Pension and Other Postretirement Benefits - Narrative (Details) - USD ($)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		4.00%
Amortization of gains and losses that are outside the corridor		5 years
Maximum annual contributions per employee		75.00%
Employer matching contribution, percent of employees' gross pay		6.00%
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-matching contribution of eligible compensation based on eligible employee's age		3.00%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-matching contribution of eligible compensation based on eligible employee's age		10.00%
Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of return		(21.28%)
Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of return		(23.03%)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected long-term return resulting from effect of 1% change		1.00%
Expected long-term return resulting from effect of one-percentage point increase		1.00%
Expected future employer contributions, year two through four		$ 0
Expected future employer contributions, after year four		$ 400,000
Weighted average discount rate related to anticipated contributions		5.75%
Pension Plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		35.00%
Pension Plan | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		50.00%
Pension Plan | Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		15.00%
Pension Plan | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		5.50%	5.50%	5.90%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year		$ 4,600,000
Actuarial gains (losses) recorded as regulatory assets and liabilities		(27,531,000)
Employer contributions		$ 0	$ 0
Pension Plan | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		4.40%	5.50%	5.90%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year		$ 500,000
Actuarial gains (losses) recorded as regulatory assets and liabilities		(4,602,000)
Employer contributions		$ 0	$ 0
Pension Plan | Texas-New Mexico Power Company | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		16.00%
Pension Plan | Texas-New Mexico Power Company | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		70.00%
Pension Plan | Texas-New Mexico Power Company | Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		14.00%
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected long-term return resulting from effect of 1% change		1.00%
Other Postretirement Benefits | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		30.00%
Other Postretirement Benefits | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		70.00%
Other Postretirement Benefits | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		4.75%	4.75%	7.00%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year		$ 800,000
Rate of return		(24.50%)
Actuarial gains (losses) recorded as regulatory assets and liabilities		$ 12,700,000
Employer matching contribution, maximum	5.00%
Employer contributions		$ 2,617,000	$ 2,709,000
Other Postretirement Benefits | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		3.80%	3.80%	5.60%
Expected long-term return on assets decrease resulting in increase net periodic costs In next fiscal year		$ 100,000
Rate of return		(27.90%)
Actuarial gains (losses) recorded as regulatory assets and liabilities		$ 1,100,000
Effect of 1%-point change in assumed health care cost trend rates on net periodic expense and APBO		0
Employer contributions		0	$ 0
Other Postretirement Benefits | PNM and TNMP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		0	0
Expected employer contributions in fiscal year through year 5		0	0
Expected employer disbursements for next fiscal year		200,000
Expected employer disbursements by employer in year 2 through year 5		9,000,000
Executive Retirement Program | Public Service Company of New Mexico
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gains (losses) recorded as regulatory assets and liabilities		1,628,000
Expected disbursements by employer		1,300,000	1,300,000
Executive Retirement Program | Texas-New Mexico Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gains (losses) recorded as regulatory assets and liabilities		2,000
Expected disbursements by employer		$ 100,000	$ 100,000
Non-US | Pension Plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investment allocation targets		13.00%