Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Significant Accounting Policies [Line Items]
Deferred debt interest	$ 65	$ 51	$ 26
Houston Electric
Significant Accounting Policies [Line Items]
Deferred debt interest	16	12	1
CERC Corp
Significant Accounting Policies [Line Items]
Deferred debt interest	43	36	22
Interest Expense
Significant Accounting Policies [Line Items]
Capitalized interest and AFUDC debt	32	26	18
Interest Expense | Houston Electric
Significant Accounting Policies [Line Items]
Capitalized interest and AFUDC debt	18	14	13
Interest Expense | CERC Corp
Significant Accounting Policies [Line Items]
Capitalized interest and AFUDC debt	6	7	3
Other Income (Expense)
Significant Accounting Policies [Line Items]
AFUDC equity	62	37	28
Other Income (Expense) | Houston Electric
Significant Accounting Policies [Line Items]
AFUDC equity	32	24	20
Other Income (Expense) | CERC Corp
Significant Accounting Policies [Line Items]
AFUDC equity	$ 14	$ 5	$ 5