Decommissioning Trust Funds (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
Debt Securities, Trading, Measurement Input	$ 546,000,000		$ 546,000,000		$ 507,000,000
Decommissioning Trust Funds [Abstract]
Accumulated Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax						$ (6,806,000)
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	(1,513,000)	$ 1,303,000	18,042,000	$ 17,472,000
Amortized cost of debt securities	$ 2,382,000,000		$ 2,382,000,000		2,366,000,000
Average coupon rate of debt securities	3.09%		3.09%
Average duration of debt securities, years			7 years 1 month 17 days
Average maturity of debt securities, years			10 years 4 months 28 days
Proceeds from the dispositions of debt securities	$ 156,000,000	407,000,000	$ 832,000,000	1,133,000,000
Gains from dispositions of debt securities, gross	9,000,000	11,000,000	38,000,000	20,000,000
Losses from dispositions of debt securities, gross	200,000	400,000	4,000,000	3,000,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	600,000		600,000
Equity Securities, FV-NI, Unrealized Gain	250,000,000		142,000,000
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts			31,000,000		13,000,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 403,800,000		$ 403,800,000		405,400,000
Average coupon rate of debt securities	2.60%		2.60%
Average duration of debt securities, years			6 years 10 months 28 days
Average maturity of debt securities, years			8 years 2 months 15 days
Proceeds from the dispositions of debt securities	$ 14,600,000	45,500,000	$ 80,900,000	78,700,000
Gains from dispositions of debt securities, gross	1,700,000	2,000,000	7,500,000	2,100,000
Losses from dispositions of debt securities, gross	3,600		200,000	100,000
Equity Securities, FV-NI, Unrealized Gain	57,200,000		27,000,000
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 576,500,000		$ 576,500,000		573,000,000
Average coupon rate of debt securities	3.73%		3.73%
Average duration of debt securities, years			7 years 3 months 18 days
Average maturity of debt securities, years			12 years 11 months 19 days
Proceeds from the dispositions of debt securities	$ 30,600,000	59,700,000	$ 132,100,000	155,400,000
Gains from dispositions of debt securities, gross	1,400,000	2,500,000	6,300,000	4,200,000
Losses from dispositions of debt securities, gross	1,300	29,000	$ 700,000	200,000
Percentage Interest in River Bend			30.00%
Equity Securities, FV-NI, Unrealized Gain	80,200,000		$ 40,200,000
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 389,700,000		$ 389,700,000		371,400,000
Average coupon rate of debt securities	2.93%		2.93%
Average duration of debt securities, years			7 years 6 months
Average maturity of debt securities, years			11 years 2 months 12 days
Proceeds from the dispositions of debt securities	$ 24,100,000	108,600,000	$ 189,700,000	238,400,000
Gains from dispositions of debt securities, gross	1,600,000	1,700,000	8,600,000	3,600,000
Losses from dispositions of debt securities, gross	9,900	$ 200,000	400,000	$ 600,000
Equity Securities, FV-NI, Unrealized Gain	54,400,000		25,700,000
Indian Point 3 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	986,000,000		986,000,000		930,000,000
Indian Point 1 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	588,000,000		588,000,000		556,000,000
Indian Point 2 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	742,000,000		742,000,000		701,000,000
Palisades [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	$ 538,000,000		$ 538,000,000		$ 498,000,000