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, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fixed Transmission Rights (FTRs) [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	$ 34.0	$ 0
Realized losses included in earnings	0	0
Unrealized gains (losses) included in earnings	2	0
Unrealized gains (losses) included in OCI	0	0
Issuances of FTRs	121.0	37.0
Unrealized gains (losses) included as a regulatory liability / asset	119.0	0
Purchases	0	0
Settlements	(229.0)	(3.0)
Balance as of End of Period	47.0	34.0
Electricity Swaps And Options [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	(133.0)	178.0	312.0
Realized losses included in earnings	(65)	(38)	(11)
Unrealized gains (losses) included in earnings	120	(35)	(4)
Unrealized gains (losses) included in OCI	131	(204)	140
Issuances of FTRs	0	0	0
Unrealized gains (losses) included as a regulatory liability / asset	0	0	0
Purchases	17	14	9
Settlements	145.0	(48.0)	(268.0)
Balance as of End of Period	215.0	(133.0)	178.0
Entergy Arkansas [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	0	0
Issuances of FTRs	4.2	0
Unrealized gains (losses) included as a regulatory liability / asset	18.1	(0.1)
Settlements	(21.6)	0.1
Balance as of End of Period	0.7	0
Entergy Louisiana [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	5.7	0
Issuances of FTRs	21.5	6.2
Unrealized gains (losses) included as a regulatory liability / asset	31.1	(0.3)
Settlements	(47.2)	(0.2)
Balance as of End of Period	11.1	5.7
Entergy Mississippi [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	1.0	0
Issuances of FTRs	15.2	1.1
Unrealized gains (losses) included as a regulatory liability / asset	6.2	0.9
Settlements	(19.0)	(1.0)
Balance as of End of Period	3.4	1.0
Entergy New Orleans [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	2.0	0
Issuances of FTRs	8.3	2.2
Unrealized gains (losses) included as a regulatory liability / asset	10.3	1.0
Settlements	(16.5)	(1.2)
Balance as of End of Period	4.1	2.0
Entergy Texas [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	18.4	0
Issuances of FTRs	33.2	20.0
Unrealized gains (losses) included as a regulatory liability / asset	26.5	(0.8)
Settlements	(65.8)	(0.8)
Balance as of End of Period	12.3	18.4
Entergy Gulf States Louisiana [Member]
Reconciliation of changes in the net assets (liabilities) for the fair value of derivatives classified as Level 3 in the fair value hierarchy [Roll Forward]
Balance as of Beginning of Period	6.7	0
Issuances of FTRs	37.3	7.2
Unrealized gains (losses) included as a regulatory liability / asset	26.7	(0.2)
Settlements	(56.3)	(0.3)
Balance as of End of Period	$ 14.4	$ 6.7