Decommissioning Trust Funds (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts			$ 276,000,000		$ 211,000,000
Amortized cost of debt securities	1,709,000,000		1,709,000,000		1,637,000,000
Average coupon rate of debt securities	3.54%		3.54%
Average duration of debt securities, years	5 years 1 month 16 days		5 years 1 month 16 days
Average maturity of debt securities, years	7 years 8 months 5 days		7 years 8 months 5 days
Proceeds from the dispositions of debt securities	284,000,000	472,000,000	1,064,000,000	1,417,000,000
Gains from dispositions of debt securities, gross	3,000,000	8,000,000	25,000,000	32,000,000
Losses from dispositions of debt securities, gross	4,000,000	200,000	7,000,000	5,000,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	240,000,000		240,000,000		202,300,000
Average coupon rate of debt securities	2.83%		2.83%
Average duration of debt securities, years	5 years 3 months 20 days		5 years 3 months 20 days
Average maturity of debt securities, years	6 years 0 months 11 days		6 years 0 months 11 days
Proceeds from the dispositions of debt securities	30,300,000	15,000,000	173,400,000	103,400,000
Gains from dispositions of debt securities, gross	600,000	100,000	9,300,000	2,800,000
Losses from dispositions of debt securities, gross	100,000	10,000	200,000	50,000
Entergy Gulf States Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	182,500,000		182,500,000		174,100,000
Average coupon rate of debt securities	4.58%		4.58%
Average duration of debt securities, years	5 years 5 months 17 days		5 years 5 months 17 days
Average maturity of debt securities, years	8 years 1 month 6 days		8 years 1 month 6 days
Proceeds from the dispositions of debt securities	19,500,000	35,900,000	66,200,000	96,700,000
Gains from dispositions of debt securities, gross	300,000	3,900,000	6,600,000	6,400,000
Losses from dispositions of debt securities, gross	20,000	700,000	30,000	30,000
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	106,800,000		106,800,000		102,600,000
Average coupon rate of debt securities	3.42%		3.42%
Average duration of debt securities, years	4 years 10 months 28 days		4 years 10 months 28 days
Average maturity of debt securities, years	8 years 6 months 12 days		8 years 6 months 12 days
Proceeds from the dispositions of debt securities	2,700,000	9,500,000	12,200,000	19,800,000
Gains from dispositions of debt securities, gross	10,000	100,000	60,000	200,000
Losses from dispositions of debt securities, gross	10,000	500	30,000	30,000
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	216,500,000		216,500,000		197,800,000
Average coupon rate of debt securities	2.57%		2.57%
Average duration of debt securities, years	4 years 5 months 21 days		4 years 5 months 21 days
Average maturity of debt securities, years	5 years 11 months 20 days		5 years 11 months 20 days
Proceeds from the dispositions of debt securities	53,400,000	91,800,000	144,600,000	315,000,000
Gains from dispositions of debt securities, gross	100,000	500,000	900,000	3,500,000
Losses from dispositions of debt securities, gross	$ 800,000	$ 50,000	$ 1,200,000	$ 200,000