XML 43 R23.htm IDEA: XBRL DOCUMENT
v3.20.2

Receivables (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2020
Receivables [Line Items] |
Accounts Receivable Details | Details for accounts receivable included on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Customer |  | $95 |  |  |  | $92 |  |  |  | $— |  |  |  | $— |  |  |  | $86 |  |  |  | $84 |
Unbilled utility revenues | 62 |  |  | 82 |  |  | — |  |  | — |  |  | 62 |  |  | 82 |
Deferred proceeds | 201 |  |  | 188 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |
Other | 54 |  |  | 47 |  |  | 20 |  |  | 16 |  |  | 33 |  |  | 31 |
Allowance for expected credit losses | (13 | ) |  | (7 | ) |  | (2 | ) |  | (1 | ) |  | (11 | ) |  | (6 | )
|  | $399 |  |  |  | $402 |  |  |  | $219 |  |  |  | $203 |  |  |  | $170 |  |  |  | $191 |
Maximum And Average Outstanding Cash Proceeds | IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Maximum outstanding aggregate cash proceeds |  | $1 |  |  |  | $103 |  |  |  | $96 |  |  |  | $108 |
Average outstanding aggregate cash proceeds | 1 |  |  | 45 |  |  | 12 |  |  | 43 |
Schedule of Sales Of Accounts Receivable Sold Under Agreement Table Text Block | The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| September 30, 2020 |  | December 31, 2019
Customer accounts receivable |  | $148 |  |  |  | $125 |
Unbilled utility revenues | 67 |  |  | 95 |
Other receivables | — |  |  | 1 |
Receivables sold to third party | 215 |  |  | 221 |
Less: cash proceeds | 1 |  |  | 27 |
Deferred proceeds | 214 |  |  | 194 |
Less: allowance for expected credit losses | 13 |  |  | 6 |
Fair value of deferred proceeds |  | $201 |  |  |  | $188 |
Additional Attributes Of Receivables Sold Under The Receivables Agreement | Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Collections |  | $561 |  |  |  | $592 |  |  |  | $1,555 |  |  |  | $1,636 |
Write-offs, net of recoveries | 1 |  |  | 3 |  |  | 4 |  |  | 11 |
IPL [Member] |
Receivables [Line Items] |
Accounts Receivable Details | Details for accounts receivable included on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Customer |  | $95 |  |  |  | $92 |  |  |  | $— |  |  |  | $— |  |  |  | $86 |  |  |  | $84 |
Unbilled utility revenues | 62 |  |  | 82 |  |  | — |  |  | — |  |  | 62 |  |  | 82 |
Deferred proceeds | 201 |  |  | 188 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |
Other | 54 |  |  | 47 |  |  | 20 |  |  | 16 |  |  | 33 |  |  | 31 |
Allowance for expected credit losses | (13 | ) |  | (7 | ) |  | (2 | ) |  | (1 | ) |  | (11 | ) |  | (6 | )
|  | $399 |  |  |  | $402 |  |  |  | $219 |  |  |  | $203 |  |  |  | $170 |  |  |  | $191 |
Maximum And Average Outstanding Cash Proceeds | IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Maximum outstanding aggregate cash proceeds |  | $1 |  |  |  | $103 |  |  |  | $96 |  |  |  | $108 |
Average outstanding aggregate cash proceeds | 1 |  |  | 45 |  |  | 12 |  |  | 43 |
Schedule of Sales Of Accounts Receivable Sold Under Agreement Table Text Block | The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
| September 30, 2020 |  | December 31, 2019
Customer accounts receivable |  | $148 |  |  |  | $125 |
Unbilled utility revenues | 67 |  |  | 95 |
Other receivables | — |  |  | 1 |
Receivables sold to third party | 215 |  |  | 221 |
Less: cash proceeds | 1 |  |  | 27 |
Deferred proceeds | 214 |  |  | 194 |
Less: allowance for expected credit losses | 13 |  |  | 6 |
Fair value of deferred proceeds |  | $201 |  |  |  | $188 |
Additional Attributes Of Receivables Sold Under The Receivables Agreement | Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Collections |  | $561 |  |  |  | $592 |  |  |  | $1,555 |  |  |  | $1,636 |
Write-offs, net of recoveries | 1 |  |  | 3 |  |  | 4 |  |  | 11 |
WPL [Member] |
Receivables [Line Items] |
Accounts Receivable Details | Details for accounts receivable included on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Customer |  | $95 |  |  |  | $92 |  |  |  | $— |  |  |  | $— |  |  |  | $86 |  |  |  | $84 |
Unbilled utility revenues | 62 |  |  | 82 |  |  | — |  |  | — |  |  | 62 |  |  | 82 |
Deferred proceeds | 201 |  |  | 188 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |
Other | 54 |  |  | 47 |  |  | 20 |  |  | 16 |  |  | 33 |  |  | 31 |
Allowance for expected credit losses | (13 | ) |  | (7 | ) |  | (2 | ) |  | (1 | ) |  | (11 | ) |  | (6 | )
|  | $399 |  |  |  | $402 |  |  |  | $219 |  |  |  | $203 |  |  |  | $170 |  |  |  | $191 |

X
- Definition Schedule of Additional Attributes of Receivables Sold Under the Agreement [Table Text Block] + References No definition available. + Details
Name: | lnt_ScheduleOfAdditionalAttributesOfReceivablesSoldUnderAgreementTableTextBlock
Namespace Prefix: | lnt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Schedule of maximum and average sales of accounts receivable cash proceeds and related costs. + References No definition available. + Details
Name: | lnt_ScheduleOfSalesOfAccountsReceivableCashProceedsAndRelatedCostsTableTextBlock
Namespace Prefix: | lnt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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 No definition available. + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of allowance for credit loss on financing receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447 + Details
Name: | us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3,4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum: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: |