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

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Amount recognized for uncertainty in income taxes classified as noncurrent.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Contingency [Line Items]
Net uncertain tax liability	$ 5		$ 5
Unrecognized tax benefits as a result of lapse of communication			$ 1
Houston Electric
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	21.00%	15.00%	21.00%	14.00%
Continuing Operations
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	22.00%	(11.00%)	26.00%	6.00%
Continuing Operations \| CERC
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	4.00%	(28.00%)	23.00%	12.00%
Discontinued Operations
Income Tax Contingency [Line Items]
Effective income tax rate (as a percent)	0.00%	24.00%	0.00%	23.00%