XML 58 R32.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Derivative Instruments (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2014
Derivative [Line Items] |
Notional Amounts Of Derivative Instruments | As of March 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):
| 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,895 |  |  | 2,912 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,753 |
FTRs (MWhs) | 3,037 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 3,037 |
Natural gas (Dths) | 29,496 |  |  | 10,842 |  |  | 2,959 |  |  | — |  |  | — |  |  | 43,297 |
Coal (tons) | 1,194 |  |  | 936 |  |  | 955 |  |  | 868 |  |  | 714 |  |  | 4,667 |
IPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,955 |  |  | 722 |  |  | — |  |  | — |  |  | — |  |  | 2,677 |
FTRs (MWhs) | 1,963 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,963 |
Natural gas (Dths) | 20,185 |  |  | 8,815 |  |  | 2,504 |  |  | — |  |  | — |  |  | 31,504 |
Coal (tons) | 203 |  |  | — |  |  | 216 |  |  | 129 |  |  | 184 |  |  | 732 |
WPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,940 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 9,076 |
FTRs (MWhs) | 1,074 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,074 |
Natural gas (Dths) | 9,311 |  |  | 2,027 |  |  | 455 |  |  | — |  |  | — |  |  | 11,793 |
Coal (tons) | 991 |  |  | 936 |  |  | 739 |  |  | 739 |  |  | 530 |  |  | 3,935 |
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 long-term liabilities and deferred credits” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013
Current derivative assets |  | $31.5 |  |  |  | $25.6 |  |  |  | $15.4 |  |  |  | $20.2 |  |  |  | $16.1 |  |  |  | $5.4 |
Non-current derivative assets | 9.8 |  |  | 1.1 |  |  | 0.5 |  |  | 0.9 |  |  | 9.3 |  |  | 0.2 |
Current derivative liabilities | 4.2 |  |  | 6.7 |  |  | 1.1 |  |  | 3.0 |  |  | 3.1 |  |  | 3.7 |
Non-current derivative liabilities | 4.8 |  |  | 14.1 |  |  | 1.1 |  |  | 2.2 |  |  | 3.7 |  |  | 11.9 |
Gains And Losses From Derivative Instruments Not Designated As Hedging Instruments | Changes in unrealized gains 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 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Three Months Ended March 31 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | $10.1 |  |  |  | $9.5 |  |  |  | $5.5 |  |  |  | $2.7 |  |  |  | $4.6 |  |  |  | $6.8 |
Regulatory liabilities | 48.1 |  |  | 16.4 |  |  | 12.1 |  |  | 8.8 |  |  | 36.0 |  |  | 7.6 |
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):
| March 31, 2014 |  | December 31, 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $9.0 |  |  |  | $2.2 |  |  |  | $6.8 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 9.0 |  |  | 2.2 |  |  | 6.8 |  |  | 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 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
March 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $41.3 |  |  |  | $32.3 |  |  |  | $15.9 |  |  |  | $9.7 |  |  |  | $25.4 |  |  |  | $22.6 |
Derivative liabilities | 9.0 |  |  | 4.9 |  |  | 2.2 |  |  | 0.9 |  |  | 6.8 |  |  | 4.0 |
December 31, 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 |
IPL [Member] |
Derivative [Line Items] |
Notional Amounts Of Derivative Instruments | As of March 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):
| 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,895 |  |  | 2,912 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,753 |
FTRs (MWhs) | 3,037 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 3,037 |
Natural gas (Dths) | 29,496 |  |  | 10,842 |  |  | 2,959 |  |  | — |  |  | — |  |  | 43,297 |
Coal (tons) | 1,194 |  |  | 936 |  |  | 955 |  |  | 868 |  |  | 714 |  |  | 4,667 |
IPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,955 |  |  | 722 |  |  | — |  |  | — |  |  | — |  |  | 2,677 |
FTRs (MWhs) | 1,963 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,963 |
Natural gas (Dths) | 20,185 |  |  | 8,815 |  |  | 2,504 |  |  | — |  |  | — |  |  | 31,504 |
Coal (tons) | 203 |  |  | — |  |  | 216 |  |  | 129 |  |  | 184 |  |  | 732 |
WPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,940 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 9,076 |
FTRs (MWhs) | 1,074 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,074 |
Natural gas (Dths) | 9,311 |  |  | 2,027 |  |  | 455 |  |  | — |  |  | — |  |  | 11,793 |
Coal (tons) | 991 |  |  | 936 |  |  | 739 |  |  | 739 |  |  | 530 |  |  | 3,935 |
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 long-term liabilities and deferred credits” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013
Current derivative assets |  | $31.5 |  |  |  | $25.6 |  |  |  | $15.4 |  |  |  | $20.2 |  |  |  | $16.1 |  |  |  | $5.4 |
Non-current derivative assets | 9.8 |  |  | 1.1 |  |  | 0.5 |  |  | 0.9 |  |  | 9.3 |  |  | 0.2 |
Current derivative liabilities | 4.2 |  |  | 6.7 |  |  | 1.1 |  |  | 3.0 |  |  | 3.1 |  |  | 3.7 |
Non-current derivative liabilities | 4.8 |  |  | 14.1 |  |  | 1.1 |  |  | 2.2 |  |  | 3.7 |  |  | 11.9 |
Gains And Losses From Derivative Instruments Not Designated As Hedging Instruments | Changes in unrealized gains 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 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Three Months Ended March 31 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | $10.1 |  |  |  | $9.5 |  |  |  | $5.5 |  |  |  | $2.7 |  |  |  | $4.6 |  |  |  | $6.8 |
Regulatory liabilities | 48.1 |  |  | 16.4 |  |  | 12.1 |  |  | 8.8 |  |  | 36.0 |  |  | 7.6 |
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):
