Decommissioning Trust Funds (Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value) (Details) - USD ($) $ in Millions	Dec. 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	$ 1,102.0	$ 134.0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	510.0	999.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	1,612.0	1,133.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	24.0	6.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	56.0	128.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	80.0	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	282.8	22.5
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	195.0	403.4
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	477.8	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	8.2	0.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	17.6	53.2
Debt Securities, Available-for-Sale, Unrealized Loss Position	25.8	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	543.8	69.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	178.4	356.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	722.2	425.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	8.8	0.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	18.1	36.5
Debt Securities, Available-for-Sale, Unrealized Loss Position	26.9	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	275.6	42.1
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	136.8	239.1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	412.4	281.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	6.8	4.5
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	20.8	38.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 27.6	$ 42.5