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Derivative Instruments (Tables) | 9 Months Ended
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Sep. 30, 2015
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):
| Electricity |  | FTRs |  | Natural Gas |  | Coal
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years
Alliant Energy | 7,024 |  |  | 2015-2018 |  | 15,793 |  |  | 2015-2016 |  | 103,867 |  |  | 2015-2020 |  | 4,918 |  |  | 2015-2018
IPL | 1,302 |  |  | 2015-2016 |  | 8,880 |  |  | 2015-2016 |  | 67,910 |  |  | 2015-2020 |  | 1,585 |  |  | 2015-2018
WPL | 5,722 |  |  | 2015-2018 |  | 6,913 |  |  | 2015-2016 |  | 35,957 |  |  | 2015-2017 |  | 3,333 |  |  | 2015-2018
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Current derivative assets |  | $19.5 |  |  |  | $30.5 |  |  |  | $17.8 |  |  |  | $27.4 |  |  |  | $1.7 |  |  |  | $3.1 |
Non-current derivative assets | 0.8 |  |  | 8.1 |  |  | 0.7 |  |  | 0.6 |  |  | 0.1 |  |  | 7.5 |
Current derivative liabilities | 35.4 |  |  | 28.1 |  |  | 15.2 |  |  | 16.4 |  |  | 20.2 |  |  | 11.7 |
Non-current derivative liabilities | 23.7 |  |  | 9.5 |  |  | 6.8 |  |  | 3.1 |  |  | 16.9 |  |  | 6.4 |
Gains And Losses From Derivative Instruments | Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Three Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($27.4 | ) |  |  | $8.3 |  |  |  | ($9.5 | ) |  |  | $7.3 |  |  |  | ($17.9 | ) |  |  | $1.0 |
Regulatory liabilities | (2.5 | ) |  | (6.2 | ) |  | (1.2 | ) |  | (2.0 | ) |  | (1.3 | ) |  | (4.2 | )
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (69.5 | ) |  | 13.8 |  |  | (33.3 | ) |  | 8.7 |  |  | (36.2 | ) |  | 5.1 |
Regulatory liabilities | (4.9 | ) |  | 63.2 |  |  | 1.0 |  |  | 13.9 |  |  | (5.9 | ) |  | 49.3 |
Credit Risk-related Contingent Features | The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered, were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Aggregate fair value |  | $59.1 |  |  |  | $37.6 |  |  |  | $22.0 |  |  |  | $19.5 |  |  |  | $37.1 |  |  |  | $18.1 |
Credit support to be posted if triggered | 59.0 |  |  | 37.4 |  |  | 22.0 |  |  | 19.5 |  |  | 37.0 |  |  | 17.9 |
Balance Sheet Offsetting | The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
September 30, 2015 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $20.3 |  |  |  | $18.0 |  |  |  | $18.5 |  |  |  | $17.3 |  |  |  | $1.8 |  |  |  | $0.7 |
Derivative liabilities | 59.1 |  |  | 56.8 |  |  | 22.0 |  |  | 20.8 |  |  | 37.1 |  |  | 36.0 |
December 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 38.6 |  |  | 33.0 |  |  | 28.0 |  |  | 24.7 |  |  | 10.6 |  |  | 8.3 |
Derivative liabilities | 37.6 |  |  | 32.0 |  |  | 19.5 |  |  | 16.2 |  |  | 18.1 |  |  | 15.8 |
IPL [Member] |
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):
| Electricity |  | FTRs |  | Natural Gas |  | Coal
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years
Alliant Energy | 7,024 |  |  | 2015-2018 |  | 15,793 |  |  | 2015-2016 |  | 103,867 |  |  | 2015-2020 |  | 4,918 |  |  | 2015-2018
IPL | 1,302 |  |  | 2015-2016 |  | 8,880 |  |  | 2015-2016 |  | 67,910 |  |  | 2015-2020 |  | 1,585 |  |  | 2015-2018
WPL | 5,722 |  |  | 2015-2018 |  | 6,913 |  |  | 2015-2016 |  | 35,957 |  |  | 2015-2017 |  | 3,333 |  |  | 2015-2018
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Current derivative assets |  | $19.5 |  |  |  | $30.5 |  |  |  | $17.8 |  |  |  | $27.4 |  |  |  | $1.7 |  |  |  | $3.1 |
Non-current derivative assets | 0.8 |  |  | 8.1 |  |  | 0.7 |  |  | 0.6 |  |  | 0.1 |  |  | 7.5 |
Current derivative liabilities | 35.4 |  |  | 28.1 |  |  | 15.2 |  |  | 16.4 |  |  | 20.2 |  |  | 11.7 |
Non-current derivative liabilities | 23.7 |  |  | 9.5 |  |  | 6.8 |  |  | 3.1 |  |  | 16.9 |  |  | 6.4 |
Gains And Losses From Derivative Instruments | Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Three Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($27.4 | ) |  |  | $8.3 |  |  |  | ($9.5 | ) |  |  | $7.3 |  |  |  | ($17.9 | ) |  |  | $1.0 |
