		218,316
Granted (in shares)		248,271
Exercised (in shares)		(273,530)
Forfeited (in shares)		(4,012)
Ending balance (in shares)		189,045	218,316
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)		$ 27.59
Granted (in dollars per share)		23.06	$ 26.49	$ 20.34
Exercised (in dollars per share)		21.01
Forfeited (in dollars per share)		29.96
Ending balance (in dollars per share)		31.11	27.59
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)		$ 23.06	$ 26.49	$ 20.34
Total fair value of restricted shares that vested		$ 5,747,000	$ 5,079,000	$ 6,507,000
Stock Options
Stock Options
Beginning balance (in shares)		305,874
Granted (in shares)		0
Exercised (in shares)		(109,433)
Forfeited (in shares)		0
Expired (in shares)		(3,000)
Ending balance (in shares)		193,441	305,874
Weighted Average Exercise Price
Beginning balance (in dollars per share)		$ 12.29
Granted (in dollars per share)		0
Exercised (in dollars per share)		15.89
Forfeited (in dollars per share)		0
Expired (in dollars per share)		30.50
Ending balance (in dollars per share)		$ 9.98	$ 12.29
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Aggregate intrinsic value of stock options outstanding		$ 5,900,000
Weighted average remaining contract life		1 year 6 months 18 days
Exercise price of stock options that are greater than the closing price (in shares)		0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted-average grant date fair value options granted (in dollars per share)		$ 0	$ 0	$ 0
Total fair value of options that vested		$ 0	$ 0	$ 0
Total intrinsic value of options exercised		$ 2,234,000	$ 1,242,000	$ 2,350,000
Performance Shares | Executive
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Shares granted (in shares)		49,682
Weighted percentage assigned to achieving market targets		60.00%
Weighted percentage assigned to achieving performance targets		40.00%
Shares excluded (in shares)		97,697
Shares approved, maximum number of shares available in year two (in shares)		137,036
Shares approved, maximum number of shares available in year three (in shares)		133,632
Performance period		3 years

Construction Program and Join94

Construction Program and Jointly-Owned Electric Generating Plants - Construction Program and Jointly-Owned Electric Generating Plants (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)generating_unit	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	$ 500,461	$ 600,076	$ 558,589
Plant in Service	7,238,285	6,944,534
Accumulated depreciation	(2,592,692)	(2,334,938)
Regulatory disallowance	27,036	15,011	167,471
Regulatory assets	$ 600,672	501,223
Operating lease, option term extensions	2 years
Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	$ 309,142	445,464	404,840
Plant in Service	5,501,070	5,359,211
Accumulated depreciation	(2,029,534)	(1,809,528)
Regulatory disallowance	27,036	15,011	167,471
Regulatory assets	459,239	365,413
Public Service Company of New Mexico | Clean Air Act, SNCR
Jointly Owned Utility Plant Interests [Line Items]
Regulatory disallowance			21,600
Texas-New Mexico Power Company
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	145,495	122,518	124,584
Plant in Service	1,504,778	1,380,584
Accumulated depreciation	(460,858)	(429,397)
Regulatory assets	141,433	135,810
Joint Projects | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	309,100
Joint Projects | Texas-New Mexico Power Company
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	145,500
Joint Projects | PNMR
Jointly Owned Utility Plant Interests [Line Items]
Construction expenditures	$ 500,500
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	$ 920,950
Accumulated depreciation	(522,750)
Construction Work in Progress	$ 8,512
Composite Interest	46.30%
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	$ 918,830
Accumulated depreciation	(353,054)
Construction Work in Progress	$ 35,038
Composite Interest	10.20%
Period of time for the original full power operating licenses	40 years
Number of units (in generating units) | generating_unit	3
Operating lease, option term extensions	20 years
Four Corners | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Number of units (in generating units) | generating_unit	2
Four Corners Units 4 and 5 (Coal) | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 204,432
Accumulated depreciation	(100,914)
Construction Work in Progress	$ 61,755
Composite Interest	13.00%
Luna (Gas) | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 70,995
Accumulated depreciation	(27,023)
Construction Work in Progress	$ (13)
Composite Interest	33.33%
San Juan Generating Station Units 2 and 3 | Public Service Company of New Mexico
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 439,400	471,800	468,200
Accumulated depreciation	(188,300)	(203,900)	(193,300)
Construction Work in Progress			2,200
Net book value	251,100	$ 139,300	277,100
Regulatory assets	$ 125,500
San Juan Generating Station Units 2 and 3 | Public Service Company of New Mexico | Clean Air Act, SNCR
Jointly Owned Utility Plant Interests [Line Items]
Regulatory disallowance			$ 127,600
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%

Construction Program and Join95

Construction Program and Jointly-Owned Electric Generating Plants - Summary of Budgeted Construction Expenditures (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)MW
Summary of Budgeted Construction Expenditures [Line Items]
2,018	$ 500.2
2,019	526.8
2,020	500.4
2,021	503.8
2,022	680.9
Total	$ 2,712.1
Solar
Summary of Budgeted Construction Expenditures [Line Items]
Public utilities, number of megawatts | MW	50
Public Service Company of New Mexico
Summary of Budgeted Construction Expenditures [Line Items]
2,018	$ 295
2,019	339
2,020	313.4
2,021	315.8
2,022	493.7
Total	1,756.9
Anticipated expansion of transmission system	170
Anticipated expansion of transmission system in 2021	100
Public Service Company of New Mexico | Solar
Summary of Budgeted Construction Expenditures [Line Items]
2,018	72.8
Public Service Company of New Mexico | Four Corners Units 4 and 5 (Coal)
Summary of Budgeted Construction Expenditures [Line Items]
Expenditures related to environmental upgrades	7.9
Public Service Company of New Mexico | San Juan Generating Station Units 1 and 4
Summary of Budgeted Construction Expenditures [Line Items]
Potential shutdown of SJGS Units 1 and 4 in 2022	300
Texas-New Mexico Power Company
Summary of Budgeted Construction Expenditures [Line Items]
2,018	185.8
2,019	170.5
2,020	170
2,021	170.5
2,022	170.1
Total	866.9
Corporate and Other
Summary of Budgeted Construction Expenditures [Line Items]
2,018	19.4
2,019	17.3
2,020	17
2,021	17.5
2,022	17.1
Total	$ 88.3

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Asset Retirement Obligations [Line Items]
ARO liabilities related to nuclear decommissioning	80.00%
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 127,519	$ 111,895	$ 104,170
Liabilities incurred	1,854	0	0
Liabilities settled	(968)	(14)	(730)
Accretion expense	10,680	9,170	8,625
Revisions to estimated cash flows	7,594	6,468	(170)
Ending balance	146,679	127,519	111,895
Public Service Company of New Mexico
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	126,601	111,049	103,182
Liabilities incurred	1,853	0	0
Liabilities settled	(944)	(14)	(506)
Accretion expense	10,603	9,098	8,543
Revisions to estimated cash flows	7,594	6,468	(170)
Ending balance	145,707	126,601	111,049
Texas-New Mexico Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	754	695	848
Liabilities incurred	0	0	0
Liabilities settled	(24)	0	(224)
Accretion expense	63	59	71
Revisions to estimated cash flows	0	0	0
Ending balance	$ 793	$ 754	$ 695

