Income Taxes (Details Textual) (USD $)	1 Months Ended	12 Months Ended				1 Months Ended			3 Months Ended	12 Months Ended	1 Months Ended
	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 UK Windfall Tax Issue [Member]	Mar. 31, 2010 Entergy Arkansas	Mar. 31, 2010 Entergy Gulf States Louisiana	Mar. 31, 2010 Entergy Louisiana [Member]	Sep. 30, 2011 Entergy Louisiana [Member]	Dec. 31, 2011 Entergy Louisiana [Member]	Mar. 31, 2010 Entergy Mississippi [Member]	Mar. 31, 2010 Entergy New Orleans [Member]	Mar. 31, 2010 Entergy Texas [Member]	Mar. 31, 2010 System Energy [Member]
Operating Loss Carryforwards [Line Items]
Total tax included in notices of deficiency					$ 82,000,000
Total tax and interest associated with issue					239,000,000
Reduction in taxable income due to accounting changes	1,300,000,000					292,000,000	132,000,000	185,000,000			48,000,000	13,000,000	45,000,000	180,000,000
Future additional tax depreciation										1,030,000,000
Reversal of deferred tax liabilities and liabilities for uncertain tax positions									422,000,000
Period for sharing benefits of settlement with customers										15 years
Regulatory charges										199,000,000
Income Taxes (Textual) [Abstract]
Effective Income Tax Rate		17.30%	32.70%	33.60%
Valuation allowance on the deferred tax assets related to state net operating loss carryovers		66,000,000
Valuation allowance on the deferred tax assets related to capital loss carryovers		13,000,000
Unrecognized tax benefits if recognized, would lower the effective income tax rates		521,000,000	605,000,000	522,000,000
Payment Made For Intercompany Obligations				289,000,000
Remaining balances of unrecognized tax benefits		3,867,000,000	4,345,000,000	3,528,000,000
Deposits with to cover uncertain tax positions		363,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		99,000,000	45,000,000	48,000,000
Reduction in taxable income within non utility nuclear				5,700,000,000
Minimum deficiency from large corporate underpayment interest rates		239,000,000
Income recognized for tax purpose under wholesale electric power purchase agreements		1,500,000,000
Gain recognized for income tax purpose on formation of a wholly-owned subsidiary		1,030,000,000
Reduction in net operating loss carryover		$ 2,500,000,000