Decommissioning Trust Funds (Securities Held) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 4,991.0	$ 4,903.0
Total Unrealized Gains	1,345.0	1,307.0
Total Unrealized Losses	16.0	29.0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	3,061.0	3,073.0
Total Unrealized Gains	1,290.0	1,260.0
Total Unrealized Losses	1.0	0
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	1,930.0	1,830.0
Total Unrealized Gains	55.0	47.0
Total Unrealized Losses	15.0	29.0
Entergy Arkansas [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	721.5	710.9
Total Unrealized Gains	224.3	219.3
Total Unrealized Losses	2.9	5.2
Entergy Arkansas [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	460.8	463.3
Total Unrealized Gains	218.6	214.0
Total Unrealized Losses	0	0
Entergy Arkansas [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	260.7	247.6
Total Unrealized Gains	5.7	5.3
Total Unrealized Losses	2.9	5.2
Entergy Gulf States Louisiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	586.2	573.7
Total Unrealized Gains	154.2	149.2
Total Unrealized Losses	1.8	3.5
Entergy Gulf States Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	359.9	370.8
Total Unrealized Gains	145.4	141.8
Total Unrealized Losses	0	0
Entergy Gulf States Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	226.3	202.9
Total Unrealized Gains	8.8	7.4
Total Unrealized Losses	1.8	3.5
Entergy Louisiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	353.6	347.3
Total Unrealized Gains	103.5	100.8
Total Unrealized Losses	1.2	1.9
Entergy Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	225.0	224.2
Total Unrealized Gains	98.3	96.1
Total Unrealized Losses	0	0
Entergy Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	128.6	123.1
Total Unrealized Gains	5.2	4.7
Total Unrealized Losses	1.2	1.9
System Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	619.3	603.9
Total Unrealized Gains	158.3	154.3
Total Unrealized Losses	0.7	1.8
System Energy [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	385.9	380.0
Total Unrealized Gains	154.8	150.8
Total Unrealized Losses	0	0
System Energy [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	233.4	223.9
Total Unrealized Gains	3.5	3.5
Total Unrealized Losses	$ 0.7	$ 1.8