Related Party Transactions (Houston Electric and CERC) - Schedule of Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Houston Electric
Related Party Transaction [Line Items]
Cash dividends paid to parent	$ 316	$ 0	$ 551
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses	0	0	0
Capital distribution to parent associated with the sale of CES	38	0	0
Cash paid to parent for property, plant and equipment below	65	0	0
Property, plant and equipment from parent	103	0	36
Houston Electric | Discontinued Operations
Related Party Transaction [Line Items]
Capital distribution to parent associated with the sale of CES	0	0	0
Houston Electric | Additional Paid-in-Capital
Related Party Transaction [Line Items]
Cash contribution from parent	1,143	130	62
Net assets acquired in the Restructuring	0	0	0
CERC Corp
Related Party Transaction [Line Items]
Cash dividends paid to parent	124	0	128
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses	720	0	0
Capital distribution to parent associated with the sale of CES	54	0	0
Cash paid to parent for property, plant and equipment below	61	0	0
Property, plant and equipment from parent	115	0	23
CERC Corp | Discontinued Operations
Related Party Transaction [Line Items]
Capital distribution to parent associated with the sale of CES	0	0	286
CERC Corp | Additional Paid-in-Capital
Related Party Transaction [Line Items]
Cash contribution from parent	289	140	337
Net assets acquired in the Restructuring	2,345	0	0
CERC Corp | Additional Paid-in-Capital | Discontinued Operations
Related Party Transaction [Line Items]
Contribution to parent for sale of Arkansas and Oklahoma Natural Gas businesses	$ 0	$ 0	$ 286