Equity (CenterPoint Energy) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (35)	$ (31)
Net deferred gain from cash flow hedges	4	1	$ 0
Prior service cost (benefit)	1	1
Actuarial losses (gain)	2	1
Reclassification of deferred gain from cash flow hedges realized in net income	(1)	0
Tax benefit (expense)	(4)	1
Other comprehensive income (loss)	18	(4)	33
Ending balance	(17)	(35)	(31)
Houston Electric
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0	0
Net deferred gain from cash flow hedges	0	0
Prior service cost (benefit)	0	0
Actuarial losses (gain)	0	0
Reclassification of deferred gain from cash flow hedges realized in net income	0	0
Tax benefit (expense)	0	0
Other comprehensive income (loss)	(1)	0	0
Ending balance	(1)	0	0
CERC
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	16	16
Net deferred gain from cash flow hedges	0	0
Prior service cost (benefit)	1	(2)
Actuarial losses (gain)	(2)	2
Reclassification of deferred gain from cash flow hedges realized in net income	0	0
Tax benefit (expense)	0	0
Other comprehensive income (loss)	1	0	6
Ending balance	17	16	$ 16
Remeasurement of pension and other postretirement plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans	16	(8)
Remeasurement of pension and other postretirement plans | Houston Electric
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans	(1)	0
Remeasurement of pension and other postretirement plans | CERC
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans	$ 2	$ 0