Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	$ 361,000		$ 342,000
Amortized cost of debt securities	$ 2,183,000		2,124,000
Average coupon rate of debt securities	3.20%
Average duration of debt securities, years	5 years 10 months 2 days
Average maturity of debt securities, years	8 years 10 months 28 days
Proceeds from the dispositions of debt securities	$ 729,000	$ 493,000
Gains from dispositions of debt securities, gross	10,000	26,000
Losses from dispositions of debt securities, gross	3,000	2,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 302,000		301,800
Average coupon rate of debt securities	2.58%
Average duration of debt securities, years	5 years 3 months
Average maturity of debt securities, years	6 years 1 month 28 days
Proceeds from the dispositions of debt securities	$ 58,600	81,900
Gains from dispositions of debt securities, gross	800	5,100
Losses from dispositions of debt securities, gross	$ 100	0
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Percentage Interest in River Bend	30.00%
Amortized cost of debt securities	$ 407,000		399,200
Average coupon rate of debt securities	3.89%
Average duration of debt securities, years	5 years 6 months 16 days
Average maturity of debt securities, years	10 years 2 months 28 days
Proceeds from the dispositions of debt securities	$ 53,800	25,600
Gains from dispositions of debt securities, gross	900	1,300
Losses from dispositions of debt securities, gross	100	10
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 286,900		$ 270,700
Average coupon rate of debt securities	1.93%
Average duration of debt securities, years	5 years 7 days
Average maturity of debt securities, years	6 years 4 months 14 days
Proceeds from the dispositions of debt securities	$ 188,500	78,400
Gains from dispositions of debt securities, gross	1,600	400
Losses from dispositions of debt securities, gross	$ 300	$ 100