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, 2017	Mar. 31, 2016
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	$ 5.0	$ 189.0
Unrealized losses included in OCI	50.0	139.0
Included as a regulatory liability/asset	0.0	0.0
Settlements	(50.0)	(145.0)
Balance as of March 31,	5.0	183.0
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	21.0	23.0
Unrealized losses included in OCI	0.0	0.0
Included as a regulatory liability/asset	17.0	7.0
Settlements	(30.0)	(21.0)
Balance as of March 31,	8.0	9.0
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	5.4	7.9
Unrealized gains included as a regulatory liability/asset	0.1	3.6
Settlements	(4.6)	(7.8)
Balance as of March 31,	0.9	3.7
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	8.5
Unrealized gains included as a regulatory liability/asset	10.8	5.3
Settlements	(15.2)	(10.5)
Balance as of March 31,	4.1	3.3
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	3.2	2.4
Unrealized gains included as a regulatory liability/asset	1.2	(0.7)
Settlements	(3.1)	(0.8)
Balance as of March 31,	1.3	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	1.1	1.5
Unrealized gains included as a regulatory liability/asset	1.8	(0.4)
Settlements	(2.4)	(0.5)
Balance as of March 31,	0.5	0.6
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	3.1	2.2
Unrealized gains included as a regulatory liability/asset	3.2	0.2
Settlements	(5.3)	(1.5)
Balance as of March 31,	$ 1.0	$ 0.9