Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 5,109	$ 8,985
Accounts receivable, net of allowance for uncollectible accounts of $1,339 and $1,751 for PNMR and PNM	89,634	87,093
Unbilled revenues	50,410	57,266
Other receivables	43,517	53,332
Materials, supplies, and fuel stock	58,699	59,643
Regulatory assets	41,478	39,120
Commodity derivative instruments	2,114	3,785
Income taxes receivable	100,699	101,477
Other current assets	40,414	31,490
Total current assets	432,074	442,191
Other Property and Investments:
Investment in PVNGS lessor notes	43,752	54,325
Investments held by NDT	197,691	188,971
Other investments	8,363	9,139
Non-utility property, net of accumulated depreciation of $135 and $131 for PNMR	4,483	4,487
Total other property and investments	254,289	256,922
Utility Plant:
Plant in service and plant held for future use	5,332,025	5,313,796
Less accumulated depreciation and amortization	1,789,039	1,774,223
Net plant in service and plant held for future use	3,542,986	3,539,573
Construction work in progress	140,147	125,287
Nuclear fuel, net of accumulated amortization of $49,605 and $42,644 for PNMR and PNM	81,376	81,627
Net utility plant	3,764,509	3,746,487
Deferred Charges and Other Assets:
Regulatory assets	543,074	555,577
Goodwill	278,297	278,297
Commodity derivative instruments	0	352
Other deferred charges	98,517	92,757
Total deferred charges and other assets	919,888	926,983
Assets	5,370,760	5,372,583
Current Liabilities:
Short-term debt	243,300	158,700
Current installments of long-term debt	2,530	2,530
Accounts payable	77,435	99,177
Customer deposits	16,040	18,176
Accrued interest and taxes	77,000	52,003
Regulatory liabilities	0	15,173
Commodity derivative instruments	4,132	1,000
Dividends declared	13,271	11,679
Current portion of accumulated deferred income taxes	258	258
Other current liabilities	60,111	75,407
Total current liabilities	494,077	434,103
Long-term Debt	1,669,926	1,669,760
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	713,483	701,545
Accumulated deferred investment tax credits	13,694	14,242
Regulatory liabilities	426,208	423,460
Asset retirement obligations	87,651	85,893
Accrued pension liability and postretirement benefit cost	157,711	224,565
Commodity derivative instruments	1,785	1,933
Other deferred credits	111,206	116,523
Total deferred credits and other liabilities	1,511,738	1,568,161
Total liabilities	3,675,741	3,672,024
Commitments and Contingencies [(See Note 9)]
Cumulative preferred stock of subsidiary without mandatory redemption requirements ($100 stated value, 10,000,000 shares authorized: issued and outstanding 115,293 shares)	11,529	11,529
Company common stockholders’ equity:
Common Stock, Value, Issued	1,176,912	1,182,819
Accumulated other comprehensive income (loss), net of income taxes	(76,691)	(81,630)
Retained earnings	504,482	506,998
Total Company common stockholders' equity	1,604,703	1,608,187
Non-controlling interest in Valencia	78,787	80,843
Total equity	1,683,490	1,689,030
Total liabilities and stockholders' equity	5,370,760	5,372,583
Public Service Company of New Mexico [Member]
Current Assets:
Cash and cash equivalents	21	3,958
Accounts receivable, net of allowance for uncollectible accounts of $1,339 and $1,751 for PNMR and PNM	69,684	69,876
Unbilled revenues	43,557	49,085
Other receivables	42,905	50,975
Affiliate receivables	9,790	9,050
Materials, supplies, and fuel stock	55,911	56,790
Regulatory assets	37,273	36,490
Commodity derivative instruments	2,114	3,785
Income taxes receivable	80,320	80,223
Other current assets	37,052	27,457
Total current assets	378,627	387,689
Other Property and Investments:
Investment in PVNGS lessor notes	43,752	54,325
Investments held by NDT	197,691	188,971
Other investments	4,196	4,034
Non-utility property, net of accumulated depreciation of $135 and $131 for PNMR	976	976
Total other property and investments	246,615	248,306
Utility Plant:
Plant in service and plant held for future use	4,139,281	4,133,532
Less accumulated depreciation and amortization	1,361,199	1,355,240
Net plant in service and plant held for future use	2,778,082	2,778,292
