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Summary Of Significant Accounting Policies (Narrative) (Details) - Minimum [Member]
Jun. 30, 2015
New Accounting Pronouncements [Line Items]  
Debt issuance costs percentage, on total long-term debt 1.00%
IPL [Member]  
New Accounting Pronouncements [Line Items]  
Debt issuance costs percentage, on total long-term debt 1.00%
WPL [Member]  
New Accounting Pronouncements [Line Items]  
Debt issuance costs percentage, on total long-term debt 1.00%