CONDENSED STATEMENTS OF CONSOLIDATED INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues:
Utility revenues	$ 2,073	$ 2,171
Non-utility revenues	94	58
Total	2,167	2,229
Expenses:
Utility natural gas, fuel and purchased power	609	797
Non-utility cost of revenues, including natural gas	64	47
Operation and maintenance	674	748
Depreciation and amortization	282	300
Taxes other than income taxes	136	126
Goodwill Impairment	185	0
Total	1,950	2,018
Operating Income	217	211
Other Income (Expense):
Gain (loss) on marketable securities	(144)	83
Gain (loss) on indexed debt securities	135	(86)
Interest expense and other finance charges	(139)	(121)
Interest expense on Securitization Bonds	(8)	(12)
Equity in earnings (loss) of unconsolidated affiliates, net	(1,475)	62
Interest Income	0	12
Interest income from Securitization Bonds	1	2
Other income (expense), net	13	6
Total	(1,617)	(54)
Income (Loss) from Continuing Operations before Income Taxes	(1,400)	157
Income tax expense (benefit)	(347)	14
Income (Loss) from Continuing Operations	(1,053)	143
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(146)	26
Net Income (Loss)	(1,199)	169
Preferred stock dividend requirement	29	29
Income (Loss) Available to Common Shareholders	$ (1,228)	$ 140
Basic earnings (loss) per common share - continuing operations	$ (2.15)	$ 0.23
Basic earnings (loss) per common share - discontinued operations	(0.29)	0.05
Basic Earnings (Loss) Per Common Share	(2.44)	0.28
Earnings Per Share, Diluted [Abstract]
Diluted earnings (loss) per common share - continuing operations	(2.15)	0.23
Diluted earnings (loss) per common share - discontinued operations	(0.29)	0.05
Diluted Earnings (Loss) Per Common Share	$ (2.44)	$ 0.28
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share [Abstract]
Weighted Average Common Shares Outstanding, Basic	502,388,000	501,521,000
Weighted Average Common Shares Outstanding, Diluted	502,388,000	503,944,000
Houston Electric [Member]
Revenues:
Total	$ 634	$ 686
Expenses:
Operation and maintenance	359	368
Depreciation and amortization	129	175
Taxes other than income taxes	64	62
Total	552	605
Operating Income	82	81
Other Income (Expense):
Interest expense and other finance charges	(41)	(40)
Interest expense on Securitization Bonds	(8)	(12)
Interest Income	1	4
Interest income from Securitization Bonds	1	2
Other income (expense), net	3	(2)
Total	(44)	(48)
Income (Loss) from Continuing Operations before Income Taxes	38	33
Income tax expense (benefit)	5	6
Net Income (Loss)	33	27
CERC Corp [Member]
Revenues:
Utility revenues	996	1,195
Non-utility revenues	15	17
Total	1,011	1,212
Expenses:
Utility natural gas, fuel and purchased power	472	687
Non-utility cost of revenues, including natural gas	6	10
Operation and maintenance	209	233
Depreciation and amortization	74	73
Taxes other than income taxes	50	49
Total	811	1,052
Operating Income	200	160
Other Income (Expense):
Interest expense and other finance charges	(30)	(29)
Interest Income	0	0
Other income (expense), net	(4)	(3)
Total	(34)	(32)
Income (Loss) from Continuing Operations before Income Taxes	166	128
Income tax expense (benefit)	35	18
Income (Loss) from Continuing Operations	131	110
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(64)	28
Net Income (Loss)	$ 67	$ 138