Segment Information - Schedule of Gross Margin (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Utility margin	$ 655,831	$ 740,455	$ 648,949
Transmission and distribution costs	98,721	94,684	81,335
Depreciation and amortization	290,775	279,128	260,805
Utility margin	1,136,937	1,261,614	1,135,020
Electricity, Generation
Segment Reporting Information [Line Items]
Energy production costs	91,610	147,347	143,931
PNM
Segment Reporting Information [Line Items]
Utility margin	409,366	516,375	466,092
Transmission and distribution costs	61,725	58,278	49,846
Depreciation and amortization	177,633	180,812	170,365
Utility margin	740,334	902,812	830,234
PNM | Electricity, Generation
Segment Reporting Information [Line Items]
Energy production costs	91,610	147,347	143,931
TNMP
Segment Reporting Information [Line Items]
Utility margin	246,465	224,080	182,857
Transmission and distribution costs	36,996	36,406	31,489
Depreciation and amortization	113,142	98,316	90,440
Utility margin	396,603	358,802	304,786
TNMP | Electricity, Generation
Segment Reporting Information [Line Items]
Energy production costs	0	0	0
Corporate and Other
Segment Reporting Information [Line Items]
Utility margin	0	0	0
Transmission and distribution costs	0	0	0
Depreciation and amortization	0	0	0
Utility margin	0	0	0
Corporate and Other | Electricity, Generation
Segment Reporting Information [Line Items]
Energy production costs	$ 0	$ 0	$ 0