Leases (Narrative) (Details) (USD $)	12 Months Ended					12 Months Ended				12 Months Ended								12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Grand Gulf [Member]	Dec. 31, 2011 Grand Gulf [Member]	Dec. 31, 2012 Entergy Arkansas [Member]	Dec. 31, 2011 Entergy Arkansas [Member]	Dec. 31, 2010 Entergy Arkansas [Member]	Aug. 31, 2010 Entergy Arkansas [Member]	Dec. 31, 2012 Entergy Gulf States Louisiana [Member]	Dec. 31, 2011 Entergy Gulf States Louisiana [Member]	Dec. 31, 2010 Entergy Gulf States Louisiana [Member]	Dec. 31, 2012 Entergy Louisiana [Member]	Dec. 31, 2011 Entergy Louisiana [Member]	Dec. 31, 2010 Entergy Louisiana [Member]	Dec. 31, 2012 Entergy Louisiana [Member] Waterford 3 [Member]	Dec. 31, 1989 Entergy Louisiana [Member] Waterford 3 [Member]	Dec. 31, 2012 Entergy Mississippi [Member]	Dec. 31, 2011 Entergy Mississippi [Member]	Dec. 31, 2010 Entergy Mississippi [Member]	Dec. 31, 2012 Entergy New Orleans [Member]	Dec. 31, 2011 Entergy New Orleans [Member]	Dec. 31, 2010 Entergy New Orleans [Member]	Dec. 31, 2012 Entergy Texas [Member]	Dec. 31, 2011 Entergy Texas [Member]	Dec. 31, 2010 Entergy Texas [Member]	Dec. 31, 2012 System Energy [Member]	Dec. 31, 2011 System Energy [Member]	Dec. 31, 2010 System Energy [Member]	Dec. 31, 2012 System Energy [Member] Grand Gulf [Member]
Rent expense	$ 69,900,000	$ 75,300,000	$ 80,800,000			$ 12,600,000	$ 13,400,000	$ 13,000,000		$ 11,900,000	$ 12,200,000	$ 12,500,000	$ 11,200,000	$ 12,200,000	$ 11,700,000			$ 5,500,000	$ 5,200,000	$ 5,500,000	$ 1,500,000	$ 1,700,000	$ 1,700,000	$ 6,400,000	$ 8,400,000	$ 7,400,000	$ 1,500,000	$ 1,600,000	$ 1,400,000
Operating lease payment and oil tank facilities lease payments						8,500,000	8,300,000	8,400,000		1,700,000	2,000,000	2,300,000						3,400,000	3,400,000	3,400,000
Sale and lease back transaction amount																	353,600,000													500,000,000
Expiration period of sale and lease back transaction																2017-07														2015-07
Value of non interest bearing first mortgage bonds	208,200,000								124,100,000
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
Implicit rate of future minimum lease payments													7.45%
Regulatory Asset				0														57,400,000	48,500,000		29,900,000	16,300,000		11,500,000	4,500,000		56,800,000	11,800,000
Net reulatory liability related to sale and leaseback transaction				$ 27,800,000	$ 2,000,000	$ 12,200,000	$ 16,400,000			$ 22,000,000	$ 30,300,000		$ 9,200,000	$ 62,600,000