Decommissioning Trust Funds (Fair Value Of Debt Securities By Contractual Maturities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair value of debt securities by contractual maturities
less than 1 year	$ 83.0	$ 53.0
1 year - 5 years	752.0	681.0
5 years - 10 years	620.0	562.0
10 years - 15 years	169.0	164.0
15 years - 20 years	52.0	61.0
20 years	154.0	210.0
Total	1,830.0	1,731.0
Entergy Arkansas [Member]
Fair value of debt securities by contractual maturities
less than 1 year	8.1	8.8
1 year - 5 years	110.9	98.6
5 years - 10 years	118.0	93.1
10 years - 15 years	3.9	5.1
15 years - 20 years	0.9	0
20 years	5.8	11.0
Total	247.6	216.6
Entergy Gulf States Louisiana [Member]
Fair value of debt securities by contractual maturities
less than 1 year	7.9	8.0
1 year - 5 years	51.2	43.5
5 years - 10 years	75.5	63.5
10 years - 15 years	55.8	55.8
15 years - 20 years	4.6	8.5
20 years	7.9	9.6
Total	202.9	188.9
Entergy Louisiana [Member]
Fair value of debt securities by contractual maturities
less than 1 year	14.8	1.9
1 year - 5 years	41.9	42.3
5 years - 10 years	37.0	24.9
10 years - 15 years	6.6	18.8
15 years - 20 years	6.2	1.7
20 years	16.6	22.3
Total	123.1	111.9
System Energy [Member]
Fair value of debt securities by contractual maturities
less than 1 year	5.5	1.3
1 year - 5 years	144.9	128.7
5 years - 10 years	44.3	53.9
10 years - 15 years	9.3	2.3
15 years - 20 years	1.6	1.4
20 years	18.3	19.4
Total	$ 223.9	$ 207.0