Short-term Borrowings and Long-term Debt - Schedule of Utilization of Credit Facilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Loans
Debt Instrument [Line Items]
Long-term line of credit	$ 0	$ 0
Loans | CenterPoint Energy
Debt Instrument [Line Items]
Long-term line of credit	0	0
Loans | SIGECO
Debt Instrument [Line Items]
Long-term line of credit	0	0
Loans | Houston Electric
Debt Instrument [Line Items]
Long-term line of credit	0	0
Loans | CERC
Debt Instrument [Line Items]
Long-term line of credit	0	0
Letters of Credit
Debt Instrument [Line Items]
Long-term line of credit	9	11
Letters of Credit | CenterPoint Energy
Debt Instrument [Line Items]
Long-term line of credit	8	11
Letters of Credit | SIGECO
Debt Instrument [Line Items]
Long-term line of credit	0	0
Letters of Credit | Houston Electric
Debt Instrument [Line Items]
Long-term line of credit	0	0
Letters of Credit | CERC
Debt Instrument [Line Items]
Long-term line of credit	1	0
Commercial Paper
Debt Instrument [Line Items]
Long-term line of credit	1,079	2,575
Commercial Paper | CenterPoint Energy
Debt Instrument [Line Items]
Long-term line of credit	$ 1,079	$ 1,770
Weighted Average Interest Rate	5.50%	4.71%
Number of days until commercial paper maturity (in days)	60 days
Commercial Paper | SIGECO
Debt Instrument [Line Items]
Long-term line of credit	$ 0	$ 0
Weighted Average Interest Rate	0.00%	0.00%
Commercial Paper | Houston Electric
Debt Instrument [Line Items]
Long-term line of credit	$ 0	$ 0
Weighted Average Interest Rate	0.00%	0.00%
Commercial Paper | CERC
Debt Instrument [Line Items]
Long-term line of credit	$ 0	$ 805
Weighted Average Interest Rate	0.00%	4.67%