Reportable Segments (Details) $ in Millions		3 Months Ended
		Mar. 31, 2020 USD ($) state	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Revenues		$ 2,167	$ 2,229
Equity in earnings from investment in Enable		(1,475)	62
Depreciation and amortization		282	300
Interest Income		0	12
Interest Expense		(139)	(121)
Income tax expense (benefit)		(347)	14
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(1,053)	143
Net income (loss) from Discontinued Operations		(146)	26
Net income (loss)		(1,199)	169
Assets		33,395		$ 35,529
Total Assets Classified as Held For Use, Current and Noncurrent		31,748		33,565
Total Assets Classified as Held For Sale, Current and Noncurrent		1,647		1,964
Interest income from Securitization Bonds		1	2
Interest on Transition and System Restoration Bonds		8	12
Houston Electric T&D [Member]
Segment Reporting Information [Line Items]
Revenues	[1]	638	689
Depreciation and amortization		129	175
Interest Income	[2]	1	4
Interest Expense	[3]	(41)	(40)
Income tax expense (benefit)		5	6
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		37	30
Interest income from Securitization Bonds		1	2
Interest on Transition and System Restoration Bonds		8	12
Houston Electric T&D [Member] | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Revenues		156	151
Houston Electric T&D [Member] | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Revenues		81	54
Indiana Electric Integrated [Member]
Segment Reporting Information [Line Items]
Revenues		129	83
Depreciation and amortization		25	16
Interest Income		0	0
Interest Expense		(6)	(3)
Income tax expense (benefit)		3	(2)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ (171)	(9)
Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Number of States in which the Entity Performs Gas Delivery Services | state		48
Revenues		$ 1,318	1,415
Depreciation and amortization		111	95
Interest Income		1	1
Interest Expense		(32)	(23)
Income tax expense (benefit)		56	26
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		204	120
Midstream Investments [Member]
Segment Reporting Information [Line Items]
Revenues		0
Equity in earnings from investment in Enable		(1,475)	62
Interest Income		0	2
Interest Expense		(14)	(12)
Income tax expense (benefit)		(361)	28
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(1,127)	24
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues		82	42
Depreciation and amortization		17	14
Interest Income		48	46
Interest Expense		(96)	(84)
Income tax expense (benefit)		(50)	(44)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		4	(22)
Operating Segments [Member] | Houston Electric T&D [Member]
Segment Reporting Information [Line Items]
Assets		10,870		11,264
Operating Segments [Member] | Indiana Electric Integrated [Member]
Segment Reporting Information [Line Items]
Assets		3,015		3,168
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Assets		13,979		14,105
Operating Segments [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Assets		915		2,473
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets		2,969		2,555
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest Income		(50)	(41)
Interest Expense		(50)	(41)
Houston Electric [Member]
Segment Reporting Information [Line Items]
Revenues		634	686
Depreciation and amortization		129	175
Interest Income		1	4
Income tax expense (benefit)		5	6
Net income (loss)		33	27
Assets		10,870		11,262
Interest income from Securitization Bonds		1	2
Interest on Transition and System Restoration Bonds		8	12
Houston Electric [Member] | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Revenues		156	151
Houston Electric [Member] | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Revenues		81	54
CERC Corp [Member]
Segment Reporting Information [Line Items]
Revenues		1,011	1,212
Depreciation and amortization		74	73
Interest Income		0	0
Interest Expense		(30)	(29)
Income tax expense (benefit)		35	18
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		131	110
Net income (loss) from Discontinued Operations		(64)	28
Net income (loss)		67	138
Assets		8,150		8,512
Total Assets Classified as Held For Use, Current and Noncurrent		7,475		7,608
Total Assets Classified as Held For Sale, Current and Noncurrent		$ 675		904
CERC Corp [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Number of States in which the Entity Performs Gas Delivery Services | state		48
Revenues		$ 1,008	1,211
Depreciation and amortization		74	73
Interest Income		1	1
Interest Expense		(21)	(19)
Income tax expense (benefit)		44	26
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		134	119
CERC Corp [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues		3	1
Interest Income		21	20
Interest Expense		(31)	(31)
Income tax expense (benefit)		(9)	(8)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(3)	(9)
CERC Corp [Member] | Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Assets		7,562		7,698
CERC Corp [Member] | Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets		(87)		$ (90)
CERC Corp [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest Income		(22)	(21)
Interest Expense		$ (22)	$ (21)

[1] CenterPoint Energy’s Houston Electric T&D’s revenues from major external customers are as follows:     Three Months Ended March 31,     2020   2019     (in millions) Affiliates of NRG   $ 156
  $ 151
Affiliates of Vistra Energy Corp.   81
  54

[2] Excludes interest income from Securitization Bonds of $1 million and $2 million for the three months ended March 31, 2020 and 2019, respectively.

[3] Excludes interest expense on Securitization Bonds of $8 million and $12 million for the three months ended March 31, 2020 and 2019, respectively