Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 122,395	$ 28,274
Accounts receivable, net of allowance for uncollectible accounts	89,844	87,038
Unbilled revenues	48,042	63,719
Other receivables	37,898	39,857
Materials, supplies, and fuel stock	66,284	63,628
Regulatory assets	33,550	47,855
Commodity derivative instruments	9,342	11,232
Income taxes receivable	4,719	6,360
Current portion of accumulated deferred income taxes	26,383	26,383
Other current assets	65,264	58,471
Total current assets	503,721	432,817
Other Property and Investments:
Investment in PVNGS lessor notes	0	9,538
Available-for-sale securities	257,464	250,145
Other investments	509	1,762
Non-utility property	3,406	3,406
Total other property and investments	261,379	264,851
Utility Plant:
Plant in service and plant held for future use	5,982,387	5,941,581
Less accumulated depreciation and amortization	1,971,832	1,939,760
Net plant in service and plant held for future use	4,010,555	4,001,821
Construction work in progress	230,014	190,389
Nuclear fuel, net of accumulated amortization	79,208	77,796
Net utility plant	4,319,777	4,270,006
Deferred Charges and Other Assets:
Regulatory assets	481,057	491,007
Goodwill	278,297	278,297
Other deferred charges	95,108	92,347
Total deferred charges and other assets	854,462	861,651
Total assets	5,939,339	5,829,325
Current Liabilities:
Short-term debt	100,000	105,600
Current installments of long-term debt	333,066	333,066
Accounts payable	102,204	110,029
Customer deposits	12,791	12,555
Accrued interest and taxes	77,234	53,863
Regulatory liabilities	178	1,703
Commodity derivative instruments	1,235	1,209
Dividends declared	16,063	16,063
Other current liabilities	50,263	70,194
Total current liabilities	693,034	704,282
Long-term Debt	1,791,941	1,642,024
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	902,901	891,111
Regulatory liabilities	470,180	466,143
Asset retirement obligations	106,267	104,170
Accrued pension liability and postretirement benefit cost	75,236	110,738
Commodity derivative instruments	277	477
Other deferred credits	100,816	103,759
Total deferred credits and other liabilities	1,655,677	1,676,398
Total liabilities	4,140,652	4,022,704
Commitments and Contingencies (See Note 11)
Cumulative preferred stock of subsidiary without mandatory redemption requirements	11,529	11,529
Company common stockholders’ equity:
Common stock outstanding	1,165,757	1,173,845
Accumulated other comprehensive income (loss), net of income taxes	(59,230)	(61,755)
Retained earnings	607,865	609,456
Total Company common stockholders' equity	1,714,392	1,721,546
Non-controlling interest in Valencia	72,766	73,546
Total equity	1,787,158	1,795,092
Total liabilities and stockholders' equity	5,939,339	5,829,325
Public Service Company of New Mexico [Member]
Current Assets:
Cash and cash equivalents	4,252	25,480
Accounts receivable, net of allowance for uncollectible accounts	67,420	67,622
Unbilled revenues	41,255	54,140
Other receivables	33,636	37,622
Affiliate receivables	8,819	8,853
Materials, supplies, and fuel stock	63,416	60,859
Regulatory assets	29,932	43,980
Commodity derivative instruments	9,342	11,232
Income taxes receivable	4,788	6,105
Current portion of accumulated deferred income taxes	12,418	12,418
Other current assets	60,399	53,095
Total current assets	335,677	381,406
Other Property and Investments:
Investment in PVNGS lessor notes	0	9,538
Available-for-sale securities	257,464	250,145
Other investments	267	397
Non-utility property	96	96
Total other property and investments	257,827	260,176
Utility Plant:
Plant in service and plant held for future use	4,614,218	4,581,066
Less accumulated depreciation and amortization	1,506,576	1,486,406
Net plant in service and plant held for future use	3,107,642	3,094,660
