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Summary Of Significant Accounting Policies (Schedule Of Average Rates Of Depreciation) (Details) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Electric - generation [Member] | IPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 3.60% |  | 3.70% | 3.50%
Electric - generation [Member] | WPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 3.30% | [1] | 3.20% | 3.30%
Electric - distribution [Member] | IPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 2.50% |  | 2.50% | 2.40%
Electric - distribution [Member] | WPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 2.70% | [1] | 2.90% | 2.90%
Gas [Member] | IPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 3.40% |  | 3.40% | 3.50%
Gas [Member] | WPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 2.50% | [1] | 2.60% | 2.60%
Other [Member] | IPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 4.40% |  | 4.50% | 4.80%
Other [Member] | WPL [Member] |  |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |
Average rate of depreciation | 5.10% | [1] | 5.30% | 5.20%
[1] | In 2012, the PSCW issued an order approving the implementation of updated depreciation rates for WPL effective January 1, 2013 as a result of a recently completed depreciation study. In 2013, the PSCW and FERC issued orders approving WPL’s requests to revise depreciation rates associated with the acquisition of Riverside effective January 1, 2013.

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- Definition Composite depreciation rate for public utility plants in service. + References No definition available. + Details
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- Details
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