Related Party Transactions Related Party Transaction (Tables)

12 Months Ended

Dec. 31, 2015

Related Party Transaction [Line Items]

Schedule of Related Party Transactions [Table Text Block]

CenterPoint Energy provides some corporate services to CERC. The costs of services have been charged directly to CERC 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 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. Additionally, 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. These charges are not necessarily indicative of what would have been incurred had CERC not been an affiliate of CenterPoint Energy. Amounts charged to and from CERC 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	$	118		$	115		$	105
Charges from CenterPoint Houston for services provided	18			17			21
Billings to CenterPoint Houston for services provided	(6		)	(5		)	(9		)
	$	130		$	127		$	117