XML 58 R97.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Commitments and Contingencies (Details) (USD $) |  |  |  |  | 0 Months Ended |  |  | 12 Months Ended |  |  |  |  |  |  | 12 Months Ended |  |  |  |  |  |  | 12 Months Ended |  | 4 Months Ended | 5 Months Ended | 12 Months Ended |  | 12 Months Ended |  | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 21, 2011 mw | Dec. 21, 2011 San Juan Generating Station [Member] | Nov. 08, 2010 Four Corners [Member] | Jun. 18, 2010 Public Service Company of New Mexico [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2011 Public Service Company of New Mexico [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Palo Verde Nuclear Generating Station [Member] Nuclear Spent Fuel And Waste Disposal [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Four Corners Units 4 and 5 (Coal) [Member] | Dec. 31, 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] Other Deferred Credits [Member] Palo Verde Nuclear Generating Station [Member] Nuclear Spent Fuel And Waste Disposal [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] Other Deferred Credits [Member] Palo Verde Nuclear Generating Station [Member] Nuclear Spent Fuel And Waste Disposal [Member] | Jan. 31, 2010 Public Service Company of New Mexico [Member] Minimum [Member] San Juan Generating Station And Four Corners [Member] opp | Jan. 31, 2010 Public Service Company of New Mexico [Member] Maximum [Member] San Juan Generating Station And Four Corners [Member] opp | Dec. 31, 2013 Public Service Company of New Mexico [Member] Coal Supply [Member] San Juan Generating Station [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] Coal Supply [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Surface [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Surface [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] Surface [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Surface [Member] San Juan Generating Station [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Underground [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2012 Public Service Company of New Mexico [Member] Underground [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Underground [Member] San Juan Generating Station [Member] Loss on Long-term Purchase Commitment [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Nuclear Plant [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Nuclear Plant [Member] Maximum [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Commercial Providers [Member] Nuclear Plant [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2013 Public Service Company of New Mexico [Member] Industry Wide Retrospective Assessment Program [Member] Nuclear Plant [Member] Palo Verde Nuclear Generating Station [Member] | Dec. 31, 2013 Pnm Electric [Member] San Juan Generating Station Units 2 and 3 [Member] | Dec. 31, 2013 PNMR and PNM [Member] Palo Verde Nuclear Generating Station Unit 3 [Member] MW | Dec. 31, 2013 Fuel and purchased power adjustment clause [Member] Public Service Company of New Mexico [Member] Minimum [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Fuel and purchased power adjustment clause [Member] Public Service Company of New Mexico [Member] Maximum [Member] San Juan Generating Station [Member] | Apr. 12, 2012 Sierra Club Allegations [Member] San Juan Generating Station [Member] | Apr. 12, 2012 Sierra Club Allegations [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Clean Air Act related to Regional Haze [Member] state | Dec. 31, 2013 Clean Air Act related to Post-Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners [Member] compliance_alternative | Dec. 31, 2013 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. 31, 2013 Mercury Control [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Mercury Control [Member] Public Service Company of New Mexico [Member] Maximum [Member] San Juan Generating Station [Member] | Dec. 31, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Unit 4 [Member] MW | Dec. 31, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member] MW | Apr. 30, 2014 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member] | Sep. 30, 2014 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member] | Dec. 31, 2013 Clean Air Act, SNCR [Member] Public Service Company of New Mexico [Member] San Juan Generating Station Units 2 and 3 [Member] MW | Dec. 31, 2013 Clean Air Act, SNCR [Member] PNMR and PNM [Member] Palo Verde Nuclear Generating Station Unit 3 [Member] MW | Dec. 31, 2013 Loss on Long-term Purchase Commitment [Member] Public Service Company of New Mexico [Member] | Dec. 31, 2012 Loss on Long-term Purchase Commitment [Member] Public Service Company of New Mexico [Member] | Dec. 31, 2013 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] Minimum [Member] San Juan Generating Station [Member] | Dec. 31, 2013 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] Maximum [Member] San Juan Generating Station [Member] | Dec. 31, 2013 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] Maximum [Member] San Juan Generating Station Units 1 and 4 [Member] | Dec. 31, 2013 Environmental Protection Agency [Member] Clean Air Act related to Post-Combustion Controls [Member] Public Service Company of New Mexico [Member] Four Corners [Member] | Dec. 31, 2013 Environmental Protection Agency [Member] WildEarth Guardians filed an action to challenge EPA's rule in the Tenth Circuit [Member] San Juan Generating Station [Member] | Dec. 31, 2013 San Juan Underground Mine Fire [Member] Fuel and purchased power adjustment clause [Member] Public Service Company of New Mexico [Member] San Juan Generating Station [Member] | Dec. 31, 2013 NMTRD Coal Severance Tax [Member] Four Corners [Member] | Dec. 31, 2013 NMTRD Coal Severance Tax [Member] Public Service Company of New Mexico [Member] Four Corners [Member] | Jan. 06, 2014 Navajo Nation Allottee Matters [Member] Public Service Company of New Mexico [Member] | Dec. 31, 2013 San Juan Generating Station [Member] Continuous Highwall Mining [Member] | Dec. 31, 2013 San Juan Generating Station [Member] SJCC Arbitration [Member] | Dec. 31, 2013 San Juan Generating Station [Member] SJCC Arbitration [Member] Public Service Company of New Mexico [Member]
