Divestitures (CenterPoint Energy and CERC) - Schedule of Assets and Liabilities Classified as Held-For-Sale (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Total current assets held for sale	$ 0	$ 2,338
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Total current liabilities held for sale	0	562
Arkansas and Oklahoma Natural Gas Businesses | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Receivables, net		46
Accrued unbilled revenues		48
Natural gas inventory		46
Materials and supplies		9
Property, plant and equipment, net		1,314
Goodwill (1)		398
Regulatory assets		471
Other		6
Total current assets held for sale		2,338
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Short term borrowings		36
Accounts payable		40
Taxes accrued		7
Customer deposits		12
Regulatory liabilities		365
Other		102
Total current liabilities held for sale		562
CERC Corp
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Total current assets held for sale	0	2,084
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Total current liabilities held for sale	$ 0	562
CERC Corp | Arkansas and Oklahoma Natural Gas Businesses | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Receivables, net		46
Accrued unbilled revenues		48
Natural gas inventory		46
Materials and supplies		9
Property, plant and equipment, net		1,314
Goodwill (1)		144
Regulatory assets		471
Other		6
Total current assets held for sale		2,084
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Short term borrowings		36
Accounts payable		40
Taxes accrued		7
Customer deposits		12
Regulatory liabilities		365
Other		102
Total current liabilities held for sale		$ 562