XML 49 R29.htm IDEA: XBRL DOCUMENT v3.21.1
Derivative Instruments (Tables)
 3 Months Ended
Mar. 31, 2021
Derivative Instruments [Line Items]  
Notional Amounts Of Derivative Instruments As of March 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):
FTRsNatural GasCoalDiesel Fuel
MWhsYearsDthsYearsTonsYearsGallonsYears
Alliant Energy
3,531 2021198,347 2021-20285,601 2021-20234,914 2021-2022
IPL1,203 202197,747 2021-20282,100 2021-2023— —
WPL2,328 2021100,600 2021-20273,501 2021-20234,914 2021-2022
Fair Value Of Financial Instruments Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):
Alliant EnergyIPLWPL
March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020
Current derivative assets$18$24$12$20$6$4
Non-current derivative assets10107931
Current derivative liabilities29—326
Non-current derivative liabilities11166957
IPL [Member]  
Derivative Instruments [Line Items]  
Notional Amounts Of Derivative Instruments As of March 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):
FTRsNatural GasCoalDiesel Fuel
MWhsYearsDthsYearsTonsYearsGallonsYears
Alliant Energy
3,531 2021198,347 2021-20285,601 2021-20234,914 2021-2022
IPL1,203 202197,747 2021-20282,100 2021-2023— —
WPL2,328 2021100,600 2021-20273,501 2021-20234,914 2021-2022
Fair Value Of Financial Instruments Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):
Alliant EnergyIPLWPL
March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020
Current derivative assets$18$24$12$20$6$4
Non-current derivative assets10107931
Current derivative liabilities29—326
Non-current derivative liabilities11166957
WPL [Member]  
Derivative Instruments [Line Items]  
Notional Amounts Of Derivative Instruments As of March 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):
FTRsNatural GasCoalDiesel Fuel
MWhsYearsDthsYearsTonsYearsGallonsYears
Alliant Energy
3,531 2021198,347 2021-20285,601 2021-20234,914 2021-2022
IPL1,203 202197,747 2021-20282,100 2021-2023— —
WPL2,328 2021100,600 2021-20273,501 2021-20234,914 2021-2022
Fair Value Of Financial Instruments Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):
Alliant EnergyIPLWPL
March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020		March 31,
2021		December 31,
2020
Current derivative assets$18$24$12$20$6$4
Non-current derivative assets10107931
Current derivative liabilities29—326
Non-current derivative liabilities11166957