Revenue Recognition - Schedule of Contract with Customers (Details) $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($)
Accounts Receivable
Opening balance as of December 31, 2023	$ 652
Closing balance as of December 31, 2024	666
Increase (decrease) in accounts receivable	14
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	516
Closing balance as of December 31, 2024	521
Increase (decrease) in other accrued unbilled revenues	5
Contract Liabilities
Opening balance as of December 31, 2023	2
Closing balance as of December 31, 2024	2
Increase (decrease) in contract liabilities	0
Revenue recognized included in the opening contract liability for the period	2
Houston Electric
Accounts Receivable
Opening balance as of December 31, 2023	275
Closing balance as of December 31, 2024	284
Increase (decrease) in accounts receivable	9
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	142
Closing balance as of December 31, 2024	137
Increase (decrease) in other accrued unbilled revenues	(5)
Contract Liabilities
Opening balance as of December 31, 2023	2
Closing balance as of December 31, 2024	2
Increase (decrease) in contract liabilities	0
Revenue recognized included in the opening contract liability for the period	2
CERC
Accounts Receivable
Opening balance as of December 31, 2023	330
Closing balance as of December 31, 2024	326
Increase (decrease) in accounts receivable	(4)
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	329
Closing balance as of December 31, 2024	338
Increase (decrease) in other accrued unbilled revenues	$ 9

Accounts Receivable for Contracts with Customers

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- Definition

Change in Accounts Receivable [Roll Forward]

+ References

No definition available.

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- Definition

Change in Contract Liability [Roll Forward]

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- Definition

Change in Other Accrued Unbilled Revenues [Roll Forward]

+ References

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- Definition

Increase (Decrease) In Contract With Customer, Asset, Other Accrued Unbilled Receivables

+ References

No definition available.

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- Definition

Increase (Decrease) in Accounts Receivable on Contracts with Customers

+ References

No definition available.

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- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-2

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- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

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- Definition

Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 912
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478345/912-310-45-11

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

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- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 912
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478345/912-310-45-2

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