Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows From Operating Activities:
Net Earnings (Loss)	$ 120,125	$ 190,934	$ (31,124)
Net Earnings	105,547	176,359	(45,215)
Adjustments to reconcile net earnings (loss) to net cash flows from operating activities:
Depreciation and amortization	206,499	195,366	186,067
PVNGS firm-sales contracts revenue	0	(2,558)	(58,289)
Bad debt expense	3,367	24,116	27,566
Deferred income tax expense	56,243	124,424	35,674
(Gain) on sale of First Choice	(1,012)	(174,925)	0
Equity in net (earnings) loss of Optim Energy	0	0	15,223
Impairment of equity investment in Optim Energy	0	0	188,176
Net unrealized (gains) losses on derivatives	(1,598)	(8,713)	29,303
Realized (gains) on investments held by NDT	(13,015)	(8,985)	(4,868)
Loss on reacquired debt	0	9,209	0
Abandonment of leased premises	7,411	0	0
Stock based compensation expense	3,585	6,556	2,894
Regulatory disallowances	0	21,402	0
Other, net	(4,115)	(939)	(1,719)
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(2,547)	(70,734)	(11,398)
Materials, supplies, and fuel stock	(5,412)	(2,200)	(1,848)
Other current assets	(2,598)	(21,979)	(42,841)
Other assets	(30,778)	(15,835)	8,559
Accounts payable	14,020	20,969	(15,462)
Accrued interest and taxes	255	7,304	34,163
Other current liabilities	(19,905)	3,460	(35,974)
Proceeds from governmental grants	21,567	2,103	0
Other liabilities	(70,743)	(6,735)	(36,750)
Net cash flows from operating activities	281,349	292,240	287,352
Cash Flows From Investing Activities:
Utility plant additions	(308,909)	(326,931)	(281,488)
Proceeds from sales of investments held by NDT	167,330	145,286	79,853
Purchases of investments held by NDT	(173,158)	(149,185)	(85,847)
Proceeds from sale of First Choice	(1,012)	(174,925)	0
Return of principal on PVNGS lessor notes	23,455	32,274	29,851
Investments in Optim Energy	0	0	(20,279)
Other, net	1,353	(17)	2,004
Net cash flows from investing activities	(285,895)	19,778	(275,906)
Cash Flows From Financing Activities:
Short-term loan	100,000	0	0
Revolving credit facilities borrowings (repayments), net	(24,000)	(139,300)	24,000
Long-term borrowings	20,000	210,000	403,845
Repayment of long-term debt	(22,387)	(110,752)	(405,970)
Purchase of preferred stock	0	(73,475)	0
Purchase of common stock	0	(125,683)	0
Proceeds from stock option exercise	11,684	5,622	1,247
Purchases to satisfy awards of common stock	(25,168)	(10,104)	(2,986)
Excess tax (shortfall) from stock-based payment arrangements	0	0	(580)
Payments received on PVNGS firm-sales contracts	0	2,558	30,476
Dividends paid	(45,137)	(45,656)	(46,254)
Valencia’s transactions with its owner	(15,630)	(16,801)	(17,745)
Proceeds from transmission interconnection arrangements	983	1,246	8,515
Repayment of transmission interconnection arrangements	(1,753)	(4,637)	0
Debt issuance costs and other	(152)	(5,349)	(5,231)
Net cash flows from financing activities	(1,560)	(312,331)	(10,683)
Change in Cash and Cash Equivalents	(6,106)	(313)	763
Cash and Cash Equivalents at Beginning of Year	15,091	15,404	14,641
Cash and Cash Equivalents at End of Year	8,985	15,091	15,404
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	113,265	116,391	119,676
Income taxes paid (refunded), net	5,302	(5,527)	(99,318)
Public Service Company of New Mexico [Member]
Cash Flows From Operating Activities:
Net Earnings (Loss)	105,601	68,538	70,861
Net Earnings	91,551	54,491	57,298
Adjustments to reconcile net earnings (loss) to net cash flows from operating activities:
Depreciation and amortization	129,514	123,216	117,619
PVNGS firm-sales contracts revenue	0	(2,558)	(58,289)
Deferred income tax expense	65,479	90,567	113,680
Net unrealized (gains) losses on derivatives	(1,598)	(3,822)	5,693
Realized (gains) on investments held by NDT	(13,015)	(8,985)	(4,868)
Regulatory disallowances	0	17,479	0
