Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Earnings Attributable to PNMR	$ 122,433	$ 113,321	$ 153,785	$ 184,609
Average Number of Common Shares:
Outstanding during period (in shares)	85,835	85,835	85,835	85,835
Vested awards of restricted stock (in shares)	266	237	291	230
Average Shares – Basic (in shares)	86,101	86,072	86,126	86,065
Dilutive Effect of Common Stock Equivalents:
Restricted stock (in shares)	35	41	52	41
Average Shares – Diluted (in shares)	86,136	86,113	86,178	86,106
Net Earnings Per Share of Common Stock:
Basic (in dollars per share)	$ 1.42	$ 1.32	$ 1.79	$ 2.14
Diluted (in dollars per share)	$ 1.42	$ 1.32	$ 1.78	$ 2.14