Regulatory liabilities | (2.5 | ) |  | (6.2 | ) |  | (1.2 | ) |  | (2.0 | ) |  | (1.3 | ) |  | (4.2 | )
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (69.5 | ) |  | 13.8 |  |  | (33.3 | ) |  | 8.7 |  |  | (36.2 | ) |  | 5.1 |
Regulatory liabilities | (4.9 | ) |  | 63.2 |  |  | 1.0 |  |  | 13.9 |  |  | (5.9 | ) |  | 49.3 |
Credit Risk-related Contingent Features | The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered, were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Aggregate fair value |  | $59.1 |  |  |  | $37.6 |  |  |  | $22.0 |  |  |  | $19.5 |  |  |  | $37.1 |  |  |  | $18.1 |
Credit support to be posted if triggered | 59.0 |  |  | 37.4 |  |  | 22.0 |  |  | 19.5 |  |  | 37.0 |  |  | 17.9 |
Balance Sheet Offsetting | The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
September 30, 2015 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $20.3 |  |  |  | $18.0 |  |  |  | $18.5 |  |  |  | $17.3 |  |  |  | $1.8 |  |  |  | $0.7 |
Derivative liabilities | 59.1 |  |  | 56.8 |  |  | 22.0 |  |  | 20.8 |  |  | 37.1 |  |  | 36.0 |
December 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 38.6 |  |  | 33.0 |  |  | 28.0 |  |  | 24.7 |  |  | 10.6 |  |  | 8.3 |
Derivative liabilities | 37.6 |  |  | 32.0 |  |  | 19.5 |  |  | 16.2 |  |  | 18.1 |  |  | 15.8 |
WPL [Member] |
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):
| Electricity |  | FTRs |  | Natural Gas |  | Coal
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years
Alliant Energy | 7,024 |  |  | 2015-2018 |  | 15,793 |  |  | 2015-2016 |  | 103,867 |  |  | 2015-2020 |  | 4,918 |  |  | 2015-2018
IPL | 1,302 |  |  | 2015-2016 |  | 8,880 |  |  | 2015-2016 |  | 67,910 |  |  | 2015-2020 |  | 1,585 |  |  | 2015-2018
WPL | 5,722 |  |  | 2015-2018 |  | 6,913 |  |  | 2015-2016 |  | 35,957 |  |  | 2015-2017 |  | 3,333 |  |  | 2015-2018
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Current derivative assets |  | $19.5 |  |  |  | $30.5 |  |  |  | $17.8 |  |  |  | $27.4 |  |  |  | $1.7 |  |  |  | $3.1 |
Non-current derivative assets | 0.8 |  |  | 8.1 |  |  | 0.7 |  |  | 0.6 |  |  | 0.1 |  |  | 7.5 |
Current derivative liabilities | 35.4 |  |  | 28.1 |  |  | 15.2 |  |  | 16.4 |  |  | 20.2 |  |  | 11.7 |
Non-current derivative liabilities | 23.7 |  |  | 9.5 |  |  | 6.8 |  |  | 3.1 |  |  | 16.9 |  |  | 6.4 |
Gains And Losses From Derivative Instruments | Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Three Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($27.4 | ) |  |  | $8.3 |  |  |  | ($9.5 | ) |  |  | $7.3 |  |  |  | ($17.9 | ) |  |  | $1.0 |
Regulatory liabilities | (2.5 | ) |  | (6.2 | ) |  | (1.2 | ) |  | (2.0 | ) |  | (1.3 | ) |  | (4.2 | )
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (69.5 | ) |  | 13.8 |  |  | (33.3 | ) |  | 8.7 |  |  | (36.2 | ) |  | 5.1 |
Regulatory liabilities | (4.9 | ) |  | 63.2 |  |  | 1.0 |  |  | 13.9 |  |  | (5.9 | ) |  | 49.3 |
Credit Risk-related Contingent Features | The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered, were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014 |  | September 30, 2015 |  | December 31, 2014
Aggregate fair value |  | $59.1 |  |  |  | $37.6 |  |  |  | $22.0 |  |  |  | $19.5 |  |  |  | $37.1 |  |  |  | $18.1 |
Credit support to be posted if triggered | 59.0 |  |  | 37.4 |  |  | 22.0 |  |  | 19.5 |  |  | 37.0 |  |  | 17.9 |
Balance Sheet Offsetting | The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
September 30, 2015 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $20.3 |  |  |  | $18.0 |  |  |  | $18.5 |  |  |  | $17.3 |  |  |  | $1.8 |  |  |  | $0.7 |
Derivative liabilities | 59.1 |  |  | 56.8 |  |  | 22.0 |  |  | 20.8 |  |  | 37.1 |  |  | 36.0 |
December 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 38.6 |  |  | 33.0 |  |  | 28.0 |  |  | 24.7 |  |  | 10.6 |  |  | 8.3 |
Derivative liabilities | 37.6 |  |  | 32.0 |  |  | 19.5 |  |  | 16.2 |  |  | 18.1 |  |  | 15.8 |

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