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Commitments and Contingencies - Coal Supply (Details) |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Feb. 17, 2022 $ / T | Dec. 31, 2020 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Jan. 31, 2016 USD ($)
Other Commitments [Line Items] |  |  |  |  |  |
Other current assets |  | $ 22,485,000 | $ 1,635,000 | $ 22,485,000 |  |
Four Corners | Coal Supply |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Payments for relief from obligations |  |  | 75,000,000 |  |  |
Public Service Company of New Mexico |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Other current assets |  | 16,924,000 | 1,456,000 | 16,924,000 |  |
Public Service Company of New Mexico | Loss on long-term purchase commitment | San Juan Generating Station |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Annual funding post-term reclamation trust |  |  | 5,200,000 | 3,200,000 | $ 5,500,000 |
Public Service Company of New Mexico | Increase in coal mine decommissioning liability |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Net expense |  |  |  |  | 800,000 |
Public Service Company of New Mexico | Mine Reclamation Trust | San Juan Generating Station |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Reclamation trust funding, next fiscal year |  |  | 5,600,000 |  |  |
Reclamation trust funding, year 2 |  |  | 0 |  |  |
Reclamation trust funding, year 3 |  |  | 0 |  |  |
Public Service Company of New Mexico | Mine Reclamation Trust | Four Corners |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Funds contributed to mine reclamation trust |  |  | 2,200,000 | 2,000,000 | $ 2,300,000 |
Funds contributed next fiscal year through year five |  |  | 2,100,000 |  |  |
Public Service Company of New Mexico | Mine Reclamation Trust | San Juan Generating Station And Four Corners |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Customer reclamation funding cost, maximum |  |  | 100,000,000 |  |  |
Public Service Company of New Mexico | Surface | Loss on long-term purchase commitment |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Liability for interim storage costs |  | 71,700,000 | 67,400,000 | 71,700,000 |  |
Public Service Company of New Mexico | Surface | Increase in coal mine decommissioning liability |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Net expense |  | 3,600,000 |  |  |  |
Public Service Company of New Mexico | Underground | Loss on long-term purchase commitment |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Liability for interim storage costs |  | 26,100,000 | 27,900,000 | 26,100,000 |  |
Public Service Company of New Mexico | Underground | Increase in coal mine decommissioning liability |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Net expense |  | 100,000 |  | 9,300,000 |  |
Public Service Company of New Mexico | San Juan Generating Station | Surface | Loss on long-term purchase commitment |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Estimate of possible loss |  |  | 74,100,000 |  |  |
Public Service Company of New Mexico | San Juan Generating Station | Underground | Loss on long-term purchase commitment |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Estimate of possible loss |  |  | 34,900,000 |  |  |
Public Service Company of New Mexico | San Juan Generating Station | Coal Supply |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Other current assets |  | $ 26,300,000 | 20,400,000 | 26,300,000 |  |
Public Service Company of New Mexico | San Juan Generating Station | Coal Supply | Subsequent Event |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Increase in price of coal (per ton) | $ / T | 5.00 |  |  |  |  |
Public Service Company of New Mexico | Four Corners | Increase in coal mine decommissioning liability |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Net expense |  |  |  | $ 2,500,000 |  |
NM Capital | San Juan Generating Station | Coal Supply |  |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |  |
Coal mine reclamation bonds to be posted with NMMMD |  |  | 118,700,000 |  |  |
Issuance in letters of credit |  |  | $ 30,300,000 |  |  | $ 30,300,000

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