Quarterly Operating Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue											$ 1,700,619
Operating revenues	322,929	399,730	347,599	317,665	322,758	390,411	323,860	305,374	1,387,923	1,342,403	1,700,619
Operating income	40,532	117,739	77,867	50,704	36,736	118,150	65,106	53,729	286,842	273,721	257,299
Net earnings	11,397	58,814	31,383	13,962	12,573	61,976	25,099	20,477	115,556	120,125	190,934
Earnings Attributable to PNMR	7,648	54,555	27,678	10,626	9,091	57,864	21,512	17,080	100,507	105,547	176,359
Net Earnings Attributable to PNMR per Common Share:
Basic (dollars per share)	$ 0.10	$ 0.68	$ 0.35	$ 0.13	$ 0.11	$ 0.73	$ 0.27	$ 0.21	$ 1.26	$ 1.32	$ 1.98
Diluted (dollars per share)	$ 0.10	$ 0.68	$ 0.34	$ 0.13	$ 0.11	$ 0.72	$ 0.27	$ 0.21	$ 1.25	$ 1.31	$ 1.96
Public Service Company of New Mexico [Member]
Segment Reporting Information [Line Items]
Operating revenues	252,702	326,026	279,690	257,894	260,023	321,731	260,094	250,416	1,116,312	1,092,264	1,057,289
Operating income	18,427	95,217	58,302	37,239	20,135	96,973	46,669	42,105	209,185	205,882	161,443
Net earnings	6,256	51,950	29,697	14,773	9,293	54,891	20,340	21,077	102,676	105,601	68,538
Earnings Attributable to PNMR	2,639	47,823	26,124	11,569	5,943	50,911	16,885	17,812	88,155	91,551	54,491
Texas-New Mexico Power Company [Member]
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue	70,227	73,704	67,909	59,771	62,736	68,680	63,766	54,958	271,611	250,140	204,045
Operating revenues									271,611	250,140	237,858
Operating income	17,210	22,254	19,667	13,054	15,862	20,970	18,897	11,791	72,185	67,520	63,842
Earnings Attributable to PNMR	$ 6,919	$ 10,106	$ 8,339	$ 3,726	$ 6,634	$ 9,084	$ 8,018	$ 3,011	$ 29,090	$ 26,747	$ 22,257