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Derivative Instruments | 12 Months Ended
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Dec. 31, 2014
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 14 for detailed discussion of derivative instruments. Notional Amounts - As of December 31, 2014, gross notional amounts by delivery year 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):
| 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,067 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 8,248 |
FTRs (MWhs) | 9,505 |  |  | — |  |  | — |  |  | — |  |  | 9,505 |
Natural gas (Dths) | 56,250 |  |  | 20,225 |  |  | 1,829 |  |  | — |  |  | 78,304 |
Coal (tons) | 1,490 |  |  | 1,899 |  |  | 1,073 |  |  | 1,113 |  |  | 5,575 |
IPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,765 |  |  | — |  |  | — |  |  | — |  |  | 1,765 |
FTRs (MWhs) | 5,503 |  |  | — |  |  | — |  |  | — |  |  | 5,503 |
Natural gas (Dths) | 39,727 |  |  | 10,178 |  |  | 1,014 |  |  | — |  |  | 50,919 |
Coal (tons) | 75 |  |  | 830 |  |  | 274 |  |  | 387 |  |  | 1,566 |
WPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,302 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 6,483 |
FTRs (MWhs) | 4,002 |  |  | — |  |  | — |  |  | — |  |  | 4,002 |
Natural gas (Dths) | 16,523 |  |  | 10,047 |  |  | 815 |  |  | — |  |  | 27,385 |
Coal (tons) | 1,415 |  |  | 1,069 |  |  | 799 |  |  | 726 |  |  | 4,009 |
Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, 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 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Current derivative assets |  | $30.5 |  |  |  | $25.6 |  |  |  | $27.4 |  |  |  | $20.2 |  |  |  | $3.1 |  |  |  | $5.4 |
Non-current derivative assets | 8.1 |  |  | 1.1 |  |  | 0.6 |  |  | 0.9 |  |  | 7.5 |  |  | 0.2 |
Current derivative liabilities | 28.1 |  |  | 6.7 |  |  | 16.4 |  |  | 3.0 |  |  | 11.7 |  |  | 3.7 |
Non-current derivative liabilities | 9.5 |  |  | 14.1 |  |  | 3.1 |  |  | 2.2 |  |  | 6.4 |  |  | 11.9 |
Changes in unrealized 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
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Regulatory assets |  | ($13.8 | ) |  |  | ($14.7 | ) |  |  | ($37.9 | ) |  |  | ($5.8 | ) |  |  | ($6.6 | ) |  |  | ($16.8 | ) |  |  | ($8.0 | ) |  |  | ($8.1 | ) |  |  | ($21.1 | )
Regulatory liabilities | 37.4 |  |  | 22.2 |  |  | 20.3 |  |  | 10.2 |  |  | 11.8 |  |  | 13.5 |  |  | 27.2 |  |  | 10.4 |  |  | 6.8 |
Net unrealized gains (losses) from commodity contracts during 2014, 2013 and 2012 were primarily due to changes in electricity and natural gas prices during such periods. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 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):
| 2014 |  | 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $37.6 |  |  |  | $19.5 |  |  |  | $18.1 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 37.4 |  |  | 19.5 |  |  | 17.9 |  |  | 20.8 |  |  | 5.2 |  |  | 15.6 |
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 at December 31 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
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 |
2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.7 |  |  | 23.5 |  |  | 21.1 |  |  | 19.5 |  |  | 5.6 |  |  | 4.0 |
Derivative liabilities | 20.8 |  |  | 17.6 |  |  | 5.2 |  |  | 3.6 |  |  | 15.6 |  |  | 14.0 |
Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.
IPL [Member] |
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 14 for detailed discussion of derivative instruments. Notional Amounts - As of December 31, 2014, gross notional amounts by delivery year 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):
| 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,067 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 8,248 |
FTRs (MWhs) | 9,505 |  |  | — |  |  | — |  |  | — |  |  | 9,505 |
Natural gas (Dths) | 56,250 |  |  | 20,225 |  |  | 1,829 |  |  | — |  |  | 78,304 |
Coal (tons) | 1,490 |  |  | 1,899 |  |  | 1,073 |  |  | 1,113 |  |  | 5,575 |
IPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,765 |  |  | — |  |  | — |  |  | — |  |  | 1,765 |
FTRs (MWhs) | 5,503 |  |  | — |  |  | — |  |  | — |  |  | 5,503 |
Natural gas (Dths) | 39,727 |  |  | 10,178 |  |  | 1,014 |  |  | — |  |  | 50,919 |
Coal (tons) | 75 |  |  | 830 |  |  | 274 |  |  | 387 |  |  | 1,566 |
WPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,302 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 6,483 |
FTRs (MWhs) | 4,002 |  |  | — |  |  | — |  |  | — |  |  | 4,002 |
Natural gas (Dths) | 16,523 |  |  | 10,047 |  |  | 815 |  |  | — |  |  | 27,385 |
Coal (tons) | 1,415 |  |  | 1,069 |  |  | 799 |  |  | 726 |  |  | 4,009 |
Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, 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 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Current derivative assets |  | $30.5 |  |  |  | $25.6 |  |  |  | $27.4 |  |  |  | $20.2 |  |  |  | $3.1 |  |  |  | $5.4 |
