Divestitures (CenterPoint Energy and CERC) - Schedule of Pre-tax Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from Continuing Operations Before Income Taxes	$ 350	$ 277	$ 970	$ 1,251
CERC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from Continuing Operations Before Income Taxes	38	10	363	876
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Energy Systems Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from Continuing Operations Before Income Taxes	$ 0	(1)	$ (4)	(5)
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Arkansas and Oklahoma Natural Gas Businesses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from Continuing Operations Before Income Taxes		0		9
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Arkansas and Oklahoma Natural Gas Businesses | CERC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from Continuing Operations Before Income Taxes		$ 0		$ 9