Regulatory Matters - Schedule of Allowed Equity Return Recognized (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	$ 45	$ 40	$ 31
Houston Electric
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	42	37	31
CERC Corp
Public Utilities, General Disclosures [Line Items]
Allowed equity return recognized	$ 2	$ 2	$ 0