Short-term Borrowings and Long-term Debt - Schedule of Debt (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) day	Dec. 31, 2022 USD ($)
Long-term debt:
Unamortized debt issuance costs	$ (35)	$ (15)
Unamortized discount and premium, net	(5)	(6)
Long-term debt	17,559	14,836
Current debt	$ 1,059	2,020
Number of days until commercial paper maturity | day	60
CenterPoint Energy
Long-term debt:
Number of days until commercial paper maturity | day	60
Houston Electric
Long-term debt:
Unamortized debt issuance costs	$ (59)	(50)
Unamortized discount and premium, net	(28)	(27)
Long-term debt	7,426	6,197
Current debt	161	156
CERC Corp
Long-term debt:
Unamortized debt issuance costs	(31)	(22)
Unamortized discount and premium, net	1	(4)
Long-term debt	4,670	3,495
Current debt	$ 4	1,842
Number of days until commercial paper maturity | day	30
CERC Corp | Inventory Financing
Long-term debt:
Current debt	$ 4	11
CERC Corp | Term Loan
Long-term debt:
Current debt	0	500
CERC Corp | CERC Debt
Long-term debt:
Current debt	$ 4	511
ZENS debt, due 2029
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	2.00%
Long-term debt:
Long-Term	$ 0	0
Current	5	7
CenterPoint Energy senior notes 1.45% to 5.989% due 2024 to 2049
Long-term debt:
Long-Term	3,250	3,050
Current	$ 850	0
CenterPoint Energy senior notes 1.45% to 5.989% due 2024 to 2049 | Minimum | CenterPoint Energy
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	1.45%
CenterPoint Energy senior notes 1.45% to 5.989% due 2024 to 2049 | Maximum | CenterPoint Energy
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	5.989%
CenterPoint Energy pollution control bonds 5.125% due 2028
Long-term debt:
Long-Term	$ 68	68
Current	$ 0	0
CenterPoint Energy pollution control bonds 5.125% due 2028 | CenterPoint Energy
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	5.125%
CenterPoint Energy commercial paper
Long-term debt:
Long-Term	$ 1,036	1,770
Current	0	0
CenterPoint Energy commercial paper | CERC Corp
Long-term debt:
Long-Term	484	805
SIGECO first mortgage bonds 3.450% to 6.00% due 2024 to 2055 | SIGECO
Long-term debt:
Long-Term	825	277
Current	$ 22	11
SIGECO first mortgage bonds 3.450% to 6.00% due 2024 to 2055 | Minimum | SIGECO
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	3.45%
SIGECO first mortgage bonds 3.450% to 6.00% due 2024 to 2055 | Maximum | SIGECO
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.00%
SIGECO securitization bonds 5.026% to 5.172% due 2036 to 2041 | SIGECO
Long-term debt:
Long-Term	$ 324	0
Current	$ 17	0
SIGECO securitization bonds 5.026% to 5.172% due 2036 to 2041 | Minimum | SIGECO
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	5.026%
SIGECO securitization bonds 5.026% to 5.172% due 2036 to 2041 | Maximum | SIGECO
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	5.172%
Other Debt
Long-term debt:
Long-Term	$ 0	0
Current	0	4
CERC Debt | CERC Corp
Long-term debt:
Long-term debt	4,670	3,495
General mortgage bonds, 2.35% to 6.95%, due 2026 to 2053 | Houston Electric
Long-term debt:
Long-Term	7,512	6,112
Current	$ 0	0
General mortgage bonds, 2.35% to 6.95%, due 2026 to 2053 | Minimum | Houston Electric
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	2.35%
General mortgage bonds, 2.35% to 6.95%, due 2026 to 2053 | Maximum | Houston Electric
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.95%
Other | Houston Electric
Long-term debt:
Long-Term	$ 1	1
Current	0	0
Transition bonds 3.028% due 2024 | Houston Electric
Long-term debt:
Long-Term	0	161
Current	$ 161	156
Transition bonds 3.028% due 2024 | Maximum | Houston Electric
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	3.028%
Senior notes 1.75% to 6.625% due 2026 to 2047 | CERC Corp
Long-term debt:
Long-Term	$ 4,120	2,620
Current	$ 0	1,331
Senior notes 1.75% to 6.625% due 2026 to 2047 | Minimum | CERC Corp
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	1.75%
Senior notes 1.75% to 6.625% due 2026 to 2047 | Maximum | CERC Corp
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.625%
Indiana Gas senior notes 6.34% to 7.08% due 2025 to 2029 | IGC
Long-term debt:
Long-Term	$ 96	96
Current	$ 0	$ 0
Indiana Gas senior notes 6.34% to 7.08% due 2025 to 2029 | Minimum | IGC
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.34%
Indiana Gas senior notes 6.34% to 7.08% due 2025 to 2029 | Maximum | IGC
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	7.08%