Decommissioning Trust Funds (Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value) (Details) - Debt Securities [Member] - USD ($) $ in Millions	Mar. 31, 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	$ 335.0	$ 134.0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	995.0	999.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	1,330.0	1,133.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	5.0	6.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	137.0	128.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	142.0	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	50.1	22.5
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	392.5	403.4
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	442.6	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	0.8	0.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	56.7	53.2
Debt Securities, Available-for-Sale, Unrealized Loss Position	57.5	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	158.3	69.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	360.6	356.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	518.9	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	2.6	0.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	37.7	36.5
Debt Securities, Available-for-Sale, Unrealized Loss Position	40.3	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	126.4	42.1
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	242.0	239.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	368.4	281.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	1.8	4.5
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	42.8	38.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 44.6	$ 42.5