Reportable Business Segments (Tables)

3 Months Ended

Mar. 31, 2019

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

As of March 31, 2019, reportable segments by Registrant were as follows:

Registrants	Houston Electric T&D	Indiana Electric Integrated	Natural Gas Distribution	Energy  Services	Infrastructure Services	Midstream Investments	Corporate and Other
CenterPoint Energy	X	X	X	X	X	X	X
Houston Electric	X
CERC			X	X			X

Financial data for reportable segments is as follows:

CenterPoint Energy

	Three Months Ended March 31,
	2019									2018
	Revenues from External Customers			Net Intersegment Revenues			Operating Income (Loss)			Revenues from External Customers			Net Intersegment Revenues			Operating Income (Loss)
	(in millions)
Houston Electric T&D	$	689	(1)	$	—		$	84		$	751	(1)	$	—		$	115
Indiana Electric Integrated	83			—			(9		)	—			—			—
Natural Gas Distribution	1,389			10			167			1,143			10			156
Energy Services	1,182			64			33			1,257			28			(26		)
Infrastructure Services	146			—			(16		)	—			—			—
Midstream Investments (2)	—			—			—			—			—			—
Corporate and Other	42			—			(14		)	4			—			6
Eliminations	—			(74		)	—			—			(38		)	—
Consolidated	$	3,531		$	—		$	245		$	3,155		$	—		$	251

(1) Houston Electric T&D revenues from major customers are as follows:

		Three Months Ended March 31,
		2019		2018
	(in millions)
Affiliates of NRG		$	151	$	161
Affiliates of Vistra Energy Corp.		54		54

(2) CenterPoint Energy’s Midstream Investments’ equity earnings, net are as follows:

		Three Months Ended March 31,
		2019		2018
	(in millions)
Enable		$	62	$	69

Houston Electric consists of a single reportable segment; therefore, a tabular reportable segment presentation has not been included.

CERC

	Three Months Ended March 31,
	2019								2018
	Revenues from External Customers		Net Intersegment Revenues			Operating Income (Loss)			Revenues from External Customers		Net Intersegment Revenues			Operating Income  (Loss)
	(in millions)
Natural Gas Distribution	$	1,185	$	10		$	164		$	1,143	$	10		$	156
Energy Services	1,182		64			33			1,257		28			(26		)
Corporate and Other	1		—			(1		)	—		—			1
Eliminations	—		(74		)	—			—		(38		)	—
Consolidated	$	2,368	$	—		$	196		$	2,400	$	—		$	131

CenterPoint Energy and CERC

	Total Assets
	March 31, 2019							December 31, 2018
	CenterPoint  Energy				CERC			CenterPoint Energy				CERC
	(in millions)
Houston Electric T&D	$	11,420			$	—		$	10,509			$	—
Indiana Electric Integrated (1)	1,953				—			—				—
Natural Gas Distribution (1)	10,492				6,904			6,956				6,956
Energy Services	1,370				1,370			1,558				1,558
Infrastructure Services (1)	814				—			—				—
Midstream Investments	2,839				—			2,482				—
Corporate and Other (1)	3,515			(3)	80			6,156			(3)	66
Unallocated Merger goodwill (2)	4,256				—			—				—
Eliminations	(2,757		)		(289		)	(652		)		(366		)
Consolidated	$	33,902			$	8,065		$	27,009			$	8,214

(1) Total assets by reportable segment include assets acquired in the Merger, which are based on preliminary estimates and are subject to change. See Note 3.

(2) CenterPoint Energy is currently assessing its reporting units subsequent to the Merger and the allocation of goodwill from the Merger to those reporting units. See Note 3.

(3) Includes pension and other postemployment-related regulatory assets of $652 million and $665 million, respectively, as of March 31, 2019 and December 31, 2018. Additionally, total assets as of December 31, 2018 included $3.9 billion of temporary investments included in Cash and cash equivalents on CenterPoint Energy’s Consolidated Balance Sheets.

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

Houston Electric T&D revenues from major customers are as follows:

		Three Months Ended March 31,
		2019		2018
	(in millions)
Affiliates of NRG		$	151	$	161
Affiliates of Vistra Energy Corp.		54		54

Midstream Investments [Table Text Block]

CenterPoint Energy’s Midstream Investments’ equity earnings, net are as follows:

		Three Months Ended March 31,
		2019		2018
	(in millions)
Enable		$	62	$	69