Risk Management and Fair Values (Assets And Liabilities At Fair Value On A Recurring Basis) (Details) (Imported) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Assets at fair value on a recurring basis
Assets other than temporary cash investments	$ 4,015,000,000	$ 3,788,000,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	4.01%
Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	193,000,000	613,000,000
Total	4,940,000,000	5,098,000,000
Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	10,000,000	30,000,000
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	2,328,000,000	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	1,687,000,000	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	375,000,000	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	37,000,000	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	320,000,000	335,000,000
Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	193,000,000	613,000,000
Total	1,666,000,000	2,034,000,000
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total	10,000,000	30,000,000
Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	439,000,000	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	677,000,000	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	37,000,000	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	320,000,000	335,000,000
Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments
Total	2,899,000,000	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	1,889,000,000	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	1,010,000,000	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	375,000,000	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	375,000,000	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	575,500,000	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		17,900,000
Total	579,400,000	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	355,300,000	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	220,200,000	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	3,900,000	3,900,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments		17,900,000
Total	100,200,000	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	3,100,000	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	93,200,000	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	3,900,000	3,900,000
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	479,200,000	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	352,200,000	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	127,000,000	129,500,000
Entergy Gulf States Louisiana [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	452,500,000	420,900,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	4.77%
Entergy Gulf States Louisiana [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	55,800,000	24,600,000
Total	595,200,000	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	2,900,000	8,600,000
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	269,500,000	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	183,000,000	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	86,900,000	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	55,800,000	24,600,000
Total	185,800,000	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	2,900,000	8,600,000
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	7,300,000	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	35,800,000	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	86,900,000	90,200,000
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	409,400,000	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	262,200,000	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	147,200,000	142,700,000
Entergy Louisiana [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	272,600,000	254,000,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.77%
Entergy Louisiana [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	7,900,000
Total	470,400,000	460,400,000
Entergy Louisiana [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	3,900,000	12,400,000
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	163,300,000	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	109,300,000	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	3,000,000	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	7,900,000
Total	255,500,000	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	3,900,000	12,400,000
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	2,000,000	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	55,700,000	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	3,000,000	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	214,900,000	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	161,300,000	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	53,600,000	53,200,000
Entergy Mississippi [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	3,900,000
Total	35,800,000
Entergy Mississippi [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Total	2,900,000	7,800,000
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	31,900,000
Total		31,800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	3,900,000
Total	35,800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Total	2,900,000	7,800,000
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	31,900,000
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	14,800,000
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	14,800,000
Entergy Texas [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19,900,000	65,100,000
Total	50,500,000	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	30,600,000	41,200,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19,900,000	65,100,000
Total	50,500,000	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	30,600,000	41,200,000
System Energy [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	459,800,000	423,400,000
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	2.87%
System Energy [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments		154,200,000
Total	459,800,000	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	264,400,000	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	195,400,000	186,200,000
System Energy [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments		154,200,000
Total	137,900,000	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	3,200,000	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	134,700,000	123,200,000
System Energy [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	321,900,000	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	261,200,000	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	$ 60,700,000	$ 63,000,000