Asset Retirement Obligations (Cumulative Decommissioning And Retirement Cost Liabilities And Expenses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Entergy Arkansas [Member]
Asset Retirement Obligations [Line Items]
Liabilities	$ 640.2	$ 602.2
Accretion	40.5	38.0
Liabilities	680.7	640.2
Entergy Gulf States Louisiana [Member]
Asset Retirement Obligations [Line Items]
Liabilities	359.8	339.9
Accretion	21.0	19.9
Liabilities	380.8	359.8
Entergy Louisiana [Member]
Asset Retirement Obligations [Line Items]
Liabilities	345.8	321.2
Accretion	23.4	24.6
Change in Cash Flow Estimate	48.9
Liabilities	418.1	345.8
Entergy Mississippi [Member]
Asset Retirement Obligations [Line Items]
Liabilities	5.7	5.4
Accretion	0.3	0.3
Liabilities	6.0	5.7
Entergy New Orleans [Member]
Asset Retirement Obligations [Line Items]
Liabilities	2.9	3.4
Accretion	0.2	0.2
Spending	(0.9)	(0.7)
Liabilities	2.2	2.9
Entergy Texas [Member]
Asset Retirement Obligations [Line Items]
Liabilities	3.9	3.6
Accretion	0.2	0.3
Liabilities	4.1	3.9
System Energy [Member]
Asset Retirement Obligations [Line Items]
Liabilities	445.4	452.8
Accretion	33.0	31.5
Change in Cash Flow Estimate		(38.9)
Liabilities	478.4	445.4
Entergy Wholesale Commodities [Member]
Asset Retirement Obligations [Line Items]
Liabilities	1,492.9	1,420.0
Accretion	119.4	115.6
Change in Cash Flow Estimate	(58.5)	(34.1)
Spending	(10.5)	(8.6)
Liabilities	$ 1,543.3	$ 1,492.9