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]
Funding for decommissioning costs in qualified and non-qualified trust funds	$ 2	$ 4.2	$ 4.9
Estimated market value of trusts for decommissioning costs	$ 293.7	$ 253.9

Commitments and Contingencies98

Commitments and Contingencies - Nuclear Spent Fuel and Waste Disposal (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station - USD ($)	May 16, 2014	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Department of energy, spent nuclear fuel removal July 2011 - June 2014
Loss Contingencies [Line Items]
PNM's share of third party settlement claim		$ 5,600,000
Litigation settlement, portion credited to customers		$ 3,600,000
Nuclear spent fuel and waste disposal
Loss Contingencies [Line Items]
Estimate of possible loss			$ 57,700,000
DOE adjusted one-mill fee	$ 0
Nuclear spent fuel and waste disposal | Other deferred credits
Loss Contingencies [Line Items]
Liability for interim storage costs			$ 12,300,000	$ 12,100,000

Commitments and Contingencies99

Commitments and Contingencies - The Clean Air Act (Details)

Dec. 31, 2015USD ($)

Dec. 16, 2015USD ($)MWhMW

Jul. 17, 2015

Dec. 20, 2013USD ($)$ / kwMW

Aug. 31, 2011generating_unit

Dec. 31, 2017USD ($)lb / MMBTUgenerating_unitjoint_ownerMW

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Jan. 31, 2016USD ($)

Jan. 26, 2016state

Jul. 31, 2015MW

Aug. 06, 2012compliance_alternative

Jul. 31, 2005T

Dec. 31, 1999state

Public Utilities, General Disclosures [Line Items]

Plant in service, held for future use, and to be abandoned

$ 7,238,285,000

$ 6,944,534,000

Accumulated depreciation and amortization

2,592,692,000

2,334,938,000

Regulatory disallowances and restructuring costs

27,036,000

15,011,000

$ 167,471,000

Reversal of deferred items related to BART at SJGS

0

0

1,826,000

Regulatory assets

$ 600,672,000

501,223,000

San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Number of other entities (in joint owner) | joint_owner

5

Four Corners

Public Utilities, General Disclosures [Line Items]

Approved lease extension term

25 years

Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Plant in service, held for future use, and to be abandoned

$ 5,501,070,000

5,359,211,000

Accumulated depreciation and amortization

2,029,534,000

1,809,528,000

Regulatory disallowances and restructuring costs

27,036,000

15,011,000

167,471,000

Reversal of deferred items related to BART at SJGS

0

0

1,826,000

Regulatory assets

$ 459,239,000

$ 365,413,000

Power to be sold to third party (in megawatts) | MW

36

Public Service Company of New Mexico | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Number of units (in generating units) | generating_unit

4

Share of costs

46.30%

Public Service Company of New Mexico | San Juan Generating Station | Surface | Loss on long-term purchase commitment

Public Utilities, General Disclosures [Line Items]

Regulatory disallowances and restructuring costs

$ 16,500,000

16,500,000

Estimate of possible loss

$ 100,400,000

Public Service Company of New Mexico | San Juan Generating Station Units 2 and 3

Public Utilities, General Disclosures [Line Items]

Recovery percentage of estimated undepreciated value

50.00%

50.00%

Plant in service, held for future use, and to be abandoned

468,200,000

$ 439,400,000

$ 471,800,000

468,200,000

Accumulated depreciation and amortization

193,300,000

188,300,000

203,900,000

193,300,000

Net undepreciated book value

267,900,000

Construction work in progress

2,200,000

2,200,000

Net book value

$ 277,100,000

251,100,000

139,300,000

277,100,000

Regulatory assets

125,500,000

Reversal of plant write-off

3,000,000

Reversal of recorded loss for other unrecoverable costs

1,000,000

Total reversed losses

$ 4,000,000

Public Service Company of New Mexico | Four Corners

Public Utilities, General Disclosures [Line Items]

Number of units (in generating units) | generating_unit

2

Public Service Company of New Mexico | Four Corners Units 4 and 5 (Coal)

Public Utilities, General Disclosures [Line Items]

Share of costs

13.00%

Plant in service, held for future use, and to be abandoned

$ 204,432,000

Accumulated depreciation and amortization

100,914,000

Construction work in progress

61,755,000

PNMR Development | Energy Equipment

Public Utilities, General Disclosures [Line Items]

Cost of installing equipment

7,600,000

Environmental Protection Agency | Public Service Company of New Mexico | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Number of units (in generating units) | generating_unit

4

Environmental Protection Agency and NMED | Public Service Company of New Mexico | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Period of time to comply after approval

15 months

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, SCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | Minimum | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Estimated total capital cost if requirement occurred

824,000,000

Clean Air Act, SCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | Maximum | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Estimated total capital cost if requirement occurred

$ 910,000,000

Clean Air Act, SNCR | San Juan Generating Station Unit 4

Public Utilities, General Disclosures [Line Items]

Number of other entities (in joint owner) | joint_owner

8

Clean Air Act, SNCR | San Juan Generating Station Unit 4 | CALIFORNIA

Public Utilities, General Disclosures [Line Items]

Number of other entities (in joint owner) | joint_owner

3

Clean Air Act, SNCR | Public Service Company of New Mexico

Public Utilities, General Disclosures [Line Items]

Estimated costs to remain unrecovered

$ 20,000,000

Regulatory disallowances and restructuring costs

$ 21,600,000

Net expense

3,700,000

Revision of net book value

900,000

Reclamation expense

4,500,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Restructuring costs

Public Utilities, General Disclosures [Line Items]

Net expense

1,700,000

Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Overall reduction of ownership (in megawatts) | MW

418

Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station Units 2 and 3

Public Utilities, General Disclosures [Line Items]

Requested time period to recover retired units NBV

20 years

20 years

20 years

Newly identified replacement solar generation (in megawatts) | MW

40

Current ownership (in megawatts) | MW

418

Recovery percentage of estimated undepreciated value

50.00%

50.00%

50.00%

Estimated undepreciated value

$ 255,300,000

$ 255,300,000

Regulatory disallowances and restructuring costs

127,600,000

Reversal of deferred items related to BART at SJGS

1,800,000

Accumulated plant write-off, disallowance

$ 128,600,000

128,600,000

Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station Units 2 and 3 | Increase in coal mine decommissioning liability

Public Utilities, General Disclosures [Line Items]

Regulatory disallowances and restructuring costs

$ 165,700,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Palo Verde Nuclear Generating Station Unit 3

Public Utilities, General Disclosures [Line Items]

Estimated undepreciated value

$ 154,900,000

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

65

132

Estimated rate base value

$ 0

Coal-fired generation (in megawatts) | MW

197

Number of megawatt hours of renewable energy certificates to be acquired and retired (in megawatt hours) | MWh

1

Percentage of ownership held by exiting owners

38.80%

Ownership percentage

38.50%

Estimated increase in cost of acquired interest due to plant in service and accumulated depreciation

$ 261,800,000

Clean Air Act, SNCR | Public Service Company of New Mexico | San Juan Generating Station Unit 3

Public Utilities, General Disclosures [Line Items]

Percentage of ownership held by exiting owners

50.00%

Ownership percentage

50.00%

Clean Air Act, SNCR | Public Service Company of New Mexico | Maximum | San Juan Generating Station Unit 4

Public Utilities, General Disclosures [Line Items]

Annual cost of renewable energy credits, maximum

$ 7,000,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | San Juan Generating Station Units 1 and 4

Public Utilities, General Disclosures [Line Items]

Portion of costs for SNCRs and BDT equipment

$ 77,700,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | Minimum | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Estimated installation capital costs

$ 85,000,000

Estimated portion of total capital costs if requirement occurred

105,000,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | Maximum | San Juan Generating Station

Public Utilities, General Disclosures [Line Items]

Estimated installation capital costs

90,000,000

Estimated portion of total capital costs if requirement occurred

$ 110,000,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs | Maximum | San Juan Generating Station Units 1 and 4

Public Utilities, General Disclosures [Line Items]

Estimated installation capital costs

$ 82,000,000

Clean Air Act, SNCR | Public Service Company of New Mexico | Scenario, plan | San Juan Generating Station Units 1 and 4

Public Utilities, General Disclosures [Line Items]

Ownership percentage

66.30%

Clean Air Act, SNCR | Public Service Company of New Mexico | Scenario, plan | San Juan Generating Station Unit 4

Public Utilities, General Disclosures [Line Items]

Ownership percentage

77.30%

Clean Air Act, SNCR | PNMR and PNM | Palo Verde Nuclear Generating Station Unit 3

Public Utilities, General Disclosures [Line Items]

Number of megawatts | MW

134

134

Proposed value per kilowatt (in dollars per kilowatt) | $ / kw

2,500

Clean Air Act, SNCR | PNMR Development | San Juan Generating Station Unit 4

Public Utilities, General Disclosures [Line Items]

Reimbursement amount

600,000

Potential acquisition of ownership (in megawatts) | MW

65

Restructuring fee

$ 3,100,000

Clean Air Act, SNCR Hearing Examiner Recommended Denial | 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

Estimated undepreciated value

$ 20,700,000

Clean Air Act, Post-2022 Coal Supply future rate case | Public Service Company of New Mexico | San Juan Generating Station Unit 4

Public Utilities, General Disclosures [Line Items]

Period of time for stipulation agreement

6 months

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 / 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

$ 88,900,000

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%

Clean Power Plan

Public Utilities, General Disclosures [Line Items]

Number of states that filed a petition against the Clean Power Plan | state

29

Commitments and Contingencie100

Commitments and Contingencies - National Ambient Air Quality Standards (Details) - Public Service Company of New Mexico	Feb. 25, 2016	Mar. 02, 2015lb / MMBTUT	Oct. 01, 2015parts_per_billion	Sep. 30, 2015parts_per_billion	May 14, 2015lb / MMBTU
Maximum | San Juan Generating Station And Four Corners
Public Utilities, General Disclosures [Line Items]
Government standard emissions limit (in parts per billion) | parts_per_billion			70	75
National Ambient Air Quality Standards, 2015 EPA Legal Settlement
Public Utilities, General Disclosures [Line Items]
Period of time to act on settlement		16 months
Emissions tons of SO2 per year (more than) | T		16,000
National Ambient Air Quality Standards, 2015 EPA Legal Settlement | Minimum
Public Utilities, General Disclosures [Line Items]
Emissions tons of SO2 per year (more than) | T		2,600
SO2 emissions rate (in pounds per MMBTU) | lb / MMBTU		0.45
National Ambient Air Quality Standards | San Juan Generating Station
Public Utilities, General Disclosures [Line Items]
Revised SO2 emissions agreed upon (in pounds per MMBTU) | lb / MMBTU					0.10
National Ambient Air Quality Standards, Proposed 2016 SO2 Rule
Public Utilities, General Disclosures [Line Items]
Period of time from state designation to provide implementation plans	36 months

Commitments and Contingencie101

Commitments and Contingencies - WEG v. OSM NEPA Lawsuit (Details) - Public Service Company of New Mexico - WEG v OSM Lawsuit	Feb. 28, 2013stateminelawsuit
Loss Contingencies [Line Items]
Number of mines affected | mine	7
Number of states | state	4
Number of claims filed for relief (in lawsuits)	15
San Juan Generating Station
Loss Contingencies [Line Items]
Number of claims filed for relief (in lawsuits)	2

Commitments and Contingencie102

Commitments and Contingencies - Coal Supply (Details)

Feb. 01, 2018USD ($)

Feb. 01, 2016USD ($)

Jan. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Feb. 20, 2018USD ($)

Jun. 30, 2017USD ($)

Feb. 01, 2017

Jul. 19, 2016USD ($)

Jul. 07, 2016payment

Mar. 31, 2016USD ($)

Other Commitments [Line Items]

Other current assets

$ 47,358,000

$ 73,444,000

Regulatory disallowances and restructuring costs

27,036,000

15,011,000

$ 167,471,000

Funds contributed to mine reclamation trust

2,300,000

1,900,000

Public Service Company of New Mexico

Other Commitments [Line Items]

Other current assets

39,904,000

67,355,000

Regulatory disallowances and restructuring costs

27,036,000

15,011,000

167,471,000

Regulatory assets

461,378,000

368,855,000

Public Service Company of New Mexico | Increase in coal mine decommissioning liability

Other Commitments [Line Items]

Net expense

4,500,000

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

5,800,000

7,000,000

4,300,000

Public Service Company of New Mexico | Mine Reclamation Trust | San Juan Generating Station

Other Commitments [Line Items]

Reclamation trust funding, next fiscal year

8,300,000

Reclamation trust funding, year 2

8,700,000

Reclamation trust funding, year 3

9,200,000

Public Service Company of New Mexico | Mine Reclamation Trust | Four Corners

Other Commitments [Line Items]

Reclamation trust funding, next fiscal year

2,300,000

Reclamation trust funding, year 2

2,300,000

Reclamation trust funding, year 3

2,300,000

Number of annual installments (in payments) | payment

13

Public Service Company of New Mexico | Surface

Other Commitments [Line Items]

Regulatory assets

100,000,000

Public Service Company of New Mexico | Surface | Loss on long-term purchase commitment

Other Commitments [Line Items]

Liability for interim storage costs

41,400,000

41,000,000

Increase (decrease) for interim storage costs liability

35,000,000

Capped amount that can be collected from retail customers for final reclamation

100,000,000

Public Service Company of New Mexico | Underground | Loss on long-term purchase commitment

Other Commitments [Line Items]

Liability for interim storage costs

14,700,000

14,000,000

Increase (decrease) for interim storage costs liability

5,000,000

Public Service Company of New Mexico | San Juan Generating Station | Surface | Loss on long-term purchase commitment

