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 ($) beneficiary	Dec. 31, 2023 USD ($) defined_benefit_plan	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Number Of Additional Plans | defined_benefit_plan		3
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	$ (547)	$ (572)	$ (547)
Discount rate period		99 years
Annuity purchase		$ 136
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net loss		(1)	(8)
Amortization of prior service cost		(1)	1
Settlement		$ 0	(67)
Defined Benefit Plan, Funded Plan, Closed
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Number Of Additional Plans | defined_benefit_plan		2
Defined Benefit Plan, Funded Plan, Frozen
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Number Of Additional Plans | defined_benefit_plan		1
Pension Plan
Components of net periodic costs [Abstract]
Service cost		$ 25	29
Interest cost		76	73	$ 59
Expected return on plan assets		(76)	(87)	(103)
Amortization of net loss		28	31	36
Settlement cost		0	126	38
Net periodic cost (credit)		$ 53	$ 172	69
Assumptions used to determine net periodic benefit (income) cost
Expected return on plan assets (as a percent)		6.50%	6.50%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 1,553	$ 2,298
Service cost		25	29
Interest cost		76	73	59
Benefits paid		(147)	(509)
Actuarial (gain) loss		41	(338)
Plan amendment		0	0
Benefit obligation, end of year	1,553	1,548	1,553	2,298
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		1,212	2,072
Employer contributions		32	35
Benefits paid		(147)	(509)
Actual investment return		107	(386)
Fair value of plan assets, end of year	1,212	1,204	1,212	$ 2,072
Funded status, end of year	(341)	(344)	(341)
Amounts Recognized in Balance Sheets
Non-current assets	0	4	0
Current liabilities — other	(7)	(7)	(7)
Other liabilities — benefit obligations	(334)	(341)	(334)
Net liability, end of year	$ (341)	$ (344)	$ (341)
Discount rate (as a percent)	5.15%	4.95%	5.15%
Rate of increase in compensation levels (as a percent)	4.99%	4.97%	4.99%
Interest crediting rate (as a percent)	3.00%	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	$ 1,548	$ 1,544	$ 1,548
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	70	69	70
Unrecognized prior service cost	0	0	0
Net amount recognized in accumulated other comprehensive loss (gain)	70	69	70
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)		2
Amortization of net loss		(3)
Amortization of prior service cost		0
Settlement		0
Total recognized in comprehensive income		(1)
Total expense recognized in net periodic cost and other comprehensive income		52
Pension Plan | Qualified Plan
Change in plan assets [Rollforward]
Employer contributions		24
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	1,497	1,496	1,497
Projected benefit obligation	1,502	1,500	1,502
Fair value of plan assets	1,212	1,204	1,212
Pension Plan | Nonqualified Plan
Change in plan assets [Rollforward]
Employer contributions		8
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	51	48	51
Projected benefit obligation	51	48	51
Fair value of plan assets	0	$ 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%
Number of beneficiaries | beneficiary	1,119
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		5.15%	2.80%	2.45%
Expected return on plan assets (as a percent)		6.50%	5.00%	5.00%
Rate of increase in compensation levels (as a percent)		4.99%	4.95%	5.05%
Pension benefits that have accumulated benefit obligations in excess of plan assets
Settlement charge	$ 47
Other Postretirement Benefits Plan
Components of net periodic costs [Abstract]
Service cost		$ 1	$ 2	$ 2
Interest cost		13	9	9
Expected return on plan assets		(5)	(5)	(4)
Amortization of prior service cost		(2)	(3)	(4)
Amortization of net loss		8	4	0
Net periodic cost (credit)		$ (1)	$ (1)	$ 3
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		5.15%	2.85%	2.50%
Expected return on plan assets (as a percent)		5.13%	3.22%	3.20%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 263	$ 336
Service cost		1	2	$ 2
Interest cost		13	9	9
Participant contributions		6	6
Benefits paid		(20)	(20)
Actuarial (gain) loss		0	(73)
Plan amendment		0	3
Benefit obligation, end of year	263	263	263	336
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		109	132
Employer contributions		7	8
Participant contributions		6	6
Benefits paid		(20)	(20)
Actual investment return		10	(17)
Fair value of plan assets, end of year	109	112	109	132
Funded status, end of year	(154)	(151)	(154)
Amounts Recognized in Balance Sheets
Current liabilities — other	(7)	(7)	(7)
Other liabilities — benefit obligations	(147)	(144)	(147)
Net liability, end of year	$ (154)	$ (151)	$ (154)
Discount rate (as a percent)	5.15%	4.95%	5.15%
Expected return on plan assets (as a percent)		5.13%	3.66%
Pension benefits that have accumulated benefit obligations in excess of plan assets
Prescription drug cost trend rate assumed for the next year - Pre-65		9.00%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	$ (36)	$ (34)	$ (36)
Unrecognized prior service cost	13	12	13
Net amount recognized in accumulated other comprehensive loss (gain)	$ (23)	(22)	$ (23)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)		0
Amortization of net loss		2
