Schedule I - Condensed Financial Information of Parent Company - Balance Sheets Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares outstanding (in shares)	85,834,874	85,834,874
PNM Resources
Condensed Financial Statements, Captions [Line Items]
Accumulated depreciation	$ 17,721	$ 16,585
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	85,834,874	85,834,874
Common stock, shares outstanding (in shares)	85,834,874	85,834,874