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Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Jun. 30, 2015 - Commodity [Member] Tons in Thousands, MWh in Thousands, Dekatherms in Thousands | Tons Dekatherms MWh
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Electricity (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 8,300
Electricity (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,909
Electricity (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 6,391
FTRs (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 21,913
FTRs (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 12,360
FTRs (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 9,553
Natural Gas (Dths) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 79,702
Natural Gas (Dths) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 44,458
Natural Gas (Dths) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 35,244
Coal (Tons) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 5,343
Coal (Tons) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 1,680
Coal (Tons) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 3,663
2015 [Member] | Electricity (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 2,432
2015 [Member] | Electricity (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,100
2015 [Member] | Electricity (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,332
2015 [Member] | FTRs (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 11,952
2015 [Member] | FTRs (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 6,664
2015 [Member] | FTRs (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 5,288
2015 [Member] | Natural Gas (Dths) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 36,167
2015 [Member] | Natural Gas (Dths) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 23,343
2015 [Member] | Natural Gas (Dths) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 12,824
2015 [Member] | Coal (Tons) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 897
2015 [Member] | Coal (Tons) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 189
2015 [Member] | Coal (Tons) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 708
2016 [Member] | Electricity (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 3,240
2016 [Member] | Electricity (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 809
2016 [Member] | Electricity (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 2,431
2016 [Member] | FTRs (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 9,961
2016 [Member] | FTRs (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 5,696
2016 [Member] | FTRs (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 4,265
2016 [Member] | Natural Gas (Dths) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 34,330
2016 [Member] | Natural Gas (Dths) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 18,103
2016 [Member] | Natural Gas (Dths) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 16,227
2016 [Member] | Coal (Tons) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 2,260
2016 [Member] | Coal (Tons) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 830
2016 [Member] | Coal (Tons) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 1,430
2017 [Member] | Electricity (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,314
2017 [Member] | Electricity (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2017 [Member] | Electricity (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,314
2017 [Member] | FTRs (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2017 [Member] | FTRs (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2017 [Member] | FTRs (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2017 [Member] | Natural Gas (Dths) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 9,079
2017 [Member] | Natural Gas (Dths) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 2,886
2017 [Member] | Natural Gas (Dths) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 6,193
2017 [Member] | Coal (Tons) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 1,073
2017 [Member] | Coal (Tons) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 274
2017 [Member] | Coal (Tons) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 799
2018 [Member] | Electricity (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,314
2018 [Member] | Electricity (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2018 [Member] | Electricity (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 1,314
2018 [Member] | FTRs (MWhs) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2018 [Member] | FTRs (MWhs) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2018 [Member] | FTRs (MWhs) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | 0
2018 [Member] | Natural Gas (Dths) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 126
2018 [Member] | Natural Gas (Dths) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 126
2018 [Member] | Natural Gas (Dths) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Dekatherms | 0
2018 [Member] | Coal (Tons) [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 1,113
2018 [Member] | Coal (Tons) [Member] | IPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 387
2018 [Member] | Coal (Tons) [Member] | WPL [Member] |
Notional Amount of Derivatives [Line Items] |
Notional unit amount of derivatives (in MWhs/Dths/Tons) | Tons | 726

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