Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (81,630)	$ (66,856)	$ (68,666)
Amounts reclassified from AOCI (pre-tax)	(5,385)	(32,476)	(27,511)
Income tax impact of amounts reclassified	2,137	12,865	11,027
Other OCI changes (pre-tax)	44,276	8,036	30,335
Income tax impact of other OCI changes	(17,538)	(3,199)	(12,041)
Total Other Comprehensive Income (Loss)	23,490	(14,774)	1,810
Ending Balance	(58,140)	(81,630)	(66,856)
Percentage of Pension Liability Adjustment Capitalized into Construction Work In Process	18.70%
Percentage of Pension Liability Adjustment Capitalized into Other Accounts	3.00%
Public Service Company of New Mexico [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(81,414)	(66,798)	(66,786)
Amounts reclassified from AOCI (pre-tax)	(5,592)	(32,658)	(30,946)
Income tax impact of amounts reclassified	2,210	12,930	12,251
Other OCI changes (pre-tax)	44,555	8,464	30,926
Income tax impact of other OCI changes	(17,636)	(3,352)	(12,243)
Total Other Comprehensive Income (Loss)	23,537	(14,616)	(12)
Ending Balance	(57,877)	(81,414)	(66,798)
Texas-New Mexico Power Company [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(216)	(58)	(1,485)
Amounts reclassified from AOCI (pre-tax)	207	182	3,010
Income tax impact of amounts reclassified	(73)	(65)	(1,073)
Other OCI changes (pre-tax)	(279)	(428)	(793)
Income tax impact of other OCI changes	98	153	283
Total Other Comprehensive Income (Loss)	(47)	(158)	1,427
Ending Balance	(263)	(216)	(58)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	16,406	15,634	16,211
Amounts reclassified from AOCI (pre-tax)	(11,956)	(37,269)	(35,251)
Income tax impact of amounts reclassified	4,734	14,755	13,956
Other OCI changes (pre-tax)	27,419	38,548	34,295
Income tax impact of other OCI changes	(10,855)	(15,262)	(13,577)
Total Other Comprehensive Income (Loss)	9,342	772	(577)
Ending Balance	25,748	16,406	15,634
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Public Service Company of New Mexico [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	16,406	15,634	16,211
Amounts reclassified from AOCI (pre-tax)	(11,956)	(37,269)	(35,251)
Income tax impact of amounts reclassified	4,734	14,755	13,956
Other OCI changes (pre-tax)	27,419	38,548	34,295
Income tax impact of other OCI changes	(10,855)	(15,262)	(13,577)
Total Other Comprehensive Income (Loss)	9,342	772	(577)
Ending Balance	25,748	16,406	15,634
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Texas-New Mexico Power Company [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	0	0	0
Amounts reclassified from AOCI (pre-tax)	0	0	0
Income tax impact of amounts reclassified	0	0	0
Other OCI changes (pre-tax)	0	0	0
Income tax impact of other OCI changes	0	0	0
Total Other Comprehensive Income (Loss)	0	0	0
Ending Balance	0	0	0
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(97,820)	(82,432)	(83,254)
Amounts reclassified from AOCI (pre-tax)	6,364	4,611	4,292
Income tax impact of amounts reclassified	(2,524)	(1,825)	(1,699)
Other OCI changes (pre-tax)	17,136	(30,084)	(2,958)
Income tax impact of other OCI changes	(6,781)	11,910	1,187
Total Other Comprehensive Income (Loss)	14,195	(15,388)	822
Ending Balance	(83,625)	(97,820)	(82,432)
Accumulated Defined Benefit Plans Adjustment [Member] | Public Service Company of New Mexico [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(97,820)	(82,432)	(82,981)
Amounts reclassified from AOCI (pre-tax)	6,364	4,611	4,278
Income tax impact of amounts reclassified	(2,524)	(1,825)	(1,694)
Other OCI changes (pre-tax)	17,136	(30,084)	(3,369)
Income tax impact of other OCI changes	(6,781)	11,910	1,334
Total Other Comprehensive Income (Loss)	14,195	(15,388)	549
Ending Balance	(83,625)	(97,820)	(82,432)
Accumulated Defined Benefit Plans Adjustment [Member] | Texas-New Mexico Power Company [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	0	0	(275)
Amounts reclassified from AOCI (pre-tax)	0	0	13
Income tax impact of amounts reclassified	0	0	(5)
Other OCI changes (pre-tax)	0	0	414
Income tax impact of other OCI changes	0	0	(147)
Total Other Comprehensive Income (Loss)	0	0	275
Ending Balance	0	0	0
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(216)	(58)	(1,623)
Amounts reclassified from AOCI (pre-tax)	207	182	3,448
Income tax impact of amounts reclassified	(73)	(65)	(1,230)
Other OCI changes (pre-tax)	(279)	(428)	(1,002)
Income tax impact of other OCI changes	98	153	349
Total Other Comprehensive Income (Loss)	(47)	(158)	1,565
Ending Balance	(263)	(216)	(58)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Public Service Company of New Mexico [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	0	0	(16)
Amounts reclassified from AOCI (pre-tax)	0	0	27
Income tax impact of amounts reclassified	0	0	(11)
Other OCI changes (pre-tax)	0	0	0
Income tax impact of other OCI changes	0	0	0
Total Other Comprehensive Income (Loss)	0	0	16
Ending Balance	0	0	0
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Texas-New Mexico Power Company [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(216)	(58)	(1,210)
Amounts reclassified from AOCI (pre-tax)	207	182	2,997
Income tax impact of amounts reclassified	(73)	(65)	(1,068)
Other OCI changes (pre-tax)	(279)	(428)	(1,207)
Income tax impact of other OCI changes	98	153	430
Total Other Comprehensive Income (Loss)	(47)	(158)	1,152
Ending Balance	$ (263)	$ (216)	$ (58)