Property, Plant and Equipment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) MW	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted-average remaining lease term (in years) - finance leases	6 years 6 months	7 years 6 months
Finance lease right of use assets, gross	$ 662	$ 179
Property plant and equipment and finance lease assets, gross	37,728	33,673
Finance lease right of use assets, accumulated amortization	41	0
Property plant and equipment and finance lease assets, accumulated depreciation and amortization	10,585	10,189
Property, Plant and Equipment, net	27,143	23,484
Finance ROU assets	621	179
Property plant and equipment and finance lease assets, net	27,143	23,484
Depreciation and Amortization [Abstract]
Depreciation	1,013	1,024	$ 961
Amortization of securitized regulatory assets	191	213	155
Other amortization	84	79	73
Total	1,288	1,316	1,189
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	659	664
Accretion expense	20	19
Revisions in estimate	(69)	(24)
Ending balance	$ 610	$ 659	664
Houston Electric
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted-average remaining lease term (in years) - finance leases	6 years 6 months	7 years 6 months
Finance lease right of use assets, gross	$ 662	$ 179
Property plant and equipment and finance lease assets, gross	17,753	15,273
Finance lease right of use assets, accumulated amortization	41	0
Property plant and equipment and finance lease assets, accumulated depreciation and amortization	4,292	4,070
Property, Plant and Equipment, net	13,461	11,203
Finance ROU assets	621	179
Property plant and equipment and finance lease assets, net	13,461	11,203
Depreciation and Amortization [Abstract]
Depreciation	434	391	368
Amortization of securitized regulatory assets	191	213	155
Other amortization	45	38	37
Total	670	642	560
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	42	43
Accretion expense	1	1
Revisions in estimate	(7)	(2)
Ending balance	36	42	43
CERC Corp
Property, Plant and Equipment, Net, by Type [Abstract]
Property plant and equipment and finance lease assets, gross	14,379	12,934
Property plant and equipment and finance lease assets, accumulated depreciation and amortization	3,973	3,826
Property, Plant and Equipment, net	10,406	9,108
Finance ROU assets	0	0
Property plant and equipment and finance lease assets, net	10,406	9,108
Depreciation and Amortization [Abstract]
Depreciation	420	466	426
Amortization of securitized regulatory assets	0	0	0
Other amortization	28	17	15
Total	448	483	441
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	479	514
Accretion expense	15	13
Revisions in estimate	(74)	(48)
Ending balance	$ 420	479	$ 514
Electric transmission and distribution
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	36 years
Property, Plant and Equipment, Gross	$ 19,154	17,156
Accumulated Depreciation & Amortization	5,317	4,658
Property, Plant and Equipment, net	$ 13,837	12,498
Electric transmission and distribution | Houston Electric
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	38 years
Property, Plant and Equipment, Gross	$ 14,791	13,321
Accumulated Depreciation & Amortization	3,556	3,502
Property, Plant and Equipment, net	$ 11,235	9,819
Electric generation
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	26 years
Property, Plant and Equipment, Gross	$ 2,120	1,807
Accumulated Depreciation & Amortization	813	1,179
Property, Plant and Equipment, net	$ 1,307	628
Natural gas distribution
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	32 years
Property, Plant and Equipment, Gross	$ 15,097	13,578
Accumulated Depreciation & Amortization	4,135	3,981
Property, Plant and Equipment, net	$ 10,962	9,597
Natural gas distribution | CERC Corp
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	32 years
Property, Plant and Equipment, Gross	$ 14,316	12,885
Accumulated Depreciation & Amortization	3,946	3,800
Property, Plant and Equipment, net	$ 10,370	9,085
Other property
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	23 years
Property, Plant and Equipment, Gross	$ 695	953
Accumulated Depreciation & Amortization	279	371
Property, Plant and Equipment, net	$ 416	582
Other property | Houston Electric
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	20 years
Property, Plant and Equipment, Gross	$ 2,300	1,773
Accumulated Depreciation & Amortization	695	568
Property, Plant and Equipment, net	$ 1,605	1,205
Other property | CERC Corp
Property, Plant and Equipment, Net, by Type [Abstract]
Weighted Average Useful Lives	17 years
Property, Plant and Equipment, Gross	$ 63	49
Accumulated Depreciation & Amortization	27	26
Property, Plant and Equipment, net	$ 36	$ 23
SIGECO
Property, Plant and Equipment, Net, by Type [Abstract]
Number of megawatts (in MW) | MW	300
SIGECO's share of cost of Warrick Unit 4	$ 198
SIGECO's share of accumulated depreciation of Warrick Unit 4	$ 162