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments to be Held in Decommissioning Trust Fund |  |  |  |  |  |  |  |  | $ 4,900,000 |  | $ 2,600,000 | $ 2,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Decommissioning Fund Investments, Fair Value |  |  |  |  |  |  |  |  | 222,500,000 |  | 189,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Gross |  |  |  |  |  | 1,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  |  |  |  |  |  |  |  |  |  |  | 58,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  | 55,700,000 |  |  | 93,300,000 |  |  |  |  |  |  |  |  |  |  |  | 80,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mine Reclamation and Closing Liability, Noncurrent |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 11,900,000 | 13,900,000 |  |  |  |  |  | 23,800,000 | 26,800,000 |  | 7,800,000 | 4,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
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 Occured |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 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 |  |  |  |  |  |  |  |  | 10.20% | [1] |  |  |  | 46.30% |  | 13.00% | 52.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net book value |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 287,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Time Period from completed application to EPA Proposed Action |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 135 days |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Time Period from EPA Proposed Action to Final Action |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 150 days |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 78 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Overall Reduction Of Ownership, in Megawatts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 340 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Number of Mega Watts of Gas-fired Generation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 276,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Number of Compliance alternatives |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Government Standard Emission Limit (pounds per MMBTU, parts per million) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.060 | 0.070 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.015 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilitites, Plant Requirment 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, Jointly Owned Utility Plant, Sale of Ownership Percentage |  |  |  |  | 48.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Current Annual Mercury Control Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contingent Estimated Annual Mercury Control Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated Total Litigation Settlement Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated Company Share Litigation Settlement Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum Megawatt Capacity from Coal and Oil-Fired Electric Generating Units under Jurisdiction of the Merucy and Air Toxics Standards |  |  | 25 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mercury Removal Rate, Percentage |  |  |  | 99.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other, net | 34,590,000 | 31,490,000 |  |  |  |  | 30,510,000 | 27,457,000 |  |  |  |  |  |  |  |  |  |  |  |  |  | 12,300,000 | 9,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Estimated Increase in Coal Cost, Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 26.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Annual Funding |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 300,000 | 3,500,000 |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Expected Funding Annual Requirements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 600,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Final Reclamation, capped amount to be collected |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets |  |  |  |  |  |  | 403,611,000 | 468,446,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preliminary estimate increased deferral related to mine fire incident |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 17,400,000 | 21,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Insurance Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 18,700,000 |  |  |  |  |  |
Public Utilities, Proposed Retroactive Surface Mining Royalty Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12.50% |  |
Public Utilities, Current Surface Mining Royalty Rate applied between 2000 and 2003 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8.00% |  |
Public Utilities, Estimated Underpaid Surface Mining Royalties under proposed rate change |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,000,000 |  |
Public Utilities, PNM Share Estimated Underpaid Surface Mining Royalties under proposed rate change |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 46.30% |  |
Public Utilities, SJCC Disputed Mining Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,500,000.0 |
