Commitments and Contingencies - Narrative (Details) $ in Millions			3 Months Ended
	Feb. 10, 2023 USD ($)	Oct. 27, 2021	Mar. 31, 2023 USD ($) surety_bond day ashPond lawsuit gasManufacturingAndStorageSite warranty_obligation	Feb. 28, 2023 class lawsuit	Jul. 05, 2022 MW	Jan. 31, 2022 MW
Long-Term Purchase Commitment [Line Items]
Number of surety bond obligations outstanding | surety_bond			66
Performance guarantee obligations outstanding face amount | $			$ 666
Percentage of work yet to be completed on projects with open surety bonds (as a percent)			36.00%
Number of warranty obligations outstanding | warranty_obligation			34
Warranty obligations outstanding face amount | $			$ 517
Energy savings commitments not guaranteed | $			1,400
Guarantor obligations, maximum exposure, undiscounted | $			$ 523
Pending lawsuits			5
Number of owned coal ash ponds | ashPond			3
Estimated project costs | $	$ 50
Pending Litigation
Long-Term Purchase Commitment [Line Items]
Pending lawsuits			2
F.B. Culley
Long-Term Purchase Commitment [Line Items]
Number of owned coal ash ponds | ashPond			2
A.B. Brown
Long-Term Purchase Commitment [Line Items]
Number of owned coal ash ponds | ashPond			1
F.B. Culley East
Long-Term Purchase Commitment [Line Items]
Number of owned coal ash ponds | ashPond			1
Indiana Gas Service Territory
Long-Term Purchase Commitment [Line Items]
Environmental remediation number of sites with potential remedial responsibility | gasManufacturingAndStorageSite			26
SIGECO
Long-Term Purchase Commitment [Line Items]
Environmental remediation number of sites with potential remedial responsibility | gasManufacturingAndStorageSite			5
CERC | Indiana Gas Service Territory
Long-Term Purchase Commitment [Line Items]
Environmental remediation number of sites with potential remedial responsibility | gasManufacturingAndStorageSite			26
Indiana Electric
Long-Term Purchase Commitment [Line Items]
Asset retirement obligation | $			$ 105
Indiana Electric | Minimum
Long-Term Purchase Commitment [Line Items]
Estimated capital expenditure to clean ash ponds | $			60
Indiana Electric | Maximum
Long-Term Purchase Commitment [Line Items]
Estimated capital expenditure to clean ash ponds | $			$ 80
Loss from Catastrophes
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				12
Loss from Catastrophes | Harris County
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				9
February 2021 Winter Storm Event | Utility Holding, LLC
Long-Term Purchase Commitment [Line Items]
Pending lawsuits | day			15
February 2021 Winter Storm Event | Loss from Catastrophes
Long-Term Purchase Commitment [Line Items]
Pending lawsuits			220
February 2021 Winter Storm Event | Loss from Catastrophes | CenterPoint Energy and Houston Electric
Long-Term Purchase Commitment [Line Items]
Pending lawsuits			155
Harris County vs. CERC - Putative | Loss from Catastrophes
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				1
Number Of Classes of Electric and Natural Gas Customers | class				2
Other Texas Lawsuits Brought By Assignee vs. Company | Loss from Catastrophes
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				2
Other Texas Lawsuits Brought By Assignee vs. Company | Loss from Catastrophes | Harris County
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				1
Other Texas Lawsuits Brought By Assignee vs. Company | Loss from Catastrophes | Tom Green County
Long-Term Purchase Commitment [Line Items]
Pending lawsuits				1
ESG
Long-Term Purchase Commitment [Line Items]
Fair value of guarantees | $			$ 0
Posey Solar
Long-Term Purchase Commitment [Line Items]
Solar array assets, useful life		35 years
Solar array generating capacity (in MW) | MW						191
Pike Solar
Long-Term Purchase Commitment [Line Items]
Solar array generating capacity (in MW) | MW					130