Decommissioning Trust Funds (Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value) (Details) - Debt Securities [Member] - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 105.0	$ 134.0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	871.0	999.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	976.0	1,133.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	1.0	6.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	93.0	128.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	94.0	134.0
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	17.5	22.5
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	376.5	403.4
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	394.0	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	0.2	0.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	42.1	53.2
Debt Securities, Available-for-Sale, Unrealized Loss Position	42.3	53.6
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	48.1	69.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	299.6	356.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	347.7	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	0.1	0.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	24.9	36.5
Debt Securities, Available-for-Sale, Unrealized Loss Position	25.0	37.4
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	39.9	42.1
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	194.8	239.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	234.7	281.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	0.2	4.5
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	26.4	38.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 26.6	$ 42.5