Regulatory and Rate Matters - PNM Solar Direct, Application for a New 345-kV Transmission Line and Wester Spirit Line (Details) $ in Millions			3 Months Ended
	Jun. 03, 2019 MW	May 31, 2019 MW	Dec. 31, 2017	May 01, 2019 USD ($) kv	Aug. 10, 2018 USD ($) kv MW
PNM Solar Direct
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw) | MW		50
PPA term		15 years
KV Transmission Line
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw) | MW	140				166
PPA term	20 years
Transmission line and associated facilities | kv				345	345
Estimated cost of project					$ 85.0
Facebook Data Center
Public Utilities, General Disclosures [Line Items]
PPA term			25 years
Estimated cost of project					$ 39.0
Estimated cost of project, percentage					4600.00%
Western Spirit Line
Public Utilities, General Disclosures [Line Items]
Estimated cost of project				$ 285.0
Estimated self-fund amount under agreement				$ 75.0
La Joya Wind | KV Transmission Line
Public Utilities, General Disclosures [Line Items]
Solar distributed generation (in mw) | MW					140