Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	$ (25,581)	$ 8,743
Amortized cost of debt securities	$ 3,376,000		$ 2,423,000
Average coupon rate of debt securities	2.59%
Average duration of debt securities, years	5 years 11 months 23 days
Average maturity of debt securities, years	8 years 5 months 12 days
Proceeds from the dispositions of debt securities	$ 524,000	400,000
Gains from dispositions of debt securities, gross	11,000	14,000
Losses from dispositions of debt securities, gross	11,000	3,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	6,400		100
Equity Securities, FV-NI, Unrealized Gain	200,000
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	5,000		31,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 419,500		420,400
Average coupon rate of debt securities	2.42%
Average duration of debt securities, years	6 years 4 months 24 days
Average maturity of debt securities, years	7 years 7 months 13 days
Proceeds from the dispositions of debt securities	$ 13,800	48,600
Gains from dispositions of debt securities, gross	800	4,500
Losses from dispositions of debt securities, gross	100	200
Equity Securities, FV-NI, Unrealized Gain	45,200
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 606,300		581,400
Average coupon rate of debt securities	3.25%
Average duration of debt securities, years	6 years 7 months 2 days
Average maturity of debt securities, years	11 years 6 months 21 days
Proceeds from the dispositions of debt securities	$ 108,400	67,400
Gains from dispositions of debt securities, gross	3,300	2,900
Losses from dispositions of debt securities, gross	$ 3,200	600
Percentage Interest in River Bend	30.00%
Equity Securities, FV-NI, Unrealized Gain	$ 64,900
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 397,000		398,400
Average coupon rate of debt securities	2.36%
Average duration of debt securities, years	6 years 3 months 21 days
Average maturity of debt securities, years	9 years 7 months 13 days
Proceeds from the dispositions of debt securities	$ 74,100	92,000
Gains from dispositions of debt securities, gross	1,200	1,700
Losses from dispositions of debt securities, gross	1,600	$ 200
Equity Securities, FV-NI, Unrealized Gain	43,100
Indian Point 3 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	970,000		991,000
Indian Point 1 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	631,000		631,000
Indian Point 2 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	760,000		794,000
Palisades [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	$ 545,000		$ 554,000