Other Commitments [Line Items]

Regulatory disallowances and restructuring costs

$ 16,500,000

$ 16,500,000

Estimate of possible loss

100,400,000

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

127,100,000

Public Service Company of New Mexico | San Juan Generating Station | Coal Supply

Other Commitments [Line Items]

Other current assets

26,300,000

$ 48,700,000

Estimated increase in coal cost

51.00%

Public Service Company of New Mexico | Four Corners

Other Commitments [Line Items]

Unrecorded unconditional purchase obligation

$ 6,500,000

NM Capital | BTMU Term Loan Agreement

Other Commitments [Line Items]

Long-term debt

$ 125,000,000

50,100,000

NM Capital | BTMU Term Loan Agreement | Subsequent Event

Other Commitments [Line Items]

Long-term debt

$ 45,100,000

NM Capital | San Juan Generating Station | Coal Supply

Other Commitments [Line Items]

Funding provided

$ 125,000,000

$ 125,000,000

Variable interest rate

7.25%

9.25%

Coal mine reclamation bonds to be posted with NMMMD

$ 118,700,000

Cash used to support bank letter or credit arrangement

30,300,000

$ 30,300,000

NM Capital | San Juan Generating Station | Coal Supply | Subsequent Event

Other Commitments [Line Items]

Variable interest rate

12.25%

NM Capital | San Juan Generating Station | Coal Supply | Subsequent Event | Westmoreland San Juan

Other Commitments [Line Items]

Principal payment received

$ 5,600,000

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

Other Commitments [Line Items]

Amount outstanding

$ 125,000,000

56,600,000

Prepayment penalty

$ 0

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

Other Commitments [Line Items]

Amount outstanding

$ 51,000,000

Commitments and Contingencie103

Commitments and Contingencies - Mining Royalty Rate (Details) - Continuous Highwall Mining - San Juan Generating Station - USD ($) $ in Millions	Aug. 31, 2013	Aug. 31, 2006	Dec. 31, 2003
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 Contingencie104

Commitments and Contingencies - Liability and Insurance Matters (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station	12 Months Ended
	Dec. 31, 2017USD ($)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	$ 38,900,000
Annual payment limitation related to incident	5,800,000
Aggregate amount of all risk insurance	2,750,000,000
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	13,000,000,000
Nuclear Plant | Maximum
Public Utilities, General Disclosures [Line Items]
Liability insurance coverage	$ 13,400,000,000

Commitments and Contingencie105

Commitments and Contingencies - Water Supply (Details) - Public Service Company of New Mexico - Palo Verde Nuclear Generating Station	1 Months Ended
	Apr. 30, 2010city
Public Utilities, General Disclosures [Line Items]
Providing water to a number of cities	5
Providing water, term	40 years

Commitments and Contingencie106

Commitments and Contingencies - Right-of-Way, Complaints, and Navajo National Allottee Matters (Details) $ in Millions	Jan. 04, 2016	Oct. 29, 2015USD ($)	Dec. 31, 2017USD ($)	Nov. 20, 2017Allotment_Parcel	Dec. 01, 2015Allotment_Parcel	Jul. 13, 2015a	Jan. 22, 2015Allotment_Parcel	Apr. 02, 2014landownerAllotment_Parcel	Feb. 27, 2014lawsuit	Jan. 06, 2014Allotment_Parcel	Sep. 30, 2012landowner
First Choice
Loss Contingencies [Line Items]
Additional tax due plus penalties and interest | $			$ 5
SPS Complaint, Federal Power Act | Public Service Company of New Mexico
Loss Contingencies [Line Items]
Amount received, including interest, under settlement | $		$ 4.2
Settlement amount passed back to customers | $		$ 2.6
Navajo Nation Allottee Matters | Public Service Company of New Mexico
Loss Contingencies [Line Items]
Number of landowners claiming to be Navajo allottees (in landowners) | landowner								43			43
Number of appraisals requested for review (in allotment parcels)										58
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	2
Number of allotment parcels at issue					5
Pending Litigation
Loss Contingencies [Line Items]
Number of claims (in lawsuits) | lawsuit									2
Written notification requirement to terminate agreement, minimum period	30 days
Settled Litigation
Loss Contingencies [Line Items]
Number of claims (in lawsuits) | lawsuit									1

Regulatory and Rate Matters - N

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

Jan. 31, 2018USD ($)

Jan. 16, 2018USD ($)

Jan. 10, 2018USD ($)

Dec. 31, 2017USD ($)

May 23, 2017USD ($)

Dec. 07, 2016USD ($)

Sep. 30, 2016USD ($)

Sep. 28, 2016USD ($)MW

Aug. 04, 2016USD ($)MW

Jan. 15, 2016USD ($)leaseMW

Aug. 27, 2015USD ($)

Jan. 15, 2015

Dec. 11, 2014USD ($)

Sep. 30, 2016USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2018USD ($)

Oct. 31, 2017USD ($)

Jul. 01, 2016USD ($)

May 31, 2016MW

Subsequent Event

Public Utilities, General Disclosures [Line Items]

Increase (decrease) in non-fuel revenue requirement

$ 10.3

Percent of non-fuel revenue requirement change implemented

50.00%

NMPRC

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 99.2

Requested return on equity

10.125%

Pre-tax regulatory disallowance

$ 27.9

$ 27.9

Public Service Company of New Mexico | NMPRC

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 62.3

Requested return on equity

9.575%

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

3 years

Initial rate increase (decrease) amount

$ 32.3

Public Service Company of New Mexico | NMPRC | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ (4.4)

$ (9.1)

Requested rate increase (decrease), duplicative amount

$ 4.7

Public Service Company of New Mexico | Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4

Public Utilities, General Disclosures [Line Items]

Net book value

49.4

49.4

Public Service Company of New Mexico | Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4 | Installation costs including construction management, gross receipts taxes, AFUDC, and other PNM costs

Public Utilities, General Disclosures [Line Items]

Portion of costs for SNCRs and BDT equipment

$ 52.3

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

Number of leases under which assets were purchased | lease

3

Estimated annual property tax expense

$ 0.8

Number of leases under which lease term was extended | lease

1

Lease term extension period

8 years

Number of megawatts | MW

114.6

114.6

Net book value

75.3

75.3

Net book value of capital improvements

39.1

39.1

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

Public Utilities, General Disclosures [Line Items]

Estimated annual property tax expense

$ 1.5

Estimated annual rent expense

$ 18.1

Number of leases under which lease term was extended | lease

4

Lease term extension period

8 years

Public Service Company of New Mexico | 2014 Electric Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 107.4

Public Service Company of New Mexico | 2015 Electric Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 123.5

Requested return on equity

10.50%

Requested rate increase (decrease) in fuel-related costs

$ (42.9)

Change in requested rate increase (decrease) in non-fuel related revenues

(0.2)

Requested rate increase (decrease) in non-fuel related revenue

121.5

$ 121.5

Proposed increase (decrease) in non-fuel revenue

$ 41.3

Proposed return on equity

9.575%

Approved rate increase (decrease)

