Risk Management and Fair Values (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Y MMBTU	Dec. 31, 2010	Dec. 31, 2009
Regulatory Assets [Line Items]
Total volume of natural gas swaps outstanding (MMBtu)	37,980,000
Risk Management and Fair Values (Textual) [Abstract]
Cash flow hedges relating to power sales as part of net unrealized gains	$ 310
Reclassified from accumulated other comprehensive income (OCI) to operating revenues	197
Maturity of cash flow hedges, before taxes	168	220	322
Maturity of cash flow hedges, Tax	59	77	113
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions	3
Planned generation sold forward from Wholesale Commodities	88.00%
Planned Generation Sold Forward under financial derivatives	47.00%
Cash flow hedges in-the-money contracts	312
Change in cash flow hedges due to ineffectiveness	$ 6.1

Cash flow hedges money contracts.

No definition available.

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ 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

+ References

No definition available.

+ 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.

+ References

No definition available.

+ Details

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

- Details

Name:	etr_RiskManagementAndFairValuesTextualAbstract
Namespace Prefix:	etr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total volume of natural gas swaps outstanding.

+ References

No definition available.

+ Details

Name:	etr_VolumeOfNaturalGasSwapsOutstanding
Namespace Prefix:	etr_
Data Type:	xbrli:integerItemType
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 period due to ineffectiveness in price risk cash flow hedges.

+ 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_GainLossOnPriceRiskCashFlowHedgeIneffectiveness
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_RegulatoryAssetLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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