Decommissioning Trust Funds (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	$ 24,000,000	$ 9,000,000
More than 12 months Fair Value	0	0
Total Fair Value	24,000,000	9,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,000,000	1,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,000,000	1,000,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	689,000,000	277,000,000
More than 12 months Fair Value	76,000,000	163,000,000
Total Fair Value	765,000,000	440,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	15,000,000	2,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,000,000	4,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	18,000,000	6,000,000
Entergy Arkansas [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	1,200,000	100,000
More than 12 months Fair Value	0	0
Total Fair Value	1,200,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	0
Entergy Arkansas [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	96,800,000	56,500,000
More than 12 months Fair Value	18,900,000	34,800,000
Total Fair Value	115,700,000	91,300,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,600,000	300,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	500,000	800,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2,100,000	1,100,000
Entergy Gulf States Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	2,500,000	100,000
More than 12 months Fair Value	0	0
Total Fair Value	2,500,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	0
Entergy Gulf States Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	79,000,000	14,000,000
More than 12 months Fair Value	2,100,000	15,000,000
Total Fair Value	81,100,000	29,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,600,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	100,000	200,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,700,000	300,000
Entergy Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	1,000,000	100,000
More than 12 months Fair Value	0	0
Total Fair Value	1,000,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	0
Entergy Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	32,100,000	19,100,000
More than 12 months Fair Value	5,700,000	12,100,000
Total Fair Value	37,800,000	31,200,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	600,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	200,000	300,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	800,000	400,000
System Energy [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	1,800,000	100,000
More than 12 months Fair Value	0	0
Total Fair Value	1,800,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	100,000	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	100,000	0
System Energy [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	74,900,000	51,600,000
More than 12 months Fair Value	1,500,000	6,500,000
Total Fair Value	76,400,000	58,100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,000,000	200,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	100,000	100,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 1,100,000	$ 300,000