Related Party Transactions (Tables)

6 Months Ended

Jun. 30, 2020

Related Party Transactions [Abstract]

Schedule of Revenues from Related Parties

The following table presents the amounts of revenues from affiliated companies included in the Partnership’s Condensed Consolidated Statements of Income.

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(In millions)
Gas transportation and storage service revenues — CenterPoint Energy	$	22	$	23	$	59	$	56
Natural gas product sales — CenterPoint Energy	1		3		1		4
Gas transportation and storage service revenues — OGE Energy	10		13		19		26
Natural gas product sales — OGE Energy	—		—		5		1
Total revenues — affiliated companies	$	33	$	39	$	84	$	87

Schedule of Natural Gas Purchased From Related Parties

The following table presents the amounts of natural gas purchased from affiliated companies included in the Partnership’s Condensed Consolidated Statements of Income.

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(In millions)
Cost of natural gas purchases — CenterPoint Energy	$	—	$	—	$	1	$	—
Cost of natural gas purchases — OGE Energy	6		7		14		13
Total cost of natural gas purchases — affiliated companies	$	6	$	7	$	15	$	13

Schedule of Amounts Charged to Partnership by Related Parties

The following table presents the amounts charged to the Partnership by affiliates for seconded employees, included primarily in Operation and maintenance and General and administrative expenses in the Partnership’s Condensed Consolidated Statements of Income.

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(In millions)
Seconded Employee Costs — OGE Energy	$	5	$	5	$	8	$	11