Revenue Recognition and Allowance for Credit Losses - Schedule of Contract Assets and Liabilities (Details) $ in Millions	9 Months Ended
Sep. 30, 2024 USD ($)
Accounts Receivable
Opening balance as of December 31, 2023	$ 652
Closing balance as of September 30, 2024	650
Increase (decrease)	(2)
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	516
Closing balance as of September 30, 2024	349
Increase (decrease) in other accrued unbilled revenues	(167)
Contract Liabilities
Opening balance as of December 31, 2023	2
Closing balance as of September 30, 2024	5
Increase (decrease) in contract liabilities	3
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 September 30, 2024	421
Increase (decrease)	146
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	142
Closing balance as of September 30, 2024	191
Increase (decrease) in other accrued unbilled revenues	49
Contract Liabilities
Opening balance as of December 31, 2023	2
Closing balance as of September 30, 2024	5
Increase (decrease) in contract liabilities	3
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 September 30, 2024	183
Increase (decrease)	(147)
Accrued Unbilled Revenues
Opening balance as of December 31, 2023	329
Closing balance as of September 30, 2024	122
Increase (decrease) in other accrued unbilled revenues	$ (207)

Accounts Receivable For Contracts With Customers

No definition available.

Name:	cnp_AccountsReceivableForContractsWithCustomers
Namespace Prefix:	cnp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Change in Accounts Receivable [Roll Forward]

+ References

No definition available.

+ Details

Name:	cnp_ChangeinAccountsReceivableRollForward
Namespace Prefix:	cnp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Change in Contract Liability [Roll Forward]

+ References

No definition available.

+ Details

Name:	cnp_ChangeinContractLiabilityRollForward
Namespace Prefix:	cnp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Change in Other Accrued Unbilled Revenues [Roll Forward]

+ References

No definition available.

+ Details

Name:	cnp_ChangeinOtherAccruedUnbilledRevenuesRollForward
Namespace Prefix:	cnp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (Decrease) In Accounts Receivable On Contracts With Customers

+ References

No definition available.

+ Details

Name:	cnp_IncreaseDecreaseInAccountsReceivableOnContractsWithCustomers
Namespace Prefix:	cnp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	cnp_IncreaseDecreaseInContractWithCustomerAssetOtherAccruedUnbilledReceivables
Namespace Prefix:	cnp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

+ Details

Name:	us-gaap_ContractWithCustomerLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

+ Details

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

+ Details

Name:	us-gaap_IncreaseDecreaseInContractWithCustomerLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

+ Details

Name:	us-gaap_UnbilledContractsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=cnp_HoustonElectricMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cnp_CercCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: