XML 83 R61.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Regulatory and Rate Matters - PNM (Details) $ in Millions |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended | 30 Months Ended |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 13, 2018 USD ($) | Mar. 17, 2018 USD ($) | Jan. 31, 2018 USD ($) | Jan. 16, 2018 USD ($) | Jan. 10, 2018 USD ($) | Jan. 03, 2018 USD ($) | Dec. 31, 2017 USD ($) MW | Nov. 08, 2017 USD ($) | Nov. 07, 2017 | Jul. 26, 2017 USD ($) GWh | Jul. 03, 2017 | Jun. 01, 2017 USD ($) GWh MW | May 23, 2017 USD ($) | Apr. 14, 2017 USD ($) GWh program | Jan. 11, 2017 USD ($) | Dec. 07, 2016 USD ($) | Sep. 28, 2016 USD ($) MW | Aug. 04, 2016 USD ($) MW | May 04, 2016 | Apr. 15, 2016 USD ($) GWh program | Jan. 15, 2016 USD ($) lease MW | Nov. 30, 2015 | Aug. 27, 2015 USD ($) | Jan. 15, 2015 | Jul. 01, 2014 | Sep. 30, 2016 USD ($) | Mar. 31, 2018 USD ($) lease MW | Dec. 31, 2017 USD ($) MW | Mar. 31, 2017 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) MW | Dec. 31, 2015 MW | Dec. 31, 2018 USD ($) | Oct. 31, 2017 USD ($) | Oct. 17, 2017 MW | May 12, 2017 USD ($) | May 05, 2017 signatory | Oct. 26, 2016 MW | Jul. 08, 2016 service_rate MW | Jul. 01, 2016 USD ($) | Jun. 30, 2016 meeting | Feb. 26, 2016 USD ($) | Jan. 31, 2016 lease MW
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in Non-fuel Revenue Requirement |  |  | $ 10.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percent of Non-fuel Revenue Requirement Change Implemented |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess return on jurisdictional equity that would require refund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
WACC |  |  |  |  |  |  |  | 9.59% | 7.71% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Application filed for new electric service rates | service_rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |
PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Planning period covered of IRP |  |  |  |  |  |  |  |  |  |  | 20 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Action plan, covered period |  |  |  |  |  |  |  |  |  |  | 4 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of statewide meetings hosted | meeting |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 17 |  |
Estimated insurance deductible |  | $ 2.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exposure to cost of repairs |  | $ 1.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
PNMR Development |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar generation capacity (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30 |  |  |  |
Construction of solar generation capacity (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |
2015 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 123.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) of non-fuel revenue |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 121.5 |  |  |  |  | $ 121.7 |  |  |  | $ 121.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hearing examiner's recommended return on equity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9.575% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hearing examiner's recommended rate increase (decrease) of non-fuel revenue |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 41.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested return on equity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimate of possible loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 150.4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) for fuel related costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (42.9) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) for non-fuel related revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (0.2) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 61.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated period of time for supreme court appeal decision |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 15 months |  |  |  |  | 7 months |  |  |  |  |  |  |  |  |  |  |  |
2014 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Future test year period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12 months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period of time after the filing of a rate case application |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13 months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts of Solar PV facilities | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 107 |  |  |  |  | 40 |  |  |  |  |  |  |  |  |  |  |
Current output in the geothermal facility (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar generation capacity (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 86.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable Energy Rider | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Recorded revenues from renewable rider |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 10.9 |  | $ 12.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable Portfolio Standard Supplemental Procurement | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts of Solar PV facilities | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable Portfolio Standard 2014 | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts for wind energy | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 204 |  |  |  |  | 102 |  |  |  |  |  |  |  |  |  |  |
Integrated Resource Plan, 2011 | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Frequency of IRP filings |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Planning period covered of IRP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Advanced Metering Infrastructure Costs | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated costs to be recovered |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 95.1 |  |  |  |  |  | $ 87.2 |
Estimated future investment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 33.0 |
Facebook Data Center |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power Purchase Agreement Term |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Facebook Data Center | Casa Mesa Wind |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar generation capacity (in megawatts) | MW |  |  |  |  |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50 |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |
Facebook Data Center | Avangrid Renewables, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar generation capacity (in megawatts) | MW |  |  |  |  |  |  | 166 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 166 |  |  | 166 |  |  |  |  |  |  |  |  |  |  |  |
Facebook Data Center | Route 66 Solar Energy Center |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar generation capacity (in megawatts) | MW |  |  |  |  |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50 |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station, Unit 2 Leases | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts purchased (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.1 |  |  |  |  |  | 64.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.1