$ 61.2

Estimated period of time for New Mexico Supreme Court Appeal decision

15 months

7 months

Minimum amount of loss of capital cost recovery

15 months

Increase (decrease) of income tax expense

$ (2.1)

Estimate of possible loss

151.1

151.1

Public Service Company of New Mexico | 2015 Electric Rate Case | San Juan Generating Station | Refined Coal

Public Utilities, General Disclosures [Line Items]

Proposed credit to retail customers

100.00%

Public Service Company of New Mexico | 2015 Electric Rate Case | Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4

Public Utilities, General Disclosures [Line Items]

Amount of equipment costs included in rate base

$ 40

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

163.3

Approved lease acquisition costs

83.7

Disallowed leasehold improvements

43.8

Pre-tax regulatory disallowance for capital costs

$ 3.1

$ 6.8

Public Service Company of New Mexico | 2015 Electric Rate Case | Palo Verde Nuclear Generating Station, Unit 1 Leases, extended

Public Utilities, General Disclosures [Line Items]

Approved recovery of assumed operating and maintenance expense savings annually related to BDT

$ 0.3

Public Service Company of New Mexico | 2015 Electric Rate Case | Alvarado square

Public Utilities, General Disclosures [Line Items]

Proposed disallowance of recovery of assets and deferred charges from retail customers

$ 4.5

Pre-tax regulatory disallowance of costs recorded as regulatory assets and deferred charges

$ 4.5

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

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 121.7

Four Corners

Public Utilities, General Disclosures [Line Items]

Pre-tax regulatory disallowance

$ 90.1

$ 148.1

Scenario, forecast

Public Utilities, General Disclosures [Line Items]

Pre-tax regulatory disallowance for capital costs

$ 36.8

$ 58

Regulatory and Rate Matters - P

Regulatory and Rate Matters - Proceeding Regarding Definition of Future Test Year (Details) - 2014 Electric Rate Case - Public Service Company of New Mexico	Nov. 30, 2015	Jul. 31, 2015	May 27, 2015
Public Utilities, General Disclosures [Line Items]
Defined future test year as period that begins a period of time following the filing of an application to increase rates (no later than)			45 days
Belief that the correct interpretation of future test year is period time after filing of an application (up to)			13 months
Motion for a temporary stay		30 days
Redefined future test year as period that begins a period of time following the filing of a rate case application (up to)	13 months

Regulatory and Rate Matters - R

Regulatory and Rate Matters - Renewable Portfolio Standard (Details) - Public Service Company of New Mexico	12 Months Ended
	Dec. 31, 2017MW	Dec. 31, 2016MW	Jun. 01, 2017GWhMW	Dec. 31, 2015MW	Dec. 31, 2013MW
Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Solar photovoltaic capacity (in mw)	107			40
Current output of solar photovoltaic capacity (in mw)	4
Solar distributed generation (in mw)	81.6
Renewable Portfolio Standard | Minimum
Public Utilities, General Disclosures [Line Items]
Reasonable cost threshold	3.00%
Renewable Portfolio Standard | Minimum | Wind
Public Utilities, General Disclosures [Line Items]
Required percentage of diversification	30.00%
Renewable Portfolio Standard | Minimum | Solar
Public Utilities, General Disclosures [Line Items]
Required percentage of diversification	20.00%
Renewable Portfolio Standard | Minimum | Distributed Generation
Public Utilities, General Disclosures [Line Items]
Required percentage of diversification	3.00%
Renewable Portfolio Standard | Minimum | Other
Public Utilities, General Disclosures [Line Items]
Required percentage of diversification	5.00%
Renewable Portfolio Standard | Required Percentage by 2011
Public Utilities, General Disclosures [Line Items]
Required percentage of renewable energy in portfolio to electric sales	10.00%
Renewable Portfolio Standard | Required Percentage by 2015
Public Utilities, General Disclosures [Line Items]
Required percentage of renewable energy in portfolio to electric sales	15.00%
Renewable Portfolio Standard | Required Percentage by 2020
Public Utilities, General Disclosures [Line Items]
Required percentage of renewable energy in portfolio to electric sales	20.00%
Renewable Portfolio Standard Supplemental Procurement
Public Utilities, General Disclosures [Line Items]
Solar photovoltaic capacity (in mw)					1.5
Renewable Portfolio Standard 2014
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)	204	102
NMPRC
Public Utilities, General Disclosures [Line Items]
Additional megawatt hours in first year (in mw) | GWh			80
Requested solar production (in mw)			50
New Mexico Wind | NMPRC
Public Utilities, General Disclosures [Line Items]
Additional megawatt hours in second year (in mw) | GWh			105
Lightning Dock Geothermal | NMPRC
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 110

Regulatory and Rate Matters - Renewable Energy Rider (Details) - Public Service Company of New Mexico - Renewable energy rider - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]
Revenue from renewable energy rider	$ 45.2	$ 42	$ 41.9
Maximum
Public Utilities, General Disclosures [Line Items]
Annual revenue to be collected	$ 43.5
NMPRC-approved return on equity	0.50%		10.50%

Regulatory and Rate Matters - E

Regulatory and Rate Matters - Energy Efficiency and Load Management (Details) $ in Millions	Nov. 08, 2017USD ($)	Nov. 07, 2017	Jul. 26, 2017USD ($)GWh	Apr. 14, 2017USD ($)GWh	Jan. 11, 2017USD ($)	Apr. 15, 2016USD ($)GWhprogram	Oct. 06, 2014USD ($)	Dec. 31, 2017	Dec. 31, 2013
Public Utilities, General Disclosures [Line Items]
Tax-adjusted WACC	9.59%	7.71%
Public Service Company of New Mexico | 2014 Energy Efficiency and Load Management Program | Disincentives/Incentives Added
Public Utilities, General Disclosures [Line Items]
Program costs related to energy efficiency							$ 25.8
Public Service Company of New Mexico | 2017 Energy Efficiency and Load Management Program | Disincentives/Incentives Added
Public Utilities, General Disclosures [Line Items]
Program costs related to energy efficiency					$ 26	$ 28
Number of energy efficiency and load management programs (in programs) | program						10
Application of incentive based on target savings						$ 2.4
Energy efficiency targeted savings (in gwh) | GWh						75
Minimum profit incentive					$ 1.8
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			$ 25.1
Application of incentive based on target savings				$ 1.9
Energy efficiency targeted savings (in gwh) | GWh				53
Projected earned incentive			$ 1.9	$ 2.1
Targeted energy savings | GWh			69	70
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			$ 28.2
Application of incentive based on target savings			$ 1.7	$ 2.1
Public Service Company of New Mexico | Maximum | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Reasonable cost threshold					3.00%				3.00%
Sliding scale profit incentive					9.00%
Public Service Company of New Mexico | Minimum | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Reasonable cost threshold								3.00%
Sliding scale profit incentive					7.10%

