Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2019	Jan. 01, 2019	Jan. 01, 2018
Debt Securities, Trading	$ 507,000	$ 389,000
Accumulated Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax					$ (6,806)	$ (632,617)
Decommissioning Fund Investments	6,404,030	6,920,164
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	14,023	6,393	$ 80,069
Amortized cost of debt securities	$ 2,366,000	2,511,000
Average coupon rate of debt securities	3.27%
Proceeds from the dispositions of debt securities	$ 1,427,000	2,406,000	3,163,000
Gains from dispositions of debt securities, gross	25,000	7,000	149,000
Losses from dispositions of debt securities, gross	$ 4,000	47,000	13,000
Average Duration of Debt Securities in Years	6 years 7 months 13 days
Average Maturity of Debt Securities, Years	10 years 5 months 1 day
Equity Securities, FV-NI, Unrealized Gain	$ 640,000
Entergy Arkansas [Member]
Decommissioning Fund Investments	1,101,283	912,049
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 405,400	389,000
Average coupon rate of debt securities	2.79%
Proceeds from the dispositions of debt securities	$ 110,600	82,100	339,400
Gains from dispositions of debt securities, gross	2,900	100	17,700
Losses from dispositions of debt securities, gross	$ 100	2,900	600
Average Duration of Debt Securities in Years	6 years 9 months 29 days
Average Maturity of Debt Securities, Years	8 years 9 months 21 days
Equity Securities, FV-NI, Unrealized Gain	$ 147,700
Entergy Louisiana [Member]
Decommissioning Fund Investments	$ 1,563,812	1,284,996
Percentage Interest in River Bend	30.00%
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 573,000	534,800
Average coupon rate of debt securities	3.82%
Proceeds from the dispositions of debt securities	$ 186,000	401,700	231,300
Gains from dispositions of debt securities, gross	4,800	2,100	12,000
Losses from dispositions of debt securities, gross	$ 300	7,500	400
Average Duration of Debt Securities in Years	6 years 9 months 18 days
Average Maturity of Debt Securities, Years	13 years 3 months 3 days
Equity Securities, FV-NI, Unrealized Gain	$ 208,100
System Energy [Member]
Decommissioning Fund Investments	1,054,098	869,543
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 371,400	367,100
Average coupon rate of debt securities	3.12%
Proceeds from the dispositions of debt securities	$ 338,100	361,900	565,400
Gains from dispositions of debt securities, gross	5,400	500	1,400
Losses from dispositions of debt securities, gross	$ 700	6,100	$ 3,300
Average Duration of Debt Securities in Years	6 years 9 months
Average Maturity of Debt Securities, Years	10 years 4 months 28 days
Equity Securities, FV-NI, Unrealized Gain	$ 140,500
Indian Point 3 [Member]
Decommissioning Fund Investments	930,000	781,000
Indian Point 1 [Member]
Decommissioning Fund Investments	556,000	471,000
Indian Point 2 [Member]
Decommissioning Fund Investments	701,000	598,000
Palisades [Member]
Decommissioning Fund Investments	498,000	444,000
Pilgrim [Member]
Decommissioning Trust Fair Values				$ 1,030,000
Decommissioning Fund Investments		1,028,000
Vermont Yankee [Member]
Decommissioning Trust Fair Values		532,000
Decommissioning Fund Investments		532,000
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	$ 13,000	$ (1,000)