Divestitures (CenterPoint Energy and CERC) - Identifiable Intangible Assets (Details) - Vectren [Member] $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated Fair Value	$ 297
Operation and maintenance agreements [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	24 years
Estimated Fair Value	$ 12
Customer Relationships [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	18 years
Estimated Fair Value	$ 200
Construction backlog [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	1 year
Estimated Fair Value	$ 27
Trade Names [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Useful Lives	10 years
Estimated Fair Value	$ 58

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ References

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