Income Taxes Schedule of Components of Income Tax Expense (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Current federal income tax	$ 0	$ (1,296)	$ 1,319
Current state income tax	(917)	(37)	(4,208)
Deferred federal income tax	50,044	51,559	119,280
Deferred state income tax	12,578	6,921	7,462
Amortization of accumulated investment tax credits	(2,192)	(2,237)	(2,318)
Total income taxes (benefit)	59,513	54,910	121,535
Public Service Company of New Mexico [Member]
Income Taxes [Line Items]
Current federal income tax	(479)	(12,951)	(46,364)
Current state income tax	(760)	(1,815)	(6,776)
Deferred federal income tax	42,806	56,194	78,673
Deferred state income tax	9,429	11,522	14,212
Amortization of accumulated investment tax credits	(2,192)	(2,237)	(2,318)
Total income taxes (benefit)	48,804	50,713	37,427
Texas-New Mexico Power Company [Member]
Income Taxes [Line Items]
Current federal income tax	(4,957)	9,152	(3,578)
Current state income tax	1,916	1,822	1,981
Deferred federal income tax	20,688	4,406	15,507
Deferred state income tax	(26)	(28)	(29)
Total income taxes (benefit)	$ 17,621	$ 15,352	$ 13,881