Fair Value of Derivative and Other Financial Instruments, Avaialbe for Sale Securities (Details) (PNMR and PNM [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	$ 226,855	$ 192,511
Available-for-sale securities, Unrealized gains	42,602	27,156
Proceeds from sales	271,140	167,330	145,286
Gross realized gains	14,308	15,907	17,493
Gross realized (losses)	(4,298)	(8,170)	(6,223)
Domestic value [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	39,460	30,044
Available-for-sale securities, Unrealized gains	14,523	5,223
Domestic growth [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	76,292	51,650
Available-for-sale securities, Unrealized gains	25,656	15,212
International and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	16,633	14,868
Available-for-sale securities, Unrealized gains	1,040	247
U.S. Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	21,941	32,592
Available-for-sale securities, Unrealized gains	158	1,305
Municipals [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	58,568	43,861
Available-for-sale securities, Unrealized gains	1,018	4,069
Corporate and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	10,605	14,868
Available-for-sale securities, Unrealized gains	207	1,100
Cash and equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	3,356	4,628
Available-for-sale securities, Unrealized gains	0	0
Measured on a recurring basis [Member] \| Nuclear Decommissioning Trust [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	222,500	189,000
Measured on a recurring basis [Member] \| Mine Reclamation Trust [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	$ 4,400	$ 3,500

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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