Decommissioning Trust Funds (Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 638.0	$ 1,102.0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	469.0	510.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	1,107.0	1,612.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	14.0	24.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	48.0	56.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	62.0	80.0
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	158.4	282.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	183.0	195.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	341.4	477.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	3.9	8.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	14.2	17.6
Debt Securities, Available-for-Sale, Unrealized Loss Position	18.1	25.8
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	324.8	543.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	165.0	178.4
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	489.8	722.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	6.7	8.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	16.4	18.1
Debt Securities, Available-for-Sale, Unrealized Loss Position	23.1	26.9
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	154.4	275.6
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	120.6	136.8
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	275.0	412.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	2.9	6.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	17.7	20.8
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 20.6	$ 27.6