XML 46 R12.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Receivables | 12 Months Ended
--- | ---
Dec. 31, 2024
Receivables [Line Items] |
Receivables | RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Customer | $113 |  |  | $121 |  |  | $— |  |  | $— |  |  | $98 |  |  | $110 |
Unbilled utility revenues | 101 |  |  | 93 |  |  | — |  |  | — |  |  | 101 |  |  | 93 |
Deferred proceeds | 163 |  |  | 216 |  |  | 163 |  |  | 216 |  |  | — |  |  | — |
Other | 58 |  |  | 53 |  |  | 29 |  |  | 26 |  |  | 29 |  |  | 24 |
Allowance for expected credit losses | (8) |  |  | (8) |  |  | — |  |  | — |  |  | (8) |  |  | (8) |
| $427 |  |  | $475 |  |  | $192 |  |  | $242 |  |  | $220 |  |  | $219 |
In 2024, gross write-offs for accounts receivable were as follows (in millions):
| Originated in 2023 |  | Originated in 2024
Alliant Energy | $12 |  | $14
IPL | 8 |  | 9
WPL | 4 |  | 5
(b) Sales of Accounts Receivable - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In March 2024, IPL amended and extended through March 2026 the purchase commitment from the third party to which it sells its receivables. IPL pays a monthly fee to the third party that varies based on interest rates, limits on cash proceeds and cash amounts received from the third party. Deferred proceeds represent IPL’s interest in the receivables sold to the third party. At IPL’s request, deferred proceeds are paid to IPL from collections of receivables, after paying any required expenses incurred by the third party and the collection agent. Corporate Services acts as collection agent for the third party and receives a fee for collection services. The Receivables Agreement can be terminated by the third party if arrears or write-offs exceed certain levels. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. IPL believes that the allowance for expected credit losses related to its sales of receivables is a reasonable approximation of credit risk of the customers that generated the receivables. Refer to Note 1 5 for discussion of the fair value of deferred proceeds. Under the Receivables Agreement, IPL has the right to receive cash proceeds, up to a certain limit, from the third party in exchange for the receivables sold. The limit on cash proceeds fluctuates between $5 million and $110 million, which IPL may change periodically throughout the year. As of December 31, 2024, the limit on cash proceeds was $110 million and IPL had $40 million of available capacity under its sales of accounts receivable program. Cash proceeds are used by IPL to meet short-term financing needs, and cannot exceed the current limit or amount of receivables available for sale, whichever is less. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):
| Maximum |  | Average
| 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022
Outstanding aggregate cash proceeds | $110 |  | $110 |  | $80 |  | $31 |  | $51 |  | $14
As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| 2024 |  | 2023
Customer accounts receivable | $137 |  | $130
Unbilled utility revenues | 108 |  | 98
Other receivables | — |  | 1
Receivables sold to third party | 245 |  | 229
Less: cash proceeds | 70 |  | 1
Deferred proceeds | 175 |  | 228
Less: allowance for expected credit losses | 12 |  | 12
Fair value of deferred proceeds | $163 |  | $216
Outstanding receivables past due | $21 |  | $22
Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| 2024 |  | 2023 |  | 2022
Collections | $2,090 |  | $2,233 |  | $2,302 |
Write-offs, net of recoveries | 12 |  | 12 |  | 9 |
IPL [Member] |
Receivables [Line Items] |
Receivables | RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Customer | $113 |  |  | $121 |  |  | $— |  |  | $— |  |  | $98 |  |  | $110 |
Unbilled utility revenues | 101 |  |  | 93 |  |  | — |  |  | — |  |  | 101 |  |  | 93 |
Deferred proceeds | 163 |  |  | 216 |  |  | 163 |  |  | 216 |  |  | — |  |  | — |
Other | 58 |  |  | 53 |  |  | 29 |  |  | 26 |  |  | 29 |  |  | 24 |
Allowance for expected credit losses | (8) |  |  | (8) |  |  | — |  |  | — |  |  | (8) |  |  | (8) |
| $427 |  |  | $475 |  |  | $192 |  |  | $242 |  |  | $220 |  |  | $219 |
