Summary Of Significant Accounting Policies (Schedule Of Allowance For Funds Used During Construction Recovery Rate) (Details)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
IPL [Member] | IPL (FERC formula) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	8.20%		8.20%		8.50%
WPL [Member] | WPL (PSCW formula - retail jurisdiction) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	8.20%	[1]	8.80%	[1]	8.80%	[1]
WPL [Member] | WPL (FERC formula - wholesale jurisdiction) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	4.50%		7.90%		6.20%
WPL [Member] | Edgewater Unit 5 and Columbia Units 1 and 2 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Accrual recorded, percentage of estimated CWIP	100.00%
WPL [Member] | Columbia Units 1-2 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Accrual recorded, percentage of estimated CWIP	50.00%
Return earned, expected percentage of estimated CWIP	50.00%

[1] Consistent with the PSCW’s retail rate case order issued in 2009, WPL accrued AFUDC on 100% of CWIP related to the Edgewater Unit 5 SCR emission controls project and the Columbia Units 1 and 2 scrubber and baghouse emission controls project in 2012 and 2011. Consistent with the PSCW’s retail rate case order issued in 2012, WPL earned a return on 50% of the estimated CWIP related to its Columbia Units 1 and 2 scrubber and baghouse emission controls project for 2013 and accrued AFUDC on the remaining 50% in 2013.