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Variable Interest Entities (Narrative) (Details) | 3 Months Ended | 4 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Sep. 30, 2021 USD ($) Rate MW | Mar. 31, 2021 USD ($) | Sep. 30, 2020 USD ($) | Mar. 31, 2021 USD ($) | Sep. 30, 2021 USD ($) Rate MW | Sep. 30, 2020 USD ($) | Dec. 31, 2020 USD ($)
Variable Interest Entity [Line Items] |  |  |  |  |  |  |
Nameplate Capacity | MW | 102 |  |  |  | 102 |  |
Wind Power Purchase Agreement, Purchase Percentage | Rate | 100.00% |  |  |  | 100.00% |  |
Additional Obligation to the Developer |  | $ 6,000,000 |  | $ 6,000,000 |  |  |
Payment to renewable generation asset developer |  |  |  |  | $ (7,400,000) | $ 0 |
Total Obligation to the Developer | $ 75,700,000 |  |  |  | 75,700,000 |  |
Total Contributions | 170,100,000 |  |  |  | 170,100,000 |  |
VIE Net Assets | 168,000,000 |  |  |  | 168,000,000 |  | $ 156,400,000
Noncontrolling interest in consolidated subsidiaries | 89,200,000 |  |  |  | 89,200,000 |  | $ 85,600,000
Net loss attributable to noncontrolling interest | $ (1,000,000) |  | $ 0 |  | $ (3,400,000) | $ 0 |
Rosewater Wind Farm |  |  |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |  |  |
Wind Power Purchase Agreement, Purchase Percentage | Rate | 100.00% |  |  |  | 100.00% |  |
NIPSCO |  |  |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |  |  |
Cash Contribution |  | 100,000 |  | 800,000 |  |  |
Tax Equity Partner |  |  |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |  |  |
Cash Contribution |  | $ 7,500,000 |  | $ 93,600,000 |  |  |

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