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Debt | 9 Months Ended
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Sep. 30, 2019
Debt [Line Items] |
Debt | DEBT NOTE 6(a) Short-term Debt - In March 2019, Alliant Energy, IPL and WPL extended their single credit facility agreement by one year, which currently expires in August 2023. As of September 30, 2019, the short-term borrowing capacity under the agreement totaled $1 billion ($450 million for Alliant Energy at the parent company, $250 million for IPL and $300 million for WPL). Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):
September 30, 2019 | Alliant Energy |  | IPL |  | WPL
Commercial paper outstanding | $349.6 |  | $— |  | $—
Commercial paper weighted average interest rates | 2.3% |  | N/A |  | N/A
Available credit facility capacity | $650.4 |  | $250.0 |  | $300.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Maximum amount outstanding (based on daily outstanding balances) | $471.7 |  | $153.3 |  | $— |  | $— |  | $89.7 |  | $75.4
Average amount outstanding (based on daily outstanding balances) | $399.5 |  | $80.8 |  | $— |  | $— |  | $27.0 |  | $23.1
Weighted average interest rates | 2.5% |  | 2.2% |  | N/A |  | N/A |  | 2.3% |  | 2.0%
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | $600.6 |  | $446.5 |  | $50.4 |  | $31.4 |  | $195.1 |  | $109.4
Average amount outstanding (based on daily outstanding balances) | $476.3 |  | $207.6 |  | $0.2 |  | $1.7 |  | $101.8 |  | $26.6
Weighted average interest rates | 2.6% |  | 2.1% |  | 2.8% |  | 2.3% |  | 2.5% |  | 1.9%
NOTE 6(b) Long-term Debt - In April 2019, IPL issued $300 million of 3.60% senior debentures due 2029. In September 2019, IPL issued $300 million of 3.50% senior debentures due 2049. The senior debentures were issued as green bonds, and all of the net proceeds have been or will be allocated for the construction and development of IPL’s wind projects. In June 2019, WPL issued $350 million of 3.00% debentures due 2029. The net proceeds from the issuance were used by WPL to reduce its outstanding commercial paper and retire its $250 million 5% debentures that matured in July 2019.
IPL [Member] |
Debt [Line Items] |
Debt | DEBT NOTE 6(a) Short-term Debt - In March 2019, Alliant Energy, IPL and WPL extended their single credit facility agreement by one year, which currently expires in August 2023. As of September 30, 2019, the short-term borrowing capacity under the agreement totaled $1 billion ($450 million for Alliant Energy at the parent company, $250 million for IPL and $300 million for WPL). Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):
September 30, 2019 | Alliant Energy |  | IPL |  | WPL
Commercial paper outstanding | $349.6 |  | $— |  | $—
Commercial paper weighted average interest rates | 2.3% |  | N/A |  | N/A
Available credit facility capacity | $650.4 |  | $250.0 |  | $300.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Maximum amount outstanding (based on daily outstanding balances) | $471.7 |  | $153.3 |  | $— |  | $— |  | $89.7 |  | $75.4
Average amount outstanding (based on daily outstanding balances) | $399.5 |  | $80.8 |  | $— |  | $— |  | $27.0 |  | $23.1
Weighted average interest rates | 2.5% |  | 2.2% |  | N/A |  | N/A |  | 2.3% |  | 2.0%
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | $600.6 |  | $446.5 |  | $50.4 |  | $31.4 |  | $195.1 |  | $109.4
Average amount outstanding (based on daily outstanding balances) | $476.3 |  | $207.6 |  | $0.2 |  | $1.7 |  | $101.8 |  | $26.6
Weighted average interest rates | 2.6% |  | 2.1% |  | 2.8% |  | 2.3% |  | 2.5% |  | 1.9%
NOTE 6(b) Long-term Debt - In April 2019, IPL issued $300 million of 3.60% senior debentures due 2029. In September 2019, IPL issued $300 million of 3.50% senior debentures due 2049. The senior debentures were issued as green bonds, and all of the net proceeds have been or will be allocated for the construction and development of IPL’s wind projects. In June 2019, WPL issued $350 million of 3.00% debentures due 2029. The net proceeds from the issuance were used by WPL to reduce its outstanding commercial paper and retire its $250 million 5% debentures that matured in July 2019.
WPL [Member] |
Debt [Line Items] |
Debt | DEBT NOTE 6(a) Short-term Debt - In March 2019, Alliant Energy, IPL and WPL extended their single credit facility agreement by one year, which currently expires in August 2023. As of September 30, 2019, the short-term borrowing capacity under the agreement totaled $1 billion ($450 million for Alliant Energy at the parent company, $250 million for IPL and $300 million for WPL). Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):
September 30, 2019 | Alliant Energy |  | IPL |  | WPL
Commercial paper outstanding | $349.6 |  | $— |  | $—
Commercial paper weighted average interest rates | 2.3% |  | N/A |  | N/A
Available credit facility capacity | $650.4 |  | $250.0 |  | $300.0
| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Maximum amount outstanding (based on daily outstanding balances) | $471.7 |  | $153.3 |  | $— |  | $— |  | $89.7 |  | $75.4
Average amount outstanding (based on daily outstanding balances) | $399.5 |  | $80.8 |  | $— |  | $— |  | $27.0 |  | $23.1
Weighted average interest rates | 2.5% |  | 2.2% |  | N/A |  | N/A |  | 2.3% |  | 2.0%
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | $600.6 |  | $446.5 |  | $50.4 |  | $31.4 |  | $195.1 |  | $109.4
Average amount outstanding (based on daily outstanding balances) | $476.3 |  | $207.6 |  | $0.2 |  | $1.7 |  | $101.8 |  | $26.6
Weighted average interest rates | 2.6% |  | 2.1% |  | 2.8% |  | 2.3% |  | 2.5% |  | 1.9%
NOTE 6(b) Long-term Debt - In April 2019, IPL issued $300 million of 3.60% senior debentures due 2029. In September 2019, IPL issued $300 million of 3.50% senior debentures due 2049. The senior debentures were issued as green bonds, and all of the net proceeds have been or will be allocated for the construction and development of IPL’s wind projects. In June 2019, WPL issued $350 million of 3.00% debentures due 2029. The net proceeds from the issuance were used by WPL to reduce its outstanding commercial paper and retire its $250 million 5% debentures that matured in July 2019.

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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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -URI http://asc.fasb.org/topic&trid=2208564 + Details
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