Related Party Transactions (Houston Electric and CERC) - Schedule of Affiliated-Related Net Interest Income (Expense) (Details) - Other Nonoperating Income (Expense) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Houston Electric
Related Party Transaction [Line Items]
Interest income (expense), net	$ 0	$ 0	$ 18
CERC Corp
Related Party Transaction [Line Items]
Interest income (expense), net	$ 0	$ 0	$ 4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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