Other, net	(120)	4,216	882
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(4,756)	(23,487)	8,145
Materials, supplies, and fuel stock	(5,268)	(2,067)	(1,665)
Other current assets	(3,014)	(14,916)	(24,434)
Other assets	(27,338)	(795)	21,569
Accounts payable	11,028	12,524	(5,542)
Accrued interest and taxes	47,666	(45,579)	(15,992)
Other current liabilities	(2,539)	15,216	(27,914)
Proceeds from governmental grants	21,567	2,103	0
Other liabilities	(54,787)	(18,612)	(50,617)
Net cash flows from operating activities	268,420	213,038	149,128
Cash Flows From Investing Activities:
Utility plant additions	(196,800)	(251,345)	(226,766)
Proceeds from sales of investments held by NDT	167,330	145,286	79,853
Purchases of investments held by NDT	(173,158)	(149,185)	(85,847)
Return of principal on PVNGS lessor notes	23,455	32,274	29,851
Other, net	(1,184)	1,782	2,319
Net cash flows from investing activities	(180,357)	(221,188)	(200,590)
Cash Flows From Financing Activities:
Revolving credit facilities borrowings (repayments), net	(44,900)	(124,000)	72,000
Long-term borrowings	20,000	160,000	403,845
Repayment of long-term debt	(20,000)	0	(403,845)
Payments received on PVNGS firm-sales contracts	0	2,558	30,476
Equity contribution from parent	0	43,000	0
Dividends paid	(34,961)	(47,862)	(28,524)
Valencia’s transactions with its owner	(15,630)	(16,801)	(17,745)
Other, net	(151)	(3,383)	(4,297)
Proceeds from transmission interconnection arrangements	983	1,246	8,515
Repayment of transmission interconnection arrangements	(1,753)	(4,637)	0
Net cash flows from financing activities	(96,412)	10,121	60,425
Change in Cash and Cash Equivalents	(8,349)	1,971	8,963
Cash and Cash Equivalents at Beginning of Year	12,307	10,336	1,373
Cash and Cash Equivalents at End of Year	3,958	12,307	10,336
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	73,036	69,995	72,392
Income taxes paid (refunded), net	(63,113)	(1,541)	(59,298)
Texas-New Mexico Power Company [Member]
Cash Flows From Operating Activities:
Net Earnings	26,747	22,257	15,982
Adjustments to reconcile net earnings (loss) to net cash flows from operating activities:
Depreciation and amortization	54,396	48,572	45,703
Deferred income tax expense	4,378	15,478	4,962
Regulatory disallowances	0	3,923	0
Other, net	(889)	(532)	23
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	2,208	(9,130)	536
Materials, supplies, and fuel stock	(143)	77	(195)
Other current assets	(3,515)	4,777	(3,011)
Other assets	(3,145)	(3,247)	(2,937)
Accounts payable	(666)	2,225	(706)
Accrued interest and taxes	9,825	(2,520)	17,442
Other current liabilities	(2,106)	513	(24)
Other liabilities	4,311	(611)	(581)
Net cash flows from operating activities	91,401	81,782	77,194
Cash Flows From Investing Activities:
Utility plant additions	(92,973)	(67,407)	(41,018)
Net cash flows from investing activities	(92,973)	(67,407)	(41,018)
Cash Flows From Financing Activities:
Short-term borrowings (repayments) – affiliate, net	27,600	(500)	(22,300)
Long-term borrowings	0	50,000	0
Repayment of long-term debt	0	(50,000)	0
Dividends paid	(26,028)	(13,714)	(13,079)
Debt issuance costs and other	0	(161)	(934)
Net cash flows from financing activities	1,572	(14,375)	(36,313)
Change in Cash and Cash Equivalents	0	0	(137)
Cash and Cash Equivalents at Beginning of Year	1	1	138
Cash and Cash Equivalents at End of Year	1	1	1
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	25,360	27,236	27,696
Income taxes paid (refunded), net	1,848	1,466	(11,705)
First Choice [Member]
Adjustments to reconcile net earnings (loss) to net cash flows from operating activities:
(Gain) on sale of First Choice	4,034	329,281	0
Cash Flows From Investing Activities:
Proceeds from sale of First Choice	4,034	329,281	0
Transaction costs for sale of First Choice	$ 0	$ (10,930)	$ 0