Regulatory Matters - Schedule of Allowed Equity Return Recognized (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	$ 41	$ 45	$ 40
Houston Electric
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	38	42	37
CERC Corp
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	$ 2	$ 2	$ 2