Related Party Transactions (Houston Electric and CERC) - Schedule of Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Houston Electric
Related Party Transaction [Line Items]
Cash dividends paid to parent	$ 367	$ 316	$ 0
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses	0	0	0
Other Significant Noncash Transaction, Value of Consideration Given	0	38	0
Cash paid to parent for property, plant and equipment below	0	65	0
Property, plant and equipment from parent	0	103	0
Houston Electric | Additional Paid-in-Capital
Related Party Transaction [Line Items]
Cash contribution from parent	885	1,143	130
Net assets acquired in the Restructuring	0	0	0
CERC Corp
Related Party Transaction [Line Items]
Cash dividends paid to parent	496	124	0
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses	0	720	0
Other Significant Noncash Transaction, Value of Consideration Given	0	54	0
Cash paid to parent for property, plant and equipment below	0	61	0
Property, plant and equipment from parent	0	115	0
CERC Corp | Additional Paid-in-Capital
Related Party Transaction [Line Items]
Cash contribution from parent	500	289	140
Net assets acquired in the Restructuring	$ 0	$ 2,345	$ 0