Decommissioning Trust Funds (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts			$ 369,000,000		$ 396,000,000
Amortized cost of debt securities	$ 2,096,000,000		$ 2,096,000,000		2,019,000,000
Average coupon rate of debt securities	3.33%		3.33%
Average duration of debt securities, years			5 years 10 months 3 days
Average maturity of debt securities, years			8 years 9 months 27 days
Proceeds from the dispositions of debt securities	$ 456,000,000	$ 445,000,000	$ 949,000,000	$ 982,000,000
Gains from dispositions of debt securities, gross	19,000,000	6,000,000	45,000,000	12,000,000
Losses from dispositions of debt securities, gross	1,000,000	1,000,000	3,000,000	3,000,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 299,100,000		$ 299,100,000		277,400,000
Average coupon rate of debt securities	2.45%		2.45%
Average duration of debt securities, years			5 years 4 months
Average maturity of debt securities, years			6 years 3 months 12 days
Proceeds from the dispositions of debt securities	$ 64,900,000	25,000,000	$ 146,800,000	70,300,000
Gains from dispositions of debt securities, gross	300,000	300,000	5,400,000	400,000
Losses from dispositions of debt securities, gross	20,000	100,000	20,000	300,000
Entergy Gulf States Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 239,800,000		$ 239,800,000		231,500,000
Average coupon rate of debt securities	4.53%		4.53%
Average duration of debt securities, years			5 years 9 months 15 days
Average maturity of debt securities, years			10 years 11 months 5 days
Proceeds from the dispositions of debt securities	$ 31,700,000	45,100,000	$ 53,400,000	75,400,000
Gains from dispositions of debt securities, gross	100,000	500,000	1,400,000	700,000
Losses from dispositions of debt securities, gross	200,000	100,000	0	200,000
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 142,200,000		$ 142,200,000		137,900,000
Average coupon rate of debt securities	2.93%		2.93%
Average duration of debt securities, years			5 years 1 month 13 days
Average maturity of debt securities, years			8 years 25 days
Proceeds from the dispositions of debt securities	$ 7,900,000	11,600,000	$ 11,800,000	29,700,000
Gains from dispositions of debt securities, gross	100,000	50,000	100,000	200,000
Losses from dispositions of debt securities, gross	6,700	200	11,600	4,100
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 264,600,000		$ 264,600,000		$ 251,000,000
Average coupon rate of debt securities	2.33%		2.33%
Average duration of debt securities, years			4 years 7 months 22 days
Average maturity of debt securities, years			6 years 2 months 10 days
Proceeds from the dispositions of debt securities	$ 83,600,000	101,300,000	$ 162,000,000	231,600,000
Gains from dispositions of debt securities, gross	400,000	400,000	800,000	1,400,000
Losses from dispositions of debt securities, gross	$ 40,000	$ 100,000	$ 100,000	$ 300,000