Commitments and Contingencies (Commitments and Contingencies Related to the Environment) (Details) (USD $)							12 Months Ended													0 Months Ended					6 Months Ended									6 Months Ended
	Dec. 21, 2011 mw	Dec. 21, 2011 San Juan Generating Station [Member]	Oct. 31, 2012 Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Jun. 30, 2014 Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member]	Jun. 26, 2014 Public Service Company of New Mexico [Member] San Juan Generating Station Units 1 and 4 [Member]	Dec. 20, 2013 Public Service Company of New Mexico [Member] San Juan Generating Station Units 1 and 4 [Member]	Dec. 31, 2013 Public Service Company of New Mexico [Member] Nuclear Spent Fuel And Waste Disposal [Member] Palo Verde Nuclear Generating Station [Member]	Jun. 30, 2014 Public Service Company of New Mexico [Member] Nuclear Spent Fuel And Waste Disposal [Member] Palo Verde Nuclear Generating Station [Member]	Jun. 30, 2014 PNM Electric [Member] San Juan Generating Station Units 2 and 3 [Member]	Jun. 30, 2014 PNMR and PNM [Member] Palo Verde Nuclear Generating Station Unit 3 [Member] MW	Jun. 30, 2014 Other Deferred Credits [Member] Public Service Company of New Mexico [Member] Nuclear Spent Fuel And Waste Disposal [Member] Palo Verde Nuclear Generating Station [Member]	Dec. 31, 2013 Other Deferred Credits [Member] Public Service Company of New Mexico [Member] Nuclear Spent Fuel And Waste Disposal [Member] Palo Verde Nuclear Generating Station [Member]	Jun. 30, 2014 Clean Air Act related to Regional Haze [Member] state	Jun. 30, 2014 Clean Air Act Related to Post Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners [Member]	Aug. 06, 2012 Clean Air Act Related to Post Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners [Member] compliance_alternative	Jun. 30, 2014 Clean Air Act Related to Post Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners Units 4 and 5 (Coal) [Member]	Dec. 20, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member] MW	Jun. 30, 2014 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 3 [Member]	Dec. 20, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 3 [Member] MW	Dec. 20, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member] MW	Jun. 30, 2014 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member]	Jun. 26, 2014 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member] MW	Dec. 20, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member] MW	Dec. 20, 2013 Clean Air Act, SNCR [Member] PNMR and PNM [Member] Palo Verde Nuclear Generating Station Unit 3 [Member] MW	Jun. 30, 2014 Mercury Control [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Jun. 30, 2014 Environmental Protection Agency [Member] WildEarth Guardians filed an action to challenge EPA's rule in the Tenth Circuit [Member] San Juan Generating Station [Member]	Jun. 30, 2014 Environmental Protection Agency [Member] Clean Air Act Related to Post Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners [Member]	Jun. 27, 2014 Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member]	Mar. 11, 2014 Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member]	Jan. 31, 2010 Minimum [Member] Public Service Company of New Mexico [Member] San Juan Generating Station And Four Corners [Member] opp	Oct. 31, 2012 Minimum [Member] Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SCR [Member] [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Oct. 31, 2012 Minimum [Member] Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Jan. 31, 2010 Maximum [Member] Public Service Company of New Mexico [Member] San Juan Generating Station And Four Corners [Member] opp	Jun. 30, 2014 Maximum [Member] Mercury Control [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Oct. 31, 2012 Maximum [Member] Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SCR [Member] [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Oct. 31, 2012 Maximum [Member] Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member]	Dec. 20, 2013 Maximum [Member] Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other PNM Costs [Member] Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Units 1 and 4 [Member]	Nov. 08, 2013 San Juan Generating Station [Member] National Ambient Air Quality Standards [Member] Public Service Company of New Mexico [Member]
Public Utilities, Commitments And Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss								$ 58,000,000						$ 80,300,000
Loss Contingency Accrual											12,100,000	11,900,000
Annual Fee, Nuclear Waste Disposal							3,000,000
Revised Annual Fee, Nuclear Waste Disposal							0
Public Utilities, Number of States To Address Regional Haze													50
Public Utilities, Potential to emit tons per year of visibility impairing pollution, maximum													250
Public Utilities, Proposed Seeking Shorter Compliance Period																										5 years
Public Utilities, Number of years after issuance of final determination to achieve compliance with requirements																											3 years
Estimated Total Capital Cost If Requirement Occurred																															824,000,000				910,000,000
Estimated Installation Capital Costs																																85,000,000				90,000,000	82,000,000
Estimated Portion of Total Capital Costs if Requirement Occured																																105,000,000				110,000,000
Jointly Owned Utility Plant, Proportionate Ownership Share			46.30%
Net book value				286,000,000
Public Utilities, Requested Time Period to Recover Retired Units NBV																				20 years
Public Utilities, Expected NBV of Units at Retirement																				205,000,000
Public Utilities, Number of Megawatts Nuclear Generation										134														134
Public Utilities, Proposed value per Kilowatt effective January 1, 2018																								2,500
Public Utilities, Additional Ownership To Be Obtained, in Megawatts																						132	78
Public Utilities, Costs to obtain additional ownership																						0
Public Utilities, Overall Reduction Of Ownership, in Megawatts																	340
Public Utilities, Ownership To Be Exchanged, in Megawatts																			78
Jointly Owned Utility Plan, Proposed Proportionate Ownership Share					59.00%	52.00%
Public Utilities, Newly Identified Replacement Gas-fired Generation, in Megawatts, December2013																				177
Public Utilities, Newly Identified Replacement Solar Generation, in Megawatts, December2013																				40
estimated cost of replacing gas fired peaking capacity due to retirement of SJGS units									268,300,000
Percentage of ownership held by exiting owners																		50.00%			38.80%
Public Utilities, Ownership Percentage																13.00%		50.00%			38.50%
Requested Expenditure, Installation Capital Costs																													1,900,000
Requested Additional Expenditure, Installation Capital Costs																												6,400,000
Public Utilities, Number of Compliance alternatives															2
Public Utilities, Plant Requirement to Meet NOx emissions Limit														0.015
Public Utilities, Plant Requirement to Meet Opacity Limit, Percentage														20.00%
Public Utilities, Rule Imposes Opacity Limitation on Certain Fugitive Dust Emissions From Coal and Material Handling Operations														20.00%
Public Utilities, Revised SO2 Emissions Agreed Upon																																						0.1
Public Utilities, Government Standard Emission Limit																														0.060			0.070
Current Annual Mercury Control Costs																									700,000
Contingent Estimated Annual Mercury Control Cost																																		$ 6,600,000
Minimum Megawatt Capacity from Coal and Oil-Fired Electric Generating Units under Jurisdiction of the Mercury and Air Toxics Standards	25
Mercury Removal Rate, Percentage		99.00%