Decommissioning Trust Funds (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) - Debt Securities [Member] - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 585.0	$ 840.0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,010.0	666.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	1,595.0	1,506.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	30.0	63.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	192.0	138.0
Debt Securities, Available-for-sale, Unrealized Loss Position	222.0	201.0
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	68.8	197.6
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	391.8	260.1
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	460.6	457.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4.3	18.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	73.8	50.5
Debt Securities, Available-for-sale, Unrealized Loss Position	78.1	69.3
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	339.7	409.9
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	354.9	207.5
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	694.6	617.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	14.9	24.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	59.6	42.9
Debt Securities, Available-for-sale, Unrealized Loss Position	74.5	67.5
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	176.1	231.9
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	263.0	198.0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	439.1	429.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	11.0	19.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	58.8	44.5
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 69.8	$ 63.7