Decommissioning Trust Funds (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) - Debt Securities [Member] - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 1,419.0	$ 770.0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	119.0	99.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	1,538.0	869.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	83.0	8.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16.0	4.0
Debt Securities, Available-for-sale, Unrealized Loss Position	99.0	12.0
Entergy Arkansas [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	332.9	183.8
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	55.8	39.5
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	388.7	223.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	21.3	2.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7.0	1.8
Debt Securities, Available-for-sale, Unrealized Loss Position	28.3	4.7
Entergy Louisiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	427.4	206.9
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	41.2	42.9
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	468.6	249.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25.1	1.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5.1	1.9
Debt Securities, Available-for-sale, Unrealized Loss Position	30.2	3.3
System Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	418.4	276.6
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	13.3	11.3
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	431.7	287.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25.5	2.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2.1	0.6
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 27.6	$ 2.9

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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