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Summary Of Significant Accounting Policies (Schedule Of Average Rates Of Depreciation) (Details)
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Electric - generation [Member] | IPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 3.40% 3.50% 3.80%
Electric - generation [Member] | WPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 3.50% 3.50% 3.60%
Electric - distribution [Member] | IPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 2.90% 2.80% 2.90%
Electric - distribution [Member] | WPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 2.60% 2.60% 2.60%
Electric - other [Member] | IPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 5.70% 5.20% 5.30%
Electric - other [Member] | WPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 7.40% 6.10% 5.80%
Gas [Member] | IPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 3.30% 3.30% 3.30%
Gas [Member] | WPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 2.40% 2.40% 2.50%
Other [Member] | IPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 6.10% 6.30% 5.90%
Other [Member] | WPL [Member]      
Public Utility, Property, Plant and Equipment [Line Items]      
Average rate of depreciation 5.40% 5.90% 5.60%