Leases (Narrative) (Details) (USD $)	12 Months Ended				1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 1989 transaction	Dec. 31, 1988 transaction	Aug. 31, 2010
Rent expense	$ 59,000,000	$ 63,700,000	$ 69,900,000
Entergy Arkansas [Member]
Rent expense	12,000,000	12,000,000	12,600,000
Operating lease payment and oil tank facilities lease payments	4,800,000	8,600,000	8,500,000
Value of non interest bearing first mortgage bonds						124,100,000.0
Regulatory Asset	59,000,000	18,600,000
Purchased Percentage Of Capacity And Energy Based On Agreement	17.10%
Entergy Gulf States Louisiana [Member]
Rent expense	10,900,000	10,900,000	11,900,000
Operating lease payment and oil tank facilities lease payments	1,700,000	2,200,000	1,700,000
Net regulatory liability related to sale and leaseback transaction	36,900,000	35,300,000
Purchased Percentage Of Capacity And Energy Based On Agreement	50.00%
Entergy Louisiana [Member]
Rent expense	9,800,000	10,100,000	11,200,000
Implicit rate of future minimum lease payments	7.45%
Net regulatory liability related to sale and leaseback transaction	45,700,000	37,000,000
Purchased Percentage Of Capacity And Energy Based On Agreement	26.90%
Entergy Louisiana [Member] | Waterford 3 [Member]
Number of sale leaseback transactions				3
Sale and lease back transaction amount				353,600,000
Expiration period of sale and lease back transaction		2017-07
Value of non interest bearing first mortgage bonds	208,200,000
Minimum percentage of adjusted capitalization to be maintained as total equity capital	30.00%
Minimum fixed charge coverage ratio to be maintained	1.50
Rolling period of fixed charge coverage ratio	12 months
Entergy Mississippi [Member]
Rent expense	4,300,000	4,600,000	5,500,000
Operating lease payment and oil tank facilities lease payments	1,600,000	3,400,000	3,400,000
Regulatory Asset	76,300,000	64,300,000
Purchased Percentage Of Capacity And Energy Based On Agreement	31.30%
Entergy New Orleans [Member]
Rent expense	1,200,000	1,300,000	1,500,000
Regulatory Asset	35,200,000	34,900,000
Purchased Percentage Of Capacity And Energy Based On Agreement	24.70%
Entergy Texas [Member]
Rent expense	3,800,000	4,100,000	6,400,000
Regulatory Asset	18,900,000	15,100,000
Capacity expense under purchase power agreements accounted for as operating leases	29,200,000	28,600,000	19,200,000
Percent of minimum payments	100.00%
System Energy [Member]
Rent expense	2,000,000	2,500,000	1,500,000
Implicit rate of future minimum lease payments		5.13%
Regulatory Asset	55,700,000	56,000,000
System Energy [Member] | Grand Gulf [Member]
Number of sale leaseback transactions					2
Sale and lease back transaction amount	500,000,000
Expiration period of sale and lease back transaction		2015-07
Regulatory Asset	0
Net regulatory liability related to sale and leaseback transaction	$ 62,900,000	$ 61,600,000