XML 81 R49.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Discontinued Operations and Assets and Liabilities Held For Sale (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |
Components Of Discontinued Operations In Consolidated Statements Of Income | A summary of the components of discontinued operations in Alliant Energy’s income statements was as follows (in millions):
| 2015 |  | 2014 |  | 2013
Operating revenues |  | $— |  |  |  | $— |  |  |  | $0.9 |
Operating expenses | 4.0 |  |  | 3.7 |  |  | 9.9 |
Loss before income taxes | (4.0 | ) |  | (3.7 | ) |  | (9.0 | )
Income tax benefit | (1.5 | ) |  | (1.3 | ) |  | (3.1 | )
Loss from discontinued operations, net of tax |  | ($2.5 | ) |  |  | ($2.4 | ) |  |  | ($5.9 | )
Assets and Liabilities Held For Sale on Consolidated Balance Sheets | As of December 31, 2014, Alliant Energy’s and IPL’s balance sheets included assets held for sale related to IPL’s Minnesota natural gas distribution assets recorded in “Other current assets” and liabilities held for sale recorded in “Other current liabilities” as follows (in millions):
Assets held for sale: |
Current assets |  | $1.1 |
Property, plant and equipment, net | 11.0 |
Non-current regulatory assets | 7.0 |
Total assets held for sale | 19.1 |
Liabilities held for sale: |
Current liabilities | 1.0 |
Other liabilities | 7.1 |
Total liabilities held for sale | 8.1 |
Net assets held for sale |  | $11.0 |
IPL [Member] |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |
Assets and Liabilities Held For Sale on Consolidated Balance Sheets | As of December 31, 2014, Alliant Energy’s and IPL’s balance sheets included assets held for sale related to IPL’s Minnesota natural gas distribution assets recorded in “Other current assets” and liabilities held for sale recorded in “Other current liabilities” as follows (in millions):
Assets held for sale: |
Current assets |  | $1.1 |
Property, plant and equipment, net | 11.0 |
Non-current regulatory assets | 7.0 |
Total assets held for sale | 19.1 |
Liabilities held for sale: |
Current liabilities | 1.0 |
Other liabilities | 7.1 |
Total liabilities held for sale | 8.1 |
Net assets held for sale |  | $11.0 |

X
- Definition Schedule of disposal groups including discontinued operations assets and liabilities and additional disclosures [Table Text Block] + References No definition available. + Details
Name: | lnt_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsAssetsAndLiabilitiesAndAdditionalDisclosuresTableTextBlock
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_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1510-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1474-107760 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 + Details
Name: | us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock
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: |