Decommissioning Trust Funds (Securities Held) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 5,453,000,000	$ 5,371,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1,613,000,000	1,589,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	5,000,000	7,000,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	3,327,000,000	3,286,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1,525,000,000	1,513,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,000,000	1,000,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	2,126,000,000	2,085,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	88,000,000	76,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	4,000,000	6,000,000
Entergy Arkansas [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	783,100,000	769,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	257,900,000	255,100,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	600,000	1,100,000
Entergy Arkansas [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	486,500,000	487,300,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	249,700,000	248,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Entergy Arkansas [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	296,600,000	282,600,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	8,200,000	6,200,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	600,000	1,100,000
Entergy Gulf States Louisiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	648,700,000	637,700,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	192,500,000	189,500,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	200,000	300,000
Entergy Gulf States Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	407,300,000	395,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	180,600,000	177,600,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Entergy Gulf States Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	241,400,000	241,800,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	11,900,000	11,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	200,000	300,000
Entergy Louisiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	391,800,000	383,600,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	127,300,000	123,600,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	200,000	400,000
Entergy Louisiana [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	245,300,000	239,600,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	119,100,000	116,700,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Entergy Louisiana [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	146,500,000	144,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	8,200,000	6,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	200,000	400,000
System Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	696,200,000	679,800,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	200,400,000	193,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	100,000	300,000
System Energy [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	431,900,000	424,500,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	192,300,000	188,000,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
System Energy [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	264,300,000	255,300,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	8,100,000	5,900,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 100,000	$ 300,000