Reportable Segments (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020 USD ($) state	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) state		Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Revenues		$ 1,575	$ 1,658	$ 3,742		$ 3,887
Equity in earnings from investment in Enable		43	74	(1,432)		136
Depreciation and amortization		297	322	579		622
Interest Income		1	1	1		13
Interest Expense		(128)	(134)	(267)		(255)
Income tax expense (benefit)		29	15	(318)		29
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		135	151	(918)		294
Net income (loss) from Discontinued Operations		(30)	44	(176)		70
Net income (loss)		105	195	(1,094)		364
Interest income from Securitization Bonds		0	1	1		3
Interest on Transition and System Restoration Bonds		7	10	15		22
Assets		32,148		32,148			$ 35,529
Total Assets Classified as Held For Use, Current and Noncurrent		32,148		32,148			33,565
Total Assets Classified as Held For Sale, Current and Noncurrent		0		0			1,964
Houston Electric T&D [Member]
Segment Reporting Information [Line Items]
Revenues	[1]	720	765	1,358		1,454
Depreciation and amortization		140	176	269		351
Interest Income	[2]	0	6	1		10
Interest Expense	[3]	(43)	(42)	(84)		(82)
Income tax expense (benefit)		16	23	21		29
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		87	100	124		130
Interest income from Securitization Bonds		0	1	1		3
Interest on Transition and System Restoration Bonds		7	10	15		22
Houston Electric T&D [Member] | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Revenues		174	165	330		316
Houston Electric T&D [Member] | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Revenues		92	59	173		113
Indiana Electric Integrated [Member]
Segment Reporting Information [Line Items]
Revenues		128	140	257		223
Depreciation and amortization		26	25	51		41
Interest Income		0	0	0		0
Interest Expense		(5)	(7)	(11)		(10)
Income tax expense (benefit)		5	3	8		1
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ 19	16	$ (152)		7
Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Number of States in which the Entity Performs Gas Delivery Services | state		48		48
Revenues		$ 641	673	$ 1,959		2,088
Depreciation and amortization		113	107	224		202
Interest Income		2	0	3		1
Interest Expense		(29)	(24)	(61)		(47)
Income tax expense (benefit)		3	1	59		27
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		33	23	237		143
Midstream Investments [Member]
Segment Reporting Information [Line Items]
Revenues				0
Equity in earnings from investment in Enable		43	74	(1,432)	[4]	136
Interest Income		1	3	1		5
Interest Expense		(13)	(14)	(27)		(26)
Income tax expense (benefit)		7	13	(354)		41
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		24	50	(1,103)		74
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues		86	80	168		122
Depreciation and amortization		18	14	35		28
Interest Income		27	39	75		85
Interest Expense		(67)	(94)	(163)		(178)
Income tax expense (benefit)		(2)	(25)	(52)		(69)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(28)	(38)	(24)		(60)
Operating Segments [Member] | Houston Electric T&D [Member]
Segment Reporting Information [Line Items]
Assets		11,097		11,097			11,264
Operating Segments [Member] | Indiana Electric Integrated [Member]
Segment Reporting Information [Line Items]
Assets		3,083		3,083			3,168
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Assets		14,055		14,055			14,105
Operating Segments [Member] | Midstream Investments [Member]
Segment Reporting Information [Line Items]
Assets		917		917			2,473
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets		2,996		2,996			2,555
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest Income		(29)	(47)	(79)		(88)
Interest Expense		(29)	(47)	(79)		(88)
Houston Electric [Member]
Segment Reporting Information [Line Items]
Revenues		720	765	1,354		1,451
Depreciation and amortization		140	176	269		351
Interest Income		0	6	1		10
Income tax expense (benefit)		16	23	21		29
Net income (loss)		87	100	120		127
Interest income from Securitization Bonds		0	1	1		3
Interest on Transition and System Restoration Bonds		7	10	15		22
Assets		11,097		11,097			11,262
Houston Electric [Member] | Affiliates of NRG Energy, Inc. [Member]
Segment Reporting Information [Line Items]
Revenues		174	165	330		316
Houston Electric [Member] | Affiliates of Vistra Energy Corp. [Member]
Segment Reporting Information [Line Items]
Revenues		92	59	173		113
CERC Corp [Member]
Segment Reporting Information [Line Items]
Revenues		483	526	1,494		1,738
Depreciation and amortization		74	73	148		146
Interest Income		0	3	0		3
Interest Expense		(29)	(30)	(59)		(59)
Income tax expense (benefit)		(4)	(5)	31		13
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		17	2	148		112
Net income (loss) from Discontinued Operations		(4)	26	(68)		54
Net income (loss)		13	28	80		166
Assets		7,595		7,595			8,512
Total Assets Classified as Held For Use, Current and Noncurrent		7,595		7,595			7,608
Total Assets Classified as Held For Sale, Current and Noncurrent		$ 0		$ 0			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		48
Revenues		$ 480	526	$ 1,488		1,737
Depreciation and amortization		74	73	148		146
Interest Income		2	2	3		3
Interest Expense		(20)	(19)	(41)		(38)
Income tax expense (benefit)		1	0	45		26
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		20	10	154		129
CERC Corp [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues		3	0	6		1
Depreciation and amortization			0			0
Interest Income		25	29	46		49
Interest Expense		(36)	(39)	(67)		(70)
Income tax expense (benefit)		(5)	(5)	(14)		(13)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(3)	(8)	(6)		(17)
CERC Corp [Member] | Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Assets		7,609		7,609			7,698
CERC Corp [Member] | Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets		(14)		(14)			$ (90)
CERC Corp [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest Income		(27)	(28)	(49)		(49)
Interest Expense		$ (27)	$ (28)	$ (49)		$ (49)

[1] CenterPoint Energy’s Houston Electric T&D’s revenues from major external customers are as follows:     Three Months Ended June 30,   Six Months Ended June 30,     2020   2019   2020   2019     (in millions) Affiliates of NRG   $ 174
  $ 165
  $ 330
  $ 316
Affiliates of Vistra Energy Corp.   92
  59
  173
  113

[2] Excludes interest income from Securitization Bonds of $-0- and $1 million for the three and six months ended June 30, 2020, respectively, and $1 million and $3 million for the three and six months ended June 30, 2019, respectively.

[3] Excludes interest expense on Securitization Bonds of $7 million and $15 million for the three and six months ended June 30, 2020, respectively, and $10 million and $22 million for the three and six months ended June 30, 2019, respectively.

[4] Includes the impairment of CenterPoint Energy’s equity method investment in Enable of $1,541 million recorded during the three months ended March 31, 2020.