Related Party Transactions and Major Customers

(a) Related Party Transactions

Houston Electric participates in a money pool through which it can borrow or invest on a short-term basis. Funding needs are aggregated and external borrowing or investing is based on the net cash position. The net funding requirements of the money pool are expected to be met with borrowings under CenterPoint Energy’s revolving credit facility or the sale of CenterPoint Energy’s commercial paper. Houston Electric had borrowings in the money pool of $60 million and investments in the money pool of $96 million as of December 31, 2017 and 2016, respectively, which are included in accounts and notes receivable-affiliated companies and accounts and notes payable-affiliated companies, respectively, in the Consolidated Balance Sheets. As of December 31, 2017, Houston Electric’s money pool borrowings had a weighted-average interest rate of 1.90%.

For the years ended December 31, 2017, 2016 and 2015, Houston Electric had affiliate related net interest income of $2 million, interest expense of $4 million and $1 million, respectively.

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/from Houston Electric for these services were as follows and are included primarily in operation and maintenance expenses:



	Year Ended December 31,
	2017			2016			2015
	(in millions)
Corporate service charges	$	188		$	179		$	176
Charges from CERC for services provided	8			7			6
Billings to CERC for services provided	(17		)	(15		)	(18		)

Houston Electric paid dividends of $180 million, $135 million and $252 million on its common shares to Utility Holding, LLC in 2017, 2016 and 2015, respectively. In 2016, CenterPoint Energy made an equity contribution of $374 million to Houston Electric.

(b) Major Customers

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



	Year Ended December 31,
	2017		2016		2015
	(in millions)
Affiliates of NRG	$	713	$	698	$	741
Affiliates of Vistra Energy Corp.	$	229	$	220	$	220