Employee Benefit Plans Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2013

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 components relating to postretirement benefits:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2012			2013			2012			2013
	(in millions)
Service Cost	1			1			1			1
Interest cost on accumulated benefit obligation	1			2			4			4
Expected return on plan assets	(1		)	(1		)	(1		)	(1		)
Amortization of prior service cost	1			—			2			1
Amortization of loss	—			1			1			2
Net periodic cost	$	2		$	3		$	7		$	7