Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Significant Accounting Policies [Line Items]
Other deferred interest	$ 33	$ 10	$ 3
LIFO Inventory Amount	101	101
Cost of replacing inventories carried at LIFO cost less than carrying value	101
Interest Expense
Significant Accounting Policies [Line Items]
Interest and AFUDC debt	44	34	27
Interest Expense | Indiana
Significant Accounting Policies [Line Items]
Interest and AFUDC debt	18	16	13
Other Income (Expense)
Significant Accounting Policies [Line Items]
AFUDC equity	37	28	25
Houston Electric
Significant Accounting Policies [Line Items]
Other deferred interest	12	1	0
Houston Electric | Interest Expense
Significant Accounting Policies [Line Items]
Interest and AFUDC debt	14	13	8
Houston Electric | Other Income (Expense)
Significant Accounting Policies [Line Items]
AFUDC equity	24	20	14
CERC Corp
Significant Accounting Policies [Line Items]
Other deferred interest	21	9	3
LIFO Inventory Amount	82	79
CERC Corp | Interest Expense
Significant Accounting Policies [Line Items]
Interest and AFUDC debt	22	16	13
CERC Corp | Other Income (Expense)
Significant Accounting Policies [Line Items]
AFUDC equity	5	5	3
CERC Corp | Other Income (Expense) | Indiana
Significant Accounting Policies [Line Items]
Interest and AFUDC debt	$ 15	$ 13	$ 10