Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Jan. 01, 2019
Debt Securities, Trading, Measurement Input	$ 521,000		$ 507,000
Decommissioning Trust Funds [Abstract]
Accumulated Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax				$ (6,806)
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	8,743	$ 8,073
Amortized cost of debt securities	$ 2,382,000		2,366,000
Average coupon rate of debt securities	3.23%
Average duration of debt securities, years	6 years 8 months 23 days
Average maturity of debt securities, years	10 years 5 months 19 days
Proceeds from the dispositions of debt securities	$ 400,000	365,000
Gains from dispositions of debt securities, gross	14,000	2,000
Losses from dispositions of debt securities, gross	3,000	2,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	3,000
Equity Securities, FV-NI, Unrealized Loss	(636,000)
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	22,000		13,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 398,900		405,400
Average coupon rate of debt securities	2.73%
Average duration of debt securities, years	6 years 10 months 13 days
Average maturity of debt securities, years	8 years 4 months 9 days
Proceeds from the dispositions of debt securities	$ 48,600	10,900
Gains from dispositions of debt securities, gross	4,500	20
Losses from dispositions of debt securities, gross	200	100
Equity Securities, FV-NI, Unrealized Loss	(147,100)
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 568,400		573,000
Average coupon rate of debt securities	3.87%
Average duration of debt securities, years	6 years 10 months 6 days
Average maturity of debt securities, years	13 years 4 months 17 days
Proceeds from the dispositions of debt securities	$ 67,400	56,200
Gains from dispositions of debt securities, gross	2,900	300
Losses from dispositions of debt securities, gross	$ 600	200
Percentage Interest in River Bend	30.00%
Equity Securities, FV-NI, Unrealized Loss	$ (200,800)
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 383,800		371,400
Average coupon rate of debt securities	2.91%
Average duration of debt securities, years	7 years 10 days
Average maturity of debt securities, years	10 years 8 months 12 days
Proceeds from the dispositions of debt securities	$ 92,000	42,100
Gains from dispositions of debt securities, gross	1,700	400
Losses from dispositions of debt securities, gross	200	$ 100
Equity Securities, FV-NI, Unrealized Loss	(140,000)
Indian Point 3 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	858,000		930,000
Indian Point 1 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	506,000		556,000
Indian Point 2 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	644,000		701,000
Palisades [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	$ 493,000		$ 498,000