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Derivative Instruments | 6 Months Ended
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Jun. 30, 2013
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of June 30, 2013 and December 31, 2012. Notional Amounts - As of June 30, 2013, 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):
| 2013 |  | 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (megawatt-hours (MWhs)) | 2,620 |  |  | 4,801 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 13,557 |
FTRs (MWs) | 26 |  |  | 22 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 48 |
Natural gas (dekatherms (Dths)) | 52,111 |  |  | 19,846 |  |  | 2,031 |  |  | 455 |  |  | — |  |  | — |  |  | 74,443 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
IPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,302 |  |  | 1,099 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 2,401 |
FTRs (MWs) | 16 |  |  | 14 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 30 |
Natural gas (Dths) | 40,455 |  |  | 13,386 |  |  | 1,581 |  |  | 455 |  |  | — |  |  | — |  |  | 55,877 |
WPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,318 |  |  | 3,702 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,156 |
FTRs (MWs) | 10 |  |  | 8 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 18 |
Natural gas (Dths) | 11,656 |  |  | 6,460 |  |  | 450 |  |  | — |  |  | — |  |  | — |  |  | 18,566 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year. Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012
Current derivative assets |  | $51.1 |  |  |  | $23.5 |  |  |  | $44.4 |  |  |  | $17.0 |  |  |  | $6.7 |  |  |  | $6.5 |
Non-current derivative assets | 9.4 |  |  | 2.7 |  |  | 0.7 |  |  | 0.5 |  |  | 8.7 |  |  | 2.2 |
Current derivative liabilities | 21.8 |  |  | 31.1 |  |  | 8.4 |  |  | 14.1 |  |  | 13.4 |  |  | 17.0 |
Non-current derivative liabilities | 15.3 |  |  | 9.3 |  |  | 1.3 |  |  | 2.0 |  |  | 14.0 |  |  | 7.3 |
Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Three Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($25.9 | ) |  |  | $7.7 |  |  |  | ($6.9 | ) |  |  | $5.0 |  |  |  | ($19.0 | ) |  |  | $2.7 |
Regulatory liabilities | 1.2 |  |  | 4.1 |  |  | (2.5 | ) |  | 4.4 |  |  | 3.7 |  |  | (0.3 | )
Six Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (16.4 | ) |  | (32.0 | ) |  | (4.2 | ) |  | (17.2 | ) |  | (12.2 | ) |  | (14.8 | )
Regulatory liabilities | 17.6 |  |  | 5.5 |  |  | 6.3 |  |  | 4.4 |  |  | 11.3 |  |  | 1.1 |
Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on June 30, 2013 was $37.1 million, $9.7 million and $27.4 million for Alliant Energy, IPL and WPL, respectively. At June 30, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on June 30, 2013, Alliant Energy, IPL and WPL would be required to post $37.1 million, $9.7 million and $27.4 million, respectively, of credit support to their counterparties. Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net the fair value amounts of derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net the fair value amounts of derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
June 30, 2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $60.5 |  |  |  | $46.3 |  |  |  | $45.1 |  |  |  | $43.4 |  |  |  | $15.4 |  |  |  | $2.9 |
Derivative liabilities | 37.1 |  |  | 22.9 |  |  | 9.7 |  |  | 8.0 |  |  | 27.4 |  |  | 14.9 |
December 31, 2012 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.2 |  |  | 19.3 |  |  | 17.5 |  |  | 14.5 |  |  | 8.7 |  |  | 4.8 |
Derivative liabilities | 40.4 |  |  | 33.0 |  |  | 16.1 |  |  | 12.6 |  |  | 24.3 |  |  | 20.4 |
As of June 30, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of June 30, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.