Regulatory and Rate Matters - I

Regulatory and Rate Matters - Integrated Resource Plan (Details) - meeting	May 04, 2016	Jul. 01, 2014	Dec. 31, 2017	Jun. 30, 2016
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
Planning period covered, IRP			20 years
Period of action plan			4 years
Number of statewide meetings				17
Public Service Company of New Mexico | NMPRC
Public Utilities, General Disclosures [Line Items]
Period of action plan		4 years
Period of time to show good cause why a docket should remain open	30 days

Regulatory and Rate Matters - A

Regulatory and Rate Matters - Application for Certificate of Convenience and Necessity (Details) - MW	Apr. 26, 2016	Jun. 30, 2015
San Juan Generating Station Units 2 and 3 | Clean Air Act, SNCR | Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Newly-identified replacement gas plant (in mw)	80	187

Regulatory and Rate Matters 114

Regulatory and Rate Matters - Advanced Metering Infrastructure Application and Facebook Data Center Project (Details) $ in Millions	3 Months Ended
	Dec. 31, 2017MW	May 12, 2017USD ($)	Jul. 08, 2016service_rateMW	Feb. 26, 2016USD ($)
Public Utilities, General Disclosures [Line Items]
Number of requested service rates | service_rate			2
Facebook Data Center
Public Utilities, General Disclosures [Line Items]
PPA term	25 years
Public Service Company of New Mexico | Advanced metering infrastructure
Public Utilities, General Disclosures [Line Items]
Application to seek recovery of costs of project | $		$ 95.1		$ 87.2
Application to seek recovery of undepreciated investment | $				$ 33
PNMR Development
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)			30
Solar capacity (in mw)			10
Casa Mesa Wind, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	50
Avangrid Renewables, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	166
Route 66 Solar Energy Center, LLC | Facebook Data Center
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)	50

Regulatory and Rate Matters - H

Regulatory and Rate Matters - Hazard Sharing Agreement (Details) - Public Service Company of New Mexico - Tri-State GWh in Millions, $ in Millions	Jun. 01, 2017	Jun. 01, 2016MW	Dec. 31, 2017USD ($)GWh	Dec. 31, 2016USD ($)GWh
Public Utilities, General Disclosures [Line Items]
Hazard sharing agreement	5 years	1 year
Agreement to sell the other party capacity and energy (in mw) | MW		100
Number of hours sold (in GWh) | GWh			827.1	482.3
Hours sold (in dollars) | $			$ 23.6	$ 12.8
Number of hours purchased (in GWh) | GWh			849	484.6
Hours purchased (in dollars) | $			$ 24.2	$ 12.9

Regulatory and Rate Matters - F

Regulatory and Rate Matters - Formula Transmission Rate Case (Details) - Public Service Company of New Mexico $ in Millions	Mar. 20, 2015USD ($)party
Wholesale Electric Transmission Rate Case
Public Utilities, General Disclosures [Line Items]
Approved additional rate increase | $	$ 1.3
Formula Transmission Rate Case
Public Utilities, General Disclosures [Line Items]
Number of additional parties entered into settlement agreement (in parties) | party	5
Return on equity	10.00%

Regulatory and Rate Matters 117

Regulatory and Rate Matters - Firm-Requirements Wholesale Customers (Details) - Public Service Company of New Mexico - Firm Requirements Wholesale Power Rate Case, Navopache $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)MW	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Serving megawatts of load under a lower tariff (in mw) | MW	10
Revenue for power sold under specific contract | $	$ 4.5	$ 20	$ 27.1

Regulatory and Rate Matters - T

Regulatory and Rate Matters - TNMP Narrative (Details) - Texas-New Mexico Power Company	Jan. 30, 2018USD ($)	Mar. 13, 2017USD ($)	Jul. 31, 2011USD ($)	Dec. 31, 2017USD ($)advanced_meter	Feb. 20, 2018customer	Oct. 02, 2015USD ($)	Jun. 20, 2014USD ($)	Aug. 15, 2013USD ($)customer$ / fee
Public Utilities, General Disclosures [Line Items]
CTC Funding amount interest minimum				15.00%
Adjustment for collection of amortization		$ (1,100,000)
Advanced Meter System Deployment and Surcharge Request
Public Utilities, General Disclosures [Line Items]
Approved deployment costs			$ 113,400,000
Period of time to collect deployment costs through surcharge period			12 years
Number of advanced meters installed | advanced_meter				242,000
Non-standard metering service cost total to be borne by opt-out customers								$ 200,000
Non-standard metering ongoing annual expenses to be borne by opt-out customers								$ 500,000
Non-standard metering ongoing expenses monthly charge							$ 36.78
Presumed number of customers that will elect non-standard meter service (in customers) | customer								1,081
Cost and savings reconciliation filed with regulators, capital cost savings						$ 71,000,000
Cost and savings reconciliation filed with regulators, operations and maintenance expense						$ 18,000,000
Program costs incurred to date				$ 1,500,000
Advanced Meter System Deployment and Surcharge Request | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Current number of customers that have elected non-standard meter service (in customers) | customer					99
Advanced Meter System Deployment and Surcharge Request | Minimum
Public Utilities, General Disclosures [Line Items]
Non-standard metering service cost initial fee range | $ / fee								63.97
Advanced Meter System Deployment and Surcharge Request | Maximum
Public Utilities, General Disclosures [Line Items]
Non-standard metering service cost initial fee range | $ / fee								168.61
Transmission Cost of Service Rates | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested increase in annual transmission service revenue	$ 600,000
Requested rate increase (decrease)	$ 3,200,000

Regulatory and Rate Matters 119

Regulatory and Rate Matters - TNMP Schedules (Details) - Texas-New Mexico Power Company - USD ($) $ in Millions	Sep. 13, 2017	Mar. 14, 2017	Sep. 08, 2016	Mar. 23, 2016	Sep. 10, 2015	Sep. 09, 2015	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2017	Feb. 29, 2016
Energy efficiency costs
Public Utilities, General Disclosures [Line Items]
Aggregate Collection Amount									$ 6	$ 5.7
Performance Bonus									$ 0.7	$ 1.5
Energy efficiency costs | Scenario, forecast
Public Utilities, General Disclosures [Line Items]
Aggregate Collection Amount							$ 6	$ 6
Performance Bonus							$ 1.1	$ 0.8
Transmission Cost of Service Rates
Public Utilities, General Disclosures [Line Items]
Approved Increase in Rate Base	$ 27.5	$ 30.2	$ 9.5	$ 25.8	$ 7	$ 27.1
Annual Increase in Revenue	$ 4.7	$ 4.8	$ 1.8	$ 4.3	$ 1.4	$ 4.4

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2008	Dec. 31, 2017	Dec. 31, 2016	Apr. 01, 2016	Dec. 31, 2015	Apr. 01, 2015	Apr. 01, 2012
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill		$ 278,297	$ 278,297		$ 278,297
Goodwill impairment	$ 174,400
Public Service Company of New Mexico
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill		51,632	51,632	$ 51,600		$ 51,600
Percentage of fair value in excess of carrying amount				25.00%
Percentage increase in expected return on equity				0.50%		0.50%
Reduced percentage of fair value in excess of carrying value				18.00%
Goodwill impairment	51,100
Texas-New Mexico Power Company
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill		$ 226,665	$ 226,665	$ 226,700
Percentage of fair value in excess of carrying amount				32.00%			26.00%
Percentage increase in expected return on equity				0.50%
Reduced percentage of fair value in excess of carrying value				21.00%
Goodwill impairment	$ 34,500

