Related Party Transactions and Major Customers (Tables)

9 Months Ended

Sep. 30, 2017

CenterPoint Energy provides some corporate services to Houston Electric. The costs of services have been charged directly to Houston Electric using methods that management believes are reasonable. These methods include negotiated usage rates, dedicated asset assignment and proportionate corporate formulas based on operating expenses, assets, gross margin, employees and a composite of assets, gross margin and employees. CERC provides certain services to Houston Electric. These services are billed at actual cost, either directly or as an allocation and include line locating and other miscellaneous services. Additionally, Houston Electric provides a number of services to CERC. These services are billed at actual cost, either directly or as an allocation and include fleet services, shop services, geographic services, surveying and right-of-way services, radio communications, data circuit management and field operations. These charges are not necessarily indicative of what would have been incurred had Houston Electric not been an affiliate. Amounts charged to and by Houston Electric for these services were as follows and are included primarily in operation and maintenance expenses:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
	(in millions)
Corporate service charges	$	41		$	43		$	127		$	131
Charges from CERC for services provided	2			2			5			5
Billings to CERC for services provided	(3		)	(4		)	(11		)	(11		)

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

Houston Electric’s transmission and distribution revenues from major customers are as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
	(in millions)
Affiliates of NRG	$	221	$	223	$	540	$	527
Affiliates of Vistra Energy Corp.	72		71		172		166