Goodwill and Other Intangibles (CenterPoint Energy and CERC) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 4,294
Disposals	134
Goodwill, ending balance	4,160	$ 4,294
Finite-Live Intangible Assets [Abstract]
Gross Carrying Amount		63
Accumulated Amortization		(25)
Net Balance		38
Depreciation and amortization expense
Finite-Live Intangible Assets [Abstract]
Amortization expense of intangible assets recorded in depreciation and amortization	3	6	$ 6
Cost of Sales
Finite-Live Intangible Assets [Abstract]
Amortization expense of intangible assets recorded in depreciation and amortization	0	1	$ 1
Customer relationships
Finite-Live Intangible Assets [Abstract]
Gross Carrying Amount		33
Accumulated Amortization		(16)
Net Balance		17
Trade names
Finite-Live Intangible Assets [Abstract]
Gross Carrying Amount		16
Accumulated Amortization		(6)
Net Balance		10
Operation and maintenance agreements
Finite-Live Intangible Assets [Abstract]
Gross Carrying Amount		12
Accumulated Amortization		(2)
Net Balance		10
Other
Finite-Live Intangible Assets [Abstract]
Gross Carrying Amount		2
Accumulated Amortization		(1)
Net Balance		1
Electric
Goodwill [Roll Forward]
Goodwill, beginning balance	936
Disposals	0
Goodwill, ending balance	936	936
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Accumulated goodwill impairment charge				$ 185
Natural Gas
Goodwill [Roll Forward]
Goodwill, beginning balance	2,920
Disposals	0
Goodwill, ending balance	2,920	2,920
Corporate and Other
Goodwill [Roll Forward]
Goodwill, beginning balance	438
Disposals	134
Goodwill, ending balance	$ 304	$ 438