Decommissioning Trust Funds (Fair Value Of Debt Securities By Contractual Maturities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair value of debt securities by contractual maturities
Less than 1 year	$ 45.0	$ 83.0
1 year - 5 years	818.0	752.0
5 years - 10 years	666.0	620.0
10 years - 15 years	166.0	169.0
15 years - 20 years	70.0	52.0
20 years+	241.0	154.0
Total	2,006.0	1,830.0
Entergy Arkansas [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	11.5	8.1
1 year - 5 years	122.6	110.9
5 years - 10 years	136.4	118.0
10 years - 15 years	3.3	3.9
15 years - 20 years	1.0	0.9
20 years+	7.5	5.8
Total	282.3	247.6
Entergy Gulf States Louisiana [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	6.1	7.9
1 year - 5 years	57.0	51.2
5 years - 10 years	74.1	75.5
10 years - 15 years	45.1	55.8
15 years - 20 years	13.8	4.6
20 years+	38.1	7.9
Total	234.2	202.9
Entergy Louisiana [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	5.0	14.8
1 year - 5 years	57.9	41.9
5 years - 10 years	41.9	37.0
10 years - 15 years	6.2	6.6
15 years - 20 years	8.3	6.2
20 years+	18.1	16.6
Total	137.4	123.1
System Energy [Member]
Fair value of debt securities by contractual maturities
Less than 1 year	6.3	5.5
1 year - 5 years	164.0	144.9
5 years - 10 years	50.7	44.3
10 years - 15 years	1.3	9.3
15 years - 20 years	2.8	1.6
20 years+	21.2	18.3
Total	$ 246.3	$ 223.9