Income Taxes (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Effective income tax rate	[1]	13.00%	15.00%	12.00%	27.00%
Net uncertain tax liability		$ 1		$ 1
Houston Electric [Member]
Effective income tax rate	[2]	19.00%	21.00%	19.00%	22.00%
Continuing Operations [Member] | CERC Corp [Member]
Effective income tax rate	[3]	0.00%	33.00%	14.00%	19.00%
Discontinued Operations [Member] | CERC Corp [Member]
Effective income tax rate	[4]		24.00%		24.00%
Federal statutory tax rate	[4]				21.00%

[1] CenterPoint Energy’s lower effective tax rate for the three and six months ended June 30, 2019 compared to the same periods for 2018 was primarily due to the following: an increase in the amount of amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions; the impact of state tax law changes that resulted in the remeasurement of state deferred taxes; and the release of a valuation allowance on certain state net operating losses that are now expected to be utilized prior to expiration due to a current period law change.

[2] Houston Electric’s lower effective tax rate for the three and six months ended June 30, 2019 compared to the same periods for 2018 was primarily due to an increase in the amount of amortization of the net regulatory EDIT liability as decreed by regulators.

[3] CERC’s lower effective tax rate on income from continuing operations for the three and six months ended June 30, 2019 compared to the same periods for 2018 was primarily due to the following: an increase in the amount of amortization of the net regulatory EDIT liability as decreed by regulators in certain jurisdictions; the impact of state tax law changes that resulted in the remeasurement of state deferred taxes; and the release of a valuation allowance on certain state net operating losses that are now expected to be utilized prior to expiration due to a current period law change. The state law changes and valuation allowance release resulted in a lower than expected effective tax rate for the three months ended June 30, 2019 as compared to the three months ended June 30, 2018.

[4] CERC’s effective tax rate on income from discontinued operations for the three and six months ended June 30, 2018 was a result of the 21% federal income tax rate plus allocable state income taxes. There are no comparable periods in 2019 since the Internal Spin was completed in the third quarter of 2018.