Variable Interest Entities (Details) (USD $)	3 Months Ended								12 Months Ended			3 Months Ended								12 Months Ended			3 Months Ended	12 Months Ended						12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Public Service Company of New Mexico [Member] LeaseAgreements InstitutionalInvestors	Sep. 30, 2013 Public Service Company of New Mexico [Member]	Jun. 30, 2013 Public Service Company of New Mexico [Member]	Mar. 31, 2013 Public Service Company of New Mexico [Member]	Dec. 31, 2012 Public Service Company of New Mexico [Member]	Sep. 30, 2012 Public Service Company of New Mexico [Member]	Jun. 30, 2012 Public Service Company of New Mexico [Member]	Mar. 31, 2012 Public Service Company of New Mexico [Member]	Dec. 31, 2013 Public Service Company of New Mexico [Member] LeaseAgreements InstitutionalInvestors	Dec. 31, 2012 Public Service Company of New Mexico [Member]	Dec. 31, 2011 Public Service Company of New Mexico [Member]	Sep. 30, 2013 Valencia [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 Valencia [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2012 Valencia [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2011 Valencia [Member] Public Service Company of New Mexico [Member]	May 30, 2008 Valencia [Member] Public Service Company of New Mexico [Member] MW	Dec. 31, 2013 Valencia [Member] Maximum [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 PVNGS [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 Delta [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2012 Delta [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2011 Delta [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 Delta [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2012 Delta [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 Palo Verde Nuclear Generating Station [Member] PVNGS [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2012 Palo Verde Nuclear Generating Station [Member] PVNGS [Member] Public Service Company of New Mexico [Member]
Variable Interest Entity [Line Items]
Number of mega watts purchased (in megawatts)																											158
Power plant total construction costs																											$ 90,000,000
Long term contract for purchase of electric power fixed costs																								18,900,000	18,800,000	18,300,000				6,400,000	6,200,000	6,000,000
Long term contract for purchase of electric power variable charges																								1,200,000	900,000	1,400,000				1,800,000	800,000	1,500,000
Variable Interest Entity, Statement Of Operation [Abstract]
Electric Revenue																								20,166,000	19,585,000	19,720,000
Operating expenses																								(5,645,000)	(5,535,000)	(5,673,000)
Earnings Attributable to non-controlling interest									14,521,000	14,050,000	14,047,000									14,521,000	14,050,000	14,047,000		(14,521,000)	(14,050,000)	(14,047,000)
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Current assets	401,539,000				442,191,000				401,539,000	442,191,000		348,502,000				387,689,000				348,502,000	387,689,000			2,658,000	3,655,000
Net property, plant and equipment																								75,137,000	77,953,000
Total Assets	5,500,210,000				5,372,583,000				5,500,210,000	5,372,583,000	5,204,613,000	4,227,616,000				4,163,907,000				4,227,616,000	4,163,907,000			77,795,000	81,608,000
Current liabilities	492,671,000				434,103,000				492,671,000	434,103,000		357,266,000				242,751,000				357,266,000	242,751,000			766,000	765,000
Owners' equity - non-controlling interest	(77,029,000)				(80,843,000)				(77,029,000)	(80,843,000)		(77,029,000)				(80,843,000)				(77,029,000)	(80,843,000)			77,029,000	80,843,000
Jointly owned utility plant, option to purchase proportionate ownership share																												50.00%
Long term contract option to purchase, purchase price - percentage of adjusted NBV																								50.00%
Long term contract option to purchase, purchase price - percentage of FMV																							50.00%
Long term contract option to purchase, number of days to set FMV																								60 days
Long term contract option to purchase, approximate approval period																								15 months
Operating Leases, Currently active with trusts												8								8
Operating Leases, trust lessors												8								8
Operating Leases, Different institutional investors of trust lessors												5								5
Operating Leases, renewal options after original lease term									6 years											2
Operating Leases, Extended lease term option																				6
Operating leases, future minimum payments due												349,561,000								349,561,000									52,500,000
Operating leases, future minimum payments due, renewal term																													145,200,000
Loss contingency, range of possible loss, portion not accrued																													154,100,000
Operating Leases, Future Minimum Payments Due, Current												49,580,000								49,580,000															26,000,000	26,000,000
Long Term Contract For Purchase of Power Term of Contract																								20 years
Long Term Contract for Purchase of Electric Power Aggregate Amount of Contract Remaining																														39,200,000
Payments to Acquire Businesses, Gross																																	23,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt																																	16,200,000	19,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt																																	3,300,000	3,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets																																	23,700,000	26,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment																																	20,300,000	23,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities																																	18,200,000	21,100,000
Intersegment revenues																																	9,500,000	7,400,000
Earnings Attributable to PNMR	$ 7,648,000	$ 54,555,000	$ 27,678,000	$ 10,626,000	$ 9,091,000	$ 57,864,000	$ 21,512,000	$ 17,080,000	$ 100,507,000	$ 105,547,000	$ 176,359,000	$ 2,639,000	$ 47,823,000	$ 26,124,000	$ 11,569,000	$ 5,943,000	$ 50,911,000	$ 16,885,000	$ 17,812,000	$ 88,155,000	$ 91,551,000	$ 54,491,000											$ 1,200,000	$ 900,000