Retirement, Other Postretirement Benefits, And Defined Contribution Plans (Actuarial Assumptions Used In Determining Net Periodic And Other Postretirement Benefit Obligation) (Details)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Periodic Pension And Other Postretirement Benefit Costs [Member]
Weighted-average rate of increase in future compensation levels	4.23%	4.23%	4.23%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	4.75%	4.75%	4.75%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Pre-65 Retirees [Member]
Assumed health care cost trend rate	6.75%	7.10%	7.25%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2024	2023	2022
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Post - 65 Retirees [Member]
Assumed health care cost trend rate	7.55%	7.70%	7.00%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2024	2023	2022
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Qualified Pension Plans [Member] \| Service Cost [Member]
Weighted-average discount rate	5.00%	4.27%	5.14%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Qualified Pension Plans [Member] \| Interest Cost [Member]
Weighted-average discount rate	3.90%	4.27%	5.14%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Other Postretirement [Member] \| Service Cost [Member]
Weighted-average discount rate	4.92%	4.23%	5.05%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Other Postretirement [Member] \| Interest Cost [Member]
Weighted-average discount rate	3.78%	4.23%	5.05%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Non-Qualified Pension Plans [Member] \| Service Cost [Member]
Weighted-average discount rate	3.65%	3.61%	4.29%
Net Periodic Pension And Other Postretirement Benefit Costs [Member] \| Non-Qualified Pension Plans [Member] \| Interest Cost [Member]
Weighted-average discount rate	3.10%	3.61%	4.29%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member]
Weighted-average rate of increase in future compensation levels	3.98%	4.23%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	4.75%	4.75%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Pre-65 Retirees [Member]
Assumed health care cost trend rate	6.55%	6.75%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2026	2024
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Post - 65 Retirees [Member]
Assumed health care cost trend rate	7.25%	7.55%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2026	2024
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Qualified Pension Plans [Member]
Blended weighted-average discount rate	4.39%	4.67%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Other Postretirement [Member]
Weighted-average discount rate	4.30%	4.60%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Non-Qualified Pension Plans [Member]
Weighted-average discount rate	3.63%	3.84%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Minimum [Member] \| Qualified Pension Plans [Member]
Weighted-average discount rate	4.30%	4.51%
Pension Postretirement Benefit Obligations And Other Postretirement Accumulated Postretirement Benefit Obligations [Member] \| Maximum [Member] \| Qualified Pension Plans [Member]
Weighted-average discount rate	4.49%	4.79%
Pension Assets [Member] \| Net Periodic Pension And Other Postretirement Benefit Costs [Member]
Expected long-term rate of return on plan assets	7.75%	8.25%	8.50%
Non-Taxables [Member] \| Net Periodic Pension And Other Postretirement Benefit Costs [Member]
Expected long-term rate of return on plan assets	7.75%	8.05%	8.30%
Taxable [Member] \| Net Periodic Pension And Other Postretirement Benefit Costs [Member]
Expected long-term rate of return on plan assets	6.00%	6.25%	6.50%

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Blended

No definition available.

Name:	etr_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateBlended
Namespace Prefix:	etr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The interest rate used to adjust for the time value of money.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Expected Long-Term Rate of Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512046

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Health Care Cost Trend Rate
-URI http://asc.fasb.org/extlink&oid=6514820

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The ultimate trend rate for health care costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanYearThatRateReachesUltimateTrendRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	etr_DefinedBenefitPlansObligationsAndCostsAxis=etr_NetPeriodicPensionAndOtherPostretirementBenefitCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlanByRetireeCategoriesAxis=etr_PreSixtyFiveRetireesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlanByRetireeCategoriesAxis=etr_PostSixtyFiveRetireesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=etr_QualifiedPensionPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlanByCostCategoriesAxis=etr_ServiceCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlanByCostCategoriesAxis=etr_InterestCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=etr_NonQualifiedPensionPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlansObligationsAndCostsAxis=etr_PensionPostretirementBenefitObligationsAndOtherPostretirementAccumulatedPostretirementBenefitObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlansDisclosuresDefinedBenefitPlanAssetsInvestmentTypeAxis=etr_PensionAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlansDisclosuresDefinedBenefitPlanAssetsInvestmentTypeAxis=etr_OtherPostretirementNonTaxableAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	etr_DefinedBenefitPlansDisclosuresDefinedBenefitPlanAssetsInvestmentTypeAxis=etr_OtherPostretirementTaxableAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: