Regulatory and Rate Matters - Four Corners Abandonment Application (Details) - Four Corners - Public Service Company of New Mexico - USD ($) $ in Millions			1 Months Ended
	Jan. 08, 2021	Nov. 01, 2020	Nov. 30, 2020
Public Utilities, General Disclosures [Line Items]
Payments for relief from obligations		$ 75.0	$ 15.0
Final payment for relief from obligations			60.0
Initial payment for relief from obligations			$ 15.0
Request issuance of energy transition bonds	$ 300.0
Forecasted undepreciated investment	272.0
Plant decommissioning and coal mine reclamation costs	4.6
Upfront financing costs	7.3
Proceeds from securitization bonds	$ 16.5
Public Service Company of New Mexico
Public Utilities, General Disclosures [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners		13.00%