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v3.10.0.1

Property, Plant, and Equipment - Plant Retirements (Details) $ in Millions | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Oct. 31, 2017 MW | Aug. 31, 2016 MW | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Plant To Be Retired |  |  |  |
Accumulated depreciation |  |  | $ 8,515.9 | $ 8,618.5
Net property, plant, and equipment |  |  | 22,000.9 | 21,347.0
Regulatory Assets |  |  | 3,855.8 | 2,840.4
Regulatory Liabilities |  |  | 4,288.4 | $ 3,760.4
UMERC |  |  |  |
Plant To Be Retired |  |  |  |
Capacity of natural gas-fired generation facility (in megawatts) | MW | 180 | 180 |  |
Pleasant Prairie power plant |  |  |  |
Plant To Be Retired |  |  |  |
Property, plant, and equipment, at carrying value |  |  | 645.9 |
Regulatory Assets |  |  | 749.5 |
Regulatory Liabilities |  |  | 103.6 |
Presque Isle power plant |  |  |  |
Plant To Be Retired |  |  |  |
Property, plant, and equipment to be retired, net |  |  | 185.4 |
Property, plant, and equipment, at carrying value |  |  | 174.8 |
Regulatory Liabilities |  |  | 10.6 |
Pulliam power plant |  |  |  |
Plant To Be Retired |  |  |  |
Property, plant, and equipment, at carrying value |  |  | 33.8 |
Regulatory Assets |  |  | 57.2 |
Regulatory Liabilities |  |  | 23.4 |
Wisconsin |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |
Restructuring Reserve Beginning of Period |  |  | 29.4 |
Payments for Restructuring |  |  | (10.7) |
Restructuring Reserve, Accrual Adjustment |  |  | (3.0) |
Restructuring Reserve End of Period |  |  | 15.7 |
Edgewater Unit 4 |  |  |  |
Plant To Be Retired |  |  |  |
Property, plant, and equipment, at carrying value |  |  | 8.1 |
Regulatory Assets |  |  | 10.0 |
Regulatory Liabilities |  |  | $ 1.9 |

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