XML 29 R79.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Derivative Instruments (Gains And Losses From Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013
Regulatory Assets [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | $ 8.3 | $ 2.2 | $ 13.8 | $ (14.2)
Regulatory Assets [Member] | IPL [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | 7.3 | (0.4) | 8.7 | (4.6)
Regulatory Assets [Member] | WPL [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | 1.0 | 2.6 | 5.1 | (9.6)
Regulatory Liabilities [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | (6.2) | (1.0) | 63.2 | 16.6
Regulatory Liabilities [Member] | IPL [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | (2.0) | 3.6 | 13.9 | 9.9
Regulatory Liabilities [Member] | WPL [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) from commodity derivative instruments | $ (4.2) | $ (4.6) | $ 49.3 | $ 6.7

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959 + Details
Name: | us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration