Earnings Per Share (CenterPoint Energy) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Income from continuing operations	$ 282	$ 202	$ 725	$ 923
Less: Preferred stock dividend requirement (Note 18)	26	13	50	37
Income available to common shareholders - basic	256	189	675	886
Income available to common shareholders -diluted	$ 256	$ 189	$ 675	$ 886
Denominator:
Weighted average common shares outstanding - basic (in shares)	631,185	629,509	630,854	629,374
Plus: Incremental shares from assumed conversions:
Weighted average common shares outstanding - diluted (in shares)	633,043	633,068	633,037	632,933
Earnings Per Common Share:
Basic Earnings Per Common Share (in dollars per share)	$ 0.41	$ 0.30	$ 1.07	$ 1.41
Diluted Earnings (Loss) Per Common Share
Diluted Earnings Per Common Share (in dollars per share)	$ 0.40	$ 0.30	$ 1.07	$ 1.40
Restricted stock
Plus: Incremental shares from assumed conversions:
Restricted stock (in shares)	1,858	3,559	2,183	3,559