Asset Retirement Obligations (Cumulative Decommissioning And Retirement Cost Liabilities And Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entergy Arkansas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	$ 924.4	$ 872.3	$ 818.4
Accretion	53.6	50.4
Change in Cash Flow Estimate	0.0	0.0
Spending	(1.5)	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	3.5
Entergy Louisiana [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	1,082.7	1,027.9	950.3
Accretion	54.8	51.0
Change in Cash Flow Estimate	0.0	24.7
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	1.9
Entergy Mississippi [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	8.7	8.3	6.8
Accretion	0.4	0.4
Change in Cash Flow Estimate	0.0	0.0
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	1.1
Entergy New Orleans [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	2.9	2.7	2.5
Accretion	0.2	0.2
Change in Cash Flow Estimate	0.0	0.0
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Entergy Texas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	6.5	6.1	4.6
Accretion	0.4	0.3
Change in Cash Flow Estimate	0.0	(0.2)
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	1.4
System Energy [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	854.2	803.4	757.9
Accretion	50.8	48.0
Change in Cash Flow Estimate	0.0	(2.5)
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Entergy Wholesale Commodities [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	0.3	0.3	0.0
Accretion	0.0	0.3
Change in Cash Flow Estimate	0.0	0.0
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Big Rock Point [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	37.9	28.0	27.8
Accretion	2.2	2.2
Change in Cash Flow Estimate	10.1	0.0
Spending	(2.4)	(2.0)
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
FitzPatrick [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	714.3	0.0
Accretion	18.1
Change in Cash Flow Estimate	0.0
Spending	0.0
Asset Retirement Obligation, Liabilities Incurred	696.2
Indian Point 1 [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	207.6	197.9	188.9
Accretion	17.1	16.3
Change in Cash Flow Estimate	(0.3)	0.0
Spending	(7.1)	(7.3)
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Indian Point 2 [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	653.1	390.1	359.7
Accretion	33.0	30.4
Change in Cash Flow Estimate	230.0	0.0
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Indian Point 3 [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	641.1	0.0
Accretion	12.1
Change in Cash Flow Estimate	162.7
Spending	0.0
Asset Retirement Obligation, Liabilities Incurred	466.3
Palisades [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	500.3	342.0	352.0
Accretion	29.5	25.2
Change in Cash Flow Estimate	128.8	(35.2)
Spending	0.0	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Pilgrim [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	602.3	551.2	383.1
Accretion	48.4	33.3
Change in Cash Flow Estimate	3.2	134.8
Spending	(0.5)	0.0
Asset Retirement Obligation, Liabilities Incurred	0.0	0.0
Vermont Yankee [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation	470.5	560.0	$ 606.3
Accretion	39.3	46.1
Change in Cash Flow Estimate	0.0	0.0
Spending	(128.8)	(92.4)
Asset Retirement Obligation, Liabilities Incurred	$ 0.0	$ 0.0

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Asset Retirement Obligation
-URI http://asc.fasb.org/extlink&oid=6505190

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848

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- Definition

Amount of asset retirement obligations incurred during the period.

+ References

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- Definition

Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

+ References

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- Definition

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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