Represents investments in or borrowings from the parent company's money pool.

No definition available.

Name:	cnp_MoneyPoolInvestmentsBorrowings
Namespace Prefix:	cnp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of outstanding investments in money pool.

+ References

No definition available.

+ Details

Name:	cnp_MoneyPoolInvestmentsWeightedAverageInterestRate
Namespace Prefix:	cnp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of net service charges from (billings to) related party during the period, excluding transactions that are eliminated in consolidated or combined financial statements.

+ References

No definition available.

+ Details

Name:	cnp_Netaffiliateservicechargesbillings
Namespace Prefix:	cnp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of selling, general and administrative expenses resulting from transactions, excluding transactions that are eliminated in consolidated or combined financial statements, with related party.

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	us-gaap_IncomeStatementLocationAxis=cnp_OperationAndMaintenanceExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=cnp_CenterpointEnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=us-gaap_InvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=cnp_AccountsandnotesreceivablepayableaffiliatecompaniesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: