Risk Management and Fair Values (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2011 Year MMBtu	Sep. 30, 2010	Sep. 30, 2011 MW GeneratingUnit Year MMBtu	Sep. 30, 2010
Risk Management and Fair Values (Textuals) [Abstract]
Cash flow hedges relating to power sales as part of net unrealized gains			$ 63
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			81
Maturity of cash flow hedges, before taxes	48	43	109	146
Maturity of cash flow hedges, Tax	17	15	38	51
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions	3.25		3.25
Planned generation sold forward from Wholesale Commodities	94.00%		94.00%
Planned Generation Sold Forward under financial derivatives	46.00%		46.00%
Dollar amount of hedge contract in a liability position	3		3
Total volume of natural gas swaps outstanding (MMBtu)	27,100,000		27,100,000
Cash flow hedges in-the-money contracts	73		73
Cash flow hedges out-of-the-money contracts	3		3
Average coupon rate of debt securities	4.15%		4.15%
Change in the value of cash flow hedges	$ 6.2		$ 8.4

Average Coupon Rate Of Debt Securities Percentage.

Name:	etr_AverageCouponRateOfDebtSecuritiesPercentage
Namespace Prefix:	etr
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash flow hedges money contracts.

+ Details

Name:	etr_CashFlowHedgesMoneyContracts
Namespace Prefix:	etr
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash flow hedges out-of-the-money contracts.

+ Details

Name:	etr_CashFlowHedgesOutOfMoneyContracts
Namespace Prefix:	etr
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Derivative Instruments Gain Loss Reclassified From Accumulated OCI Into Income Effective Portion, Tax.

+ Details

Name:	etr_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionTax
Namespace Prefix:	etr
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Dollar amount of hedge contract in a liability position.

+ Details

Name:	etr_HedgeContractsInLiabilityPosition
Namespace Prefix:	etr
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum length of time over which Company is currently hedging the variability in future cash flows with derivatives for forecasted power transactions.

+ Details

Name:	etr_MaximumLengthOfTimeOverWhichCompanyIsCurrentlyHedgingVariabilityInFutureCashFlowsForForecastedPowerTransactions
Namespace Prefix:	etr
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Planned Generation From Non Nuclear Power Plants Sold Forward Under Financial Hedges

+ Details

Name:	etr_PlannedGenerationFromNonNuclearPowerPlantsSoldForwardUnderFinancialDerivatives
Namespace Prefix:	etr
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Planned Generation Sold Forward From Wholesale Commodities.

+ Details

Name:	etr_PlannedGenerationSoldForwardFromNonUtilityNuclearPowerPlants
Namespace Prefix:	etr
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Risk Management and Fair Values.

+ Details

Name:	etr_RiskManagementAndFairValuesTextualsAbstract
Namespace Prefix:	etr
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total volume of natural gas swaps outstanding.

+ Details

Name:	etr_VolumeOfNaturalGasSwapsOutstanding
Namespace Prefix:	etr
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant

- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

+ Details

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph b

-Clause 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4D

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624177-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net gain (loss) recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

+ Details

Name:	us-gaap_GainLossOnCashFlowHedgeIneffectivenessNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) related to derivatives designated as cash flow hedging instruments, recorded in results of operations to the extent that the cash flow hedge is determined to be ineffective.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

+ Details

Name:	us-gaap_UnrealizedGainLossOnCashFlowHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration