Income Taxes - Reconciliation of Unrecognized Tax Benefits (Expense) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, interest on income taxes expense	$ 0	$ 0	$ 0
PNMR
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	13,714,000	13,152,000	10,693,000
Additions based on tax positions	1,444,000	305,000	2,286,000
Reductions for tax positions of prior years	(4,000)
Additions for tax positions of prior years		257,000	173,000
Settlement payments	0	0	0
Ending balance	15,154,000	13,714,000	13,152,000
Unrecognized tax benefits that would impact effective tax rate	13,600,000
Public Service Company of New Mexico
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	10,771,000	10,230,000	7,776,000
Additions based on tax positions	1,437,000	295,000	2,286,000
Reductions for tax positions of prior years	(7,000)
Additions for tax positions of prior years		246,000	168,000
Settlement payments	0	0	0
Ending balance	12,201,000	10,771,000	10,230,000
Unrecognized tax benefits that would impact effective tax rate	10,600,000
Unrecognized tax benefits, interest on income taxes expense	0	0	0
Texas-New Mexico Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	141,000	119,000	114,000
Additions based on tax positions	7,000	11,000	0
Additions for tax positions of prior years	3,000	11,000	5,000
Settlement payments	0	0	0
Ending balance	151,000	141,000	119,000
Unrecognized tax benefits that would impact effective tax rate	200,000
Unrecognized tax benefits, interest on income taxes expense	$ 0	$ 0	$ 0