Income Taxes Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Aug. 31, 2015	Mar. 31, 2015	Oct. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Income tax benefit resulting from 2006-2007 audit		$ 20,000
Tax Deduction Related to Nuclear Decommissioning Tax Liability	$ 118,000
Increase to 2009 Federal Income Tax Liability	2,400
Operating Losses, Carryover Amount				$ 1,900,000	$ 12,300,000
Regulatory Liability, Noncurrent				1,258,329	1,383,609
Prior period tax claim related to nuclear decommissioning liability	$ 9,300,000
Subsequent Event [Member]
Deferred Tax Assets, Other			$ 335,000
Regulatory Liability, Noncurrent			107,000
Regulatory Liability Net Of Tax			$ 66,000
Entergy Arkansas [Member]
Income tax benefit resulting from 2006-2007 audit		4,000
Regulatory Liability, Noncurrent				232,811	254,036
Entergy Louisiana [Member]
Income tax benefit resulting from 2006-2007 audit		6,000
Regulatory Liability, Noncurrent				516,964	546,084
System Energy [Member]
Income tax benefit resulting from 2006-2007 audit		$ 1,000
Regulatory Liability, Noncurrent				$ 322,855	$ 371,110