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	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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]
Included in earnings	$ 3.0	$ 120.0	$ (35.0)
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	47.0	34.0	0.0
Total gains (losses) for the period (a)	(1.0)	2.0	0.0
Included in OCI	0.0	0.0	0.0
Issuances of FTRs	80.0	121.0	37.0
Gains (losses) included as a regulatory liability/asset	63.0	119.0	0.0
Purchases	0.0	0.0	0.0
Settlements	(166.0)	(229.0)	(3.0)
Balance as of End of Period	23.0	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	215.0	(133.0)	178.0
Total gains (losses) for the period (a)	(20.0)	55.0	(73.0)
Included in OCI	254.0	131.0	(204.0)
Issuances of FTRs	0.0	0.0	0.0
Gains (losses) included as a regulatory liability/asset	0.0	0.0	0.0
Purchases	15.0	17.0	14.0
Settlements	(275.0)	145.0	(48.0)
Balance as of End of Period	189.0	215.0	(133.0)
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	0.7	0.0
Issuances of FTRs	7.0	4.2
Gains (losses) included as a regulatory liability/asset	68.9	18.1
Settlements	(68.7)	(21.6)
Balance as of End of Period	7.9	0.7	0.0
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	25.5	12.4
Issuances of FTRs	48.3	58.8
Gains (losses) included as a regulatory liability/asset	(9.9)	57.8
Settlements	(55.4)	(103.5)
Balance as of End of Period	8.5	25.5	12.4
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	3.4	1.0
Issuances of FTRs	5.4	15.2
Gains (losses) included as a regulatory liability/asset	10.1	6.2
Settlements	(16.5)	(19.0)
Balance as of End of Period	2.4	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	4.1	2.0
Issuances of FTRs	7.3	8.3
Gains (losses) included as a regulatory liability/asset	(1.4)	10.3
Settlements	(8.5)	(16.5)
Balance as of End of Period	1.5	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	12.3	18.4
Issuances of FTRs	11.4	33.2
Gains (losses) included as a regulatory liability/asset	(4.7)	26.5
Settlements	(16.8)	(65.8)
Balance as of End of Period	$ 2.2	$ 12.3	$ 18.4