Net interest income (expense) related to affiliate investments or borrowings

No definition available.

Name:	cehe_InterestIncomeExpenseNetRelatedParty
Namespace Prefix:	cehe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Investments in Money Pool

+ References

No definition available.

+ Details

Name:	cehe_InvestmentsInMoneyPool
Namespace Prefix:	cehe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Money Pool Borrowings

+ References

No definition available.

+ Details

Name:	cehe_MoneyPoolBorrowings
Namespace Prefix:	cehe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents disclosure of the total aggregate cash dividends paid to the entity by consolidated subsidiaries, by unconsolidated subsidiaries, and by 50% or less owned persons accounted for using the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(b))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.9-06)
-URI http://asc.fasb.org/extlink&oid=6882215&loc=d3e537971-122884

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from parent as a source of financing that is recorded as additional paid in capital.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_ProceedsFromContributionsFromParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

Name:	us-gaap_MajorCustomersAxis=cehe_AffiliatesOfNrgEnergyIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=cehe_AffiliatesOfEnergyFutureHoldingsCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

Related Party Transactions and Major Customers (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Investments in Money Pool	$ 96								$ 96
Money Pool Borrowings					$ 312					$ 312
Debt, Weighted Average Interest Rate	1.04%								1.04%
Interest Income (Expense) Net, Related Party									$ (4)	(1)	$ (1)
Cash Dividends Paid to Parent Company									135	252	0
Proceeds from Contributions from Parent									374	0	90
Revenues	$ 731	$ 909	$ 763	$ 656	$ 697	$ 827	$ 705	$ 617	3,059	2,846	2,846
Affiliates of NRG Energy, Inc. [Member]
Related Party Transaction [Line Items]
Revenues									698	741	735
Affiliates of Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Revenues									220	220	189
Operation And Maintenance Expense [Member] \| CenterPoint Energy [Member]
Related Party Transaction [Line Items]
Corporate service charges									179	176	159
Operation And Maintenance Expense [Member] \| CERC Corp [Member]
Related Party Transaction [Line Items]
Corporate service charges									7	6	5
Related Party Transaction, Other Revenues from Transactions with Related Party									$ (15)	$ (18)	$ (17)