Summary of the Business and Significant Accounting Policies - Inventories/Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, Inventory [Line Items]
Inventory	$ 66,733	$ 65,061
Coal
Public Utilities, Inventory [Line Items]
Inventory	985	2,973
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	65,748	62,088
Public Service Company of New Mexico
Public Utilities, Inventory [Line Items]
Inventory	55,890	57,942
Public Service Company of New Mexico | Coal
Public Utilities, Inventory [Line Items]
Inventory	985	2,973
Public Service Company of New Mexico | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 54,905	$ 54,969
Public Service Company of New Mexico | Electric plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	2.55%	2.48%	2.47%
Public Service Company of New Mexico | Common, intangible, and general plant
Public Utilities, Inventory [Line Items]
Depreciation average rates used	7.83%	7.91%	7.65%
Texas-New Mexico Power Company
Public Utilities, Inventory [Line Items]
Depreciation average rates used	3.72%	3.88%	3.95%
Inventory	$ 10,843	$ 7,119
Texas-New Mexico Power Company | Coal
Public Utilities, Inventory [Line Items]
Inventory	0	0
Texas-New Mexico Power Company | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 10,843	$ 7,119