Public Utilities, PNM Share of SJCC Disputed Mining Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 700,000 |
Public Utilities, PNM Share of SJCC Disputed Mining Costs to pass through FPPAC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 500,000 |
Public Utilities, Potential Unbilled Mining Costs Owed to SJCC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,200,000.0 |
Public Utilities, Potential Overbilled Mining Costs SJCC Owes to SJGS Owners |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,100,000.0 |
Public Utilities, Potential Capital Improvements billed as Mining Costs to SJGS Owners |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13,900,000.0 |
Public Utilities, PNM Share of arbitration ruling |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 46.30%
Public Utilities, FFPAC Percentage of mining costs overbilled or unbilled ruled by arbitration |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 33.00%
Public Utilities, FFPAC Percentage of capital improvements billed as mining costs ruled by arbitration |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25.00%
Public Utilities, Assessed Coal Severance Surtax Penalty and Interest |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30,000,000 |  |  |  |  |
Public Utilities, PNM Share Assessed Coal Severance Surtax Penalty and Interest to pass through FFPAC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8.00% |  |  |  |
Public Utilities, Liability Insurance Coverage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13,600,000,000 | 375,000,000 | 13,200,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Ownership Percentage in Nuclear Reactor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10.20% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Maximum Potential Assessment Per Incident |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 38,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Annual Payment Limitation Related to Incident |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Aggregate Amount of All Risk Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,750,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Sublimit Amount under Nuclear Electric Insurance Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,500,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Maximum Amount under Nuclear Electic Insurance Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of allotment parcels' appraisal requested for review |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 58 |  |  |
[1] | Includes interest in PVNGS Unit 3, interest in common facilities for all PVNGS units, and owned interests in PVNGS Units 1 and 2.

X
- Definition Contingent Estimated Annual Mercury Control Cost + References No definition available. + Details
Name: | pnm_ContingentEstimatedAnnualMercuryControlCost
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Current Annual Mercury Control Costs + References No definition available. + Details
Name: | pnm_CurrentAnnualMercuryControlCosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Estimated Company Share Litigation Settlement Cost + References No definition available. + Details
Name: | pnm_EstimatedCompanyShareLitigationSettlementCost
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition estimated cost of replacing gas fired peaking capacity due to retirement of SJGS units + References No definition available. + Details
Name: | pnm_EstimatedCostOfReplacingGasFiredPeakingCapacityDueToRetirementOfSjgsUnits
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated Installation Capital Costs + References No definition available. + Details
Name: | pnm_EstimatedInstallationCapitalCosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated Portion of Total Capital Costs if Requirement Occured + References No definition available. + Details
Name: | pnm_EstimatedPortionOfTotalCapitalCostsIfRequirementOccured
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated Total Capital Cost If Requirement Occured + References No definition available. + Details
Name: | pnm_EstimatedTotalCapitalCostIfRequirementOccured
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated Total Litigation Settlement Cost + References No definition available. + Details
Name: | pnm_EstimatedTotalLitigationSettlementCost
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Final Reclamation, capped amount to be collected + References No definition available. + Details
Name: | pnm_FinalReclamationCappedAmountToBeCollected
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Mercury Removal Rate, Percentage + References No definition available. + Details
Name: | pnm_MercuryRemovalRatePercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Minimum Megawatt Capacity from Coal and Oil-Fired Electric Generating Units under Jurisdiction of the Merucy and Air Toxics Standards + References No definition available. + Details
Name: | pnm_MinimumMegawattCapacityFromCoalAndOilFiredElectricGeneratingUnitsUnderJurisdictionOfMerucyAndAirToxicsStandards
Namespace Prefix: | pnm_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Net book value + References No definition available. + Details
Name: | pnm_NetBookValue
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of allotment parcels' appraisal requested for review + References No definition available. + Details
Name: | pnm_Numberofallotmentparcelsappraisalrequestedforreview
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Preliminary estimate increased deferral related to mine fire incident + References No definition available. + Details
