Decommissioning Trust Funds (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) - Debt Securities [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 12.0	$ 3.0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	770.0	187.0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	99.0	2.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	869.0	189.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	8.0	3.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4.0	0.0
Entergy Arkansas [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	4.7	0.3
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	183.8	29.9
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	39.5	0.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	223.3	29.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2.9	0.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1.8	0.0
Entergy Louisiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	3.3	0.5
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	206.9	36.4
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	42.9	0.8
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	249.8	37.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1.4	0.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1.9	0.0
System Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	2.9	0.8
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	276.6	28.9
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	11.3	0.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	287.9	28.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2.3	0.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	$ 0.6	$ 0.0