Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Long-term Purchase Commitment [Table Text Block]

As of December 31, 2018, minimum payment obligations for natural gas supply commitments are approximately:

	(in millions)
2019	$	454
2020	430
2021	343
2022	231
2023	154
2024 and beyond	1,446

Lease Commitments [Table Text Block]

The following table sets forth information concerning the Registrants’ obligations under non-cancelable long-term operating leases as of December 31, 2018, which primarily consist of rental agreements for real property:            

	CenterPoint Energy		Houston Electric		CERC
	(in millions)
2019	$	6	$	1	$	5
2020	6		—		5
2021	5		—		4
2022	4		—		4
2023	3		—		3
2024 and beyond	12		—		11
Total	$	36	$	1	$	32

Schedule of Rent Expense [Table Text Block]

	Year Ended December 31,
	2018						2017						2016
	CenterPoint Energy		Houston Electric		CERC		CenterPoint Energy		Houston Electric		CERC		CenterPoint Energy		Houston Electric		CERC
	(in millions)
Lease expense	$	9	$	1	$	8	$	10	$	1	$	9	$	10	$	1	$	9