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, 2018	Mar. 31, 2017
Electricity Swaps And Options [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Realized Gain (Loss) Included In Earnings	$ 14.0	$ 0.0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	(65.0)	5.0
Unrealized losses included in OCI	91.0	50.0
Included as a regulatory liability/asset	0.0	0.0
Settlements	35.0	(50.0)
Balance as of March 31,	75.0	5.0
Fixed Transmission Rights (FTRs) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Realized Gain (Loss) Included In Earnings	(1.0)	0.0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	21.0	21.0
Unrealized losses included in OCI	0.0	0.0
Included as a regulatory liability/asset	20.0	17.0
Settlements	(32.0)	(30.0)
Balance as of March 31,	8.0	8.0
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	3.0	5.4
Included as a regulatory liability/asset	6.8
Unrealized gains included as a regulatory liability/asset		0.1
Settlements	(8.0)	(4.6)
Balance as of March 31,	1.8	0.9
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	10.2	8.5
Included as a regulatory liability/asset	10.8
Unrealized gains included as a regulatory liability/asset		10.8
Settlements	(17.6)	(15.2)
Balance as of March 31,	3.4	4.1
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	2.1	3.2
Included as a regulatory liability/asset	6.6
Unrealized gains included as a regulatory liability/asset		1.2
Settlements	(7.8)	(3.1)
Balance as of March 31,	0.9	1.3
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	2.2	1.1
Included as a regulatory liability/asset	1.8
Unrealized gains included as a regulatory liability/asset		1.8
Settlements	(3.3)	(2.4)
Balance as of March 31,	0.7	0.5
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	3.4	3.1
Included as a regulatory liability/asset	(5.5)
Unrealized gains included as a regulatory liability/asset		3.2
Settlements	3.5	(5.3)
Balance as of March 31,	$ 1.4	$ 1.0