Risk Management and Fair Values (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 Y	Sep. 30, 2012	Sep. 30, 2013 MWh Y	Sep. 30, 2012	Dec. 31, 2012
Risk Management and Fair Values [Abstract]
Derivative, Collateral, Obligation to Return Cash	$ 7		$ 7		$ 56
Cash flow hedges relating to power sales as part of net unrealized gains			7
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			6
Maturity of cash flow hedges, before taxes	35	61	38	232
Maturity of cash flow hedges, Tax	13	21	14	81
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years	2.25		2.25
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			82.00%
Planned Generation Sold Forward under financial derivatives	59.00%		59.00%
Total planned generation for remainder of the period			11,000,000
Change in cash flow hedges due to ineffectiveness	1.8	1.2	2.3	1.6
Dollar amount of hedge contract in a liability position	32	2	32	2
Total volume of natural gas swaps outstanding (MMBtu)	19,081,000		19,081,000
Cash flow hedges in-the-money contracts	85		85
Cash flow hedges out-of-money contracts	$ 36		$ 36
Entergy Gulf States Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	7,600,000		7,600,000
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	8,540,000		8,540,000
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	2,010,000		2,010,000
Entergy New Orleans
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	931,000		931,000