Related Party Transactions and Major Customers Related Party Transactions and Major Customers (Tables)

12 Months Ended

Dec. 31, 2015

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

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



	Year Ended December 31,
	2015		2014		2013
	(in millions)
Affiliates of NRG	$	741	$	735	$	658
Affiliates of Energy Future Holdings Corp.	$	220	$	189	$	167

CenterPoint Energy provides some corporate services to CenterPoint Houston. The costs of services have been charged directly to CenterPoint Houston 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. CenterPoint Energy Resources Corp. (CERC Corp., and together with its subsidiaries, CERC) provides certain services to CenterPoint Houston. These services are billed at actual cost, either directly or as an allocation and include line locating and other miscellaneous services. Additionally, CenterPoint Houston 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, radio communications, data circuit management and field operations. These charges are not necessarily indicative of what would have been incurred had CenterPoint Houston not been an affiliate. Amounts charged to CenterPoint Houston for these services were as follows and are included primarily in operation and maintenance expenses:



	Year Ended December 31,
	2015			2014			2013
	(in millions)
Corporate service charges	$	176		$	159		$	147

Charges from CERC for services provided	6			5			9

Billings to CERC for services provided	(18		)	(17		)	(21		)