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, 2016	Dec. 31, 2015	Dec. 31, 2014
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	$ 0.0	$ 3.0	$ 120.0
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	23.0	47.0	34.0
Total gains (losses) for the period (a)	0.0	(1.0)	2.0
Included in OCI	0.0	0.0	0.0
Issuances of financial transmission rights	55.0	80.0	121.0
Gains (losses) included as a regulatory liability/asset	68.0	63.0	119.0
Purchases	0.0	0.0	0.0
Settlements	(125.0)	(166.0)	(229.0)
Balance as of End of Period	21.0	23.0	47.0
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	189.0	215.0	(133.0)
Total gains (losses) for the period (a)	(10.0)	(20.0)	55.0
Included in OCI	135.0	254.0	131.0
Issuances of financial transmission rights	0.0	0.0	0.0
Gains (losses) included as a regulatory liability/asset	0.0	0.0	0.0
Purchases	0.0	15.0	17.0
Settlements	(309.0)	(275.0)	145.0
Balance as of End of Period	5.0	189.0	215.0
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	7.9	0.7
Issuances of financial transmission rights	18.8	7.0
Gains (losses) included as a regulatory liability/asset	1.9	68.9
Settlements	(23.2)	(68.7)
Balance as of End of Period	5.4	7.9	0.7
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	8.5	25.5
Issuances of financial transmission rights	18.1	48.3
Gains (losses) included as a regulatory liability/asset	51.6	(9.9)
Settlements	(69.7)	(55.4)
Balance as of End of Period	8.5	8.5	25.5
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	2.4	3.4
Issuances of financial transmission rights	5.9	5.4
Gains (losses) included as a regulatory liability/asset	11.5	10.1
Settlements	(16.6)	(16.5)
Balance as of End of Period	3.2	2.4	3.4
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	1.5	4.1
Issuances of financial transmission rights	2.8	7.3
Gains (losses) included as a regulatory liability/asset	0.9	(1.4)
Settlements	(4.1)	(8.5)
Balance as of End of Period	1.1	1.5	4.1
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	2.2	12.3
Issuances of financial transmission rights	9.3	11.4
Gains (losses) included as a regulatory liability/asset	1.8	(4.7)
Settlements	(10.2)	(16.8)
Balance as of End of Period	$ 3.1	$ 2.2	$ 12.3