Decommissioning Trust Funds (Fair Value Of Debt Securities By Contractual Maturities) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair value of debt securities by contractual maturities
1 year - 5 years	$ 692.0	$ 473.0
5 years - 10 years	600.0	655.0
10 years - 15 years	150.0	389.0
15 years - 20 years	158.0	130.0
20 years+	394.0	530.0
Total	2,070.0	2,177.0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	76.0	0.0
Entergy Arkansas [Member]
Fair value of debt securities by contractual maturities
1 year - 5 years	153.6	91.7
5 years - 10 years	220.8	217.4
10 years - 15 years	47.9	146.0
15 years - 20 years	27.3	35.7
20 years+	25.9	35.5
Total	509.3	526.3
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	33.8	0.0
Entergy Louisiana [Member]
Fair value of debt securities by contractual maturities
1 year - 5 years	193.9	157.8
5 years - 10 years	170.0	173.0
10 years - 15 years	68.5	123.0
15 years - 20 years	82.9	80.2
20 years+	203.0	260.2
Total	747.5	794.2
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	29.2	0.0
System Energy [Member]
Fair value of debt securities by contractual maturities
1 year - 5 years	217.3	156.8
5 years - 10 years	136.1	161.8
10 years - 15 years	9.5	58.6
15 years - 20 years	31.1	1.9
20 years+	98.7	145.4
Total	499.6	524.5
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	$ 6.9	$ 0.0