Derivative Instruments - Narrative (Details) $ in Millions	1 Months Ended
	Sep. 30, 2023 USD ($) Agreement	Aug. 31, 2023 USD ($)	Oct. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)
CenterPoint Energy
Derivative [Line Items]
Debt instrument, face amount		$ 400
CenterPoint Energy | 3-Year Rate
Derivative [Line Items]
Forward interest rate derivative notional amount				$ 75
U.S. treasury rate term (in years)		3 years
SIGECO
Derivative [Line Items]
Number of instruments held | Agreement	2
SIGECO | 5-Year Rate
Derivative [Line Items]
Forward interest rate derivative notional amount	$ 50
U.S. treasury rate term (in years)	5 years
SIGECO | 7-Year Rate
Derivative [Line Items]
Forward interest rate derivative notional amount	$ 38
U.S. treasury rate term (in years)	7 years
SIGECO | Subsequent Event
Derivative [Line Items]
Debt instrument, face amount			$ 470