Regulatory Matters - Schedule of Allowed Equity Return Recognized (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]
Allowed equity return not recognized	$ 205		$ 205		$ 188
Allowed equity return recognized	14	$ 14	32	$ 36
Houston Electric
Public Utilities, General Disclosures [Line Items]
Allowed equity return not recognized	81		81		82
Allowed equity return recognized	14	12	30	33
CERC
Public Utilities, General Disclosures [Line Items]
Allowed equity return not recognized	66		66		$ 54
Allowed equity return recognized	$ 0	$ 1	$ 1	$ 2