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Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 9 Months Ended
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Sep. 30, 2014
Income Taxes [Line Items] |
Increase (decrease) non-current deferred tax liabilities | $ 177.6
IPL [Member] |
Income Taxes [Line Items] |
Increase (decrease) non-current deferred tax liabilities | 123.6
WPL [Member] |
Income Taxes [Line Items] |
Increase (decrease) non-current deferred tax liabilities | $ 54.6

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- Definition Increase Decrease In Deferred Income Taxes Noncurrent Liabilities + References No definition available. + Details
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