Accumulated Other Comprehens121

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 1,675,952
Amounts reclassified from AOCI (pre-tax)	(10,534)	$ (15,871)	$ (22,579)
Income tax impact of amounts reclassified	4,087	6,193	8,849
Other OCI changes (pre-tax)	32,778	(18,597)	6,665
Income tax impact of other OCI changes	(12,234)	7,256	(2,612)
Total Other Comprehensive Income (Loss)	14,097	(21,019)	(9,677)
Reclassification of stranded income taxes to retained earnings	(17,586)
Ending Balance	1,695,253	1,675,952
Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	1,397,872
Amounts reclassified from AOCI (pre-tax)	(11,115)	(16,635)	(22,579)
Income tax impact of amounts reclassified	4,312	6,491	8,849
Other OCI changes (pre-tax)	31,778	(17,723)	6,593
Income tax impact of other OCI changes	(11,846)	6,915	(2,584)
Total Other Comprehensive Income (Loss)	13,129	(20,952)	(9,721)
Reclassification of stranded income taxes to retained earnings	(17,794)
Ending Balance	1,422,174	1,397,872
AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(92,451)	(71,432)	(61,755)
Total Other Comprehensive Income (Loss)	14,097	(21,019)	(9,677)
Reclassification of stranded income taxes to retained earnings	(17,586)
Ending Balance	(95,940)	(92,451)	(71,432)
AOCI | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(92,428)	(71,476)	(61,755)
Total Other Comprehensive Income (Loss)	13,129	(20,952)	(9,721)
Reclassification of stranded income taxes to retained earnings	(17,794)
Ending Balance	(97,093)	(92,428)	(71,476)
Unrealized Gains on Available-for-Sale Securities | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	4,320	17,346	28,008
Amounts reclassified from AOCI (pre-tax)	(17,567)	(22,139)	(28,531)
Income tax impact of amounts reclassified	6,816	8,639	11,181
Other OCI changes (pre-tax)	28,160	778	10,998
Income tax impact of other OCI changes	(10,927)	(304)	(4,310)
Total Other Comprehensive Income (Loss)	6,482	(13,026)	(10,662)
Reclassification of stranded income taxes to retained earnings	2,367
Ending Balance	13,169	4,320	17,346
Pension Liability Adjustment | Public Service Company of New Mexico
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(96,748)	(88,822)	(89,763)
Amounts reclassified from AOCI (pre-tax)	6,452	5,504	5,952
Income tax impact of amounts reclassified	(2,504)	(2,148)	(2,332)
Other OCI changes (pre-tax)	3,618	(18,501)	(4,405)
Income tax impact of other OCI changes	(919)	7,219	1,726
Total Other Comprehensive Income (Loss)	6,647	(7,926)	941
Reclassification of stranded income taxes to retained earnings	(20,161)
Ending Balance	(110,262)	(96,748)	(88,822)
Fair Value Adjustment for Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(23)	44	0
Amounts reclassified from AOCI (pre-tax)	581	764	0
Income tax impact of amounts reclassified	(225)	(298)	0
Other OCI changes (pre-tax)	1,000	(874)	72
Income tax impact of other OCI changes	(388)	341	(28)
Total Other Comprehensive Income (Loss)	968	(67)	44
Reclassification of stranded income taxes to retained earnings	208
Ending Balance	$ 1,153	$ (23)	$ 44

Quarterly Operating Results 122

Quarterly Operating Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating revenues	$ 332,605	$ 419,900	$ 362,320	$ 330,178	$ 336,225	$ 400,374	$ 315,391	$ 310,961	$ 1,445,003	$ 1,362,951	$ 1,439,082
Operating income	22,936	142,484	85,105	55,960	63,584	108,071	64,822	41,508	306,485	277,985	124,350
Net earnings (loss)	(50,585)	78,327	41,231	26,446	28,423	58,556	30,952	13,965	95,419	131,896	31,078
Net Earnings Attributable to PNMR	$ (54,282)	$ 73,739	$ 37,555	$ 22,862	$ 24,809	$ 54,418	$ 27,076	$ 10,546	$ 79,874	$ 116,849	$ 15,640
Net Earnings Attributable to PNMR per Common Share:
Basic (in dollars per share)	$ (0.68)	$ 0.92	$ 0.47	$ 0.29	$ 0.32	$ 0.68	$ 0.34	$ 0.13	$ 1	$ 1.47	$ 0.20
Diluted (in dollars per share)	$ (0.68)	$ 0.92	$ 0.47	$ 0.29	$ 0.31	$ 0.68	$ 0.34	$ 0.13	$ 1	$ 1.46	$ 0.20
Federal income tax rate change									$ 57,461	$ 0	$ 0
Public Service Company of New Mexico
Segment Reporting Information [Line Items]
Operating revenues	$ 249,321	$ 327,254	$ 276,097	$ 251,558	$ 255,685	$ 311,276	$ 233,346	$ 235,606	1,104,230	1,035,913	1,131,195
Operating income	1,778	113,252	59,164	38,331	42,976	80,057	41,760	23,297	212,525	188,090	33,380
Net earnings (loss)	(28,456)	65,283	30,476	20,110	19,594	44,990	19,793	7,561	87,413	91,938	(324)
Net Earnings Attributable to PNMR	(32,021)	60,827	26,932	16,658	16,112	40,984	16,049	4,274	72,396	77,419	(15,234)
Net Earnings Attributable to PNMR per Common Share:
Federal income tax rate change									29,606	0	0
Texas-New Mexico Power Company
Segment Reporting Information [Line Items]
Operating revenues									340,773	327,038	307,887
Operating revenues	83,284	92,646	86,223	78,620	80,540	89,098	82,045	75,355
Operating income	19,879	29,474	26,286	17,965	21,353	28,359	23,375	18,554	93,604	91,641	90,033
Net Earnings Attributable to PNMR	1,024	$ 14,727	$ 12,204	$ 7,604	$ 9,855	$ 13,853	$ 10,508	$ 7,456	35,559	41,672	41,963
Net Earnings Attributable to PNMR per Common Share:
Federal income tax rate change									7,865	$ 0	$ 0
NMPRC
Net Earnings Attributable to PNMR per Common Share:
Pre-tax regulatory disallowance	$ 27,900								$ 27,900

