Income Taxes (Narrative) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Sep. 30, 2008
Parent Company [Member]
Income tax benefit resulting from Act 55 financing settlement	$ 172
Entergy Gulf States Louisiana [Member]
Proceeds from the LA Act 55 financing		274.7
Income tax benefit resulting from Act 55 financing settlement	20
Regulatory charge resulting from tax settlement	28
Net-of-tax regulatory charge resulting from tax settlement	17
Entergy Louisiana [Member]
Proceeds from the LA Act 55 financing		679.0
Income tax benefit resulting from Act 55 financing settlement	143
Regulatory charge resulting from tax settlement	137
Net-of-tax regulatory charge resulting from tax settlement	$ 84