Unconsolidated Affiliate (CenterPoint Energy and CERC) - Summarized Balance Sheet Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 02, 2021
Schedule of Equity Method Investments [Line Items]
Current assets	$ 7,355	$ 2,920
Current liabilities	4,287	4,825
Total shareholders’ equity	9,415	8,348	$ 8,359
Enable Midstream Partners
Schedule of Equity Method Investments [Line Items]
Current assets		381		$ 594
Non-current assets		11,348		11,227
Current liabilities		582		1,254
Non-current liabilities		4,052		3,281
Non-controlling interest		26		26
Preferred equity		362		362
Accumulated other comprehensive loss		(6)		(1)
Total shareholders’ equity		6,713		6,899
CenterPoint Energy’s ownership interest in Enable partners’ equity		3,601		3,701
CenterPoint Energy’s basis difference (2)		(2,819)		(2,732)
Investment in unconsolidated affiliates		782		$ 969
Equity method investment, impairment	$ 0	$ 1,541	$ 0