Franchises and Significant Customers	12 Months Ended
Dec. 31, 2018
Franchises and Significant Customers [Abstract]
Franchises And Significant Customers	Franchises and Significant Customers Franchises The Company operates under franchise agreements with several cities in its service territory, including one with El Paso, Texas, the largest city it serves. The franchise agreement allows the Company to utilize public rights-of-way necessary to serve its customers within El Paso. Pursuant to the El Paso franchise agreement, the Company pays to the City of El Paso, on a quarterly basis, a fee equal to 5.00% of gross revenues the Company receives for the generation, transmission and distribution of electrical energy and other services within the city. The 2005 El Paso franchise agreement set the franchise fee at 3.25% of gross revenues, but that amount has since been adjusted by two amendments. The 2010 amendment added an incremental fee equal to 0.75% of gross revenues to be placed in a restricted fund to be used by the city solely for economic development and renewable energy purposes. The 2018 amendment, approved on March 20, 2018, and applicable to bills issued on or after October 1, 2018, increased the dedicated incremental fee by 1.00% of gross revenues and extended the term of the franchise agreement by 30 years. Any assignment of the franchise agreement, including a deemed assignment as a result of a change in control of the Company, requires the consent of the City of El Paso. The El Paso franchise agreement is set to expire on July 31, 2060. The Company does not have a written franchise agreement with Las Cruces, New Mexico, the second largest city in its service territory. The Company utilizes public rights-of-way necessary to service its customers within Las Cruces under an implied franchise pursuant to state law by satisfying all obligations under the franchise agreement that expired on April 30, 2009. The Company pays the City of Las Cruces a franchise fee of 2.00% of gross revenues the Company receives from services within the City of Las Cruces. The Company also maintains franchise agreements with other municipalities, and applicable counties, within its service territories. Military Installations The Company serves HAFB, White Sands Missile Range ("White Sands") and Fort Bliss. These military installations represent approximately 2.6% of the Company's annual retail revenues. In July 2014, the Company signed an agreement with Fort Bliss under which Fort Bliss takes retail electric service from the Company under the applicable Texas tariffs. The Company serves White Sands under the applicable New Mexico tariffs. In August 2016, the Company signed a contract with HAFB under which the Company provides retail electric service and limited wheeling services to HAFB under the applicable New Mexico tariffs. As stated in the contract, HAFB will purchase the full output of a Company-owned 5 MW solar facility upon its completed construction, which occurred on October 18, 2018. HAFB's other power requirements are provided under the applicable New Mexico tariffs with limited wheeling services under the contract.

Franchises and Significant Customers

Franchises

The Company operates under franchise agreements with several cities in its service territory, including one with El Paso, Texas, the largest city it serves. The franchise agreement allows the Company to utilize public rights-of-way necessary to serve its customers within El Paso. Pursuant to the El Paso franchise agreement, the Company pays to the City of El Paso, on a quarterly basis, a fee equal to 5.00% of gross revenues the Company receives for the generation, transmission and distribution of electrical energy and other services within the city. The 2005 El Paso franchise agreement set the franchise fee at 3.25% of gross revenues, but that amount has since been adjusted by two amendments. The 2010 amendment added an incremental fee equal to 0.75% of gross revenues to be placed in a restricted fund to be used by the city solely for economic development and renewable energy purposes. The 2018 amendment, approved on March 20, 2018, and applicable to bills issued on or after October 1, 2018, increased the dedicated incremental fee by 1.00% of gross revenues and extended the term of the franchise agreement by 30 years. Any assignment of the franchise agreement, including a deemed assignment as a result of a change in control of the Company, requires the consent of the City of El Paso. The El Paso franchise agreement is set to expire on July 31, 2060.

The Company does not have a written franchise agreement with Las Cruces, New Mexico, the second largest city in its service territory. The Company utilizes public rights-of-way necessary to service its customers within Las Cruces under an implied franchise pursuant to state law by satisfying all obligations under the franchise agreement that expired on April 30, 2009. The Company pays the City of Las Cruces a franchise fee of 2.00% of gross revenues the Company receives from services within the City of Las Cruces.

The Company also maintains franchise agreements with other municipalities, and applicable counties, within its service territories.

Military Installations

The Company serves HAFB, White Sands Missile Range ("White Sands") and Fort Bliss. These military installations represent approximately 2.6% of the Company's annual retail revenues. In July 2014, the Company signed an agreement with Fort Bliss under which Fort Bliss takes retail electric service from the Company under the applicable Texas tariffs. The Company serves White Sands under the applicable New Mexico tariffs. In August 2016, the Company signed a contract with HAFB under which the Company provides retail electric service and limited wheeling services to HAFB under the applicable New Mexico tariffs. As stated in the contract, HAFB will purchase the full output of a Company-owned 5 MW solar facility upon its completed construction, which occurred on October 18, 2018. HAFB's other power requirements are provided under the applicable New Mexico tariffs with limited wheeling services under the contract.