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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Issuance of Fixed Transmission Rights			$ 0.0	$ 0.0
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	$ 204.0	$ (88.0)	215.0	(133.0)
Total gains (losses) for the period (a)	(2.0)	(6.0)	(15.0)	21.0
Unrealized losses included in OCI	49.0	37.0	154.0	(182.0)
Included as a regulatory liability/asset	0.0	0.0	0.0	0.0
Purchases	0.0	7.0	14.0	15.0
Settlements	(88.0)	(41.0)	(205.0)	188.0
Balance as of September 30,	163.0	(91.0)	163.0	(91.0)
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	67.0	144.0	47.0	34.0
Total gains (losses) for the period (a)	0.0	0.0	(1.0)	0.0
Unrealized losses included in OCI	0.0	0.0	0.0	0.0
Included as a regulatory liability/asset	31.0	(13.0)	51.0	110.0
Issuance of Fixed Transmission Rights			80.0	121.0
Purchases	0.0	0.0	0.0	0.0
Settlements	(51.0)	(48.0)	(130.0)	(182.0)
Balance as of September 30,	47.0	83.0	47.0	83.0
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	9.1	3.0	0.7	0.0
Issuance of Fixed Transmission Rights			7.0	4.2
Unrealized gains included as a regulatory liability/asset	16.5	2.4	52.6	13.0
Settlements	(13.9)	(4.9)	(48.6)	(16.7)
Balance as of September 30,	11.7	0.5	11.7	0.5
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	19.5	23.6	11.1	5.7
Issuance of Fixed Transmission Rights			21.5	21.5
Unrealized gains included as a regulatory liability/asset	(4.2)	4.5	(1.7)	21.3
Settlements	(4.8)	(13.4)	(20.4)	(33.8)
Balance as of September 30,	10.5	14.7	10.5	14.7
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	4.9	12.7	3.4	1.0
Issuance of Fixed Transmission Rights			5.4	15.2
Unrealized gains included as a regulatory liability/asset	6.1	(3.3)	9.4	5.5
Settlements	(6.7)	(3.3)	(13.9)	(15.6)
Balance as of September 30,	4.3	6.1	4.3	6.1
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	6.7	8.5	4.1	2.0
Issuance of Fixed Transmission Rights			7.3	8.3
Unrealized gains included as a regulatory liability/asset	(1.2)	2.6	0.1	7.1
Settlements	(1.5)	(5.1)	(7.5)	(11.4)
Balance as of September 30,	4.0	6.0	4.0	6.0
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	7.9	47.8	12.3	18.4
Issuance of Fixed Transmission Rights			11.4	33.2
Unrealized gains included as a regulatory liability/asset	7.3	(10.5)	(8.7)	31.9
Settlements	(10.9)	(9.8)	(10.7)	(56.0)
Balance as of September 30,	$ 4.3	$ 27.5	$ 4.3	$ 27.5