Decommissioning Trust Funds (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) counterparty	Dec. 31, 2015 USD ($) counterparty	Dec. 31, 2014 USD ($)
Decommissioning Fund Investments	$ 5,723,897	$ 5,349,953
Number of Derivative Contract Counterparties in a Liability Position | counterparty	3	2
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	$ 399,000	$ 342,000
Amortized cost of debt securities	$ 2,212,000	2,124,000
Average coupon rate of debt securities	3.21%
Proceeds from the dispositions of debt securities	$ 2,409,000	2,492,000	$ 1,872,000
Gains from dispositions of debt securities, gross	32,000	72,000	39,000
Losses from dispositions of debt securities, gross	$ 13,000	13,000	8,000
Average Duration of Debt Securities in Years	5 years 10 months 21 days
Average Maturity of Debt Securities, Years	9 years 4 months 22 days
Hedge Contracts In Liability Position	$ 8,000	2,000
Entergy Arkansas [Member]
Decommissioning Fund Investments	834,735	771,313
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 310,100	301,800
Average coupon rate of debt securities	2.65%
Proceeds from the dispositions of debt securities	$ 197,400	213,000	181,500
Gains from dispositions of debt securities, gross	1,800	5,900	8,700
Losses from dispositions of debt securities, gross	$ 800	300	300
Average Duration of Debt Securities in Years	5 years 4 months 15 days
Average Maturity of Debt Securities, Years	6 years 3 months 23 days
Entergy Louisiana [Member]
Decommissioning Fund Investments	$ 1,140,707	1,042,293
Percentage Interest in River Bend	30.00%
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 421,900	399,200
Average coupon rate of debt securities	3.78%
Proceeds from the dispositions of debt securities	$ 219,200	123,500	216,700
Gains from dispositions of debt securities, gross	3,900	1,900	2,200
Losses from dispositions of debt securities, gross	$ 400	300	300
Average Duration of Debt Securities in Years	5 years 7 months 3 days
Average Maturity of Debt Securities, Years	10 years 11 months 27 days
System Energy [Member]
Decommissioning Fund Investments	$ 780,496	701,460
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 309,100	270,700
Average coupon rate of debt securities	1.89%
Proceeds from the dispositions of debt securities	$ 499,300	390,400	392,900
Gains from dispositions of debt securities, gross	3,500	3,300	1,800
Losses from dispositions of debt securities, gross	$ 1,700	$ 500	$ 900
Average Duration of Debt Securities in Years	5 years 15 days
Average Maturity of Debt Securities, Years	6 years 3 months 20 days
Indian Point 3 [Member]
Decommissioning Fund Investments	$ 719,000
FitzPatrick [Member]
Decommissioning Fund Investments	785,000
Indian Point 1 [Member]
Decommissioning Fund Investments	443,000
Indian Point 2 [Member]
Decommissioning Fund Investments	564,000
Palisades [Member]
Decommissioning Fund Investments	412,000
Pilgrim [Member]
Decommissioning Fund Investments	960,000
Vermont Yankee [Member]
Decommissioning Fund Investments	$ 584,000