XML 107 R91.htm IDEA: XBRL DOCUMENT v3.24.2.u1
Regulatory and Rate Matters - Fours Corners, Summer Peak Resource Adequacy, 2026 Resource Application, Grid Modernization Application (Details)
$ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Oct. 25, 2023
MW
batteryStorageAgreement
Oct. 03, 2022
USD ($)
Jan. 08, 2021
USD ($)
Nov. 30, 2020
USD ($)
Jun. 30, 2023
USD ($)
Jun. 30, 2023
USD ($)
Dec. 31, 2020
USD ($)
Public Utilities, General Disclosures [Line Items]              
Number of battery storage agreements | batteryStorageAgreement 3            
PNM              
Public Utilities, General Disclosures [Line Items]              
Grid modernization investment | $   $ 344.0          
Grid modernization, initial term   6 years          
Grid modernization term   11 years          
PNM | Solar Agreement One              
Public Utilities, General Disclosures [Line Items]              
Number of megawatts available in purchase power agreement (in megawatts) | MW 100            
PNM | Battery Storage Agreement One              
Public Utilities, General Disclosures [Line Items]              
Number of megawatts available in purchase power agreement (in megawatts) | MW 100            
PNM | Battery Storage Agreement Two              
Public Utilities, General Disclosures [Line Items]              
Number of megawatts available in purchase power agreement (in megawatts) | MW 100            
PNM | Battery Storage Agreement Three              
Public Utilities, General Disclosures [Line Items]              
Number of megawatts available in purchase power agreement (in megawatts) | MW 50            
PNM | Solar Agreement Two              
Public Utilities, General Disclosures [Line Items]              
Number of megawatts available in purchase power agreement (in megawatts) | MW 60            
PNM | Four Corners              
Public Utilities, General Disclosures [Line Items]              
Payments for relief from obligations | $       $ 15.0     $ 75.0
Final payment for relief from obligations | $             $ 60.0
Request issuance of energy transition bonds | $     $ 300.0        
Regulatory disallowance | $         $ 3.7 $ 3.7  
PNM | Four Corners | PNM              
Public Utilities, General Disclosures [Line Items]              
Noncontrolling interest, ownership percentage by noncontrolling owners             13.00%