Earnings Per Share (CenterPoint Energy) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Income from continuing operations	$ 202	$ 150	$ 923	$ 630
Less: Preferred stock dividend requirement	13	23	37	82
Income available to common shareholders from continuing operations - basic	189	127	886	548
Income available to common shareholders from continuing operations - diluted	189	127	886	548
Income available to common shareholders from discontinued operations - basic	0	68	0	202
Income available to common shareholders from discontinued operations - diluted	0	68	0	202
Income available to common shareholders - basic and diluted	189	195	886	750
Income available to common shareholders - basic and diluted	$ 189	$ 195	$ 886	$ 750
Denominator:
Weighted average common shares outstanding - basic	629,509,000	604,607,000	629,374,000	580,819,000
Plus: Incremental shares from assumed conversions:
Weighted average common shares outstanding - diluted	633,068,000	609,382,000	632,933,000	601,403,000
Earnings Per Common Share:
Basic earnings per common share - continuing operations (in dollars per share)	$ 0.30	$ 0.21	$ 1.41	$ 0.94
Basic earnings per common share - discontinued operations (in dollars per share)	0	0.11	0	0.35
Basic Earnings Per Common Share (in dollars per share)	0.30	0.32	1.41	1.29
Diluted Earnings (Loss) Per Common Share
Diluted earnings per common share - continuing operations (in dollars per share)	0.30	0.21	1.40	0.91
Diluted earnings per common share - discontinued operations (in dollars per share)	0	0.11	0	0.34
Diluted Earnings Per Common Share (in dollars per share)	$ 0.30	$ 0.32	$ 1.40	$ 1.25
Series C Preferred Stock
Plus: Incremental shares from assumed conversions:
Series C Preferred Stock	0	0	0	15,809,000
Series B Preferred Stock
Numerator:
Less: Preferred stock dividend requirement	$ 0	$ 11	$ 0	$ 45
Anti-dilutive Incremental Shares Excluded from Denominator for Diluted Earnings Computation:
Amount of antidilutive shares excluded from computation of earnings per share (in shares)	0	24,179,000	0	31,962,000
Restricted stock
Plus: Incremental shares from assumed conversions:
Restricted stock	3,559,000	4,775,000	3,559,000	4,775,000