Net book value of capitalized improvements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 39.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net book value |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 75.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of leases under which assets were purchased | lease |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3
Estimated annual property tax expense |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.8 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of leases under which lease term was extended | lease |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lease term extension period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of megawatts nuclear generation (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 114.6 | 114.6 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 114.6 |  |  |  |  |
Palo Verde Nuclear Generating Station, Unit 2 Leases | 2015 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disallowance of the recovery underpreciated costs of capitalized leasehold improvements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 43.8 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Initial rate base value |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 83.7 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hearing examiner's proposed disallowance of recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 163.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period of time for which capital improvements were disallowed |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 15 months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-tax regulatory disallowance |  |  |  |  |  |  | $ 3.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 6.8 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Alvarado square | 2015 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hearing examiner's recommended amount to not be recovered from retail customers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-tax regulatory disallowance of costs recorded as regulatory assets and deferred charges |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station, Unit 1 Leases, extended | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated annual property tax expense |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated annual rent expense |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 18.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of leases under which lease term was extended | lease |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lease term extension period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station, Unit 1 Leases, extended | 2015 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Recovery of assumed operating and maintenance expense savings annually |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4 | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net book value |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 49.4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4 | 2015 Electric Rate Case | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested base rate increase (decrease) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 40.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Installation Costs Including Construction Management, Gross Receipts Taxes, AFUDC, and Other Costs | Clean Air Act, Balanced Draft Technology | San Juan Generating Station Units 1 and 4 | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Installation Capital Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 52.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
NMPRC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 99.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested return on equity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10.125% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of additional signatories | signatory |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13 |  |  |  |  |  |
Period of time for proposed return to customers the benefit of the reduction in New Mexico's corporate income tax rate |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory disallowance |  |  |  |  |  |  | $ 27.9 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 27.9 |  |  | $ 27.9 |  |  |  |  |  |  |  |  |  |  |  |
Proposed revision to rider that will allow for recovery |  |  |  |  |  |  |  |  |  |  |  | $ 43.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Action plan, covered period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
NMPRC | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) |  |  |  | $ (4.4) | $ (9.1) |  |  |  |  |  |  |  | $ 62.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested initial rate increase (decrease) |  |  |  |  |  |  |  |  |  |  |  |  | $ 32.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested return on equity |  |  |  |  |  |  |  |  |  |  |  |  | 9.575% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period of time for proposed return to customers the benefit of the reduction in New Mexico's corporate income tax rate |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease) duplicative amount |  |  |  | $ 4.7 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested approval to procure additional gigawatt hours in year 1 | GWh |  |  |  |  |  |  |  |  |  |  |  | 80 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested approval to procure a new solar facilities to be constructed (in megawatts) | MW |  |  |  |  |  |  |  |  |  |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50 |  |  |  |  |  |  |  |
Action plan, covered period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notice of Proposed Dismissal, period to show good cause |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30 days |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required Percentage by 2011 | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of renewable energy in portfolio to electric sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required Percentage by 2015 | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of renewable energy in portfolio to electric sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 15.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required Percentage by 2020 | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of renewable energy in portfolio to electric sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Profit incentive sliding scale multiplier |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7.10% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum | Wind | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of diversification |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum | Solar | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of diversification |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum | Distributed generation | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of diversification |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum | Other | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Required percentage of diversification |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum | Renewable Portfolio Standard | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reasonable cost threshold |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.00% |  |  |  |  |  |  |  |  |  |  |  | 3.