| March 31, 2014 |  | December 31, 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $9.0 |  |  |  | $2.2 |  |  |  | $6.8 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 9.0 |  |  | 2.2 |  |  | 6.8 |  |  | 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 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
March 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $41.3 |  |  |  | $32.3 |  |  |  | $15.9 |  |  |  | $9.7 |  |  |  | $25.4 |  |  |  | $22.6 |
Derivative liabilities | 9.0 |  |  | 4.9 |  |  | 2.2 |  |  | 0.9 |  |  | 6.8 |  |  | 4.0 |
December 31, 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 |
WPL [Member] |
Derivative [Line Items] |
Notional Amounts Of Derivative Instruments | As of March 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):
| 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | Total
Alliant Energy |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 4,895 |  |  | 2,912 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 11,753 |
FTRs (MWhs) | 3,037 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 3,037 |
Natural gas (Dths) | 29,496 |  |  | 10,842 |  |  | 2,959 |  |  | — |  |  | — |  |  | 43,297 |
Coal (tons) | 1,194 |  |  | 936 |  |  | 955 |  |  | 868 |  |  | 714 |  |  | 4,667 |
IPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 1,955 |  |  | 722 |  |  | — |  |  | — |  |  | — |  |  | 2,677 |
FTRs (MWhs) | 1,963 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,963 |
Natural gas (Dths) | 20,185 |  |  | 8,815 |  |  | 2,504 |  |  | — |  |  | — |  |  | 31,504 |
Coal (tons) | 203 |  |  | — |  |  | 216 |  |  | 129 |  |  | 184 |  |  | 732 |
WPL |  |  |  |  |  |  |  |  |  |  |
Electricity (MWhs) | 2,940 |  |  | 2,190 |  |  | 1,318 |  |  | 1,314 |  |  | 1,314 |  |  | 9,076 |
FTRs (MWhs) | 1,074 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,074 |
Natural gas (Dths) | 9,311 |  |  | 2,027 |  |  | 455 |  |  | — |  |  | — |  |  | 11,793 |
Coal (tons) | 991 |  |  | 936 |  |  | 739 |  |  | 739 |  |  | 530 |  |  | 3,935 |
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 long-term liabilities and deferred credits” on the balance sheets as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Commodity contracts | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013 |  | March 31, 2014 |  | December 31, 2013
Current derivative assets |  | $31.5 |  |  |  | $25.6 |  |  |  | $15.4 |  |  |  | $20.2 |  |  |  | $16.1 |  |  |  | $5.4 |
Non-current derivative assets | 9.8 |  |  | 1.1 |  |  | 0.5 |  |  | 0.9 |  |  | 9.3 |  |  | 0.2 |
Current derivative liabilities | 4.2 |  |  | 6.7 |  |  | 1.1 |  |  | 3.0 |  |  | 3.1 |  |  | 3.7 |
Non-current derivative liabilities | 4.8 |  |  | 14.1 |  |  | 1.1 |  |  | 2.2 |  |  | 3.7 |  |  | 11.9 |
Gains And Losses From Derivative Instruments Not Designated As Hedging Instruments | Changes in unrealized gains 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 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Three Months Ended March 31 |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  | $10.1 |  |  |  | $9.5 |  |  |  | $5.5 |  |  |  | $2.7 |  |  |  | $4.6 |  |  |  | $6.8 |
Regulatory liabilities | 48.1 |  |  | 16.4 |  |  | 12.1 |  |  | 8.8 |  |  | 36.0 |  |  | 7.6 |
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):
| March 31, 2014 |  | December 31, 2013
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Aggregate fair value |  | $9.0 |  |  |  | $2.2 |  |  |  | $6.8 |  |  |  | $20.8 |  |  |  | $5.2 |  |  |  | $15.6 |
Credit support to be posted if triggered | 9.0 |  |  | 2.2 |  |  | 6.8 |  |  | 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 as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| Gross |  |  |  | Gross |  |  |  | Gross |  |
| (as reported) |  | Net |  | (as reported) |  | Net |  | (as reported) |  | Net
March 31, 2014 |  |  |  |  |  |  |  |  |  |  |
Derivative assets |  | $41.3 |  |  |  | $32.3 |  |  |  | $15.9 |  |  |  | $9.7 |  |  |  | $25.4 |  |  |  | $22.6 |
Derivative liabilities | 9.0 |  |  | 4.9 |  |  | 2.2 |  |  | 0.9 |  |  | 6.8 |  |  | 4.0 |
December 31, 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 |

X
- Definition Credit Risk Related Contingent Features [Table Text Block] + References No definition available. + Details
Name: | lnt_CreditRiskRelatedContingentFeaturesTableTextBlock
Namespace Prefix: | lnt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of derivative and other financial assets and liabilities that are subject to offsetting, including master netting arrangements. + References No definition available. + Details
Name: | lnt_OffsettingAssetsAndLiabilitiesTableTextBlock
Namespace Prefix: | lnt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of the location and amount of derivative instruments and nonderivative instruments designated as hedging instruments reported before netting adjustments, and the amount of gain (loss) on derivative instruments and nonderivative instruments designated and qualified 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 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 Reference 2: 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 + Details
Name: | us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position. + References Reference 1: 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 + Details
Name: | us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the notional amounts of outstanding derivative positions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959 + Details
Name: | us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration