Risk Management and Fair Values (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013 Y	Jun. 30, 2012	Jun. 30, 2013 MWh Y	Jun. 30, 2012	Dec. 31, 2012
Risk Management and Fair Values [Abstract]
Derivative, Collateral, Obligation to Return Cash	$ 29		$ 29		$ 56
Cash flow hedges relating to power sales as part of net unrealized gains			58
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			40
Maturity of cash flow hedges, before taxes	4	101	2	171
Maturity of cash flow hedges, Tax	2	35	1	60
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years	2.5		2.5
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			83.00%
Planned Generation Sold Forward under financial derivatives	50.00%		50.00%
Total planned generation for remainder of the period			21,000,000
Change in cash flow hedges due to ineffectiveness	0.8	0.6	0.5	0.4
Dollar amount of hedge contract in a liability position	10		10
Total volume of natural gas swaps outstanding (MMBtu)	35,585,000		35,585,000
Cash flow hedges in-the-money contracts	94		94
Cash flow hedges out-of-money contracts	$ 11		$ 11
Entergy Gulf States Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	11,530,000		11,530,000
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	14,910,000		14,910,000
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	8,860,000		8,860,000
Entergy New Orleans
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu)	285,000		285,000