Electric Operating Revenues - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) MW	Dec. 31, 2020 USD ($)	Jan. 01, 2019	Jan. 01, 2018 MW
Contract with Customers, Asset and Liability [Roll Forward]
Allowance for credit loss	$ (1,100,000)	$ 6,800,000
Other receivables, allowance for credit loss	1,000,000	0
Capitalized contract cost, amortization period			5 years
Contract assets	600,000	0
Texas-New Mexico Power Company
Contract with Customers, Asset and Liability [Roll Forward]
Regulatory assets from defaulting REP's	$ 800,000
Public Service Company of New Mexico
Contract with Customers, Asset and Liability [Roll Forward]
Expected exposure to market risk (in megawatts) | MW	65			65
Power to be sold to third party (in megawatts) | MW	36			36
Contract with customers, net	$ 86,800,000	$ 86,200,000