Construction work in progress	199,367	169,673
Nuclear fuel, net of accumulated amortization	79,208	77,796
Net utility plant	3,386,217	3,342,129
Deferred Charges and Other Assets:
Regulatory assets	349,295	357,045
Goodwill	51,632	51,632
Other deferred charges	83,839	81,264
Total deferred charges and other assets	484,766	489,941
Total assets	4,464,487	4,473,652
Current Liabilities:
Current installments of long-term debt	214,300	214,300
Accounts payable	83,257	86,055
Affiliate payables	15,812	18,232
Customer deposits	12,791	12,555
Accrued interest and taxes	51,015	29,298
Regulatory liabilities	178	1,703
Commodity derivative instruments	1,235	1,209
Dividends declared	132	132
Other current liabilities	36,923	52,053
Total current liabilities	415,643	415,537
Long-term Debt	1,276,366	1,276,357
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	725,130	715,814
Regulatory liabilities	429,698	425,481
Asset retirement obligations	105,258	103,182
Accrued pension liability and postretirement benefit cost	67,706	102,850
Commodity derivative instruments	277	477
Other deferred credits	84,743	86,023
Total deferred credits and other liabilities	1,412,812	1,433,827
Total liabilities	3,104,821	3,125,721
Commitments and Contingencies (See Note 11)
Cumulative preferred stock of subsidiary without mandatory redemption requirements	11,529	11,529
Company common stockholders’ equity:
Common stock outstanding	1,061,776	1,061,776
Accumulated other comprehensive income (loss), net of income taxes	(59,230)	(61,755)
Retained earnings	272,825	262,835
Total Company common stockholders' equity	1,275,371	1,262,856
Non-controlling interest in Valencia	72,766	73,546
Total equity	1,348,137	1,336,402
Total liabilities and stockholders' equity	4,464,487	4,473,652
Texas-New Mexico Power Company [Member]
Current Assets:
Cash and cash equivalents	352	1
Accounts receivable, net of allowance for uncollectible accounts	22,424	19,416
Unbilled revenues	6,787	9,579
Other receivables	1,220	2,063
Materials, supplies, and fuel stock	2,868	2,769
Regulatory assets	3,618	3,875
Current portion of accumulated deferred income taxes	6,398	6,398
Other current assets	1,057	938
Total current assets	44,724	45,039
Other Property and Investments:
Other investments	242	242
Non-utility property	2,240	2,240
Total other property and investments	2,482	2,482
Utility Plant:
Plant in service and plant held for future use	1,188,967	1,182,112
Less accumulated depreciation and amortization	383,711	375,407
Net plant in service and plant held for future use	805,256	806,705
Construction work in progress	23,427	16,538
Net utility plant	828,683	823,243
Deferred Charges and Other Assets:
Regulatory assets	131,762	133,962
Goodwill	226,665	226,665
Other deferred charges	9,094	8,850
Total deferred charges and other assets	367,521	369,477
Total assets	1,243,410	1,240,241
Current Liabilities:
Short-term debt	0	5,000
Short-term debt – affiliate	28,500	22,700
Accounts payable	9,101	14,203
Affiliate payables	2,120	2,469
Accrued interest and taxes	26,568	28,574
Other current liabilities	2,986	2,271
Total current liabilities	69,275	75,217
Long-term Debt	365,575	365,667
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	222,171	217,945
Regulatory liabilities	40,482	40,662
Asset retirement obligations	866	848
Accrued pension liability and postretirement benefit cost	7,530	7,888
Other deferred credits	5,152	7,349
Total deferred credits and other liabilities	276,201	274,692
Total liabilities	711,051	715,576
Commitments and Contingencies (See Note 11)
Company common stockholders’ equity:
Common stock outstanding	64	64
Paid-in-capital	404,166	404,166
Retained earnings	128,129	120,435
Total Company common stockholders' equity	532,359	524,665
Total liabilities and stockholders' equity	$ 1,243,410	$ 1,240,241