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Financing - Long-term Debt (Details) - USD ($) | Jan. 18, 2019 | Mar. 29, 2019 | Feb. 26, 2019 | Feb. 22, 2019 | Dec. 31, 2018 | Dec. 21, 2018 | Jul. 31, 2018 | May 14, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jul. 20, 2017 | Dec. 21, 2016 | Dec. 17, 2015
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Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total |  |  |  |  | $ 2,666,345,000 |  |  |  | $ 2,431,507,000 |  |  |  |
Principal, less current maturities |  |  |  |  | 0 |  |  |  | 257,293,000 |  |  |  |
Long-term debt, excluding current maturities, gross |  |  |  |  | 2,666,345,000 |  |  |  | 2,174,214,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | (3,765,000) |  |  |  | (6,138,000) |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities |  |  |  |  | 0 |  |  |  | 398,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities |  |  |  |  | (3,765,000) |  |  |  | (6,536,000) |  |  |  |
PNMR 2016 Two-Year Term Loan due December 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  |  |  |  |  |  |  |  | $ 100,000,000.0 |
PNMR 2018 Two-Year Term Loan due December 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  | $ 50,000,000 |  |  |  |  |  |  |
Public Service Company of New Mexico |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total |  |  |  |  | 1,665,845,000 |  |  |  | 1,665,870,000 |  |  |  |
Principal, less current maturities |  |  |  |  | 0 |  |  |  | 25,000 |  |  |  |
Long-term debt, excluding current maturities, gross |  |  |  |  | 1,665,845,000 |  |  |  | 1,665,845,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 9,355,000 |  |  |  | 7,960,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities |  |  |  |  | 0 |  |  |  | 2,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities |  |  |  |  | $ 9,355,000 |  |  |  | $ 7,958,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 1.875% due April 2033, mandatory tender - October 1, 2021 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 1.875% |  |  |  | 1.875% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 146,000,000 |  |  |  | $ 146,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 1,022,000 |  |  |  | $ 1,383,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 6.25% due January 2038 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 6.25% |  |  |  | 6.25% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 36,000,000 |  |  |  | $ 36,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 216,000 |  |  |  | 228,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.125% due June 2040, mandatory tender - June 1, 2022 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 2.125% |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 37,000,000 |  |  |  | 37,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 314,000 |  |  |  | $ 404,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.20% due June 2040, mandatory tender - June 1, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 5.20% |  |  |  | 5.20% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 40,045,000 |  |  |  | $ 40,045,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 62,000 |  |  |  | $ 105,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.90% due June 2040 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 5.90% |  |  |  | 5.90% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 255,000,000 |  |  |  | $ 255,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 1,950,000 |  |  |  | $ 2,040,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 6.25% due June 2040 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 6.25% |  |  |  | 6.25% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 11,500,000 |  |  |  | $ 11,500,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 88,000 |  |  |  | 92,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.45% due September 2042, mandatory tender - June 1, 2022 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 2.45% |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 20,000,000 |  |  |  | 20,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 119,000 |  |  |  | $ 153,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 2.40% due June 2043, mandatory tender - June 1, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 2.40% |  |  |  | 2.40% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 39,300,000 |  |  |  | $ 39,300,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 146,000 |  |  |  | $ 243,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.20% due June 2043, mandatory tender - June 1, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 5.20% |  |  |  | 5.20% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 21,000,000 |  |  |  | $ 21,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 31,000 |  |  |  | $ 53,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 7.95% due May 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 7.95% |  |  |  | 7.95% |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 7.50% due August 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 7.50% |  |  |  | 7.50% |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 5.35% due October 2021 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 5.35% |  |  |  | 5.35% |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.15% due May 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.15% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.45% due May 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.45% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.85% due August 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.85% |  |  |  | 3.85% |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.68% due May 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.68% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.78% due August 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.78% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 3.93% due May 2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.93% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 4.22% due May 2038 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 4.22% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 4.50% due May 2048 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 4.50% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes, Pollution Control Revenue Bonds: | 4.60% due August 2048 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 4.60% |  |  |  |  |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 7.95% due May 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  |  |  |  | 7.95% |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 0 |  |  |  | $ 350,000,000 | $ 450,000,000.0 |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 272,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 7.50% due August 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  |  |  | 7.50% |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 0 |  |  |  | 100,025,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 73,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 5.35% due October 2021 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 160,000,000 |  |  |  | 160,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 455,000 |  |  |  | 617,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.15% due May 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 55,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 338,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.45% due May 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 104,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 666,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.85% due August 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 250,000,000 |  |  |  | 250,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 1,974,000 |  |  |  | 2,274,000 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.68% due May 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 88,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 581,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.78% due August 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 15,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 101,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 3.93% due May 2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 38,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 256,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.22% due May 2038 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 45,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 307,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.50% due May 2048 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 20,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 138,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | 4.60% due August 2048 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | 85,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 590,000 |  |  |  | 0 |  |  |  |
Public Service Company of New Mexico | Senior Unsecured Notes: | PNM 2017 Term Loan due January 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 200,000,000 |  |  |  | 200,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 1,000 |  |  |  | 23,000 |  |  |  |
Texas-New Mexico Power Company |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total |  |  |  |  | 560,500,000 |  |  |  | 465,500,000 |  |  |  |
Principal, less current maturities |  |  |  |  | 0 |  |  |  | 0 |  |  |  |
Long-term debt, excluding current maturities, gross |  |  |  |  | 560,500,000 |  |  |  | 465,500,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | (14,898,000) |  |  |  | (15,120,000) |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities |  |  |  |  | 0 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities |  |  |  |  | $ (14,898,000) |  |  |  | $ (15,120,000) |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 9.50% due April 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 9.50% |  |  |  | 9.50% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 172,302,000 |  |  |  | $ 172,302,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 206,000 |  |  |  | $ 1,032,000 |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 6.95% due April 2043 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 6.95% |  |  |  | 6.95% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 93,198,000 |  |  |  | $ 93,198,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ (17,347,000) |  |  |  | $ (18,057,000) |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 4.03% due July 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 4.03% |  |  |  | 4.03% |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 80,000,000 |  |  |  | $ 80,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 580,000 |  |  |  | $ 686,000 |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.53% due February 2026 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 60,000,000.0
Stated percentage |  |  |  |  | 3.53% |  |  |  | 3.53% |  |  |  | 3.53%
Unsecured long-term debt, noncurrent |  |  |  |  | $ 60,000,000 |  |  |  | $ 60,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 585,000 |  |  |  | 667,000 |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.22% due August 2027 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.22% |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 60,000,000 |  |  |  | 60,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 494,000 |  |  |  | 552,000 |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | 3.85% due June 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  |  | 3.85% |  |  |  |  |  |  |  |
Unsecured long-term debt, noncurrent |  |  |  |  | $ 60,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 584,000 |  |  |  | 0 |  |  |  |
Texas-New Mexico Power Company | First Mortgage Bonds: | TNMP 2018 Term Loan due July 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 35,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 0 |  |  |  |
PNMR |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total |  |  |  |  | 440,000,000 |  |  |  | 300,137,000 |  |  |  |
Principal, less current maturities |  |  |  |  | 0 |  |  |  | 257,268,000 |  |  |  |
Long-term debt, excluding current maturities, gross |  |  |  |  | 440,000,000 |  |  |  | 42,869,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 1,778,000 |  |  |  | 1,022,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, Less current maturities |  |  |  |  | 0 |  |  |  | 396,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net, excluding current maturities |  |  |  |  | 1,778,000 |  |  |  | 626,000 |  |  |  |
PNMR | PNMR 2015 Term Loan due March 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 0 |  |  |  | 150,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 12,000 |  |  |  |
PNMR | BTMU Term Loan |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 0 |  |  |  | 50,137,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 1,001,000 |  |  |  |
PNMR | PNMR 2016 Two-Year Term Loan due December 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 0 |  |  |  | 100,000,000 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 0 |  |  |  | 9,000 |  |  |  |
PNMR | PNMR 3.25% 2018 SUNs due March 2021 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 300,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 1,690,000 |  |  |  | 0 |  |  |  |
PNMR | PNMR Development Term Loan due November 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 90,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | 88,000 |  |  |  | 0 |  |  |  |
PNMR | PNMR 2018 Two-Year Term Loan due December 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  |  |  | 50,000,000 |  |  |  | 0 |  |  |  |
Unamortized Discounts, (Premiums), and Issuance Costs, net |  |  |  |  | $ 0 |  |  |  | $ 0 |  |  |  |
Subsequent Event | PNM | PNM 2019 Term Loan |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount | $ 250,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Texas-New Mexico Power Company | Mortgages | TNMP 2019 Bond Purchase Agreement |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  | $ 225,000,000 | $ 305,000,000.0 |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  | 400.00% |  |  |  |  |  |  |  |  |  |
Subsequent Event | Texas-New Mexico Power Company | Senior Unsecured Notes: | 9.50% due April 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Extinguishment of debt | $ 172,300,000 |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage | 9.50% |  |  |  |  |  |  |  |  |  |  |  |
JPMorgan Chase Bank, N.A. and U.S. Bank National Association | Public Service Company of New Mexico | Notes Payable to Banks | PNM 2017 Term Loan due January 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  | $ 200,000,000.0 |  |
Stated percentage |  |  |  |  | 3.26% |  |  |  |  |  |  |  |
JPMorgan Chase Bank, N.A. and U.S. Bank National Association | Subsequent Event | Public Service Company of New Mexico | Notes Payable to Banks | PNM 2019 Term Loan |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated percentage |  |  |  | 3.13% |  |  |  |  |  |  |  |  |

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