IPL [Member] |
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of June 30, 2013 and December 31, 2012. Notional Amounts - As of June 30, 2013, 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):
| 2013 |  | 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (megawatt-hours (MWhs)) | 2,620 |  |  | 4,801 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 13,557 |
FTRs (MWs) | 26 |  |  | 22 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 48 |
Natural gas (dekatherms (Dths)) | 52,111 |  |  | 19,846 |  |  | 2,031 |  |  | 455 |  |  | — |  |  | — |  |  | 74,443 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
IPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,302 |  |  | 1,099 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 2,401 |
FTRs (MWs) | 16 |  |  | 14 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 30 |
Natural gas (Dths) | 40,455 |  |  | 13,386 |  |  | 1,581 |  |  | 455 |  |  | — |  |  | — |  |  | 55,877 |
WPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,318 |  |  | 3,702 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,156 |
FTRs (MWs) | 10 |  |  | 8 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 18 |
Natural gas (Dths) | 11,656 |  |  | 6,460 |  |  | 450 |  |  | — |  |  | — |  |  | — |  |  | 18,566 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year. Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012
Current derivative assets |  | $51.1 |  |  |  | $23.5 |  |  |  | $44.4 |  |  |  | $17.0 |  |  |  | $6.7 |  |  |  | $6.5 |
Non-current derivative assets | 9.4 |  |  | 2.7 |  |  | 0.7 |  |  | 0.5 |  |  | 8.7 |  |  | 2.2 |
Current derivative liabilities | 21.8 |  |  | 31.1 |  |  | 8.4 |  |  | 14.1 |  |  | 13.4 |  |  | 17.0 |
Non-current derivative liabilities | 15.3 |  |  | 9.3 |  |  | 1.3 |  |  | 2.0 |  |  | 14.0 |  |  | 7.3 |
Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Three Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($25.9 | ) |  |  | $7.7 |  |  |  | ($6.9 | ) |  |  | $5.0 |  |  |  | ($19.0 | ) |  |  | $2.7 |
Regulatory liabilities | 1.2 |  |  | 4.1 |  |  | (2.5 | ) |  | 4.4 |  |  | 3.7 |  |  | (0.3 | )
Six Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (16.4 | ) |  | (32.0 | ) |  | (4.2 | ) |  | (17.2 | ) |  | (12.2 | ) |  | (14.8 | )
Regulatory liabilities | 17.6 |  |  | 5.5 |  |  | 6.3 |  |  | 4.4 |  |  | 11.3 |  |  | 1.1 |
Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on June 30, 2013 was $37.1 million, $9.7 million and $27.4 million for Alliant Energy, IPL and WPL, respectively. At June 30, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on June 30, 2013, Alliant Energy, IPL and WPL would be required to post $37.1 million, $9.7 million and $27.4 million, respectively, of credit support to their counterparties. Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net the fair value amounts of derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net the fair value amounts of derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
June 30, 2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $60.5 |  |  |  | $46.3 |  |  |  | $45.1 |  |  |  | $43.4 |  |  |  | $15.4 |  |  |  | $2.9 |
Derivative liabilities | 37.1 |  |  | 22.9 |  |  | 9.7 |  |  | 8.0 |  |  | 27.4 |  |  | 14.9 |
December 31, 2012 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.2 |  |  | 19.3 |  |  | 17.5 |  |  | 14.5 |  |  | 8.7 |  |  | 4.8 |
Derivative liabilities | 40.4 |  |  | 33.0 |  |  | 16.1 |  |  | 12.6 |  |  | 24.3 |  |  | 20.4 |
As of June 30, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of June 30, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.
