XML 51 R32.htm IDEA: XBRL DOCUMENT
v3.23.3

Derivative Instruments (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2023
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2023, 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):
| Electricity |  | FTRs |  | Natural Gas |  | Coal |  |
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years |  |  |  |
Alliant Energy | 1,661 |  | 2023-2026 |  | 18,122 |  |  | 2023-2024 |  | 180,519 |  |  | 2023-2032 |  | 370 |  |  | 2023 |  |  |  |
IPL | 746 |  | 2023-2026 |  | 8,078 |  |  | 2023-2024 |  | 85,457 |  |  | 2023-2030 |  | 217 |  |  | 2023 |  |  |  |
WPL | 915 |  | 2023-2026 |  | 10,044 |  |  | 2023-2024 |  | 95,062 |  |  | 2023-2032 |  | 153 |  |  | 2023 |  |  |  |
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 Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Current derivative assets | $67 |  | $111 |  | $51 |  | $69 |  | $16 |  | $42
Non-current derivative assets | 62 |  | 126 |  | 34 |  | 69 |  | 28 |  | 57
Current derivative liabilities | 32 |  | 59 |  | 15 |  | 40 |  | 17 |  | 19
Non-current derivative liabilities | 34 |  | 20 |  | 6 |  | 6 |  | 28 |  | 14
Balance Sheet Offsetting | 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, 2023 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | $129 |  | $108 |  | $85 |  | $73 |  | $44 |  | $35
Derivative liabilities | 66 |  | 45 |  | 21 |  | 9 |  | 45 |  | 36
December 31, 2022 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 237 |  | 193 |  | 138 |  | 108 |  | 99 |  | 85
Derivative liabilities | 79 |  | 35 |  | 46 |  | 16 |  | 33 |  | 19
IPL [Member] |
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2023, 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):
| Electricity |  | FTRs |  | Natural Gas |  | Coal |  |
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years |  |  |  |
Alliant Energy | 1,661 |  | 2023-2026 |  | 18,122 |  |  | 2023-2024 |  | 180,519 |  |  | 2023-2032 |  | 370 |  |  | 2023 |  |  |  |
IPL | 746 |  | 2023-2026 |  | 8,078 |  |  | 2023-2024 |  | 85,457 |  |  | 2023-2030 |  | 217 |  |  | 2023 |  |  |  |
WPL | 915 |  | 2023-2026 |  | 10,044 |  |  | 2023-2024 |  | 95,062 |  |  | 2023-2032 |  | 153 |  |  | 2023 |  |  |  |
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 Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Current derivative assets | $67 |  | $111 |  | $51 |  | $69 |  | $16 |  | $42
Non-current derivative assets | 62 |  | 126 |  | 34 |  | 69 |  | 28 |  | 57
Current derivative liabilities | 32 |  | 59 |  | 15 |  | 40 |  | 17 |  | 19
Non-current derivative liabilities | 34 |  | 20 |  | 6 |  | 6 |  | 28 |  | 14
Balance Sheet Offsetting | 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, 2023 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | $129 |  | $108 |  | $85 |  | $73 |  | $44 |  | $35
Derivative liabilities | 66 |  | 45 |  | 21 |  | 9 |  | 45 |  | 36
December 31, 2022 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 237 |  | 193 |  | 138 |  | 108 |  | 99 |  | 85
Derivative liabilities | 79 |  | 35 |  | 46 |  | 16 |  | 33 |  | 19
WPL [Member] |
Derivative Instruments [Line Items] |
Notional Amounts Of Derivative Instruments | As of September 30, 2023, 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):
| Electricity |  | FTRs |  | Natural Gas |  | Coal |  |
| MWhs |  | Years |  | MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years |  |  |  |
Alliant Energy | 1,661 |  | 2023-2026 |  | 18,122 |  |  | 2023-2024 |  | 180,519 |  |  | 2023-2032 |  | 370 |  |  | 2023 |  |  |  |
IPL | 746 |  | 2023-2026 |  | 8,078 |  |  | 2023-2024 |  | 85,457 |  |  | 2023-2030 |  | 217 |  |  | 2023 |  |  |  |
WPL | 915 |  | 2023-2026 |  | 10,044 |  |  | 2023-2024 |  | 95,062 |  |  | 2023-2032 |  | 153 |  |  | 2023 |  |  |  |
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 Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Current derivative assets | $67 |  | $111 |  | $51 |  | $69 |  | $16 |  | $42
Non-current derivative assets | 62 |  | 126 |  | 34 |  | 69 |  | 28 |  | 57
Current derivative liabilities | 32 |  | 59 |  | 15 |  | 40 |  | 17 |  | 19
Non-current derivative liabilities | 34 |  | 20 |  | 6 |  | 6 |  | 28 |  | 14
Balance Sheet Offsetting | 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, 2023 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | $129 |  | $108 |  | $85 |  | $73 |  | $44 |  | $35
Derivative liabilities | 66 |  | 45 |  | 21 |  | 9 |  | 45 |  | 36
December 31, 2022 |  |  |  |  |  |  |  |  |  |  |
Derivative assets | 237 |  | 193 |  | 138 |  | 108 |  | 99 |  | 85
Derivative liabilities | 79 |  | 35 |  | 46 |  | 16 |  | 33 |  | 19

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of derivative and other financial assets that are subject to offsetting, including master netting arrangements. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-4 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 + Details
Name: | us-gaap_OffsettingAssetsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types: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://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4B + Details
Name: | us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the notional amounts of outstanding derivative positions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A + Details
Name: | us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=lnt_IplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lnt_WplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |