Regulatory and Rate Matters - Energy Efficiency and Load Management (Details) - PNM $ in Millions	Apr. 17, 2023 USD ($) program	Apr. 15, 2020 USD ($) MMBTU GWh program
Energy Efficiency and Load Management Program
Public Utilities, General Disclosures [Line Items]
Number of programs | program	10	12
Program costs related to energy efficiency, in year one	$ 34.5	$ 31.4
Program costs related to energy efficiency, in year two	35.4	31.0
Program costs related to energy efficiency, in year three	$ 36.5	$ 29.6
2021 Energy Efficiency Annual Report | Disincentives and Incentives Added
Public Utilities, General Disclosures [Line Items]
Energy efficiency and load management programs targeted energy savings (in Gigawatts) | GWh		94
Minimum | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Profit incentive sliding scale multiplier	0.071	0.071
Energy efficiency and load management programs targeted energy savings (in Gigawatts) | MMBTU		80
Maximum | Energy Efficiency and Load Management Program
Public Utilities, General Disclosures [Line Items]
Profit incentive sliding scale multiplier	0.0882