Schedule I - Condensed Finan123

Schedule I - Condensed Financial Information of Parent Company - Statements of Earnings (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Operating Expenses									$ 1,138,518	$ 1,084,966	$ 1,314,732
Operating income	$ 22,936	$ 142,484	$ 85,105	$ 55,960	$ 63,584	$ 108,071	$ 64,822	$ 41,508	306,485	277,985	124,350
Other Income and Deductions:
Other income									19,515	17,796	26,833
Net other income and deductions									46,899	45,822	36,663
Interest Charges									127,625	128,633	114,860
Earnings before Income Taxes									225,759	195,174	46,153
Income Taxes									130,340	63,278	15,075
Net Earnings Attributable to Company	$ (54,282)	$ 73,739	$ 37,555	$ 22,862	$ 24,809	$ 54,418	$ 27,076	$ 10,546	79,874	116,849	15,640
PNM Resources
Condensed Financial Statements, Captions [Line Items]
Operating Revenues									0	0	0
Operating Expenses									2,902	2,871	1,221
Operating income									(2,902)	(2,871)	(1,221)
Other Income and Deductions:
Equity in earnings of subsidiaries									111,877	122,252	27,352
Other income									1,181	1,711	747
Net other income and deductions									113,058	123,963	28,099
Interest Charges									12,490	8,102	8,275
Earnings before Income Taxes									97,666	112,990	18,603
Income Taxes									17,792	(3,859)	2,963
Net Earnings Attributable to Company									$ 79,874	$ 116,849	$ 15,640

Schedule I - Condensed Finan124

Schedule I - Condensed Financial Information of Parent Company - Statement of Cash flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	$ 524,462	$ 415,454	$ 386,874
Cash Flows From Investing Activities:
Net cash flows from investing activities	(466,163)	(699,375)	(544,528)
Cash Flows From Financing Activities:
Short-term loan		100,000	50,000
Repayment of short-term loan	0	(150,000)	0
Revolving credit facility borrowings (repayments), net	18,300	86,500	95,000
Long-term borrowings	317,000	603,500	463,605
Repayment of long-term debt	(274,070)	(303,793)	(333,066)
Proceeds from stock option exercise	1,739	7,028	5,619
Dividends paid	(77,792)	(70,623)	(64,251)
Other, net	(2,942)	(2,104)	(4,396)
Net cash flows from financing activities	(58,847)	242,392	175,431
Change in Cash and Cash Equivalents	(548)	(41,529)	17,777
Cash and Cash Equivalents at Beginning of Period	4,522	46,051	28,274
Cash and Cash Equivalents at End of Period	3,974	4,522	46,051
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	120,955	115,043	103,382
Income taxes paid (refunded), net	625	(307)	(1,890)
PNM Resources
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	(7,814)	5,702	1,375
Cash Flows From Investing Activities:
Utility plant additions	(180)	341	368
Investments in subsidiaries	(50,000)	(98,343)	(175,000)
Cash dividends from subsidiaries	105,084	35,959	127,688
Net cash flows from investing activities	54,904	(62,043)	(46,944)
Cash Flows From Financing Activities:
Short-term loan		100,000	50,000
Repayment of short-term loan	0	(150,000)	0
Revolving credit facility borrowings (repayments), net	42,600	84,500	41,000
Long-term borrowings		100,000	150,000
Repayment of long-term debt	0	0	(118,766)
Proceeds from stock option exercise	1,739	7,028	5,619
Purchases to satisfy awards of common stock	(13,929)	(15,451)	(17,720)
Dividends paid	(77,264)	(70,095)	(63,723)
Other, net	(269)	(28)	(782)
Net cash flows from financing activities	(47,123)	55,954	45,628
Change in Cash and Cash Equivalents	(33)	(387)	59
Cash and Cash Equivalents at Beginning of Period	54	441	382
Cash and Cash Equivalents at End of Period	21	54	441
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	10,899	5,906	7,559
Income taxes paid (refunded), net	$ 0	$ 0	$ (730)

Schedule I - Condensed Finan125

Schedule I - Condensed Financial Information of Parent Company - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 3,974	$ 4,522	$ 46,051	$ 28,274
Income taxes receivable	6,879	6,066
Other, net	47,358	73,444
Total current assets	294,420	378,039
Property, plant and equipment, net of accumulated depreciation of $13,229 and $12,291	4,980,227	4,904,715
Other long-term assets	503	547
Total assets	6,646,103	6,471,080	6,009,328
Liabilities and Stockholders’ Equity
Short-term debt	305,400	287,100
Current maturities of long-term debt	256,895	273,348
Accrued interest and taxes	62,357	61,871
Other current liabilities	53,850	59,314
Total current liabilities	835,644	805,108
Long-term debt	2,180,750	2,119,364
Total liabilities	4,873,126	4,714,679
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 79,653,624 shares)	1,157,665	1,163,661
Accumulated other comprehensive income (loss), net of tax	(95,940)	(92,451)
Retained earnings	633,528	604,742
Total PNMR common stockholders’ equity	1,695,253	1,675,952
Total liabilities and stockholders' equity	6,646,103	6,471,080
PNM Resources
Assets
Cash and cash equivalents	21	54	$ 441	$ 382
Intercompany receivables	96,227	92,234
Income taxes receivable	1,818	0
Other, net	1,937	233
Total current assets	100,003	92,521
Property, plant and equipment, net of accumulated depreciation of $13,229 and $12,291	26,546	26,366
Investment in subsidiaries	2,056,198	1,986,276
Other long-term assets	66,090	79,314
Total long-term assets	2,148,834	2,091,956
Total assets	2,248,837	2,184,477
Liabilities and Stockholders’ Equity
Short-term debt	265,600	226,100
Short-term debt-affiliate	11,919	8,819
Current maturities of long-term debt	249,979	0
Accrued interest and taxes	1,661	1,333
Other current liabilities	21,274	19,374
Total current liabilities	550,433	255,626
Long-term debt	0	249,895
Other long-term liabilities	3,151	3,004
Total liabilities	553,584	508,525
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 79,653,624 shares)	1,157,665	1,163,661
Accumulated other comprehensive income (loss), net of tax	(95,940)	(92,451)
Retained earnings	633,528	604,742
Total PNMR common stockholders’ equity	1,695,253	1,675,952
Total liabilities and stockholders' equity	$ 2,248,837	$ 2,184,477

Schedule I - Condensed Finan126

Schedule I - Condensed Financial Information of Parent Company - Balance Sheets (Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	79,653,624	79,653,624
Common stock, shares outstanding	79,653,624	79,653,624
PNM Resources
Condensed Financial Statements, Captions [Line Items]
Accumulated depreciation	$ 13,229	$ 12,291
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	79,653,624	79,653,624
Common stock, shares outstanding	79,653,624	79,653,624

Schedule II - Valuation and 127

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 1,209	$ 1,397	$ 1,466
Charged to costs and expenses	2,619	2,885	3,358
Charged to other accounts	0	0	0
Write-offs	2,747	3,073	3,427
Balance at end of year	1,081	1,209	1,397
Public Service Company of New Mexico
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	1,209	1,397	1,466
Charged to costs and expenses	2,615	2,871	3,344
Charged to other accounts	0	0	0
Write-offs	2,743	3,059	3,413
Balance at end of year	1,081	1,209	1,397
Texas-New Mexico Power Company
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	0	0	0
Charged to costs and expenses	4	14	14
Charged to other accounts	0	0	0
Write-offs	4	14	14
Balance at end of year	$ 0	$ 0	$ 0