Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019	Jan. 01, 2018
Debt Securities, Trading	$ 507,000
Accumulated Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax				$ (6,806)	$ (633,000)
Decommissioning Fund Investments	7,253,215	$ 6,404,030
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	17,586	14,023	$ 6,393
Amortized cost of debt securities	$ 2,423,000	2,366,000
Average coupon rate of debt securities	3.01%
Proceeds from the dispositions of debt securities	$ 1,024,000	1,427,000	2,406,000
Gains from dispositions of debt securities, gross	47,000	25,000	7,000
Losses from dispositions of debt securities, gross	$ 4,000	4,000	47,000
Average Duration of Debt Securities in Years	7 years 4 months 9 days
Average Maturity of Debt Securities, Years	10 years 8 months 19 days
Equity Securities, FV-NI, Unrealized Gain	$ 531,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	100
Entergy Arkansas [Member]
Decommissioning Fund Investments	1,273,921	1,101,283
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 420,400	405,400
Average coupon rate of debt securities	2.57%
Proceeds from the dispositions of debt securities	$ 94,500	110,600	82,100
Gains from dispositions of debt securities, gross	8,800	2,900	100
Losses from dispositions of debt securities, gross	$ 200	100	2,900
Average Duration of Debt Securities in Years	6 years 11 months 19 days
Average Maturity of Debt Securities, Years	8 years 2 months 26 days
Equity Securities, FV-NI, Unrealized Gain	$ 116,800
Entergy Louisiana [Member]
Decommissioning Fund Investments	$ 1,794,042	1,563,812
Percentage Interest in River Bend	30.00%
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 581,400	573,000
Average coupon rate of debt securities	3.64%
Proceeds from the dispositions of debt securities	$ 159,700	186,000	401,700
Gains from dispositions of debt securities, gross	8,100	4,800	2,100
Losses from dispositions of debt securities, gross	$ 700	300	7,500
Average Duration of Debt Securities in Years	7 years 3 months
Average Maturity of Debt Securities, Years	12 years 8 months 23 days
Equity Securities, FV-NI, Unrealized Gain	$ 163,600
System Energy [Member]
Decommissioning Fund Investments	1,215,868	1,054,098
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 398,400	371,400
Average coupon rate of debt securities	2.74%
Proceeds from the dispositions of debt securities	$ 252,200	338,100	361,900
Gains from dispositions of debt securities, gross	11,500	5,400	500
Losses from dispositions of debt securities, gross	$ 600	700	$ 6,100
Average Duration of Debt Securities in Years	7 years 6 months 14 days
Average Maturity of Debt Securities, Years	11 years 1 month 2 days
Equity Securities, FV-NI, Unrealized Gain	$ 111,100
Indian Point 3 [Member]
Decommissioning Trust Fair Values	991,000	930,000
Indian Point 1 [Member]
Decommissioning Trust Fair Values	631,000	556,000
Indian Point 2 [Member]
Decommissioning Trust Fair Values	794,000	701,000
Palisades [Member]
Decommissioning Trust Fair Values	554,000	498,000
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	$ 31,000	$ 13,000