Summary Of Significant Accounting Policies (Schedule Of Amortization Expense on Emissions Allowance) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 0	$ 0	$ 13.4
IPL [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	0	0	12.9
WPL [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 0	$ 0	$ 0.5