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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	$ 0.0	$ 0.0	$ 0.0	$ 0.0
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	4.0	(9.0)	4.0	(9.0)
Fair Value Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Purchases	0.0	0.0	0.0	0.0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	5.0	183.0	5.0	189.0
Unrealized losses included in OCI	43.0	(53.0)	93.0	86.0
Included as a regulatory liability/asset	0.0	0.0	0.0	0.0
Settlements	(14.0)	(55.0)	(64.0)	(200.0)
Balance as of June 30,	38.0	66.0	38.0	66.0
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	0.0	0.0	0.0	0.0
Issuance of Fixed Transmission Rights	62.0	55.0	62.0	55.0
Fair Value Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Purchases	0.0	0.0	0.0	0.0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	8.0	9.0	21.0	23.0
Unrealized losses included in OCI	0.0	0.0	0.0	0.0
Included as a regulatory liability/asset	31.0	20.0	48.0	27.0
Settlements	(44.0)	(38.0)	(74.0)	(59.0)
Balance as of June 30,	57.0	46.0	57.0	46.0
Fixed Transmission Rights (FTRs) [Member] | Entergy Arkansas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	8.9	18.8	8.9	18.8
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	0.9	3.7	5.4	7.9
Unrealized gains included as a regulatory liability/asset	9.0	(3.0)	9.1	0.6
Settlements	(10.5)	(5.5)	(15.1)	(13.3)
Balance as of June 30,	8.3	14.0	8.3	14.0
Fixed Transmission Rights (FTRs) [Member] | Entergy Louisiana [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	31.0	18.1	31.0	18.1
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	4.1	3.3	8.5	8.5
Unrealized gains included as a regulatory liability/asset	7.5	16.4	18.3	21.7
Settlements	(14.3)	(21.6)	(29.5)	(32.1)
Balance as of June 30,	28.3	16.2	28.3	16.2
Fixed Transmission Rights (FTRs) [Member] | Entergy Mississippi [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	9.6	5.9	9.6	5.9
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	1.3	0.9	3.2	2.4
Unrealized gains included as a regulatory liability/asset	6.7	2.4	7.9	1.7
Settlements	(8.5)	(3.6)	(11.6)	(4.4)
Balance as of June 30,	9.1	5.6	9.1	5.6
Fixed Transmission Rights (FTRs) [Member] | Entergy New Orleans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	5.0	2.8	5.0	2.8
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	0.5	0.6	1.1	1.5
Unrealized gains included as a regulatory liability/asset	3.1	0.0	4.8	(0.4)
Settlements	(3.4)	(1.4)	(5.7)	(1.9)
Balance as of June 30,	5.2	2.0	5.2	2.0
Fixed Transmission Rights (FTRs) [Member] | Entergy Texas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Issuance of Fixed Transmission Rights	7.1	9.3	7.1	9.3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	1.0	0.9	3.1	2.2
Unrealized gains included as a regulatory liability/asset	4.3	3.2	7.4	3.4
Settlements	(6.9)	(5.4)	(12.1)	(6.9)
Balance as of June 30,	$ 5.5	$ 8.0	$ 5.5	$ 8.0