Amortization of prior service cost		(1)
Settlement		0
Total recognized in comprehensive income		1
Total expense recognized in net periodic cost and other comprehensive income		$ 0
Minimum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	6.50%	7.25%	6.50%
Maximum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	23.66%	22.76%	23.66%
Houston Electric
Amounts Recognized in Balance Sheets
Other liabilities — benefit obligations	$ (38)	$ (32)	$ (38)
Houston Electric | Pension Plan | Qualified Plan
Change in plan assets [Rollforward]
Employer contributions		0
Houston Electric | Pension Plan | Nonqualified Plan
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	4	4
Expected return on plan assets		(4)	(4)	(3)
Amortization of prior service cost		(5)	(4)	(5)
Amortization of net loss		4	2	0
Net periodic cost (credit)		$ (8)	$ (6)	$ (4)
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		5.15%	2.85%	2.50%
Expected return on plan assets (as a percent)		5.26%	3.32%	3.30%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 115	$ 148
Service cost		0	0	$ 0
Interest cost		5	4	4
Participant contributions		2	2
Benefits paid		(8)	(7)
Actuarial (gain) loss		(1)	(32)
Plan amendment		0	0
Benefit obligation, end of year	115	113	115	148
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		84	104
Employer contributions		0	1
Participant contributions		2	2
Benefits paid		(8)	(7)
Actual investment return		8	(16)
Fair value of plan assets, end of year	84	86	84	104
Funded status, end of year	(31)	(27)	(31)
Amounts Recognized in Balance Sheets
Current liabilities — other	0	0	0
Other liabilities — benefit obligations	(31)	(27)	(31)
Net liability, end of year	$ (31)	$ (27)	$ (31)
Discount rate (as a percent)	5.15%	4.95%	5.15%
Expected return on plan assets (as a percent)		5.26%	3.75%
Pension benefits that have accumulated benefit obligations in excess of plan assets
Prescription drug cost trend rate assumed for the next year - Pre-65		9.00%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%	4.50%
Houston Electric | Minimum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	6.50%	7.25%	6.50%
Houston Electric | Maximum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	23.66%	22.76%	23.66%
CERC Corp
Amounts Recognized in Balance Sheets
Other liabilities — benefit obligations	$ (76)	$ (74)	$ (76)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Amortization of net loss		(2)	(1)
Amortization of prior service cost		2	1
Settlement		0	0
CERC Corp | Pension Plan | Qualified Plan
Change in plan assets [Rollforward]
Employer contributions		0
CERC Corp | Pension Plan | Nonqualified Plan
Change in plan assets [Rollforward]
Employer contributions		0
CERC Corp | Other Postretirement Benefits Plan
Components of net periodic costs [Abstract]
Service cost		1	1	1
Interest cost		5	3	3
Expected return on plan assets		(1)	(1)	(1)
Amortization of prior service cost		2	2	1
Amortization of net loss		3	1	0
Net periodic cost (credit)		$ 4	$ 4	$ 4
Assumptions used to determine net periodic benefit (income) cost
Discount rate (as a percent)		5.15%	2.85%	2.50%
Expected return on plan assets (as a percent)		4.69%	2.86%	2.85%
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of year		$ 92	$ 118
Service cost		1	1	$ 1
Interest cost		5	3	3
Participant contributions		3	3
Benefits paid		(8)	(8)
Actuarial (gain) loss		0	(27)
Plan amendment		0	2
Benefit obligation, end of year	92	93	92	118
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of year		25	29
Employer contributions		4	4
Participant contributions		3	3
Benefits paid		(8)	(8)
Actual investment return		2	(3)
Fair value of plan assets, end of year	25	26	25	29
Funded status, end of year	(67)	(67)	(67)
Amounts Recognized in Balance Sheets
Current liabilities — other	(4)	(4)	(4)
Other liabilities — benefit obligations	(64)	(63)	(64)
Net liability, end of year	$ (68)	$ (67)	$ (68)
Discount rate (as a percent)	5.15%	4.95%	5.15%
Expected return on plan assets (as a percent)		4.69%	3.35%
Pension benefits that have accumulated benefit obligations in excess of plan assets
Prescription drug cost trend rate assumed for the next year - Pre-65		9.00%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%	4.50%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss (gain)	$ (28)	$ (27)	$ (28)
Unrecognized prior service cost	11	10	11
Net amount recognized in accumulated other comprehensive loss (gain)	$ (17)	(17)	$ (17)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss (gain)		1
Amortization of net loss		(2)
Amortization of prior service cost		1
Settlement		0
Total recognized in comprehensive income		0
Total expense recognized in net periodic cost and other comprehensive income		$ 4
CERC Corp | Minimum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	6.50%	7.25%	6.50%
CERC Corp | Maximum | Other Postretirement Benefits Plan
Pension benefits that have accumulated benefit obligations in excess of plan assets
Health care cost trend rate assumed for the next year	23.66%	22.76%	23.66%
Operation And Maintenance Expense | Pension Plan
Components of net periodic costs [Abstract]
Service cost		$ 25	$ 29	39
Change in benefit obligation [Roll Forward]
Service cost		$ 25	$ 29	$ 39