Stock-Based Incentive Compensation Plans and Employee Benefit Plans - Pension and Postretirement Benefits (Details) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($) beneficiary	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Components of net periodic costs [Abstract]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net	Other income (expense), net	Other income (expense), net
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net	Other income (expense), net	Other income (expense), net
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net	Other income (expense), net	Other income (expense), net
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net	Other income (expense), net	Other income (expense), net
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net	Other income (expense), net	Other income (expense), net
Amounts Recognized in Balance Sheets
Other liabilities — benefit obligations		$ (550)	$ (572)
Discount rate period		99 years
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net actuarial loss (gain)		$ (2)	(1)
Amortization of prior service cost		(1)	(1)
Pension Plan
Components of net periodic costs [Abstract]
Service cost		25	25
Interest cost		73	76	$ 73
Expected return on plan assets		(75)	(76)	(87)
Amortization of net loss		28	28	31
Settlement cost		0	0	126
Net periodic cost (credit)		51	53	172
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		1,548	1,553
Service cost		25	25
Interest cost		73	76	73
Benefits paid		(127)	(147)
Actuarial (gain) loss		(42)	41
Benefit obligation, end of year	$ 1,553	1,477	1,548	1,553
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		1,204	1,212
Employer contributions		30	32
Benefits paid		(127)	(147)
Actual investment return		25	107
Fair value of plan assets, end of year	1,212	1,132	1,204	$ 1,212
Funded status, end of year		(345)	(344)
Amounts Recognized in Balance Sheets
Non-current assets		7	4
Current liabilities — other		(7)	(7)
Other liabilities — benefit obligations		(345)	(341)
Net liability, end of year		$ (345)	$ (344)
Discount rate (as a percent)		5.60%	4.95%
Expected return on plan assets (as a percent)		7.00%	6.50%
Rate of increase in compensation levels (as a percent)		4.79%	4.97%
Interest crediting rate (as a percent)		3.00%	3.00%
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation for all defined benefit pension plans		$ 1,475	$ 1,544
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)		52	69
Unrecognized prior service cost		0	0
Net amount recognized in accumulated other comprehensive loss (income)		52	69
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)		(13)
Amortization of net actuarial loss (gain)		(4)
Amortization of prior service cost		0
Settlement		0
Total recognized in comprehensive income		(17)
Total recognized in net periodic costs and other comprehensive income		34
Pension Plan | Qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		23
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation		1,431	1,496
Projected benefit obligation		1,433	1,500
Fair value of plan assets		1,132	1,204
Pension Plan | Non-qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		7
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation		44	48
Projected benefit obligation		44	48
Fair value of plan assets		$ 0	$ 0
Pension Plan | CenterPoint Energy
Defined Benefit Plan Disclosure [Line Items]
Decrease in benefit obligation from transfer	138
Decrease in plan assets	$ 136
Change in benefit obligation (as a percent)	9.40%
Settlement charge	$ 47
Number of beneficiaries | beneficiary	1,119
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		4.95%	5.15%	2.80%
Expected return on plan assets (as a percent)		6.50%	6.50%	5.00%
Rate of increase in compensation levels (as a percent)		4.97%	4.99%	4.95%
Other Postretirement Benefits Plan
Components of net periodic costs [Abstract]
Service cost		$ 1	$ 1	$ 2
Interest cost		13	13	9
Expected return on plan assets		(6)	(5)	(5)
Amortization of prior service cost		(2)	(2)	(3)
Amortization of net loss		8	8	4
Net periodic cost (credit)		$ (2)	$ (1)	$ (1)
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		4.95%	5.15%	2.85%
Expected return on plan assets (as a percent)		5.21%	5.13%	3.22%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 263	$ 263
Service cost		1	1	$ 2
Interest cost		13	13	9
Participant contributions		5	6
Benefits paid		(21)	(20)
Actuarial (gain) loss		(22)	0
Other transfers		3	0
Benefit obligation, end of year	$ 263	242	263	263
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		112	109
Employer contributions		9	7
Participant contributions		5	6
Benefits paid		(21)	(20)
Actual investment return		6	10
Other transfers		(8)	0
Fair value of plan assets, end of year	109	103	112	109
Funded status, end of year		(139)	(151)
Amounts Recognized in Balance Sheets
Current liabilities — other		(8)	(7)
Other liabilities — benefit obligations		(131)	(144)
Net liability, end of year		$ (139)	$ (151)
Discount rate (as a percent)		5.60%	4.95%
Expected return on plan assets (as a percent)		5.21%	5.13%
Prescription drug cost trend rate assumed for the next year - Pre-65		10.00%	9.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)		$ (34)	$ (34)
