Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Supplemental Cash Flow Information [Abstract]
Interest, net of capitalized interest	$ 219	$ 261
Income tax payments (refunds), net	267	13
Accounts payable related to capital expenditures	352	249
ROU assets obtained in exchange for lease liabilities	1	2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	555		$ 230
Restricted cash included in Prepaid expenses and other current assets	22		24
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	577	157	254	$ 167
Houston Electric
Supplemental Cash Flow Information [Abstract]
Interest, net of capitalized interest	96	92
Income tax payments (refunds), net	130	0
Accounts payable related to capital expenditures	221	185
ROU assets obtained in exchange for lease liabilities	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	78		214
Restricted cash included in Prepaid expenses and other current assets	18		19
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	96	137	233	154
Houston Electric | Bond Companies
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	78		92
CERC
Supplemental Cash Flow Information [Abstract]
Interest, net of capitalized interest	41	59
Income tax payments (refunds), net	5	(11)
Accounts payable related to capital expenditures	147	99
ROU assets obtained in exchange for lease liabilities	0	1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	3		15
Restricted cash included in Prepaid expenses and other current assets	0		0
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	$ 3	$ 2	$ 15	$ 6