CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Utility revenues	$ 1,538	$ 1,548	$ 5,087	$ 5,284
Non-utility revenues	84	110	277	261
Total	1,622	1,658	5,364	5,545
Expenses:
Utility natural gas, fuel and purchased power	170	171	981	1,228
Non-utility cost of revenues, including natural gas	63	80	196	188
Operation and maintenance	659	621	1,976	2,042
Depreciation and amortization	306	316	885	938
Taxes other than income taxes	122	113	387	352
Goodwill Impairment	0	0	185	0
Total	1,320	1,301	4,610	4,748
Operating Income	302	357	754	797
Other Income (Expense):
Gain on marketable securities	83	59	14	206
Loss on indexed debt securities	(84)	(62)	(25)	(216)
Interest expense and other finance charges	(121)	(134)	(388)	(389)
Interest expense on Securitization Bonds	(7)	(9)	(22)	(31)
Equity in earnings (loss) of unconsolidated affiliates, net	(67)	77	(1,499)	213
Interest Income	1	3	2	16
Interest income from Securitization Bonds	0	1	1	4
Other income (expense), net	10	5	44	20
Total	(185)	(60)	(1,873)	(177)
Income (Loss) from Continuing Operations before Income Taxes	117	297	(1,119)	620
Income tax expense (benefit)	(10)	46	(328)	75
Income (Loss) from Continuing Operations	127	251	(791)	545
Income (Loss) from Discontinued Operations	(6)	19	(182)	89
Net Income (Loss)	121	270	(973)	634
Income allocated to preferred shareholders	52	29	127	88
Income (Loss) Available to Common Shareholders	$ 69	$ 241	$ (1,100)	$ 546
Basic earnings (loss) per common share - continuing operations	$ 0.14	$ 0.44	$ (1.75)	$ 0.91
Basic earnings (loss) per common share - discontinued operations	(0.01)	0.04	(0.35)	0.18
Basic Earnings (Loss) Per Common Share	0.13	0.48	(2.10)	1.09
Earnings Per Share, Diluted [Abstract]
Diluted earnings (loss) per common share - continuing operations	0.14	0.44	(1.75)	0.91
Diluted earnings (loss) per common share - discontinued operations	(0.01)	0.03	(0.35)	0.17
Diluted Earnings (Loss) Per Common Share	$ 0.13	$ 0.47	$ (2.10)	$ 1.08
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share [Abstract]
Discontinued Operation, Tax Effect of Discontinued Operation	$ 0	$ 16	$ 21	$ 38
Weighted Average Common Shares Outstanding, Basic	544,811,000	502,228,000	525,160,000	501,986,000
Weighted Average Common Shares Outstanding, Diluted	548,188,000	505,080,000	525,160,000	504,838,000
Houston Electric [Member]
Revenues:
Total	$ 828	$ 859	$ 2,182	$ 2,310
Expenses:
Operation and maintenance	381	359	1,104	1,086
Depreciation and amortization	151	168	420	519
Taxes other than income taxes	64	63	192	186
Total	596	590	1,716	1,791
Operating Income	232	269	466	519
Other Income (Expense):
Interest expense and other finance charges	(43)	(41)	(127)	(123)
Interest expense on Securitization Bonds	(7)	(9)	(22)	(31)
Interest Income	1	8	2	18
Interest income from Securitization Bonds	0	1	1	4
Other income (expense), net	0	(2)	4	(5)
Total	(49)	(43)	(142)	(137)
Income (Loss) from Continuing Operations before Income Taxes	183	226	324	382
Income tax expense (benefit)	26	41	47	70
Net Income (Loss)	157	185	277	312
CERC Corp [Member]
Revenues:
Utility revenues	415	398	1,878	2,106
Non-utility revenues	11	22	42	52
Total	426	420	1,920	2,158
Expenses:
Utility natural gas, fuel and purchased power	106	105	715	978
Non-utility cost of revenues, including natural gas	2	11	15	29
Operation and maintenance	186	181	574	608
Depreciation and amortization	78	72	226	218
Taxes other than income taxes	40	33	134	120
Total	412	402	1,664	1,953
Operating Income	14	18	256	205
Other Income (Expense):
Interest expense and other finance charges	(28)	(28)	(87)	(87)
Interest Income	0	1	0	4
Other income (expense), net	(1)	(4)	(5)	(10)
Total	(29)	(31)	(92)	(93)
Income (Loss) from Continuing Operations before Income Taxes	(15)	(13)	164	112
Income tax expense (benefit)	(9)	(3)	22	10
Income (Loss) from Continuing Operations	(6)	(10)	142	102
Income (Loss) from Discontinued Operations	2	3	(66)	57
Net Income (Loss)	(4)	(7)	76	159
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share [Abstract]
Discontinued Operation, Tax Effect of Discontinued Operation	$ 1	$ 2	$ (2)	$ 15