NATURE OF OPERATIONS AND FINANCIAL STATEMENT PRESENTATION Nature of Operations (Details)	9 Months Ended
Sep. 30, 2014 sqmi customer
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Entity Number Of Customers	415,000
Area In Which Subsidiary Generates Transmits And Distributes Electricity To Retail Electric Customers	1,155

Area in which subsidiary generates transmits and distributes electricity to retail electric customers.

No definition available.

Name:	tep_AreaInWhichSubsidiaryGeneratesTransmitsAndDistributesElectricityToRetailElectricCustomers
Namespace Prefix:	tep_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration