Electric Operating Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Contracts with customers	$ 1,914,868	$ 2,250,217	$ 1,744,681
Alternative revenue programs	6,607	(19,485)	(3,764)
Other electric operating revenue	17,723	18,823	38,956
Electric Operating Revenues	1,939,198	2,249,555	1,779,873
Electricity
Disaggregation of Revenue [Line Items]
Electric Operating Revenues	1,939,198	2,249,555	1,779,873
Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers	295,306	263,203	182,032
Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers	9,415	9,207	8,564
Wholesale energy sales
Disaggregation of Revenue [Line Items]
Contracts with customers	248,801	534,196	184,132
PNM
Disaggregation of Revenue [Line Items]
Contracts with customers	1,376,806	1,747,310	1,327,172
Alternative revenue programs	9,419	692	(4,108)
Other electric operating revenue	17,723	18,823	38,956
Electric Operating Revenues	1,403,948	1,766,825	1,362,020
PNM \| Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers	159,475	149,421	87,880
PNM \| Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers	5,676	5,390	4,770
PNM \| Wholesale energy sales
Disaggregation of Revenue [Line Items]
Contracts with customers	248,801	534,196	184,132
TNMP
Disaggregation of Revenue [Line Items]
Contracts with customers	538,062	502,907	417,509
Alternative revenue programs	(2,812)	(20,177)	344
Other electric operating revenue	0	0	0
Electric Operating Revenues	535,250	482,730	417,853
TNMP \| Transmission
Disaggregation of Revenue [Line Items]
Contracts with customers	135,831	113,782	94,152
TNMP \| Miscellaneous
Disaggregation of Revenue [Line Items]
Contracts with customers	3,739	3,817	3,794
TNMP \| Wholesale energy sales
Disaggregation of Revenue [Line Items]
Contracts with customers	0	0	0
Residential \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	616,401	672,650	643,516
Residential \| PNM \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	425,448	484,699	484,720
Residential \| TNMP \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	190,953	187,951	158,796
Commercial \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	547,218	576,222	544,787
Commercial \| PNM \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	391,964	422,163	419,251
Commercial \| TNMP \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	155,254	154,059	125,536
Industrial \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	135,592	122,021	117,568
Industrial \| PNM \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	90,084	85,102	88,479
Industrial \| TNMP \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	45,508	36,919	29,089
Public authority \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	27,795	27,709	28,862
Public authority \| PNM \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	21,018	21,330	22,720
Public authority \| TNMP \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	6,777	6,379	6,142
Economy energy service \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	34,340	45,009	35,220
Economy energy service \| PNM \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	34,340	45,009	35,220
Economy energy service \| TNMP \| Electricity
Disaggregation of Revenue [Line Items]
Contracts with customers	$ 0	$ 0	$ 0

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