Fair Value of Derivative and Other Financial Instruments - Items not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
PNMR
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 3,915,010	$ 3,571,382
PNMR | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	3,698,919	3,295,150
Public Service Company of New Mexico
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,975,987	1,818,169
Public Service Company of New Mexico | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,881,110	1,696,620
Texas-New Mexico Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,039,023	1,006,722
Texas-New Mexico Power Company | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 918,050	$ 853,673