Subsequent Events (CenterPoint Energy) (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended
		May 05, 2020	Apr. 24, 2020	Apr. 01, 2020	Mar. 31, 2020	Mar. 31, 2019	Apr. 13, 2020	Apr. 09, 2020
Subsequent Event [Line Items]
Dividends declared per share					$ 0.2900	$ 0.0000
Expected cash distribution from equity method investment					$ 70	$ 74
Common Stock [Member]
Subsequent Event [Line Items]
Dividends declared per share					$ 0.2875	$ 0.2775
Series B Preferred Stock [Member]
Subsequent Event [Line Items]
Preferred stock dividends declared					$ 17.5000	$ 0.0000
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends payable, date declared			Apr. 24, 2020
Dividends payable, date of record			May 21, 2020
Dividends payable, date to be paid			Jun. 11, 2020
Dividends declared per share	[1]		$ 0.1500
Subsequent Event [Member] | Series B Preferred Stock [Member]
Subsequent Event [Line Items]
Dividends payable, date declared			Apr. 24, 2020
Dividends payable, date of record			May 15, 2020
Dividends payable, date to be paid			Jun. 01, 2020
Preferred stock dividends declared			$ 17.5000
Common Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]
Subsequent Event [Line Items]
Quarterly cash distribution, declaration date		May 05, 2020
Quarterly cash distribution, date of record		May 19, 2020
Quarterly cash distribution, distribution date		May 27, 2020
Quarterly cash distribution declared per share	[2]	$ 0.16525
Expected cash distribution from equity method investment		$ 39
Percentage Reduction of Dividend or Distribution Amount				50.00%
Series A Preferred Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]
Subsequent Event [Line Items]
Quarterly cash distribution, declaration date		May 05, 2020
Quarterly cash distribution, date of record		May 05, 2020
Quarterly cash distribution, distribution date		May 15, 2020
Quarterly cash distribution declared per share		$ 0.62500
Expected cash distribution from cost method investment		$ 9
Previous Dividend or Distribution [Member] | Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends declared per share	[1]			$ 0.2900
Previous Dividend or Distribution [Member] | Common Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]
Subsequent Event [Line Items]
Quarterly cash distribution declared per share				0.3305
Revised Dividend or Distribution [Member] | Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends declared per share	[1]			0.1500
Revised Dividend or Distribution [Member] | Common Units [Member] | Subsequent Event [Member] | Enable Midstream Partners [Member]
Subsequent Event [Line Items]
Quarterly cash distribution declared per share				$ 0.16525
Infrastructure Services [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Sales price of outstanding equity interests								$ 850
Houston Electric [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
ERCOT Loan, COVID-19 ERP							$ 5

[1] On April 1, 2020, in response to the reduction in cash flow related to the reduction in Enable quarterly common unit distributions announced by Enable on April 1, 2020, CenterPoint Energy announced a reduction of its quarterly common stock dividend per share from $0.2900 to $0.1500.

[2] On April 1, 2020, Enable announced a reduction in its quarterly distributions per common unit from $0.3305 distributed for the fourth quarter 2019 to $0.16525, representing a 50% reduction.