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Profit incentive sliding scale multiplier |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New Mexico Wind | NMPRC | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested approval to procure additional gigawatt hours in year 2 | GWh |  |  |  |  |  |  |  |  |  |  |  | 105 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lightning Dock Geothermal | NMPRC | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested approval to procure additional gigawatt hours in year 1 | GWh |  |  |  |  |  |  |  |  |  |  |  | 55 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested approval to procure additional gigawatt hours in year 2 | GWh |  |  |  |  |  |  |  |  |  |  |  | 77 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disincentives/Incentives Adder | 2017 Energy Efficiency and Load Management Program | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of programs in the proposed program portfolio | program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Program portfolio's total budget |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 26.0 |  |  |  |  | $ 28.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Incentive based on target savings |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2.4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Targeted savings (in gigawatt hours) | GWh |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 75 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Profit incentive |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1.8 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disincentives/Incentives Adder | Proposed 2018 Portfolio | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of programs in the proposed program portfolio | program |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Program portfolio's total budget |  |  |  |  |  |  |  | $ 23.6 |  |  |  |  |  | $ 25.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Incentive based on target savings |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1.9 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Targeted savings (in gigawatt hours) | GWh |  |  |  |  |  |  |  |  |  |  |  |  |  | 53 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Projected incentive earnings |  |  |  |  |  |  |  |  |  | $ 1.9 |  |  |  | $ 2.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Targeted savings (in gigawatt hours) | GWh |  |  |  |  |  |  |  |  |  | 69 |  |  |  | 70 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disincentives/Incentives Adder | Proposed 2019 Portfolio | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of programs in the proposed program portfolio | program |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Program portfolio's total budget |  |  |  |  |  |  |  | $ 24.9 |  |  |  |  |  | $ 28.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Incentive based on target savings |  |  |  |  |  |  |  |  |  | $ 1.7 |  |  |  | $ 2.1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent event | Disincentives/Incentives Adder | Proposed 2018 Portfolio | PNM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Projected incentive earnings | $ 2.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Four Corners |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Disallowance |  |  |  |  |  | $ 47.6 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory disallowance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 90.1 |  |  |  |  |  | $ 148.1 |  |  |
Forecast |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-tax regulatory disallowance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 36.8 |  |  | $ 58.0 |  |  |  |  |  |  |  |  |  |

X
- Definition Estimated annual property tax expense + References No definition available. + Details
Name: | pnm_Estimatedannualpropertytaxexpense
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Estimated annual rent expense + References No definition available. + Details
Name: | pnm_Estimatedannualrentexpense
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Future Test Year Period + References No definition available. + Details
Name: | pnm_FutureTestYearPeriod
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Future test year period, Revised, Number of days following the filing of application for rate increase + References No definition available. + Details
Name: | pnm_FuturetestyearperiodRevisedNumberofdaysfollowingthefilingofapplicationforrateincrease
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Lease term extension period + References No definition available. + Details
Name: | pnm_Leasetermextensionperiod
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Notice of Proposed Dismissal, Period to Show Cause + References No definition available. + Details
Name: | pnm_LossContingencyNoticeofProposedDismissalPeriodtoShowCause
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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 Net book value, Capital improvements + References No definition available. + Details
Name: | pnm_NetbookvalueCapitalimprovements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of Mega Watts Purchased + References No definition available. + Details
Name: | pnm_NumberOfMegaWattsPurchased
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period of time for which capital improvements were disallowed + References No definition available. + Details
Name: | pnm_Periodoftimeforwhichcapitalimprovementsweredisallowed
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Power Purchase Agreement Term + References No definition available. + Details
Name: | pnm_PowerPurchaseAgreementTerm
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Pubic Utilities, Requested Rate Increase (Decrease), Initial Increase Amount + References No definition available. + Details
Name: | pnm_PubicUtilitiesRequestedRateIncreaseDecreaseInitialIncreaseAmount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Anticipated future profit incentive + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnticipatedfutureprofitincentive
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Approved lease acquisition costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesApprovedleaseacquisitioncosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Approved recovery, Operating and Maintenance savings related to Balanced Draft Technology + References No definition available. + Details
Name: | pnm_PublicUtilitiesApprovedrecoveryOperatingandMaintenancesavingsrelatedtoBalancedDraftTechnology
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Change in Requested Rate increase (Decrease), fuel related costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesChangeinRequestedRateincreaseDecreasefuelrelatedcosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Change in Requested Rate increase (Decrease), non-fuel amount + References No definition available. + Details
Name: | pnm_PublicUtilitiesChangeinRequestedRateincreaseDecreasenonfuelamount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Commitments And Contingencies [Line Items] + References No definition available. + Details
