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Income Taxes (Schedule Of Effective Income Tax Rates) (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 21.00% | 21.00% | 21.00% | 21.00%
State income taxes, net of federal benefits | 7.00% | 6.90% | 7.10% | 6.90%
Production tax credits | (9.30%) | (5.40%) | (9.10%) | (5.40%)
Effect of rate-making on property-related differences | (5.60%) | (6.30%) | (5.70%) | (6.70%)
Amortization of excess deferred taxes | (1.10%) | (0.10%) | (1.10%) | (0.30%)
Adjustment for prior period taxes | (1.80%) | (5.70%) | (0.70%) | (2.60%)
IPL's tax benefit riders | (0.80%) | (2.30%) | (0.70%) | (2.20%)
Federal Tax Reform adjustments | 0.00% | (2.50%) | 0.00% | (1.20%)
Other items, net | (0.20%) | (0.30%) | (1.00%) | (0.70%)
Overall income tax rate | 9.20% | 5.30% | 9.80% | 8.80%
IPL [Member] |  |  |  |
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 21.00% | 21.00% | 21.00% | 21.00%
State income taxes, net of federal benefits | 8.10% | 7.70% | 8.10% | 7.70%
Production tax credits | (14.70%) | (5.50%) | (14.30%) | (5.40%)
Effect of rate-making on property-related differences | (9.00%) | (11.50%) | (9.30%) | (12.00%)
Amortization of excess deferred taxes | (0.30%) | 0.00% | (0.30%) | 0.00%
Adjustment for prior period taxes | 1.30% | (10.20%) | 0.60% | (5.40%)
IPL's tax benefit riders | (1.50%) | (4.80%) | (1.50%) | (4.60%)
Federal Tax Reform adjustments | 0.00% | (0.90%) | 0.00% | (0.50%)
Other items, net | (0.30%) | (0.60%) | (0.10%) | (1.00%)
Overall income tax rate | 4.60% | (4.80%) | 4.20% | (0.20%)
WPL [Member] |  |  |  |
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 21.00% | 21.00% | 21.00% | 21.00%
State income taxes, net of federal benefits | 6.20% | 6.20% | 6.20% | 6.20%
Production tax credits | (4.40%) | (6.40%) | (4.50%) | (6.60%)
Effect of rate-making on property-related differences | (2.80%) | (2.10%) | (2.60%) | (2.30%)
Amortization of excess deferred taxes | (1.70%) | (0.10%) | (1.70%) | (0.10%)
Adjustment for prior period taxes | 0.40% | 0.00% | (0.30%) | 0.00%
Federal Tax Reform adjustments | 0.00% | (6.40%) | 0.00% | (2.80%)
Other items, net | (0.20%) | (0.40%) | (0.40%) | (1.20%)
Overall income tax rate | 18.50% | 11.80% | 17.70% | 14.20%

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