Name: | pnm_PreliminaryEstimateIncreasedDeferralRelatedToMineFireIncident
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Additional Ownership To Be Obtained, in Megawatts + References No definition available. + Details
Name: | pnm_PublicUtilitiesAdditionalOwnershipToBeObtainedinMegawatts
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Aggregate Amount of All Risk Insurance + References No definition available. + Details
Name: | pnm_PublicUtilitiesAggregateAmountOfAllRiskInsurance
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Annual Funding + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFunding
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Annual Payment Limitation Related to Incident + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualPaymentLimitationRelatedToIncident
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Assessed Coal Severance Surtax Penalty and Interest + References No definition available. + Details
Name: | pnm_PublicUtilitiesAssessedCoalSeveranceSurtaxPenaltyandInterest
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Current Surface Mining Royalty Rate applied between 2000 and 2003 + References No definition available. + Details
Name: | pnm_PublicUtilitiesCurrentSurfaceMiningRoyaltyRateappliedbetween2000and2003
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Estimated Increase in Coal Cost, Percentage + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedIncreaseinCoalCostPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Estimated Underpaid Surface Mining Royalties under proposed rate change + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedUnderpaidSurfaceMiningRoyaltiesunderproposedratechange
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Expected Funding Annual Requirements + References No definition available. + Details
Name: | pnm_PublicUtilitiesExpectedFundingAnnualRequirements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Expected NBV of Units at Retirement + References No definition available. + Details
Name: | pnm_PublicUtilitiesExpectedNBVofUnitsatRetirement
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, FFPAC Percentage of capital improvements billed as mining costs ruled by arbitration + References No definition available. + Details
Name: | pnm_PublicUtilitiesFFPACPercentageofcapitalimprovementsbilledasminingcostsruledbyarbitration
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Percentage of PNM Share of mining costs overbilled or unbilled, as ruled by arbitration, that will pass through FFPAC + References No definition available. + Details
Name: | pnm_PublicUtilitiesFFPACPercentageofminingcostsoverbilledorunbilledruledbyarbitration
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Government Standard Emission Limit + References No definition available. + Details
Name: | pnm_PublicUtilitiesGovernmentStandardEmissionLimit
Namespace Prefix: | pnm_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Insurance Recovery + References No definition available. + Details
Name: | pnm_PublicUtilitiesInsuranceRecovery
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Jointly Owned Utility Plant, Sale of Ownership Percentage + References No definition available. + Details
Name: | pnm_PublicUtilitiesJointlyOwnedUtilityPlantSaleofOwnershipPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Liability Insurance Coverage + References No definition available. + Details
Name: | pnm_PublicUtilitiesLiabilityInsuranceCoverage
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Maximum Amount under Nuclear Electic Insurance Limited + References No definition available. + Details
Name: | pnm_PublicUtilitiesMaximumAmountUnderNuclearElecticInsuranceLimited
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Maximum Potential Assessment Per Incident + References No definition available. + Details
Name: | pnm_PublicUtilitiesMaximumPotentialAssessmentPerIncident
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Newly Identified Replacement Gas-fired Generation, in Megawatts, December2013 + References No definition available. + Details
Name: | pnm_PublicUtilitiesNewlyIdentifiedReplacementGasfiredGenerationinMegawattsDecember2013
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Newly Identified Replacement Solar Generation, in Megawatts, December2013 + References No definition available. + Details
Name: | pnm_PublicUtilitiesNewlyIdentifiedReplacementSolarGenerationinMegawattsDecember2013
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of Compliance alternatives + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberOfComplianceAlternatives
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of Megawatts Nuclear Generation + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofMegawattsNuclearGeneration
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of States To Address Regional Haze + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberOfStatesToAddressRegionalHaze
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of years after issuance of final determination to achieve compliance with requirements + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberOfYearsAfterIssuanceOfFinalDeterminationToAchieveComplianceWithRequirements
Namespace Prefix: | pnm_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Overall Reduction Of Ownership, in Megawatts + References No definition available. + Details
Name: | pnm_PublicUtilitiesOverallReductionOfOwnershipinMegawatts
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Ownership Percentage + References No definition available. + Details
Name: | pnm_PublicUtilitiesOwnershipPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Ownership Percentage in Nuclear Reactor + References No definition available. + Details
Name: | pnm_PublicUtilitiesOwnershipPercentageInNuclearReactor
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, PNM Share Assessed Coal Severance Surtax Penalty and Interest to pass through FFPAC + References No definition available. + Details
Name: | pnm_PublicUtilitiesPNMShareAssessedCoalSeveranceSurtaxPenaltyandInteresttopassthroughFFPAC
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, PNM Share Estimated Underpaid Surface Mining Royalties under proposed rate change + References No definition available. + Details
Name: | pnm_PublicUtilitiesPNMShareEstimatedUnderpaidSurfaceMiningRoyaltiesunderproposedratechange
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, PNM Share of arbitration ruling + References No definition available. + Details
Name: | pnm_PublicUtilitiesPNMShareofarbitrationruling
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, PNM Share of SJCC Disputed Mining Costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesPNMShareofSJCCDisputedMiningCosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, PNM Share of SJCC Disputed Mining Costs to pass through FPPAC + References No definition available. + Details
Name: | pnm_PublicUtilitiesPNMShareofSJCCDisputedMiningCoststopassthroughFPPAC
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Potential Capital Improvements billed as Mining Costs to SJGS Owners + References No definition available. + Details
Name: | pnm_PublicUtilitiesPotentialCapitalImprovementsbilledasMiningCoststoSJGSOwners
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Potential Overbilled Mining Costs SJCC Owes to SJGS Owners + References No definition available. + Details
Name: | pnm_PublicUtilitiesPotentialOverbilledMiningCostsSJCCOwestoSJGSOwners
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Potential to emit tons per year of visibility impairing pollution, maximum + References No definition available. + Details
Name: | pnm_PublicUtilitiesPotentialToEmitTonsPerYearOfVisibilityImpairingPollutionMaximum
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Potential Unbilled Mining Costs Owed to SJCC + References No definition available. + Details
Name: | pnm_PublicUtilitiesPotentialUnbilledMiningCostsOwedtoSJCC
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Proposed Retroactive Surface Mining Royalty Rate + References No definition available. + Details
Name: | pnm_PublicUtilitiesProposedRetroactiveSurfaceMiningRoyaltyRate
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Proposed Seeking Shorter Compliance Period + References No definition available. + Details
Name: | pnm_PublicUtilitiesProposedSeekingShorterCompliancePeriod
Namespace Prefix: | pnm_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Proposed value per Kilowatt effective January 1, 2018 + References No definition available. + Details
Name: | pnm_PublicUtilitiesProposedvalueperKilowatteffectiveJanuary12018
Namespace Prefix: | pnm_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Requested Time Period to Recover Retired Units NBV + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequestedTimePeriodtoRecoverRetiredUnitsNBV
Namespace Prefix: | pnm_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Rule Imposes Opacity Limitation on Certain Fugitive Dust Emissions From Coal and Material Handling Operations + References No definition available. + Details
Name: | pnm_PublicUtilitiesRuleImposesOpacityLimitationOnCertainFugitiveDustEmissionsFromCoalAndMaterialHandlingOperations
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, SJCC Disputed Mining Costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesSJCCDisputedMiningCosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Sublimit Amount under Nuclear Electric Insurance Limited + References No definition available. + Details
Name: | pnm_PublicUtilitiesSublimitAmountUnderNuclearElectricInsuranceLimited
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Time Period from completed application to EPA Proposed Action + References No definition available. + Details
Name: | pnm_PublicUtilitiesTimePeriodfromcompletedapplicationtoEPAProposedAction
Namespace Prefix: | pnm_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Time Period from EPA Proposed Action to Final Action + References No definition available. + Details
Name: | pnm_PublicUtilitiesTimePeriodfromEPAProposedActiontoFinalAction
Namespace Prefix: | pnm_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilitites, Plant Requirment to Meet Opacity Limit, Percentage + References No definition available. + Details
Name: | pnm_PublicUtilititesPlantRequirmentToMeetOpacityLimitPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_DecommissioningTrustAssetsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The proportionate share of interest (percent) in a jointly owned utility plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C + Details
Name: | us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of judgment or settlement awarded to (against) the entity in respect of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 8 -Article 5 + Details
Name: | us-gaap_OtherAssetsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash outflow for the purchase of investments that will be held in a decommissioning trust fund. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToInvestInDecommissioningFund
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_RegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant