Reportable Segments (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Financial Data for Business Segments [Table Text Block]

Financial data for reportable segments and products and services are as follows:

CenterPoint Energy

	Revenues from External Customers		Equity in Earnings of Unconsolidated Affiliates		Depreciation and Amortization		Interest Income		Interest Expense		Income Tax Expense (Benefit)		Net Income (Loss)
	(in millions)
For the year ended December 31, 2020:
Electric	$	3,470	$	—	$	663	$	3	$	(220)	$	72	$	230
Natural Gas	3,631		—		454		8		(153)		125		278
Midstream Investments	—		(1,428)		—		1		(54)		(364)		(1,116)
Corporate and Other	317		—		72		103		(213)		(107)		17
Eliminations	—		—		—		(111)		111		—		—
Continuing Operations	$	7,418	$	(1,428)	$	1,189	$	4	$	(529)	$	(274)	(591)
Discontinued Operations, net													(182)
Consolidated													$	(773)
For the year ended December 31, 2019:
Electric	$	3,519	$	—	$	739	$	27	$	(225)	$	96	$	419
Natural Gas	3,750		—		420		6		(144)		2		251
Midstream Investments	—		229		—		8		(53)		53		131
Corporate and Other	295		1		66		126		(290)		(59)		(119)
Eliminations	—		—		—		(145)		145		—		—
Continuing Operations	$	7,564	$	230	$	1,225	$	22	$	(567)	$	92	682
Discontinued Operations, net													109
Consolidated													$	791
For the year ended December 31, 2018:
Electric	$	3,232	$	—	$	917	$	5	$	(197)	$	89	$	334
Natural Gas	3,031		—		280		1		(122)		31		98
Midstream Investments	—		307		—		—		(10)		73		224
Corporate and Other	14		—		33		66		(135)		(38)		(260)
Eliminations	—		—		—		(44)		44		—		—
Continuing Operations	$	6,277	$	307	$	1,230	$	28	$	(420)	$	155	396
Discontinued Operations, net													(28)
Consolidated													$	368

	Total Assets						Expenditures for Long-lived Assets
	December 31,						December 31,
	2020		2019		2018		2020		2019		2018
	(in millions)
Electric	$	14,493	$	14,432	$	10,509	$	1,281	$	1,216	$	952
Natural Gas	14,976		14,002		7,188		1,139		1,098		638
Midstream Investments	913		2,473		2,482		—		—		—
Corporate and Other, net of eliminations (1)	3,089		2,658		5,805		95		194		110
Continuing Operations	33,471		33,565		25,984		2,515		2,508		1,700
Assets Held for Sale/Discontinued Operations	—		1,964		1,109		21		79		20
Consolidated	$	33,471	$	35,529	$	27,093	$	2,536	$	2,587	$	1,720

(1)Total assets included pension and other postemployment-related regulatory assets of $540 million, $584 million and $665 million as of December 31, 2020, 2019 and 2018, respectively. 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’s revenues from major external customers are as follows (CenterPoint Energy and Houston Electric):

	Year Ended December 31,
	2020		2019		2018
	(in millions)
Affiliates of NRG	$	749	$	727	$	705
Affiliates of Vistra Energy Corp.	404		263		251

Revenues by Products and Services [Table Text Block]

Revenues by Products and Services:

	Year Ended December 31,
	2020						2019						2018
Revenues by Products and Services:	CenterPoint Energy		Houston Electric		CERC		CenterPoint Energy		Houston Electric		CERC		CenterPoint Energy		Houston Electric		CERC
	(in millions)
Electric delivery	$	2,941	$	2,911	$	—	$	3,019	$	2,990	$	—	$	3,232	$	3,234	$	—
Retail electric sales	515		—		—		486		—		—		—		—		—
Wholesale electric sales	14		—		—		14		—		—		—		—		—
Retail gas sales	3,462		—		2,594		3,563		—		2,831		2,857		—		2,857
Gas transportation and processing	15		—		15		33		—		33		32		—		32
Energy products and services	471		—		154		449		—		154		156		—		142
Total	$	7,418	$	2,911	$	2,763	$	7,564	$	2,990	$	3,018	$	6,277	$	3,234	$	3,031