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Regulatory and Rate Matters - Advanced Metering Infrastructure Application and Facebook Data Center Project (Details) | 3 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2017 MW | Dec. 31, 2017 power_purchase_agreement Facility MW | Feb. 08, 2021 MW | Dec. 31, 2020 | Mar. 27, 2020 MW | Dec. 31, 2019 MW
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Ownership percentage |  |  |  | 50.00% |  |
Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
PPA term | 25 years |  |  |  |  |
Facebook Data Center | Subsequent Event |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) |  |  | 190 |  |  |
Number of megawatts in battery storage facilities (in megawatts) |  |  | 100 |  |  |
Solar generation capacity expected to be operational (in megawatts) |  |  | 50 |  |  |
Public Service Company of New Mexico |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) |  |  |  |  | 300 |
Number of megawatts in battery storage facilities (in megawatts) |  |  |  |  | 40 |
PNMR Development |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) |  |  |  |  |  | 130
Ownership percentage |  |  |  |  |  | 50.00%
PNMR Development | Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) | 50 | 50 |  |  |  |
Casa Mesa Wind, LLC | Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) | 50 | 50 |  |  |  |
Avangrid Renewables, LLC | Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) | 166 | 166 |  |  |  |
Route 66 Solar Energy Center, LLC | Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) | 50 | 50 |  |  |  |
NMRD | Facebook Data Center |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Solar distributed generation (in mw) | 100 | 100 |  |  |  |
Number of additional PPAs | power_purchase_agreement |  | 2 |  |  |  |
Number of solar facilities | Facility |  | 2 |  |  |  |

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