Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

CERC’s employees participate in CenterPoint Energy’s postretirement benefit plan. CERC’s net periodic cost includes the following component relating to postretirement benefits:

	Three Months Ended
	March 31,
	2017		2016
	(in millions)
Interest cost on accumulated benefit obligation	$	1	$	1
Net periodic cost	$	1	$	1