Unrecognized prior service cost		9	12
Net amount recognized in accumulated other comprehensive loss (income)		(25)	$ (22)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)		(4)
Amortization of net actuarial loss (gain)		2
Amortization of prior service cost		(1)
Settlement		0
Total recognized in comprehensive income		(3)
Total recognized in net periodic costs and other comprehensive income		$ 1
Minimum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		6.75%	7.25%
Maximum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		13.74%	22.76%
Houston Electric
Amounts Recognized in Balance Sheets
Other liabilities — benefit obligations		$ (32)	$ (32)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net actuarial loss (gain)		0	0
Amortization of prior service cost		0	0
Houston Electric | Pension Plan | Qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		0
Houston Electric | Pension Plan | Non-qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		0
Houston Electric | Other Postretirement Benefits Plan
Components of net periodic costs [Abstract]
Service cost		0	0	0
Interest cost		5	5	4
Expected return on plan assets		(4)	(4)	(4)
Amortization of prior service cost		(5)	(5)	(4)
Amortization of net loss		4	4	2
Net periodic cost (credit)		$ (8)	$ (8)	$ (6)
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		4.95%	5.15%	2.85%
Expected return on plan assets (as a percent)		5.36%	5.26%	3.32%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 113	$ 115
Service cost		0	0	$ 0
Interest cost		5	5	4
Participant contributions		2	2
Benefits paid		(8)	(8)
Actuarial (gain) loss		(9)	(1)
Other transfers		1	0
Benefit obligation, end of year	115	104	113	115
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		86	84
Employer contributions		1	0
Participant contributions		2	2
Benefits paid		(8)	(8)
Actual investment return		4	8
Other transfers		(8)	0
Fair value of plan assets, end of year	84	77	86	84
Funded status, end of year		(27)	(27)
Amounts Recognized in Balance Sheets
Current liabilities — other		0	0
Other liabilities — benefit obligations		(27)	(27)
Net liability, end of year		$ (27)	$ (27)
Discount rate (as a percent)		5.60%	4.95%
Expected return on plan assets (as a percent)		5.36%	5.26%
Prescription drug cost trend rate assumed for the next year - Pre-65		10.00%	9.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		4.50%	4.50%
Houston Electric | Minimum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		6.75%	7.25%
Houston Electric | Maximum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		13.74%	22.76%
CERC
Amounts Recognized in Balance Sheets
Other liabilities — benefit obligations		$ (63)	$ (74)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net actuarial loss (gain)		2	(2)
Amortization of prior service cost		(1)	2
CERC | Pension Plan | Qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		0
CERC | Pension Plan | Non-qualified pension plans
Change in plan assets [Rollforward]
Employer contributions		0
CERC | Other Postretirement Benefits Plan
Components of net periodic costs [Abstract]
Service cost		1	1	1
Interest cost		4	5	3
Expected return on plan assets		(1)	(1)	(1)
Amortization of prior service cost		2	2	2
Amortization of net loss		3	3	1
Net periodic cost (credit)		$ 3	$ 4	$ 4
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		4.95%	5.15%	2.85%
Expected return on plan assets (as a percent)		4.77%	4.69%	2.86%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 93	$ 92
Service cost		1	1	$ 1
Interest cost		4	5	3
Participant contributions		2	3
Benefits paid		(9)	(8)
Actuarial (gain) loss		(8)	0
Other transfers		2	0
Benefit obligation, end of year	92	85	93	92
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		26	25
Employer contributions		5	4
Participant contributions		2	3
Benefits paid		(9)	(8)
Actual investment return		2	2
Other transfers		0	0
Fair value of plan assets, end of year	$ 25	26	26	25
Funded status, end of year		(59)	(67)
Amounts Recognized in Balance Sheets
Current liabilities — other		(4)	(4)
Other liabilities — benefit obligations		(55)	(63)
Net liability, end of year		$ (59)	$ (67)
Discount rate (as a percent)		5.60%	4.95%
Expected return on plan assets (as a percent)		4.77%	4.69%
Prescription drug cost trend rate assumed for the next year - Pre-65		10.00%	9.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)		$ (26)	$ (27)
Unrecognized prior service cost		8	10
Net amount recognized in accumulated other comprehensive loss (income)		(18)	$ (17)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)		0
Amortization of net actuarial loss (gain)		(2)
Amortization of prior service cost		1
Settlement		0
Total recognized in comprehensive income		(1)
Total recognized in net periodic costs and other comprehensive income		$ 2
CERC | Minimum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		6.75%	7.25%
CERC | Maximum | Other Postretirement Benefits Plan
Amounts Recognized in Balance Sheets
Health care cost trend rate assumed for the next year		13.74%	22.76%
Operation And Maintenance Expense | Pension Plan
Components of net periodic costs [Abstract]
Service cost		$ 25	$ 25	29
Change in benefit obligation [Roll Forward]
Service cost		$ 25	$ 25	$ 29