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Discontinued Operations And Assets And Liabilities Held For Sale (Components Of Assets And Liabilities Held For Sale In Consolidated Balance Sheets) (Details) - Alliant Energy and IPL [Member] - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2015 | Jun. 30, 2015 | Dec. 31, 2014
Electric distribution assets [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Current assets |  | $ 9.3 | $ 9.3 |
Property, plant and equipment, net |  | 125.0 | 125.0 |
Non-current regulatory assets |  | 20.5 | 20.5 |
Carrying value adjustment of net assets sold | [1] | (8.8) | (8.8) |
Total assets held for sale |  | 146.0 | 146.0 |
Current liabilities |  | 2.4 | 2.4 |
Other liabilities |  | 12.6 | 12.6 |
Total liabilities held for sale |  | 15.0 | 15.0 |
Net assets held for sale |  | 131.0 | 131.0 |
Loss on sale of Minnesota distribution assets |  | $ 9.0 | $ 9.0 |
Gas distribution assets [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Current assets |  |  |  | $ 1.1
Property, plant and equipment, net |  |  |  | 11.0
Non-current regulatory assets |  |  |  | 7.0
Carrying value adjustment of net assets sold | [1] |  |  | 0.0
Total assets held for sale |  |  |  | 19.1
Current liabilities |  |  |  | 1.0
Other liabilities |  |  |  | 7.1
Total liabilities held for sale |  |  |  | 8.1
Net assets held for sale |  |  |  | $ 11.0
[1] | The carrying value of IPL’s Minnesota electric distribution assets classified as held for sale exceeded the expected proceeds, less costs to sell. As a result, Alliant Energy and IPL recorded a pre-tax charge of $9 million in the second quarter of 2015 related to the Minnesota electric distribution assets.

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