Revolving Credit Facilities, Lines Of Credit And Short-Term Borrowings (Book Value And The Fair Value Of Long-Term Debt) (Details) (USD $)	Mar. 31, 2012
Short-term Debt [Line Items]
Long-term Debt, Fair Value	$ 12,565,095,000
Long-term Debt, Book Value	12,436,380,000
Notes payable to power authority	134,000,000
Entergy Arkansas [Member]
Short-term Debt [Line Items]
Long term DOE obligations	181,000,000
Entergy Louisiana [Member]
Short-term Debt [Line Items]
Capital Lease Obligations	169,000,000
System Energy [Member]
Short-term Debt [Line Items]
Capital Lease Obligations	$ 139,000,000