XML 32 R11.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Common Equity | 9 Months Ended
--- | ---
Sep. 30, 2018
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2018 | 231,348,646 |
At-the-market offering program | 4,171,013 |
Shareowner Direct Plan issuances | 450,133 |
Equity-based compensation plans (Note 10(b)) | 5,078 |
Other | (38,423 | )
Shares outstanding, September 30, 2018 | 235,936,447 |
Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018, and $0.315 and $0.945 for the three and nine months ended September 30, 2017. At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018, Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million, net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017, Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017, IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.
IPL [Member] |
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2018 | 231,348,646 |
At-the-market offering program | 4,171,013 |
Shareowner Direct Plan issuances | 450,133 |
Equity-based compensation plans (Note 10(b)) | 5,078 |
Other | (38,423 | )
Shares outstanding, September 30, 2018 | 235,936,447 |
Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018, and $0.315 and $0.945 for the three and nine months ended September 30, 2017. At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018, Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million, net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017, Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017, IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.
WPL [Member] |
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2018 | 231,348,646 |
At-the-market offering program | 4,171,013 |
Shareowner Direct Plan issuances | 450,133 |
Equity-based compensation plans (Note 10(b)) | 5,078 |
Other | (38,423 | )
Shares outstanding, September 30, 2018 | 235,936,447 |
Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018, and $0.315 and $0.945 for the three and nine months ended September 30, 2017. At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018, Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million, net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017, Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017, IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.

X
- Definition Common Equity [Line Items] + References No definition available. + Details
Name: | lnt_CommonEquityLineItems
Namespace Prefix: | lnt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -URI http://asc.fasb.org/topic&trid=2208762 + Details
Name: | us-gaap_StockholdersEquityNoteDisclosureTextBlock
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: |