Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2013

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

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

	Three Months Ended September 30,						Nine Months Ended September 30,
	2012			2013			2012			2013
	(in millions)
Interest cost	$	4		$	3		$	12		$	10
Expected return on plan assets	(2		)	(2		)	(5		)	(5		)
Amortization of loss	1			1			2			3
Amortization of transition obligation	2			2			5			4
Net periodic cost	$	5		$	4		$	14		$	12