Condensed Statements of Consolidated Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Utility revenues	$ 1,652	$ 1,476	$ 4,136	$ 3,549
Non-utility revenues	90	99	153	193
Total	1,742	1,575	4,289	3,742
Expenses:
Utility natural gas, fuel and purchased power	258	202	1,193	811
Non-utility cost of revenues, including natural gas	58	69	98	133
Operation and maintenance	677	643	1,346	1,317
Depreciation and amortization	327	297	634	579
Taxes other than income taxes	126	129	269	265
Goodwill impairment	0	0	0	185
Total	1,446	1,340	3,540	3,290
Operating Income	296	235	749	452
Other Income (Expense):
Gain (loss) on marketable securities	75	75	52	(69)
Gain (loss) on indexed debt securities	(77)	(76)	(51)	59
Interest expense and other finance charges	(119)	(128)	(232)	(267)
Interest expense on Securitization Bonds	(5)	(7)	(11)	(15)
Equity in earnings (loss) of unconsolidated affiliates, net	67	43	175	(1,432)
Other income, net	11	22	3	36
Total	(48)	(71)	(64)	(1,688)
Income (Loss) from Continuing Operations Before Income Taxes	248	164	685	(1,236)
Income tax expense (benefit)	(3)	29	71	(318)
Income (Loss) from Continuing Operations	251	135	614	(918)
Net loss from discontinued operations	0	(30)	0	(176)
Net Income (Loss)	251	105	614	(1,094)
Income allocated to preferred shareholders	30	46	59	75
Income (Loss) Available to Common Shareholders	$ 221	$ 59	$ 555	$ (1,169)
Basic Earnings (Loss) Per Common Share [Abstract]
Basic earnings (loss) per common share - continuing operations (in dollars per share)	$ 0.38	$ 0.17	$ 0.98	$ (1.93)
Basic earnings (loss) per common share - discontinued operations (in dollars per share)	0	(0.06)	0	(0.34)
Basic Earnings (Loss) Per Common Share (in dollars per share)	0.38	0.11	0.98	(2.27)
Diluted Earnings (Loss) Per Common Share [Abstract]
Diluted earnings (loss) per common share - continuing operations (in dollars per share)	0.37	0.17	0.93	(1.93)
Diluted earnings (loss) per common share - discontinued operations (in dollars per share)	0	(0.06)	0	(0.34)
Diluted Earnings (Loss) Per Common Share (in dollars per share)	$ 0.37	$ 0.11	$ 0.93	$ (2.27)
Weighted Average Common Shares Outstanding, Basic	585,720,000	528,066,000	568,728,000	515,227,000
Weighted Average Common Shares Outstanding, Diluted	596,330,000	530,837,000	596,130,000	515,227,000
Houston Electric
Revenues:
Total	$ 786	$ 720	$ 1,470	$ 1,354
Expenses:
Operation and maintenance	390	364	763	723
Depreciation and amortization	161	140	302	269
Taxes other than income taxes	65	64	128	128
Total	616	568	1,193	1,120
Operating Income	170	152	277	234
Other Income (Expense):
Interest expense and other finance charges	(47)	(43)	(92)	(84)
Interest expense on Securitization Bonds	(5)	(7)	(11)	(15)
Other income, net	3	1	8	6
Total	(49)	(49)	(95)	(93)
Income (Loss) from Continuing Operations Before Income Taxes	121	103	182	141
Income tax expense (benefit)	18	16	26	21
Net Income (Loss)	103	87	156	120
CERC Corp
Revenues:
Utility revenues	549	467	1,717	1,463
Non-utility revenues	25	16	34	31
Total	574	483	1,751	1,494
Expenses:
Utility natural gas, fuel and purchased power	182	137	805	609
Non-utility cost of revenues, including natural gas	10	7	12	13
Operation and maintenance	194	179	392	388
Depreciation and amortization	80	74	160	148
Taxes other than income taxes	44	44	100	94
Total	510	441	1,469	1,252
Operating Income	64	42	282	242
Other Income (Expense):
Interest expense and other finance charges	(25)	(29)	(49)	(59)
Other income, net	1	0	0	(4)
Total	(24)	(29)	(49)	(63)
Income (Loss) from Continuing Operations Before Income Taxes	40	13	233	179
Income tax expense (benefit)	(18)	(4)	24	31
Income (Loss) from Continuing Operations	58	17	209	148
Net loss from discontinued operations	0	(4)	0	(68)
Net Income (Loss)	$ 58	$ 13	$ 209	$ 80