In 2024, gross write-offs for accounts receivable were as follows (in millions):
| Originated in 2023 |  | Originated in 2024
Alliant Energy | $12 |  | $14
IPL | 8 |  | 9
WPL | 4 |  | 5
(b) Sales of Accounts Receivable - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In March 2024, IPL amended and extended through March 2026 the purchase commitment from the third party to which it sells its receivables. IPL pays a monthly fee to the third party that varies based on interest rates, limits on cash proceeds and cash amounts received from the third party. Deferred proceeds represent IPL’s interest in the receivables sold to the third party. At IPL’s request, deferred proceeds are paid to IPL from collections of receivables, after paying any required expenses incurred by the third party and the collection agent. Corporate Services acts as collection agent for the third party and receives a fee for collection services. The Receivables Agreement can be terminated by the third party if arrears or write-offs exceed certain levels. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. IPL believes that the allowance for expected credit losses related to its sales of receivables is a reasonable approximation of credit risk of the customers that generated the receivables. Refer to Note 1 5 for discussion of the fair value of deferred proceeds. Under the Receivables Agreement, IPL has the right to receive cash proceeds, up to a certain limit, from the third party in exchange for the receivables sold. The limit on cash proceeds fluctuates between $5 million and $110 million, which IPL may change periodically throughout the year. As of December 31, 2024, the limit on cash proceeds was $110 million and IPL had $40 million of available capacity under its sales of accounts receivable program. Cash proceeds are used by IPL to meet short-term financing needs, and cannot exceed the current limit or amount of receivables available for sale, whichever is less. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):
| Maximum |  | Average
| 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022
Outstanding aggregate cash proceeds | $110 |  | $110 |  | $80 |  | $31 |  | $51 |  | $14
As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| 2024 |  | 2023
Customer accounts receivable | $137 |  | $130
Unbilled utility revenues | 108 |  | 98
Other receivables | — |  | 1
Receivables sold to third party | 245 |  | 229
Less: cash proceeds | 70 |  | 1
Deferred proceeds | 175 |  | 228
Less: allowance for expected credit losses | 12 |  | 12
Fair value of deferred proceeds | $163 |  | $216
Outstanding receivables past due | $21 |  | $22
Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| 2024 |  | 2023 |  | 2022
Collections | $2,090 |  | $2,233 |  | $2,302 |
Write-offs, net of recoveries | 12 |  | 12 |  | 9 |
WPL [Member] |
Receivables [Line Items] |
Receivables | RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Customer | $113 |  |  | $121 |  |  | $— |  |  | $— |  |  | $98 |  |  | $110 |
Unbilled utility revenues | 101 |  |  | 93 |  |  | — |  |  | — |  |  | 101 |  |  | 93 |
Deferred proceeds | 163 |  |  | 216 |  |  | 163 |  |  | 216 |  |  | — |  |  | — |
Other | 58 |  |  | 53 |  |  | 29 |  |  | 26 |  |  | 29 |  |  | 24 |
Allowance for expected credit losses | (8) |  |  | (8) |  |  | — |  |  | — |  |  | (8) |  |  | (8) |
| $427 |  |  | $475 |  |  | $192 |  |  | $242 |  |  | $220 |  |  | $219 |
In 2024, gross write-offs for accounts receivable were as follows (in millions):
| Originated in 2023 |  | Originated in 2024
Alliant Energy | $12 |  | $14
IPL | 8 |  | 9
WPL | 4 |  | 5

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/2009/role/commonPracticeRef -Topic 310 -SubTopic 20 -Name Accounting Standards Codification -Section 40 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481628/310-20-40-7 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for claims held for amounts due to entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/310-10/tableOfContent Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 + Details
Name: | us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock
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: |