Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	13.00%	46.00%	16.00%	29.00%
Deferred remeasurement benefit			$ 25
Change in valuation allowance, income tax benefit			21
Interest and penalties on uncertain tax liability	$ 30		30
Increase in unrecognized tax benefits is reasonably possible as a result of a lapse in statutes	$ 3		$ 3
Houston Electric
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	20.00%	21.00%	20.00%	22.00%
CERC
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	24.00%	20.00%	19.00%	22.00%
Deferred remeasurement benefit			$ 24
Change in valuation allowance, income tax benefit			$ 21

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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- Definition

Amount of increase reasonably possible in the next twelve months for the unrecognized tax benefit.

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- Definition

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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