Earnings and Dividends Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Earnings Attributable to PNMR	$ 169,530	$ 195,829	$ 172,775
Average Number of Common Shares:
Outstanding during year (in shares)	85,835	85,835	79,941
Vested awards of restricted stock (in shares)	287	235	216
Average Shares – Basic (in shares)	86,122	86,070	80,157
Dilutive Effect of Common Stock Equivalents:
PNMR 2020 Forward Equity Sale Agreements (in shares)	0	0	106
Stock options and restricted stock (in shares)	47	41	40
Average Shares – Diluted (in shares)	86,169	86,111	80,303
Net Earnings Attributable to PNMR Per Share of Common Stock:
Basic (in dollars per share)	$ 1.97	$ 2.28	$ 2.16
Diluted (in dollars per share)	1.97	2.27	2.15
Dividends Declared per Common Share (in dollars per share)	$ 1.41	$ 1.33	$ 1.25