Divestitures (CenterPoint Energy and CERC) - Schedule of Pre-tax Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income before income taxes	$ 1,087	$ 1,417	$ 778
CERC Corp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income before income taxes	486	961	466
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 before income taxes	$ (4)	2	(3)
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 before income taxes		9	78
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Arkansas and Oklahoma Natural Gas Businesses | CERC Corp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income before income taxes		$ 9	$ 78