Pension and Other Postretirement Benefits - Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.00%
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.74%	3.00%	2.66%
Discount rate for determining net periodic benefit cost	3.00%	2.66%	3.42%
Expected return on plan assets	5.50%	5.50%	5.90%
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.75%	2.99%	2.65%
Discount rate for determining net periodic benefit cost	2.99%	2.65%	3.42%
Expected return on plan assets	4.75%	4.75%	7.00%
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.73%	3.02%	2.68%
Discount rate for determining net periodic benefit cost	3.02%	2.68%	3.44%
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.75%	3.01%	2.69%
Discount rate for determining net periodic benefit cost	3.01%	2.69%	3.46%
Expected return on plan assets	4.40%	5.50%	5.90%
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.75%	2.99%	2.65%
Discount rate for determining net periodic benefit cost	2.99%	2.65%	3.42%
Expected return on plan assets	3.80%	3.80%	5.60%
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining PBO and APBO	5.75%	3.01%	2.69%
Discount rate for determining net periodic benefit cost	3.01%	2.69%	3.46%