Risk Management and Fair Values (Reconciliation Of Changes In The Net Assets (Liabilities) For The Fair Value Of Derivatives Classified As Level 3 In The Fair Value Hierarchy) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Electricity Swaps And Options [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	$ 189.0	$ 215.0
Total gains (losses) for the period (a)	0.0	(35.0)
Unrealized losses included in OCI	139.0	(26.0)
Included as a regulatory liability/asset	0.0	0.0
Purchases	0.0	10.0
Settlements	(145.0)	(19.0)
Balance as of March 31,	183.0	145.0
Fixed Transmission Rights (FTRs) [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	23.0	47.0
Total gains (losses) for the period (a)	0.0	0.0
Unrealized losses included in OCI	0.0	0.0
Included as a regulatory liability/asset	7.0	1.0
Purchases	0.0	0.0
Settlements	(21.0)	(33.0)
Balance as of March 31,	9.0	15.0
Fixed Transmission Rights (FTRs) [Member] | Entergy Arkansas [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	7.9	0.7
Unrealized gains included as a regulatory liability/asset	3.6	15.0
Settlements	(7.8)	(15.1)
Balance as of March 31,	3.7	0.6
Fixed Transmission Rights (FTRs) [Member] | Entergy Louisiana [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	8.5	25.5
Unrealized gains included as a regulatory liability/asset	5.3	(2.2)
Settlements	(10.5)	(14.5)
Balance as of March 31,	3.3	8.8
Fixed Transmission Rights (FTRs) [Member] | Entergy Mississippi [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	2.4	3.4
Unrealized gains included as a regulatory liability/asset	(0.7)	0.8
Settlements	(0.8)	(3.3)
Balance as of March 31,	0.9	0.9
Fixed Transmission Rights (FTRs) [Member] | Entergy New Orleans [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	1.5	4.1
Unrealized gains included as a regulatory liability/asset	(0.4)	(1.1)
Settlements	(0.5)	(1.6)
Balance as of March 31,	0.6	1.4
Fixed Transmission Rights (FTRs) [Member] | Entergy Texas [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	2.2	12.3
Unrealized gains included as a regulatory liability/asset	0.2	(10.3)
Settlements	(1.5)	1.4
Balance as of March 31,	$ 0.9	$ 3.4