Name: | pnm_PublicUtilitiesCommitmentsAndContingenciesLineItems
Namespace Prefix: | pnm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Disallowed leasehold improvements + References No definition available. + Details
Name: | pnm_PublicUtilitiesDisallowedleaseholdimprovements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Energy Efficiency Targeted Savings, GWh + References No definition available. + Details
Name: | pnm_PublicUtilitiesEnergyEfficiencyTargetedSavingsGWh
Namespace Prefix: | pnm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Energy Efficiency and Load Management Programs, Number of Programs + References No definition available. + Details
Name: | pnm_PublicUtilitiesEnergyEfficiencyandLoadManagementProgramsNumberofPrograms
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Energy Efficiency and Load Management Programs, Profit Incentive, Minimum + References No definition available. + Details
Name: | pnm_PublicUtilitiesEnergyEfficiencyandLoadManagementProgramsProfitIncentiveMinimum
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Energy Efficiency and Load Management Programs, Projected Earned Incentive + References No definition available. + Details
Name: | pnm_PublicUtilitiesEnergyEfficiencyandLoadManagementProgramsProjectedEarnedIncentive
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Energy Efficiency and Load Management Programs, Targeted Energy Savings + References No definition available. + Details
Name: | pnm_PublicUtilitiesEnergyEfficiencyandLoadManagementProgramsTargetedEnergySavings
Namespace Prefix: | pnm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Estimated Future Investment + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedFutureInvestment
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Estimated Insurance deductible + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedInsurancedeductible
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Estimated costs to be recovered + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedcoststoberecovered
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Estimated period of time for supreme court appeal decision + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedperiodoftimeforsupremecourtappealdecision
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Frequency of IRP filings + References No definition available. + Details
Name: | pnm_PublicUtilitiesFrequencyofIRPfilings
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Hearing Examiner Proposed disallowance, Lease Abandonment costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesHearingExaminerProposeddisallowanceLeaseAbandonmentcosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Hearing Examiner Proposed disallowance, Lease Acquisition costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesHearingExaminerProposeddisallowanceLeaseAcquisitioncosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Hearing Examiner Recommended Rate increase (Decrease), non-fuel amount + References No definition available. + Details
Name: | pnm_PublicUtilitiesHearingExaminerRecommendedRateincreaseDecreasenonfuelamount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Hearing Examiner Recommended Return on Equity, Percentage + References No definition available. + Details
Name: | pnm_PublicUtilitiesHearingExaminerRecommendedReturnonEquityPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Increase (Decrease) in Non-fuel Revenue Requirement + References No definition available. + Details
Name: | pnm_PublicUtilitiesIncreaseDecreaseinNonfuelRevenueRequirement
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Integrated Resource Plan, Action Plan, Period + References No definition available. + Details
Name: | pnm_PublicUtilitiesIntegratedResourcePlanActionPlanPeriod
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Integrated Resource Plan, Number of Statewide Meetings + References No definition available. + Details
Name: | pnm_PublicUtilitiesIntegratedResourcePlanNumberofStatewideMeetings
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of Mega Watts of Solar Photovoltaic Capacity + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberOfMegaWattsOfSolarPhotovoltaicCapacity
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Public Utilities, Number of Mega Watts of Solar Photovoltaic Capacity, Current Output + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofMegaWattsofSolarPhotovoltaicCapacityCurrentOutput
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of Mega Watts of Wind Energy Capacity + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofMegaWattsofWindEnergyCapacity
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

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 Requested Rates + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofRequestedRates
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of leases under which assets were purchased + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofleasesunderwhichassetswerepurchased
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Number of leases under which lease term was extended + References No definition available. + Details
Name: | pnm_PublicUtilitiesNumberofleasesunderwhichleasetermwasextended
Namespace Prefix: | pnm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Percent of Non-fuel Revenue Requirement Change Implemented + References No definition available. + Details
Name: | pnm_PublicUtilitiesPercentofNonfuelRevenueRequirementChangeImplemented
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Planning Period Covered of IRP + References No definition available. + Details
Name: | pnm_PublicUtilitiesPlanningPeriodCoveredOfIrp
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Profit incentive sliding scale multiplier + References No definition available. + Details
Name: | pnm_PublicUtilitiesProfitincentiveslidingscalemultiplier
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Program Costs Related To Energy Efficiency + References No definition available. + Details
Name: | pnm_PublicUtilitiesProgramCostsRelatedToEnergyEfficiency
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Proposed Term to Provide Customers with Benefits Related to Reduction in State Corporate Income Tax Rate + References No definition available. + Details
Name: | pnm_PublicUtilitiesProposedTermtoProvideCustomerswithBenefitsRelatedtoReductioninStateCorporateIncomeTaxRate
Namespace Prefix: | pnm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reasonable Cost Threshold + References No definition available. + Details
Name: | pnm_PublicUtilitiesReasonableCostThreshold
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Regulatory Disallowance capital improvements + References No definition available. + Details
Name: | pnm_PublicUtilitiesRegulatoryDisallowancecapitalimprovements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Regulatory disallowance, Lease Abandonment costs + References No definition available. + Details
Name: | pnm_PublicUtilitiesRegulatorydisallowanceLeaseAbandonmentcosts
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Renewable Energy Procurement Plan, Proposed Recovery, Amount + References No definition available. + Details
