Long-term Debt (Tables)

3 Months Ended

Mar. 31, 2013

Line of Credit Facility [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

Revolving Credit Facility. As of December 31, 2012 and March 31, 2013, CenterPoint Houston had the following revolving credit facility and utilization of such facility (in millions):

		December 31, 2012				March 31, 2013
Size of Facility		Loans		Letters of Credit		Loans		Letters of Credit
$	300	$	—	$	4	$	—	$	4