Decommissioning Trust Funds (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	$ 7.0	$ 0
More than 12 months Fair Value	0	0
Total Fair Value	7.0	0
Less than 12 Months Gross Unrealized Losses	1.0	0
More than 12 Months Gross Unrealized Losses	0	0
Total Gross Unrealized Losses	1.0	0
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	171.0	892.0
More than 12 months Fair Value	242.0	60.0
Total Fair Value	413.0	952.0
Less than 12 Months Gross Unrealized Losses	1.0	24.0
More than 12 Months Gross Unrealized Losses	7.0	5.0
Total Gross Unrealized Losses	8.0	29.0
Entergy Arkansas [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	0	0
More than 12 months Fair Value	0	0
Total Fair Value	0	0
Less than 12 Months Gross Unrealized Losses	0	0
More than 12 Months Gross Unrealized Losses	0	0
Total Gross Unrealized Losses	0	0
Entergy Arkansas [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	30.9	153.2
More than 12 months Fair Value	54.2	6.9
Total Fair Value	85.1	160.1
Less than 12 Months Gross Unrealized Losses	0.1	4.8
More than 12 Months Gross Unrealized Losses	1.4	0.4
Total Gross Unrealized Losses	1.5	5.2
Entergy Gulf States Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	0	0
More than 12 months Fair Value	0	0
Total Fair Value	0	0
Less than 12 Months Gross Unrealized Losses	0	0
More than 12 Months Gross Unrealized Losses	0	0
Total Gross Unrealized Losses	0	0
Entergy Gulf States Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	8.2	91.9
More than 12 months Fair Value	30.7	4.6
Total Fair Value	38.9	96.5
Less than 12 Months Gross Unrealized Losses	0	3.1
More than 12 Months Gross Unrealized Losses	0.9	0.4
Total Gross Unrealized Losses	0.9	3.5
Entergy Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	0	0
More than 12 months Fair Value	0	0
Total Fair Value	0	0
Less than 12 Months Gross Unrealized Losses	0	0
More than 12 Months Gross Unrealized Losses	0	0
Total Gross Unrealized Losses	0	0
Entergy Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	7.2	38.3
More than 12 months Fair Value	21.2	1.7
Total Fair Value	28.4	40.0
Less than 12 Months Gross Unrealized Losses	0	1.7
More than 12 Months Gross Unrealized Losses	0.7	0.2
Total Gross Unrealized Losses	0.7	1.9
System Energy [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	0	0
More than 12 months Fair Value	0	0
Total Fair Value	0	0
Less than 12 Months Gross Unrealized Losses	0	0
More than 12 Months Gross Unrealized Losses	0	0
Total Gross Unrealized Losses	0	0
System Energy [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	28.1	121.7
More than 12 months Fair Value	14.7	0.9
Total Fair Value	42.8	122.6
Less than 12 Months Gross Unrealized Losses	0	1.7
More than 12 Months Gross Unrealized Losses	0.3	0.1
Total Gross Unrealized Losses	$ 0.3	$ 1.8