Transactions With Affiliates (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
RS Cogen [Member]
Intercompany operating expenses			$ 3.2		$ 2.8
Entergy Arkansas [Member]
Intercompany revenues	131.2		349.9		324.0
Intercompany operating expenses	596.6	[1]	656.1	[1]	580.7	[1]
Intercompany interest and investment income	0		0		0
Entergy Arkansas [Member] | Entergy Power [Member]
Intercompany operating expenses			3.3		1.4
Entergy Gulf States Louisiana [Member]
Intercompany revenues	418.0		383.1		380.6
Intercompany operating expenses	773.1	[2]	672.8	[2]	532.3	[2]
Intercompany interest and investment income	30.3		27.5		28.2
Entergy Gulf States Louisiana [Member] | RS Cogen [Member]
Intercompany operating expenses			3.2		2.8
Entergy Louisiana [Member]
Intercompany revenues	258.5		114.9		138.2
Intercompany operating expenses	490.9	[3]	667.6	[3]	597.4	[3]
Intercompany interest and investment income	87.6		78.2		78.2
Entergy Louisiana [Member] | Entergy Power [Member]
Intercompany operating expenses			8.1		14.3
Entergy Mississippi [Member]
Intercompany revenues	169.8		107.3		36.1
Intercompany operating expenses	367.6		399.0		352.7
Intercompany interest and investment income	0		0		0
Entergy New Orleans [Member]
Intercompany revenues	76.8		27.0		43.9
Intercompany operating expenses	241.5	[4]	279.6	[4]	247.2	[4]
Intercompany interest and investment income	0		0		0
Entergy New Orleans [Member] | Entergy Power [Member]
Intercompany operating expenses			8.0		14.1
Entergy Texas [Member]
Intercompany revenues	316.1		369.4		313.2
Intercompany operating expenses	445.3		418.1		386.1
Intercompany interest and investment income	0		0		0.1
System Energy [Member]
Intercompany revenues	664.4		735.1		622.1
Intercompany operating expenses	156.7		175.2		147.4
Intercompany interest and investment income	$ 0		$ 0		$ 0

[1] Includes power purchased from Entergy Power of $3.3 million in 2013 and $1.4 million in 2012.

[2] Includes power purchased from RS Cogen of $3.2 million in 2013 and $2.8 million in 2012.

[3] Includes power purchased from Entergy Power of $8.1 million in 2013 and $14.3 million in 2012.

[4] Includes power purchased from Entergy Power of $8 million in 2013 and $14.1 million in 2012.