Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Effective Tax Rate [Line Items]
Income tax rates for continuing operations	13.30%	19.50%	13.00%	28.30%
IPL [Member]
Effective Tax Rate [Line Items]
Income tax rates for continuing operations	(24.70%)	(12.00%)	(24.30%)	22.60%
WPL [Member]
Effective Tax Rate [Line Items]
Income tax rates for continuing operations	33.10%	34.60%	32.50%	39.40%