Risk Management and Fair Values (Assets And Liabilities At Fair Value On A Recurring Basis) (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Assets at fair value on a recurring basis
Assets other than temporary cash investments	$ 4,176,000,000	$ 3,788,000,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.88%
Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	653,000,000	613,000,000
Total	5,433,000,000	5,098,000,000
Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total		30,000,000
Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	10,000,000
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	2,453,000,000	2,129,000,000
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	1,723,000,000	1,659,000,000
Power Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	218,000,000	312,000,000
Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	52,000,000	50,000,000
Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	324,000,000	335,000,000
Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	653,000,000	613,000,000
Total	2,167,000,000	2,034,000,000
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total		30,000,000
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Total	10,000,000
Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	421,000,000	397,000,000
Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	707,000,000	639,000,000
Fair Value Inputs Level 1 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	52,000,000	50,000,000
Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	324,000,000	335,000,000
Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments
Total	3,048,000,000	2,752,000,000
Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total
Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	2,032,000,000	1,732,000,000
Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	1,016,000,000	1,020,000,000
Fair Value Inputs Level 2 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 2 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments
Total	218,000,000	312,000,000
Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total
Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	218,000,000	312,000,000
Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Entergy Arkansas [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	599,900,000	541,700,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.35%
Entergy Arkansas [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	36,200,000	17,900,000
Total	644,500,000	563,500,000
Entergy Arkansas [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	378,800,000	329,400,000
Entergy Arkansas [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	221,100,000	212,300,000
Entergy Arkansas [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	8,400,000	3,900,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	36,200,000	17,900,000
Total	145,200,000	110,900,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	5,000,000	6,300,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	95,600,000	82,800,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	8,400,000	3,900,000
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	499,300,000	452,600,000
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	373,800,000	323,100,000
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	125,500,000	129,500,000
Entergy Gulf States Louisiana [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	475,000,000	420,900,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	4.68%
Entergy Gulf States Louisiana [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	156,300,000	24,600,000
Total	721,300,000	535,700,000
Entergy Gulf States Louisiana [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total		8,600,000
Entergy Gulf States Louisiana [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	3,000,000
Entergy Gulf States Louisiana [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	289,400,000	238,700,000
Entergy Gulf States Louisiana [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	185,600,000	182,200,000
Entergy Gulf States Louisiana [Member] | Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	87,000,000	90,200,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	156,300,000	24,600,000
Total	293,800,000	159,400,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total		8,600,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Total	3,000,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	7,800,000	5,100,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	39,700,000	39,500,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	87,000,000	90,200,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	427,500,000	376,300,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	281,600,000	233,600,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	145,900,000	142,700,000
Entergy Louisiana [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	285,500,000	254,000,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.74%
Entergy Louisiana [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	148,500,000
Total	637,500,000	460,400,000
Entergy Louisiana [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total		12,400,000
Entergy Louisiana [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	4,800,000
Entergy Louisiana [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	174,000,000	149,200,000
Entergy Louisiana [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	111,500,000	104,800,000
Entergy Louisiana [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	11,800,000	5,200,000
Entergy Louisiana [Member] | Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	186,900,000	201,200,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	148,500,000
Total	406,200,000	260,900,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total		12,400,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Total	4,800,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	1,300,000	2,900,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	52,900,000	51,600,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	11,800,000	5,200,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	186,900,000	201,200,000
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	231,300,000	199,500,000
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	172,700,000	146,300,000
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	58,600,000	53,200,000
Entergy Mississippi [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	26,600,000
Total	60,700,000
Entergy Mississippi [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total		7,800,000
Entergy Mississippi [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	2,300,000
Entergy Mississippi [Member] | Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	31,800,000
Total		31,800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	26,600,000
Total	60,700,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total		7,800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Total	2,300,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	31,800,000
Total		31,800,000
Entergy New Orleans | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments		9,300,000
Total		21,300,000
Entergy New Orleans | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total		1,500,000
Entergy New Orleans | Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments		12,000,000
Total	18,800,000
Entergy New Orleans | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments		9,300,000
Total		21,300,000
Entergy New Orleans | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total		1,500,000
Entergy New Orleans | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments		12,000,000
Total	18,800,000
Entergy Texas [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	62,800,000	65,100,000
Total	94,900,000	106,300,000
Entergy Texas [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	32,100,000	41,200,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	62,800,000	65,100,000
Total	94,900,000	106,300,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	32,100,000	41,200,000
System Energy [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	484,200,000	423,400,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	2.67%
System Energy [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19,800,000	154,200,000
Total	504,000,000	577,600,000
System Energy [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	280,000,000	237,200,000
System Energy [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	204,200,000	186,200,000
System Energy [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19,800,000	154,200,000
Total	158,800,000	280,100,000
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	500,000	2,700,000
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	138,500,000	123,200,000
System Energy [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	345,200,000	297,500,000
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	279,500,000	234,500,000
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	$ 65,700,000	$ 63,000,000