CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Utility revenues	$ 1,476	$ 1,565	$ 3,549	$ 3,736
Non-utility revenues	99	93	193	151
Total	1,575	1,658	3,742	3,887
Expenses:
Utility natural gas, fuel and purchased power	202	260	811	1,057
Non-utility cost of revenues, including natural gas	69	61	133	108
Operation and maintenance	643	673	1,317	1,421
Depreciation and amortization	297	322	579	622
Taxes other than income taxes	129	113	265	239
Goodwill Impairment	0	0	185	0
Total	1,340	1,429	3,290	3,447
Operating Income	235	229	452	440
Other Income (Expense):
Gain (loss) on marketable securities	75	64	(69)	147
Gain (loss) on indexed debt securities	(76)	(68)	59	(154)
Interest expense and other finance charges	(128)	(134)	(267)	(255)
Interest expense on Securitization Bonds	(7)	(10)	(15)	(22)
Equity in earnings (loss) of unconsolidated affiliates, net	43	74	(1,432)	136
Interest Income	1	1	1	13
Interest income from Securitization Bonds	0	1	1	3
Other income (expense), net	21	9	34	15
Total	(71)	(63)	(1,688)	(117)
Income (Loss) from Continuing Operations before Income Taxes	164	166	(1,236)	323
Income tax expense (benefit)	29	15	(318)	29
Income (Loss) from Continuing Operations	135	151	(918)	294
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(30)	44	(176)	70
Net Income (Loss)	105	195	(1,094)	364
Income allocated to preferred shareholders	46	30	75	59
Income (Loss) Available to Common Shareholders	$ 59	$ 165	$ (1,169)	$ 305
Basic earnings (loss) per common share - continuing operations	$ 0.17	$ 0.24	$ (1.93)	$ 0.47
Basic earnings (loss) per common share - discontinued operations	(0.06)	0.09	(0.34)	0.14
Basic Earnings (Loss) Per Common Share	0.11	0.33	(2.27)	0.61
Earnings Per Share, Diluted [Abstract]
Diluted earnings (loss) per common share - continuing operations	0.17	0.24	(1.93)	0.47
Diluted earnings (loss) per common share - discontinued operations	(0.06)	0.09	(0.34)	0.14
Diluted Earnings (Loss) Per Common Share	$ 0.11	$ 0.33	$ (2.27)	$ 0.61
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share [Abstract]
Weighted Average Common Shares Outstanding, Basic	528,066,000	502,200,000	515,227,000	501,862,000
Weighted Average Common Shares Outstanding, Diluted	530,837,000	504,831,000	515,227,000	504,493,000
Houston Electric [Member]
Revenues:
Total	$ 720	$ 765	$ 1,354	$ 1,451
Expenses:
Operation and maintenance	364	359	723	727
Depreciation and amortization	140	176	269	351
Taxes other than income taxes	64	61	128	123
Total	568	596	1,120	1,201
Operating Income	152	169	234	250
Other Income (Expense):
Interest expense and other finance charges	(43)	(42)	(84)	(82)
Interest expense on Securitization Bonds	(7)	(10)	(15)	(22)
Interest Income	0	6	1	10
Interest income from Securitization Bonds	0	1	1	3
Other income (expense), net	1	(1)	4	(3)
Total	(49)	(46)	(93)	(94)
Income (Loss) from Continuing Operations before Income Taxes	103	123	141	156
Income tax expense (benefit)	16	23	21	29
Net Income (Loss)	87	100	120	127
CERC Corp [Member]
Revenues:
Utility revenues	467	513	1,463	1,708
Non-utility revenues	16	13	31	30
Total	483	526	1,494	1,738
Expenses:
Utility natural gas, fuel and purchased power	137	186	609	873
Non-utility cost of revenues, including natural gas	7	8	13	18
Operation and maintenance	179	194	388	427
Depreciation and amortization	74	73	148	146
Taxes other than income taxes	44	38	94	87
Total	441	499	1,252	1,551
Operating Income	42	27	242	187
Other Income (Expense):
Interest expense and other finance charges	(29)	(30)	(59)	(59)
Interest Income	0	3	0	3
Other income (expense), net	0	(3)	(4)	(6)
Total	(29)	(30)	(63)	(62)
Income (Loss) from Continuing Operations before Income Taxes	13	(3)	179	125
Income tax expense (benefit)	(4)	(5)	31	13
Income (Loss) from Continuing Operations	17	2	148	112
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(4)	26	(68)	54
Net Income (Loss)	$ 13	$ 28	$ 80	$ 166