Short-term Borrowings and Long-term Debt - Schedule of Revolving Credit Facilities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Debt Instrument [Line Items]
Size of Facility	$ 4,000
SIGECO
Debt Instrument [Line Items]
Size of Facility	250
Houston Electric
Debt Instrument [Line Items]
Size of Facility	300
CERC
Debt Instrument [Line Items]
Size of Facility	$ 1,050
Line of Credit | Maximum
Debt Instrument [Line Items]
Percentage on limitation of debt to total capitalization under covenant amended (in hundredths) (as a percent)	70.00%
Line of Credit | SIGECO
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.125%
Ratio of indebtedness to net capital (as a percent)	0.650
Percentage on limitation of debt to total capitalization under covenant (as a percent)	47.60%
Line of Credit | Houston Electric
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.25%
Ratio of indebtedness to net capital (as a percent)	0.675
Percentage on limitation of debt to total capitalization under covenant (as a percent)	53.00%
Line of Credit | Houston Electric | Maximum
Debt Instrument [Line Items]
Percentage on limitation of debt to total capitalization under covenant amended (in hundredths) (as a percent)	70.00%
Line of Credit | CERC
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.125%
Ratio of indebtedness to net capital (as a percent)	0.650
Percentage on limitation of debt to total capitalization under covenant (as a percent)	38.50%
Parent Company
Debt Instrument [Line Items]
Size of Facility	$ 2,400
Parent Company | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.50%
Ratio of indebtedness to net capital (as a percent)	0.650
Percentage on limitation of debt to total capitalization under covenant (as a percent)	59.10%
Restoration Cost Expected Cost	$ 100
Consecutive period for system restoration costs to exceed $100 million (in months)	12 months