Pension and Other Postretirement Benefits - APBO, PBO, Fair Value of Plan Assets, and Funded Status of the Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Accrued pension liability and postretirement benefit cost	$ 32,799	$ 19,057
Public Service Company of New Mexico
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Accrued pension liability and postretirement benefit cost	32,007	18,718
Public Service Company of New Mexico | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	584,061	630,904
Service cost	0	0	$ 0
Interest cost	16,857	16,143	19,941
Actuarial (gain)	(118,552)	(19,372)
Benefits paid	(48,721)	(43,614)
Settlements	0	0
Balance at end of year	433,645	584,061	630,904
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	576,707	587,530
Actual return on plan assets	(117,523)	32,791
Employer contributions	0	0
Fair value of plan assets at end of year	410,463	576,707	587,530
Funded status – asset (liability) for pension benefits	(23,182)	(7,354)
Public Service Company of New Mexico | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	66,984	75,196
Service cost	10	23	38
Interest cost	1,914	1,907	2,453
Participant contributions	1,431	1,617
Actuarial (gain)	(14,829)	(5,053)
Benefits paid	(6,396)	(6,706)
Curtailment loss	836	0	0
Balance at end of year	49,950	66,984	75,196
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	95,805	93,402
Actual return on plan assets	(23,156)	4,783
Employer contributions	2,617	2,709
Participant contributions	1,431	1,617
Benefits paid	(6,396)	(6,706)
Fair value of plan assets at end of year	70,301	95,805	93,402
Funded status – asset (liability) for pension benefits	20,351	28,821
Public Service Company of New Mexico | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	12,612	14,222
Service cost	0	0	0
Interest cost	362	363	491
Actuarial (gain)	(1,628)	(657)
Benefits paid	(1,304)	(1,316)
Balance at end of year	10,042	12,612	14,222
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Less current liability	1,217	1,248
Accrued pension liability and postretirement benefit cost	8,825	11,364
Texas-New Mexico Power Company
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Accrued pension liability and postretirement benefit cost	792	339
Texas-New Mexico Power Company | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	59,609	67,390
Service cost	0	0	0
Interest cost	1,720	1,741	2,177
Actuarial (gain)	(11,711)	(3,306)
Benefits paid	(3,403)	(3,678)
Settlements	(2,254)	(2,538)
Balance at end of year	43,961	59,609	67,390
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	62,942	66,149
Actual return on plan assets	(13,838)	3,009
Employer contributions	0	0
Fair value of plan assets at end of year	43,447	62,942	66,149
Funded status – asset (liability) for pension benefits	(514)	3,333
Texas-New Mexico Power Company | Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	10,570	11,938
Service cost	38	45	46
Interest cost	307	308	373
Participant contributions	219	135
Actuarial (gain)	(2,788)	(1,141)
Benefits paid	(641)	(715)
Curtailment loss	0	0
Balance at end of year	7,705	10,570	11,938
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	12,593	12,885
Actual return on plan assets	(3,453)	288
Employer contributions	0	0
Participant contributions	219	135
Benefits paid	(641)	(715)
Fair value of plan assets at end of year	8,718	12,593	12,885
Funded status – asset (liability) for pension benefits	1,013	2,023
Texas-New Mexico Power Company | Executive Retirement Program
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	406	678
Service cost	0	0	0
Interest cost	11	17	22
Actuarial (gain)	(2)	(211)
Benefits paid	(71)	(78)
Balance at end of year	344	406	$ 678
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Less current liability	66	67
Accrued pension liability and postretirement benefit cost	$ 278	$ 339