WPL [Member] |
Derivative [Line Items] |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of June 30, 2013 and December 31, 2012. Notional Amounts - As of June 30, 2013, 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):
| 2013 |  | 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (megawatt-hours (MWhs)) | 2,620 |  |  | 4,801 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 13,557 |
FTRs (MWs) | 26 |  |  | 22 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 48 |
Natural gas (dekatherms (Dths)) | 52,111 |  |  | 19,846 |  |  | 2,031 |  |  | 455 |  |  | — |  |  | — |  |  | 74,443 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
IPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,302 |  |  | 1,099 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 2,401 |
FTRs (MWs) | 16 |  |  | 14 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 30 |
Natural gas (Dths) | 40,455 |  |  | 13,386 |  |  | 1,581 |  |  | 455 |  |  | — |  |  | — |  |  | 55,877 |
WPL |  |  |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,318 |  |  | 3,702 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,156 |
FTRs (MWs) | 10 |  |  | 8 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 18 |
Natural gas (Dths) | 11,656 |  |  | 6,460 |  |  | 450 |  |  | — |  |  | — |  |  | — |  |  | 18,566 |
Coal (tons) | 448 |  |  | 981 |  |  | 562 |  |  | — |  |  | — |  |  | — |  |  | 1,991 |
The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year. Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012 |  | June 30, 2013 |  | December 31, 2012
Current derivative assets |  | $51.1 |  |  |  | $23.5 |  |  |  | $44.4 |  |  |  | $17.0 |  |  |  | $6.7 |  |  |  | $6.5 |
Non-current derivative assets | 9.4 |  |  | 2.7 |  |  | 0.7 |  |  | 0.5 |  |  | 8.7 |  |  | 2.2 |
Current derivative liabilities | 21.8 |  |  | 31.1 |  |  | 8.4 |  |  | 14.1 |  |  | 13.4 |  |  | 17.0 |
Non-current derivative liabilities | 15.3 |  |  | 9.3 |  |  | 1.3 |  |  | 2.0 |  |  | 14.0 |  |  | 7.3 |
Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Three Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | ($25.9 | ) |  |  | $7.7 |  |  |  | ($6.9 | ) |  |  | $5.0 |  |  |  | ($19.0 | ) |  |  | $2.7 |
Regulatory liabilities | 1.2 |  |  | 4.1 |  |  | (2.5 | ) |  | 4.4 |  |  | 3.7 |  |  | (0.3 | )
Six Months Ended June 30 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | (16.4 | ) |  | (32.0 | ) |  | (4.2 | ) |  | (17.2 | ) |  | (12.2 | ) |  | (14.8 | )
Regulatory liabilities | 17.6 |  |  | 5.5 |  |  | 6.3 |  |  | 4.4 |  |  | 11.3 |  |  | 1.1 |
Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on June 30, 2013 was $37.1 million, $9.7 million and $27.4 million for Alliant Energy, IPL and WPL, respectively. At June 30, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on June 30, 2013, Alliant Energy, IPL and WPL would be required to post $37.1 million, $9.7 million and $27.4 million, respectively, of credit support to their counterparties. Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net the fair value amounts of derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net the fair value amounts of derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
June 30, 2013 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $60.5 |  |  |  | $46.3 |  |  |  | $45.1 |  |  |  | $43.4 |  |  |  | $15.4 |  |  |  | $2.9 |
Derivative liabilities | 37.1 |  |  | 22.9 |  |  | 9.7 |  |  | 8.0 |  |  | 27.4 |  |  | 14.9 |
December 31, 2012 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 26.2 |  |  | 19.3 |  |  | 17.5 |  |  | 14.5 |  |  | 8.7 |  |  | 4.8 |
Derivative liabilities | 40.4 |  |  | 33.0 |  |  | 16.1 |  |  | 12.6 |  |  | 24.3 |  |  | 20.4 |
As of June 30, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of June 30, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.

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- Definition The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41638-113959 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4E -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624181-113959 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41635-113959 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5708773-113959 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(n)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 Reference 11: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 12: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4K -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5708775-113959 Reference 13: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986 Reference 14: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 45 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 15: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80784-113994 Reference 16: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41620-113959 Reference 17: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959 Reference 18: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959 Reference 19: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579240-113959 Reference 20: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41641-113959 Reference 21: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959 Reference 22: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624177-113959 + Details
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