Goodwill and Other Intangibles (CenterPoint Energy and CERC) - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Goodwill [Line Items]
Loss on sale	$ 0	$ 0	$ 12	$ (303)
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Energy Systems Group
Goodwill [Line Items]
Held for sale	$ 134		134
Loss on sale			$ 12