Related Party Transactions and Major Customers (Tables)

6 Months Ended

Jun. 30, 2015

Related Party Transactions [Abstract]

Schedule of Related Party Transactions [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
	(in millions)
Corporate service charges	$	44	$	39	$	86	$	76

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:

	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
	(in millions)
Affiliates of NRG	$	172	$	164	$	356	$	330
Affiliates of Energy Future Holdings Corp.	$	51	$	41	$	103	$	81