Rate And Regulatory Matters (Narrative) (Details) (USD $)	1 Months Ended						3 Months Ended	12 Months Ended	1 Months Ended
	May 31, 2012	Apr. 30, 2012	Feb. 29, 2012	Jan. 31, 2012	Dec. 31, 2011	Nov. 30, 2011	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011 Entergy Mississippi [Member]	Dec. 31, 2005 Minimum [Member]
Rate and Regulatory Matters [Abstract]
High Damages Range in Texas Lawsuit							$ 972,000,000
Low Damages Range In Texas Lawsuit							153,000,000
Charges Above Prevailing Market Prices							57,000,000
Proceeds From Sale of Preferred Membership Units			51,000,000
Class A preferred membership units sold to third party			500,000
Revised Increase In Rate Base Request		105,000,000
Recommended Increase in Rate Base		66,000,000
Adjustment To Accumulated Deferred Income Taxes							29,000,000
Adjustment To Regulatory Asset For Income Taxes							75,300,000
Adjustment To Income Tax Expense							46,300,000
Basis Point Bandwidth Range				50
Basis Point Bandwidth				10.50%
Amount Collected From Customers			156,000,000
Increase In Base Rate Reflecting Return On Common Equity						112,000,000
Request filed for refund of fuel cost recovery over collections					43,000,000
Refund for fuel cost recovery								67,000,000
Rate reduction	$ 100,000
Public Utilities Earned Return On Common Equity		9.60%		10.48%		10.60%	11.54%		10.92%
Payments from utility operating companies as percentage of average production cost										0.00%