v3.26.3
Pension and Other Postretirement Benefit Plans - Narrative (Details) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Pension Plan        
Defined Benefit Plan Disclosure [Line Items]        
Defined benefit plan, assumptions used calculating benefit obligation related to anticipated contributions, weighted average discount rate     5.50%  
Pension Plan | Public Service Company of New Mexico        
Defined Benefit Plan Disclosure [Line Items]        
Contributions by employer $ 0 $ 0 $ 0 $ 0
Estimated employer contributions for remainder of fiscal year through year four 0   0  
Pension Plan | Texas-New Mexico Power Company        
Defined Benefit Plan Disclosure [Line Items]        
Contributions by employer 0 0 0 0
Estimated employer contributions for remainder of fiscal year through year four 0   0  
OPEB Plan | Public Service Company of New Mexico        
Defined Benefit Plan Disclosure [Line Items]        
Contributions by employer 0 0 0 0
Disbursements by employer 900,000 100,000 2,300,000 200,000
Estimated disbursement by employer, current year     3,200,000  
Disbursements by employer, year one through four     11,200,000  
OPEB Plan | Texas-New Mexico Power Company        
Defined Benefit Plan Disclosure [Line Items]        
Contributions by employer 0 0 0 0
Disbursements by employer, year one through four 0 0 0 0
Executive Retirement Program | Public Service Company of New Mexico        
Defined Benefit Plan Disclosure [Line Items]        
Contributions by employer $ 300,000 $ 400,000 900,000 $ 900,000
Estimated disbursement by employer, current year     1,100,000  
Disbursements by employer, year one through four     $ 3,800,000