Decommissioning Trust Funds (Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 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	$ 565.0	$ 1,102.0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	438.0	510.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	1,003.0	1,612.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	17.0	24.0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	43.0	56.0
Debt Securities, Available-for-Sale, Unrealized Loss Position	60.0	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	141.8	282.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	174.0	195.0
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	315.8	477.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	4.6	8.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	12.9	17.6
Debt Securities, Available-for-Sale, Unrealized Loss Position	17.5	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	318.7	543.8
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	150.6	178.4
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	469.3	722.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	9.4	8.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	14.7	18.1
Debt Securities, Available-for-Sale, Unrealized Loss Position	24.1	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	104.2	275.6
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	113.8	136.8
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	218.0	412.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	3.3	6.8
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	15.7	20.8
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 19.0	$ 27.6