Decommissioning Trust Funds (Fair Value Of Debt Securities By Contractual Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair value of debt securities by contractual maturities
1 year - 5 years	$ 473.0	$ 672.0
5 years - 10 years	655.0	852.0
10 years - 15 years	389.0	377.0
15 years - 20 years	130.0	144.0
20 years+	530.0	576.0
Total	2,177.0	2,617.0
Debt Securities Available For Sale Maturity Allocated And Single Maturity Date Within One Year Negative Fair Value	0.0	(4.0)
Entergy Arkansas [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	0.0	0.0
1 year - 5 years	91.7	113.1
5 years - 10 years	217.4	189.8
10 years - 15 years	146.0	81.4
15 years - 20 years	35.7	28.5
20 years+	35.5	35.1
Total	526.3	447.9
Entergy Louisiana [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	0.0	0.0
1 year - 5 years	157.8	117.0
5 years - 10 years	173.0	159.4
10 years - 15 years	123.0	101.2
15 years - 20 years	80.2	66.9
20 years+	260.2	187.7
Total	794.2	632.2
System Energy [Member]
Fair value of debt securities by contractual maturities
1 year - 5 years	156.8	134.7
5 years - 10 years	161.8	141.5
10 years - 15 years	58.6	31.5
15 years - 20 years	1.9	5.3
20 years+	145.4	115.8
Total	524.5	427.7
Debt Securities Available For Sale Maturity Allocated And Single Maturity Date Within One Year Negative Fair Value	$ 0.0	$ (1.1)