Fair Value of Derivative and Other Financial Instruments, Recurring (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 235,894	$ 226,855
PNM Resources [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	2,072,872	1,905,230
Investment In PVNGS lessor notes	32,712	57,279
Other investments	2,406	3,196
PNM Resources [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Investment In PVNGS lessor notes	0	0
Other investments	546	690
PNM Resources [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	2,072,872	1,905,230
Investment In PVNGS lessor notes	0	0
Other investments	0	0
PNM Resources [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Investment In PVNGS lessor notes	32,712	57,279
Other investments	1,860	2,506
Public Service Company of New Mexico [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,525,625	1,382,938
Investment In PVNGS lessor notes	32,712	57,279
Other investments	300	445
Public Service Company of New Mexico [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Investment In PVNGS lessor notes	0	0
Other investments	300	445
Public Service Company of New Mexico [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,525,625	1,382,938
Investment In PVNGS lessor notes	0	0
Other investments	0	0
Public Service Company of New Mexico [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Investment In PVNGS lessor notes	32,712	57,279
Other investments	0	0
Texas-New Mexico Power Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	422,583	390,814
Other investments	245	245
Texas-New Mexico Power Company [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Other investments	245	245
Texas-New Mexico Power Company [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	422,583	390,814
Other investments	0	0
Texas-New Mexico Power Company [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Other investments	0	0
Reported Value Measurement [Member] | PNM Resources [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,875,172	1,745,420
Investment In PVNGS lessor notes	31,469	52,958
Other investments	1,667	1,835
Reported Value Measurement [Member] | Public Service Company of New Mexico [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,390,647	1,290,618
Investment In PVNGS lessor notes	31,469	52,958
Other investments	300	445
Reported Value Measurement [Member] | Texas-New Mexico Power Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	365,759	336,036
Other investments	245	245
Cash and equivalents [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,338	3,356
Domestic value [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	41,917	39,460
Domestic growth [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	74,647	76,292
International and other [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	16,957	16,633
U.S. Government [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	19,616	21,941
Municipals [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	67,595	58,568
Corporate and other [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	11,824	10,605
Fair Value, Measurements, Recurring [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	235,894	226,855
Fair Value, Measurements, Recurring [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	157,268	158,180
Fair Value, Measurements, Recurring [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	78,626	68,675
Fair Value, Measurements, Recurring [Member] | Commodity Contract [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative instruments, Assets	5,232	7,066
Commodity derivative instruments, Liabilities	(2,058)	(3,793)
Commodity derivative instruments, Net	3,174	3,273
Fair Value, Measurements, Recurring [Member] | Commodity Contract [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative instruments, Assets	0	0
Commodity derivative instruments, Liabilities	0	0
Commodity derivative instruments, Net	0	0
Fair Value, Measurements, Recurring [Member] | Commodity Contract [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative instruments, Assets	5,232	7,066
Commodity derivative instruments, Liabilities	(2,058)	(3,793)
Commodity derivative instruments, Net	3,174	3,273
Fair Value, Measurements, Recurring [Member] | Cash and equivalents [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,338	3,356
Fair Value, Measurements, Recurring [Member] | Cash and equivalents [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,338	3,356
Fair Value, Measurements, Recurring [Member] | Cash and equivalents [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Domestic value [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	41,917	39,460
Fair Value, Measurements, Recurring [Member] | Domestic value [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	41,917	39,460
Fair Value, Measurements, Recurring [Member] | Domestic value [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Domestic growth [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	74,647	76,292
Fair Value, Measurements, Recurring [Member] | Domestic growth [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	74,647	76,292
Fair Value, Measurements, Recurring [Member] | Domestic growth [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | International and other [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	16,957	16,633
Fair Value, Measurements, Recurring [Member] | International and other [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	16,957	16,633
Fair Value, Measurements, Recurring [Member] | International and other [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | U.S. Government [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	19,616	21,941
Fair Value, Measurements, Recurring [Member] | U.S. Government [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	17,865	20,194
Fair Value, Measurements, Recurring [Member] | U.S. Government [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,751	1,747
Fair Value, Measurements, Recurring [Member] | Municipals [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	67,595	58,568
Fair Value, Measurements, Recurring [Member] | Municipals [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Municipals [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	67,595	58,568
Fair Value, Measurements, Recurring [Member] | Corporate and other [Member] | PNMR and PNM [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	11,824	10,605
Fair Value, Measurements, Recurring [Member] | Corporate and other [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	2,544	2,245
Fair Value, Measurements, Recurring [Member] | Corporate and other [Member] | PNMR and PNM [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 9,280	$ 8,360