Segment Information - Schedule of Summarized Financial Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Electric Operating Revenues	$ 2,249,555	$ 1,779,873	$ 1,523,012
Gross margin	740,455	648,949	606,727
Other operating expenses	563,001	542,760	514,878
Depreciation and amortization	304,853	284,107	275,612
Operating income	393,760	308,153	285,281
Interest income	16,095	14,662	14,223
Other income (deductions)	(70,637)	18,491	22,840
Interest charges	(127,908)	(96,877)	(114,392)
Earnings before Income Taxes	211,310	244,429	207,952
Income taxes (benefit)	26,130	32,582	20,636
Net Earnings	185,180	211,847	187,316
Valencia non-controlling interest	(15,122)	(15,490)	(14,013)
Subsidiary preferred stock dividends	(528)	(528)	(528)
Net Earnings Attributable to PNMR	169,530	195,829	172,775
Total Assets	9,257,377	8,666,885	7,939,854
Goodwill	278,297	278,297	278,297
Utility margin	$ 1,261,614	1,135,020	1,075,771
PNM
Segment Reporting Information [Line Items]
Number of operating segments | segment	1
Gross margin	$ 516,375	466,092	441,831
Other operating expenses	460,513	438,372	414,445
Depreciation and amortization	180,812	170,365	165,325
Operating income	261,487	221,497	214,897
Interest income	14,816	14,605	14,469
Other income (deductions)	(77,012)	13,809	17,120
Interest charges	(61,073)	(51,360)	(64,615)
Earnings before Income Taxes	138,218	198,551	181,871
Income taxes (benefit)	19,198	26,992	21,857
Net Earnings	119,020	171,559	160,014
Valencia non-controlling interest	(15,122)	(15,490)	(14,013)
Subsidiary preferred stock dividends	(528)	(528)	(528)
Net Earnings Attributable to PNMR	103,370	155,541	145,473
Total Assets	6,272,166	6,060,133	5,581,033
Goodwill	51,632	51,632	51,632
Utility margin	$ 902,812	830,234	794,667
TNMP
Segment Reporting Information [Line Items]
Number of operating segments | segment	1
Gross margin	$ 224,080	182,857	164,896
Other operating expenses	124,519	114,228	104,852
Depreciation and amortization	98,316	90,440	87,799
Operating income	135,967	100,118	88,453
Interest income	0	0	0
Other income (deductions)	8,653	5,408	6,828
Interest charges	(37,192)	(33,735)	(30,388)
Earnings before Income Taxes	107,428	71,791	64,893
Income taxes (benefit)	15,161	7,912	6,308
Net Earnings	92,267	63,879	58,585
Valencia non-controlling interest	0	0	0
Subsidiary preferred stock dividends	0	0	0
Net Earnings Attributable to PNMR	92,267	63,879	58,585
Total Assets	2,746,601	2,364,772	2,132,580
Goodwill	226,665	226,665	226,665
Utility margin	358,802	304,786	281,104
Corporate and Other
Segment Reporting Information [Line Items]
Gross margin	0	0	0
Other operating expenses	(22,031)	(9,840)	(4,419)
Depreciation and amortization	25,725	23,302	22,488
Operating income	(3,694)	(13,462)	(18,069)
Interest income	1,279	57	(246)
Other income (deductions)	(2,278)	(726)	(1,108)
Interest charges	(29,643)	(11,782)	(19,389)
Earnings before Income Taxes	(34,336)	(25,913)	(38,812)
Income taxes (benefit)	(8,229)	(2,322)	(7,529)
Net Earnings	(26,107)	(23,591)	(31,283)
Valencia non-controlling interest	0	0	0
Subsidiary preferred stock dividends	0	0	0
Net Earnings Attributable to PNMR	(26,107)	(23,591)	(31,283)
Total Assets	238,610	241,980	226,241
Goodwill	0	0	0
Utility margin	0	0	0
Electricity
Segment Reporting Information [Line Items]
Electric Operating Revenues	2,249,555	1,779,873	1,523,012
Cost of energy	987,941	644,853	447,241
Utility margin	1,261,614	1,135,020	1,075,771
Electricity | PNM
Segment Reporting Information [Line Items]
Electric Operating Revenues	1,766,825	1,362,020	1,139,834
Cost of energy	864,013	531,786	345,167
Utility margin	902,812	830,234	794,667
Electricity | TNMP
Segment Reporting Information [Line Items]
Electric Operating Revenues	482,730	417,853	383,178
Cost of energy	123,928	113,067	102,074
Utility margin	358,802	304,786	281,104
Electricity | Corporate and Other
Segment Reporting Information [Line Items]
Electric Operating Revenues	0	0	0
Cost of energy	0	0	0
Utility margin	$ 0	$ 0	$ 0