Supplemental Disclosure of Cash Flow Information - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019		Dec. 31, 2019	Dec. 31, 2018
Interest, net of capitalized interest		$ 324	$ 364
Income tax payments, net		117	174
Accounts payable related to capital expenditures		220	178
ROU assets obtained in exchange for lease liabilities (1)		14	43	[1]
Beneficial conversion feature		32	0
Amortization of Beneficial Conversion Feature	$ (16)	(25)	0
Cash and Cash Equivalents, at Carrying Value	185	185			$ 241
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	208	208	297		271	$ 4,278
Prepaid expenses and other current assets [Member]
Restricted cash	23	23			30
Houston Electric [Member]
Interest, net of capitalized interest		176	203
Income tax payments, net		33	93
Accounts payable related to capital expenditures		121	91
ROU assets obtained in exchange for lease liabilities (1)		0	1	[1]
Beneficial conversion feature		0	0
Amortization of Beneficial Conversion Feature		0	0
Cash and Cash Equivalents, at Carrying Value	172	172			216
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	188	188	247		235	370
Houston Electric [Member] | Prepaid expenses and other current assets [Member]
Restricted cash	16	16			19
CERC Corp [Member]
Interest, net of capitalized interest		88	88
Income tax payments, net		4	3
Accounts payable related to capital expenditures		72	75
ROU assets obtained in exchange for lease liabilities (1)		5	28	[1]
Beneficial conversion feature		0	0
Amortization of Beneficial Conversion Feature		0	0
Cash and Cash Equivalents, at Carrying Value	2	2			2
Total cash, cash equivalents and restricted cash shown in Condensed Statements of Consolidated Cash Flows	2	2	$ 2		2	$ 25
CERC Corp [Member] | Prepaid expenses and other current assets [Member]
Restricted cash	$ 0	$ 0			$ 0

[1] 2019 includes the transition impact of adoption of ASU 2016-02 Leases.