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Debt | 9 Months Ended
--- | ---
Sep. 30, 2015
Debt [Line Items] |
Debt | DEBT (a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by the credit facilities was as follows (dollars in millions):
| Alliant Energy |  | Parent |  |  |  |
September 30, 2015 | (Consolidated) |  | Company |  | IPL |  | WPL
Commercial paper: |  |  |  |  |  |  |
Amount outstanding | $109.1 |  | $109.1 |  | $— |  | $—
Weighted average remaining maturity | 3 days |  | 3 days |  | N/A |  | N/A
Weighted average interest rates | 0.4% |  | 0.4% |  | N/A |  | N/A
Available credit facility capacity | $890.9 |  | $190.9 |  | $300.0 |  | $400.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $185.0 |
Average amount outstanding (based on daily outstanding balances) |  | $122.4 |  |  |  | $307.1 |  |  |  | $0.5 |  |  |  | $0.4 |  |  | $— |  |  | $157.9 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.3 | % |  | N/A |  | 0.1 | %
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $204.7 |
Average amount outstanding (based on daily outstanding balances) |  | $114.5 |  |  |  | $281.9 |  |  |  | $0.2 |  |  |  | $0.3 |  |  | $— |  |  | $157.5 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.2 | % |  | N/A |  | 0.1 | %
(b) Long-term Debt - In June 2015, IPL retired its $150.0 million, 3.3% senior debentures. In August 2015, IPL issued $250.0 million of 3.4% senior debentures due 2025. The proceeds from the issuance were used by IPL to reduce commercial paper classified as long-term debt by $111 million, reduce cash proceeds received from its sales of accounts receivable program and for general corporate purposes. In August 2015, WPL retired its $14.6 million, 5.375% pollution control revenue bonds. In September 2015, WPL retired its $16.0 million, 5% pollution control revenue bonds.
IPL [Member] |
Debt [Line Items] |
Debt | DEBT (a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by the credit facilities was as follows (dollars in millions):
| Alliant Energy |  | Parent |  |  |  |
September 30, 2015 | (Consolidated) |  | Company |  | IPL |  | WPL
Commercial paper: |  |  |  |  |  |  |
Amount outstanding | $109.1 |  | $109.1 |  | $— |  | $—
Weighted average remaining maturity | 3 days |  | 3 days |  | N/A |  | N/A
Weighted average interest rates | 0.4% |  | 0.4% |  | N/A |  | N/A
Available credit facility capacity | $890.9 |  | $190.9 |  | $300.0 |  | $400.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $185.0 |
Average amount outstanding (based on daily outstanding balances) |  | $122.4 |  |  |  | $307.1 |  |  |  | $0.5 |  |  |  | $0.4 |  |  | $— |  |  | $157.9 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.3 | % |  | N/A |  | 0.1 | %
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $204.7 |
Average amount outstanding (based on daily outstanding balances) |  | $114.5 |  |  |  | $281.9 |  |  |  | $0.2 |  |  |  | $0.3 |  |  | $— |  |  | $157.5 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.2 | % |  | N/A |  | 0.1 | %
(b) Long-term Debt - In June 2015, IPL retired its $150.0 million, 3.3% senior debentures. In August 2015, IPL issued $250.0 million of 3.4% senior debentures due 2025. The proceeds from the issuance were used by IPL to reduce commercial paper classified as long-term debt by $111 million, reduce cash proceeds received from its sales of accounts receivable program and for general corporate purposes.
WPL [Member] |
Debt [Line Items] |
Debt | DEBT (a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by the credit facilities was as follows (dollars in millions):
| Alliant Energy |  | Parent |  |  |  |
September 30, 2015 | (Consolidated) |  | Company |  | IPL |  | WPL
Commercial paper: |  |  |  |  |  |  |
Amount outstanding | $109.1 |  | $109.1 |  | $— |  | $—
Weighted average remaining maturity | 3 days |  | 3 days |  | N/A |  | N/A
Weighted average interest rates | 0.4% |  | 0.4% |  | N/A |  | N/A
Available credit facility capacity | $890.9 |  | $190.9 |  | $300.0 |  | $400.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $185.0 |
Average amount outstanding (based on daily outstanding balances) |  | $122.4 |  |  |  | $307.1 |  |  |  | $0.5 |  |  |  | $0.4 |  |  | $— |  |  | $157.9 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.3 | % |  | N/A |  | 0.1 | %
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) |  | $181.2 |  |  |  | $353.8 |  |  |  | $18.4 |  |  |  | $38.0 |  |  | $— |  |  | $204.7 |
Average amount outstanding (based on daily outstanding balances) |  | $114.5 |  |  |  | $281.9 |  |  |  | $0.2 |  |  |  | $0.3 |  |  | $— |  |  | $157.5 |
Weighted average interest rates | 0.4 | % |  | 0.2 | % |  | 0.4 | % |  | 0.2 | % |  | N/A |  | 0.1 | %
(b) Long-term Debt - In June 2015, IPL retired its $150.0 million, 3.3% senior debentures. In August 2015, IPL issued $250.0 million of 3.4% senior debentures due 2025. The proceeds from the issuance were used by IPL to reduce commercial paper classified as long-term debt by $111 million, reduce cash proceeds received from its sales of accounts receivable program and for general corporate purposes. In August 2015, WPL retired its $14.6 million, 5.375% pollution control revenue bonds. In September 2015, WPL retired its $16.0 million, 5% pollution control revenue bonds.

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- Definition The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
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- 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
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