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Regulatory and Rate Matters - SJGS Abandonment Application (Details) $ in Millions |  |  | 12 Months Ended |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 01, 2020 USD ($) | Jul. 01, 2019 USD ($) scenario MW | Dec. 31, 2020 USD ($) | Nov. 13, 2020 MW | Sep. 28, 2020 USD ($) MW | Jun. 30, 2020 USD ($) | Jun. 24, 2020 MW | Mar. 27, 2020 MMBTU MW | Feb. 21, 2020 USD ($) | May 31, 2019 MW
PNM Solar Direct |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  |  |  |  | 50
Replacement Resource Portfolio Two | Hearing Examiners Approach Two |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts for natural gas facility (in Megawatts) |  |  |  |  |  |  | 200 |  |  |
Replacement Resource Portfolio Four | Hearing Examiners Approach One |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts for demand response (in Megawatts) |  |  |  |  |  |  | 24 |  |  |
Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  |  |  |  | 40 |  |
Solar distributed generation (in mw) |  |  |  |  |  |  |  | 300 |  |
Solar generation capacity, power purchase agreements (in Megawatts) | MMBTU |  |  |  |  |  |  |  | 20 |  |
Public Service Company of New Mexico | PNM Solar Direct |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  |  | 50 |  |
Public Service Company of New Mexico | Replacement Resource Portfolio One | Hearing Examiners Approach One |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  |  |  | 150 |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  | 300 |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Two | Hearing Examiners Approach One |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  |  |  | 20 |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  | 50 |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Three |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  | 100 | 100 |  |  |  |  |
Solar distributed generation (in mw) |  |  |  | 200 | 200 |  |  |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Three | Hearing Examiners Approach One |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  |  |  | 100 |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  | 200 |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Four |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  | 30 | 30 |  |  |  |  |
Solar distributed generation (in mw) |  |  |  | 100 | 100 |  |  |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Four | Hearing Examiners Approach One |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  |  |  | 30 |  |  |
Solar distributed generation (in mw) |  |  |  |  |  |  | 100 |  |  |
Public Service Company of New Mexico | Replacement Resource Portfolio Five |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  | 130 | 130 |  |  |  |  |
Solar distributed generation (in mw) |  |  |  | 299 | 299 |  |  |  |  |
San Juan Generating Station |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Estimated costs of replacement resources | $ |  |  |  |  | $ 8.1 |  |  |  |  |
San Juan Generating Station | Other deferred credits |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  | $ 38.1 |  |  |  |  |  |  |
San Juan Generating Station | Employee Severance |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  |  |  |  | $ 9.4 |  |  |  |
San Juan Generating Station | Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Number of megawatts in natural gas-fired peaking plant (in megawatts) |  | 280 |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  | 70 |  |  |  |  |  |  |  |
Solar distributed generation (in mw) |  | 350 |  |  |  |  |  |  |  |
Number of megawatts in battery storage facilities, replacement resource scenario (in megawatts) |  | 60 |  |  |  |  |  |  |  |
Number of replacement resource scenarios | scenario |  | 3 |  |  |  |  |  |  |  |
Request issuance of energy transition bonds | $ | $ 361.0 | $ 361.0 |  |  |  |  |  |  |  |
Forecasted undepreciated investment | $ |  |  | 283.0 |  |  |  |  |  | $ 361.0 |
Plant decommissioning and coal mine reclamation costs | $ |  |  | 28.6 |  |  |  |  |  |  |
Upfront financing costs | $ |  |  | 9.6 |  |  |  |  |  |  |
Severance costs | $ |  |  | 20.0 |  |  |  |  |  |  |
Proceeds from securitization bonds | $ |  | $ 19.8 |  |  |  |  |  |  |  |
San Juan Generating Station | Public Service Company of New Mexico | Other deferred credits |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  | $ 36.8 |  |  |  |  |  |  |
San Juan Generating Station | Public Service Company of New Mexico | Employee Severance |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  |  |  |  | 8.1 |  |  |  |
San Juan Generating Station | Public Service Company of New Mexico | Other Restructuring |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  |  |  |  | 8.9 |  |  |  |
San Juan Generating Station | Public Service Company of New Mexico | Economic Development and Workforce Training Costs |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Restructuring reserve | $ |  |  |  |  |  | $ 19.8 |  |  |  |

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