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, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 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	$ 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	145.0	(86.0)	215.0	(133.0)
Total gains (losses) for the period (a)	22.0	6.0	(13.0)	27.0
Unrealized losses included in OCI	131.0	(57.0)	105.0	(219.0)
Included as a regulatory liability/asset	0.0	0.0	0.0	0.0
Purchases	4.0	3.0	14.0	8.0
Settlements	(98.0)	46.0	(117.0)	229.0
Balance as of June 30,	204.0	(88.0)	204.0	(88.0)
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	15.0	25.0	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	18.0	86.0	20.0	123.0
Issuance of Fixed Transmission Rights	80.0	121.0	80.0	121.0
Purchases	0.0	0.0	0.0	0.0
Settlements	(46.0)	(88.0)	(79.0)	(134.0)
Balance as of June 30,	67.0	144.0	67.0	144.0
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	0.6	2.7	0.7	0.0
Issuance of Fixed Transmission Rights	7.0	4.2	7.0	4.2
Unrealized gains included as a regulatory liability/asset	21.1	2.8	36.1	10.6
Settlements	(19.6)	(6.7)	(34.7)	(11.8)
Balance as of June 30,	9.1	3.0	9.1	3.0
Fixed Transmission Rights (FTRs) [Member] | Entergy Gulf States Louisiana [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of Period	5.0	5.4	14.4	6.7
Issuance of Fixed Transmission Rights	26.7	37.3	26.7	37.3
Unrealized gains included as a regulatory liability/asset	(5.2)	30.6	(7.2)	38.3
Settlements	(8.7)	(26.1)	(16.1)	(35.1)
Balance as of June 30,	17.8	47.2	17.8	47.2
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	3.8	3.0	11.1	5.7
Issuance of Fixed Transmission Rights	21.5	21.5	21.5	21.5
Unrealized gains included as a regulatory liability/asset	2.8	11.5	2.5	16.8
Settlements	(8.6)	(12.4)	(15.6)	(20.4)
Balance as of June 30,	19.5	23.6	19.5	23.6
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	0.9	4.8	3.4	1.0
Issuance of Fixed Transmission Rights	5.4	15.2	5.4	15.2
Unrealized gains included as a regulatory liability/asset	2.5	(2.8)	3.3	8.8
Settlements	(3.9)	(4.5)	(7.2)	(12.3)
Balance as of June 30,	4.9	12.7	4.9	12.7
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	1.4	1.0	4.1	2.0
Issuance of Fixed Transmission Rights	7.3	8.3	7.3	8.3
Unrealized gains included as a regulatory liability/asset	2.5	2.5	1.3	4.5
Settlements	(4.5)	(3.3)	(6.0)	(6.3)
Balance as of June 30,	6.7	8.5	6.7	8.5
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	7.4	12.3	18.4
Issuance of Fixed Transmission Rights	11.4	33.2	11.4	33.2
Unrealized gains included as a regulatory liability/asset	(5.7)	40.6	(16.0)	42.4
Settlements	(1.2)	(33.4)	0.2	(46.2)
Balance as of June 30,	$ 7.9	$ 47.8	$ 7.9	$ 47.8