Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 104,170	$ 96,135	$ 85,893
Liabilities incurred	0	0	0
Liabilities settled	(730)	0	(79)
Accretion expense	8,625	7,984	7,245
Revisions to estimated cash flows	(170)	51	3,076
Ending balance	111,895	104,170	96,135
Public Service Company of New Mexico [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	103,182	95,225	85,042
Liabilities incurred	0	0	0
Liabilities settled	(506)	0	(67)
Accretion expense	8,543	7,906	7,174
Revisions to estimated cash flows	(170)	51	3,076
Ending balance	111,049	103,182	95,225
Public Service Company of New Mexico [Member] | Palo Verde Nuclear Generating Station [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Increase (decrease) to asset retirement obligation	1,000	500
Public Service Company of New Mexico [Member] | San Juan Generating Station [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Increase (decrease) to asset retirement obligation	(1,200)	2,500
Texas-New Mexico Power Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	848	782	732
Liabilities incurred	0	0	0
Liabilities settled	(224)	0	(12)
Accretion expense	71	66	62
Revisions to estimated cash flows	0	0	0
Ending balance	$ 695	$ 848	$ 782