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INVESTMENT IN AMERICAN TRANSMISSION COMPANY - CHANGES TO INVESTMENT (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | Dec. 31, 2016
Changes to investment in ATC |  |  |  |  |
Investment in ATC, balance at beginning of period |  |  | $ 1,443.9 |  |
Add: Earnings from equity method investment | $ 39.2 | $ 38.3 | 122.9 | $ 107.7 |
Investment in ATC, balance at end of period | $ 1,560.8 |  | $ 1,560.8 |  |
ATC |  |  |  |  |
Investment in ATC |  |  |  |  |
Ownership interest in ATC (as a percent) | 60.00% |  | 60.00% |  |
Changes to investment in ATC |  |  |  |  |
Investment in ATC, balance at beginning of period | $ 1,544.0 | 1,425.0 | $ 1,443.9 | 1,380.9 |
Add: Earnings from equity method investment | 39.2 | 38.3 | 122.9 | 107.7 |
Add: Capital contributions | 12.8 | 15.0 | 63.3 | 27.1 |
Acquisition of Integrys's investment in ATC | 0.0 | 0.0 | 0.0 | (1.0) |
Add: Adjustment to equity method goodwill | 0.0 | 0.0 | 0.0 | 10.4 |
Less: Distributions | 35.2 | 25.2 | 69.2 | 71.9 |
Less: Other | 0.0 | 0.0 | 0.1 | 0.1 |
Investment in ATC, balance at end of period | $ 1,560.8 | $ 1,453.1 | $ 1,560.8 | $ 1,453.1 |
Dividends Receivable |  |  |  |  | $ 35.2

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