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v3.19.3

Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Debt [Line Items] |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | $ 471.7 | $ 153.3 | $ 600.6 | $ 446.5
Average amount outstanding (based on daily outstanding balances) | $ 399.5 | $ 80.8 | $ 476.3 | $ 207.6
Weighted average interest rates | 2.50% | 2.20% | 2.60% | 2.10%
IPL [Member] |  |  |  |
Debt [Line Items] |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | $ 0.0 | $ 0.0 | $ 50.4 | $ 31.4
Average amount outstanding (based on daily outstanding balances) | 0.0 | 0.0 | $ 0.2 | $ 1.7
Weighted average interest rates |  |  | 2.80% | 2.30%
WPL [Member] |  |  |  |
Debt [Line Items] |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) | 89.7 | 75.4 | $ 195.1 | $ 109.4
Average amount outstanding (based on daily outstanding balances) | $ 27.0 | $ 23.1 | $ 101.8 | $ 26.6
Weighted average interest rates | 2.30% | 2.00% | 2.50% | 1.90%

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