XML 82 R55.htm IDEA: XBRL DOCUMENT v3.4.0.3
Regulatory and Rate Matters - TNMP Narrative (Details) - Texas-New Mexico Power Company [Member] - Advanced Meter System Deployment and Surcharge Request [Member]
 1 Months Ended 3 Months Ended
Jul. 30, 2011
USD ($)
Mar. 31, 2016
USD ($)
Apr. 22, 2016
customer
Oct. 02, 2015
USD ($)
Aug. 15, 2013
USD ($)
customer
Public Utilities, General Disclosures [Line Items]          
Approved deployment costs $ 113,400,000        
Collection of deployment costs through surcharge period 12 years        
Completion period of advanced meter deployment 5 years        
Recovery in cost through initial fees         $ 200,000
Ongoing annual expenses         500,000
Approved non-standard metering ongoing expenses monthly charge         $ 36.78
Presumed number of customers that will elect non-standard meter service (in customers) | customer         1,081
Cost and savings reconciliation filed with regulators, capital cost savings       $ 71,000,000  
Cost and savings reconciliation filed with regulators, operations and maintenance savings       $ 18,000,000  
Program costs incurred to date   $ 1,500,000      
Subsequent Event [Member]          
Public Utilities, General Disclosures [Line Items]          
Current number of customers that have elected non-standard meter service (in customers) | customer     98    
Minimum [Member]          
Public Utilities, General Disclosures [Line Items]          
Approved non-standard metering service cost, initial fee range         $ 63.97
Maximum [Member]          
Public Utilities, General Disclosures [Line Items]          
Approved non-standard metering service cost, initial fee range         $ 168.61