Construction work in progress	108,556	102,329
Nuclear fuel, net of accumulated amortization of $49,605 and $42,644 for PNMR and PNM	81,376	81,627
Net utility plant	2,968,014	2,962,248
Deferred Charges and Other Assets:
Regulatory assets	423,208	431,956
Goodwill	51,632	51,632
Commodity derivative instruments	0	352
Other deferred charges	87,161	81,724
Total deferred charges and other assets	562,001	565,664
Assets	4,155,257	4,163,907
Current Liabilities:
Short-term debt	88,900	21,100
Accounts payable	56,186	73,914
Customer deposits	16,040	18,176
Affiliate payables	15,432	25,340
Accrued interest and taxes	51,424	30,320
Regulatory liabilities	0	15,172
Commodity derivative instruments	4,132	1,000
Dividends declared	132	132
Current portion of accumulated deferred income taxes	3,447	3,447
Other current liabilities	40,667	54,150
Total current liabilities	276,360	242,751
Long-term Debt	1,215,589	1,215,579
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	584,511	573,881
Accumulated deferred investment tax credits	13,694	14,242
Regulatory liabilities	380,887	379,841
Asset retirement obligations	86,782	85,042
Accrued pension liability and postretirement benefit cost	143,307	208,618
Commodity derivative instruments	1,785	1,933
Other deferred credits	91,626	95,585
Total deferred credits and other liabilities	1,302,592	1,359,142
Total liabilities	2,794,541	2,817,472
Commitments and Contingencies [(See Note 9)]
Cumulative Preferred Stock of Subsidiary without mandatory redemption requirements	11,529	11,529
Company common stockholders’ equity:
Common Stock, Value, Issued	1,061,776	1,061,776
Accumulated other comprehensive income (loss), net of income taxes	(76,514)	(81,414)
Retained earnings	285,138	273,701
Total Company common stockholders' equity	1,270,400	1,254,063
Non-controlling interest in Valencia	78,787	80,843
Total equity	1,349,187	1,334,906
Total liabilities and stockholders' equity	4,155,257	4,163,907
Texas-New Mexico Power Company [Member]
Current Assets:
Cash and cash equivalents	1	1
Accounts receivable, net of allowance for uncollectible accounts of $1,339 and $1,751 for PNMR and PNM	19,950	17,217
Unbilled revenues	6,853	8,181
Other receivables	762	2,359
Materials, supplies, and fuel stock	2,788	2,853
Regulatory assets	4,205	2,630
Current portion of accumulated deferred income taxes	1,131	1,131
Other current assets	841	1,107
Total current assets	36,531	35,479
Other Property and Investments:
Other investments	281	281
Non-utility property, net of accumulated depreciation of $135 and $131 for PNMR	2,240	2,240
Total other property and investments	2,521	2,521
Utility Plant:
Plant in service and plant held for future use	1,022,770	1,009,108
Less accumulated depreciation and amortization	346,365	339,315
Net plant in service and plant held for future use	676,405	669,793
Construction work in progress	28,207	19,801
Net utility plant	704,612	689,594
Deferred Charges and Other Assets:
Regulatory assets	119,866	123,621
Goodwill	226,665	226,665
Other deferred charges	8,747	8,349
Total deferred charges and other assets	355,278	358,635
Assets	1,098,942	1,086,229
Current Liabilities:
Short-term debt – affiliate	5,600	28,300
Short-term debt	25,000	0
Accounts payable	12,045	8,848
Affiliate payables	2,597	4,381
Accrued interest and taxes	31,177	30,491
Other current liabilities	10,251	8,854
Total current liabilities	86,670	80,874
Long-term Debt	311,745	311,589
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	166,302	163,710
Regulatory liabilities	45,321	43,619
Asset retirement obligations	747	732
Accrued pension liability and postretirement benefit cost	14,404	15,947
Other deferred credits	6,174	5,944
Total deferred credits and other liabilities	232,948	229,952
Total liabilities	631,363	622,415
Commitments and Contingencies [(See Note 9)]
Company common stockholders’ equity:
Common Stock, Value, Issued	64	64
Paid-in-capital	390,366	390,366
Accumulated other comprehensive income (loss), net of income taxes	(177)	(216)
Retained earnings	77,326	73,600
Total Company common stockholders' equity	467,579	463,814
Total liabilities and stockholders' equity	$ 1,098,942	$ 1,086,229