Unconsolidated Affiliate (CenterPoint Energy and CERC) - Distributions Received from Enable (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares	Feb. 18, 2021
Schedule of Equity Method Investments [Line Items]
Distributions from unconsolidated affiliates	$ 155	$ 113	$ 261
Total distributions received from Enable	$ 189	$ 229	$ 339
Enable series A distribution rate (as a percent)	0.10			0.085
Enable Midstream Partners | Common Stock
Schedule of Equity Method Investments [Line Items]
Distribution per share of common units | $ / shares	$ 0.6610	$ 0.8263	$ 1.2970
Distributions from unconsolidated affiliates	$ 155	$ 193	$ 303
Enable Midstream Partners | Cumulative Preferred Stock
Schedule of Equity Method Investments [Line Items]
Distribution per share of Series A preferred units | $ / shares	$ 2.2965	$ 2.5000	$ 2.5000
Expected cash distribution on Enable's Series A Preferred Units	$ 34	$ 36	$ 36