Condensed Consolidated Balance Sheets - PNMR (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Allowance for uncollectible accounts	$ 6,392	$ 7,265
Accumulated depreciation, nuclear fuel	$ 47,131	$ 41,181
Cumulative preferred stock of subsidiary, stated value (in dollars per share)	$ 100	$ 100
Cumulative preferred stock of subsidiary, shares authorized (in shares)	10,000,000	10,000,000
Cumulative preferred stock of subsidiary, shares issued (in shares)	115,293	115,293
Cumulative preferred stock of subsidiary, shares outstanding (in shares)	115,293	115,293
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