Regulatory and Rate Matters - Renewable Portfolio Standard (Details) - Public Service Company of New Mexico $ in Millions			12 Months Ended
	Jun. 01, 2022 USD ($)	Jun. 01, 2021 USD ($)	Dec. 31, 2022 MW	Oct. 14, 2022 MW	Jul. 29, 2020 MW
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw)				200	650
Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Solar photovoltaic capacity (in mw)			158
Solar distributed generation (in mw)			239.1
Renewable energy rider, including excess return
Public Utilities, General Disclosures [Line Items]
NMPRC-approved return on equity			0.50%
NMPRC
Public Utilities, General Disclosures [Line Items]
Proposed revision to rider that will allow for recovery | $	$ 61.0	$ 66.9
New Mexico Wind | Renewable Portfolio Standard 2014
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)			200
Red Mesa Wind | Renewable Portfolio Standard 2014
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)			102
La Joya Wind | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Wind energy capacity (in mw)			140
Lightning Dock Geothermal | Renewable Portfolio Standard
Public Utilities, General Disclosures [Line Items]
Geothermal energy capacity (in mw)			11