Non-current derivative assets | 8.1 |  |  | 1.1 |  |  | 0.6 |  |  | 0.9 |  |  | 7.5 |  |  | 0.2 |
Current derivative liabilities | 28.1 |  |  | 6.7 |  |  | 16.4 |  |  | 3.0 |  |  | 11.7 |  |  | 3.7 |
Non-current derivative liabilities | 9.5 |  |  | 14.1 |  |  | 3.1 |  |  | 2.2 |  |  | 6.4 |  |  | 11.9 |
Changes in unrealized 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
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Regulatory assets |  | ($13.8 | ) |  |  | ($14.7 | ) |  |  | ($37.9 | ) |  |  | ($5.8 | ) |  |  | ($6.6 | ) |  |  | ($16.8 | ) |  |  | ($8.0 | ) |  |  | ($8.1 | ) |  |  | ($21.1 | )
Regulatory liabilities | 37.4 |  |  | 22.2 |  |  | 20.3 |  |  | 10.2 |  |  | 11.8 |  |  | 13.5 |  |  | 27.2 |  |  | 10.4 |  |  | 6.8 |
Net unrealized gains (losses) from commodity contracts during 2014, 2013 and 2012 were primarily due to changes in electricity and natural gas prices during such periods. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 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):
| 2014 |  | 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $37.6 |  |  |  | $19.5 |  |  |  | $18.1 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 37.4 |  |  | 19.5 |  |  | 17.9 |  |  | 20.8 |  |  | 5.2 |  |  | 15.6 |
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 at December 31 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
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 |
2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.7 |  |  | 23.5 |  |  | 21.1 |  |  | 19.5 |  |  | 5.6 |  |  | 4.0 |
Derivative liabilities | 20.8 |  |  | 17.6 |  |  | 5.2 |  |  | 3.6 |  |  | 15.6 |  |  | 14.0 |
Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.
WPL [Member] |
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 14 for detailed discussion of derivative instruments. Notional Amounts - As of December 31, 2014, gross notional amounts by delivery year 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):
| 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,067 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 8,248 |
FTRs (MWhs) | 9,505 |  |  | — |  |  | — |  |  | — |  |  | 9,505 |
Natural gas (Dths) | 56,250 |  |  | 20,225 |  |  | 1,829 |  |  | — |  |  | 78,304 |
Coal (tons) | 1,490 |  |  | 1,899 |  |  | 1,073 |  |  | 1,113 |  |  | 5,575 |
IPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,765 |  |  | — |  |  | — |  |  | — |  |  | 1,765 |
FTRs (MWhs) | 5,503 |  |  | — |  |  | — |  |  | — |  |  | 5,503 |
Natural gas (Dths) | 39,727 |  |  | 10,178 |  |  | 1,014 |  |  | — |  |  | 50,919 |
Coal (tons) | 75 |  |  | 830 |  |  | 274 |  |  | 387 |  |  | 1,566 |
WPL |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,302 |  |  | 1,553 |  |  | 1,314 |  |  | 1,314 |  |  | 6,483 |
FTRs (MWhs) | 4,002 |  |  | — |  |  | — |  |  | — |  |  | 4,002 |
Natural gas (Dths) | 16,523 |  |  | 10,047 |  |  | 815 |  |  | — |  |  | 27,385 |
Coal (tons) | 1,415 |  |  | 1,069 |  |  | 799 |  |  | 726 |  |  | 4,009 |
Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, 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 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Current derivative assets |  | $30.5 |  |  |  | $25.6 |  |  |  | $27.4 |  |  |  | $20.2 |  |  |  | $3.1 |  |  |  | $5.4 |
Non-current derivative assets | 8.1 |  |  | 1.1 |  |  | 0.6 |  |  | 0.9 |  |  | 7.5 |  |  | 0.2 |
Current derivative liabilities | 28.1 |  |  | 6.7 |  |  | 16.4 |  |  | 3.0 |  |  | 11.7 |  |  | 3.7 |
Non-current derivative liabilities | 9.5 |  |  | 14.1 |  |  | 3.1 |  |  | 2.2 |  |  | 6.4 |  |  | 11.9 |
Changes in unrealized 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
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Regulatory assets |  | ($13.8 | ) |  |  | ($14.7 | ) |  |  | ($37.9 | ) |  |  | ($5.8 | ) |  |  | ($6.6 | ) |  |  | ($16.8 | ) |  |  | ($8.0 | ) |  |  | ($8.1 | ) |  |  | ($21.1 | )
Regulatory liabilities | 37.4 |  |  | 22.2 |  |  | 20.3 |  |  | 10.2 |  |  | 11.8 |  |  | 13.5 |  |  | 27.2 |  |  | 10.4 |  |  | 6.8 |
Net unrealized gains (losses) from commodity contracts during 2014, 2013 and 2012 were primarily due to changes in electricity and natural gas prices during such periods. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 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):
| 2014 |  | 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $37.6 |  |  |  | $19.5 |  |  |  | $18.1 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 37.4 |  |  | 19.5 |  |  | 17.9 |  |  | 20.8 |  |  | 5.2 |  |  | 15.6 |
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 at December 31 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
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 |
2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.7 |  |  | 23.5 |  |  | 21.1 |  |  | 19.5 |  |  | 5.6 |  |  | 4.0 |
Derivative liabilities | 20.8 |  |  | 17.6 |  |  | 5.2 |  |  | 3.6 |  |  | 15.6 |  |  | 14.0 |
Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

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