Leases (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016	Aug. 31, 2010	Dec. 31, 1989	Dec. 31, 1988
Rent expense		$ 53,100,000	$ 44,400,000	$ 63,900,000
Entergy Arkansas [Member]
Rent expense		7,500,000	8,000,000	13,600,000
Payments For Railcar Operating Lease		4,000,000	3,400,000	4,700,000
Value of non interest bearing first mortgage bonds						$ 124,100,000
Regulatory Asset		$ 176,900,000	128,500,000
Purchased Percentage Of Capacity And Energy Based On Agreement		17.10%
Entergy Louisiana [Member]
Portion of Waterford 3 purchase price satisfied through issuance of debt	$ 52,000,000
Rent expense		$ 23,000,000	17,800,000	21,800,000
Payments For Railcar Operating Lease		300,000	300,000	1,100,000
Cash payment representing the purchase price to acquire the undivided interests in Waterford 3	$ 60,000,000
Value of non interest bearing first mortgage bonds						$ 207,200,000
Net regulatory liability related to sale and leaseback transaction		$ 32,400,000	$ 53,900,000		$ 16,100,000
Purchased Percentage Of Capacity And Energy Based On Agreement		26.90%
Entergy Louisiana [Member] | Purchased Power Agreement [Domain]
Percentage Of Capacity And Energy Purchased Under Purchased Power Agreement		50.00%
Entergy Louisiana [Member] | Waterford 3 [Member]
Sale and lease back transaction amount							$ 353,600,000
Implicit rate of future minimum lease payments			8.09%
Liability related to undivided interests in Waterford 3				62,700,000
Reduction in liability related to undivided interest in Waterford 3				2,700,000
Reduced liability related to undivided interests in Waterford 3				60,000,000
Entergy Mississippi [Member]
Rent expense		$ 5,600,000	$ 4,000,000	5,400,000
Regulatory Asset		$ 91,600,000	82,000,000
Purchased Percentage Of Capacity And Energy Based On Agreement		31.30%
Oil Tank Facilities Lease Payments		$ 1,600,000	1,600,000	1,600,000
Entergy New Orleans [Member]
Rent expense		2,500,000	900,000	1,600,000
Regulatory Asset		$ 44,800,000	40,100,000
Purchased Percentage Of Capacity And Energy Based On Agreement		24.70%
Entergy Texas [Member]
Rent expense		$ 3,400,000	2,800,000	4,000,000
Regulatory Asset		55,200,000	33,500,000
Capacity expense under purchase power agreements accounted for as operating leases		$ 34,100,000	26,100,000	29,900,000
Entergy Texas [Member] | Purchased Power Agreement [Domain]
Percent of minimum payments		100.00%
System Energy [Member]
Rent expense		$ 2,200,000	1,600,000	$ 2,900,000
Regulatory Asset		67,900,000	69,700,000
System Energy [Member] | Grand Gulf [Member]
Year Two		$ 17,188,000
Sale and lease back transaction amount								$ 500,000,000
Implicit rate of future minimum lease payments		5.13%
Regulatory Asset		$ 0
Net regulatory liability related to sale and leaseback transaction		$ 55,600,000	$ 55,600,000