Name: | pnm_PublicUtilitiesRenewableEnergyProcurementPlanProposedRecoveryAmount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Renewable Energy Procurement Plan, Requested Additional Megawatt Hours, Year 1 + References No definition available. + Details
Name: | pnm_PublicUtilitiesRenewableEnergyProcurementPlanRequestedAdditionalMegawattHoursYear1
Namespace Prefix: | pnm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Renewable Energy Procurement Plan, Requested Additional Megawatt Hours, Year 2 + References No definition available. + Details
Name: | pnm_PublicUtilitiesRenewableEnergyProcurementPlanRequestedAdditionalMegawattHoursYear2
Namespace Prefix: | pnm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Renewable Energy Procurement Plan, Requested Solar Facility Construction, Megawatts + References No definition available. + Details
Name: | pnm_PublicUtilitiesRenewableEnergyProcurementPlanRequestedSolarFacilityConstructionMegawatts
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Requested Rate Increase (Decrease), Duplicative Amount + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequestedRateIncreaseDecreaseDuplicativeAmount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Requested Rate increase (Decrease), Balanced Draft Technology Cost Recovery + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequestedRateincreaseDecreaseBalancedDraftTechnologyCostRecovery
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Requested Rate increase (Decrease), non-fuel amount + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequestedRateincreaseDecreasenonfuelamount
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Regulated Operations, Required Percentage of Diversification + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequiredPercentageOfDiversification
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Regulated Operations, Required Percentage of Renewable Energy in Portfolio to Electric Sales + References No definition available. + Details
Name: | pnm_PublicUtilitiesRequiredPercentageOfRenewableEnergyInPortfolioToElectricSales
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Return on Equity, Regulatory Disallowance + References No definition available. + Details
Name: | pnm_PublicUtilitiesReturnonEquityRegulatoryDisallowance
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Revenue from Renewable energy rider + References No definition available. + Details
Name: | pnm_PublicUtilitiesRevenuefromRenewableenergyrider
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Public Utilities, Solar generation capacity in Megawatts + References No definition available. + Details
Name: | pnm_PublicUtilitiesSolargenerationcapacityinMegawatts
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Solar generation capacity in Megawatts, current construction + References No definition available. + Details
Name: | pnm_PublicUtilitiesSolargenerationcapacityinMegawattscurrentconstruction
Namespace Prefix: | pnm_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, excess return on jurisdictional equity that would require refund + References No definition available. + Details
Name: | pnm_PublicUtilitiesexcessreturnonjurisdictionalequitythatwouldrequirerefund
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Regulatory Disallowance + References No definition available. + Details
Name: | pnm_RegulatoryDisallowance
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfPropertyRepairsAndMaintenance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueInputsDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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=82911808&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=82911808&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's requested return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=77990344&loc=SL6759159-111685 + Details
Name: | us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=pnm_PublicServiceCompanyOfNewMexicoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnm_PNMRDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_A2015ElectricRateCaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_A2014ElectricRateCaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_RenewablePortfolioStandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_RenewableEnergyRiderMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_RenewablePortfolioStandardSupplementalProcurementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_RenewablePortfolioStandard2014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_IntegratedResourcePlan2011Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_AdvancedmeteringinfrastructureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_FacebookDataCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnm_CasaMesaWindMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnm_AvangridRenewablesLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnm_Route66SolarEnergyCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=pnm_PaloVerdeNuclearGeneratingStationUnit2LeasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=pnm_AlvaradosquareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=pnm_PaloVerdeNuclearGeneratingStationUnit1LeasesextendedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis=pnm_CleanAirActBalancedDraftTechnologyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=pnm_SanJuanGeneratingStationUnits1And4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_PublicUtilitiesCommitmentsAndContingenciesByNatureOfExpenseAxis=pnm_InstallationCostsIncludingConstructionManagementGrossReceiptsTaxesAfudcAndOtherPnmCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=pnm_NMPRCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DateOfRegulatoryActionAxis=pnm_RequiredPercentageBy2011Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DateOfRegulatoryActionAxis=pnm_RequiredPercentageBy2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DateOfRegulatoryActionAxis=pnm_RequiredPercentageBy2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DiversificationByTypeAxis=pnm_WindEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DiversificationByTypeAxis=pnm_SolarEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DiversificationByTypeAxis=pnm_DistributedGenerationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_DiversificationByTypeAxis=pnm_RenewableTechnologiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=pnm_NewMexicoWindMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=pnm_LightningDockGeothermalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_TypeOfRegulatoryCostAxis=pnm_DisincentivesIncentivesAdderMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_A2017EnergyEfficiencyandLoadManagementProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_EnergyEfficiencyandLoadManagementProgramProposed2018PortfolioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pnm_ScheduleOfRegulatoryRateMattersAxis=pnm_EnergyEfficiencyandLoadManagementProgramProposed2019PortfolioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=pnm_FourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |